A rare complication of idiopathic osteosclerosis.

Med Oral Patol Oral Cir Bucal. 2007 May;12(3):E233-4

Authors: Marques Silva L, Guimaraes AL, Dilascio ML, Castro WH, Gomez RS

Idiopathic osteosclerosis (IO) is described as a localized no expansible radiopacity with unknown etiology. The IO is generally asymptomatic and could appear as round, elliptical or irregular in shape. The internal aspect is usually uniformly radiopaque. IO should be distinguished from condensing osteitis of dental origin, or other alveolar bone related radiopacities such as periapical cemental dysplasia. This condition may cause changes in tooth position or problems during orthodontic treatment. The purpose of the present study is to report a case of tooth resorption caused by ectopic eruption rote caused by IO. This condition represents a rare complication of IO.

PMID: 17468722 [PubMed - indexed for MEDLINE]

Root resorption and orthodontic treatment. Review of the literature.

Minerva Stomatol. 2007 Jan-Feb;56(1-2):31-44

Authors: Pizzo G, Licata ME, Guiglia R, Giuliana G

The aim of this paper was to provide a systematic review of the literature on the root resorption caused by orthodontic treatment. Original papers on this subject, published in English from January 2000 until December 2005, were located in the MEDLINE/PubMed database. Other sources were taken from the references of the selected papers. Root resorption is the most common sequela of the orthodontic treatment. It is an inflammatory process that leads to an ischemic necrosis localized in the periodontal ligament when the orthodontic force is applied. The onset and progression of root resorption are associated with risk factors related to the orthodontic treatment such as the duration of treatment, the magnitude of the force applied, the direction of the tooth movement, the method of force application (continuous versus intermittent), the orthodontic movement. Patient-related risk factors are the individual susceptibility on a genetic basis, some systemic diseases, anomalies in root morphology, dental trauma, and previous endodontic treatment. The prevention of root resorption during the orthodontic treatment may be performed controlling the risk factors. The periodic radiographic control during the treatment is necessary in order to detect the occurrence of root damages and quickly reassess the treatment goals.

PMID: 17287705 [PubMed - indexed for MEDLINE]

Biological markers for evaluation of root resorption.

Arch Oral Biol. 2007 Mar;52(3):203-8

Authors: Balducci L, Ramachandran A, Hao J, Narayanan K, Evans C, George A

BACKGROUND: External apical root resorption is a pathologic consequence of orthodontic tooth movement. Cementum and dentin are removed from the root surface while active force is present. OBJECTIVE: The aim of this study was to identify and quantify extracellular matrix proteins, dentin matrix protein 1 (DMP1), dentin phosphophoryn (PP), and dentin sialoprotein (DSP) in the gingival crevicular fluid (GCF) of subjects undergoing orthodontic treatment. METHODS: Subjects with mild (less than 2mm) and severe (more than 2mm) root resorption during orthodontic treatment were identified by radiographs. A control group of subjects with neither signs of root loss nor undergoing orthodontic treatment was also identified. GCF was collected from the upper incisors by using filter paper strips (Periopaper). The absorbed GCF was eluted and the proteins were separated by SDS-PAGE analysis and stained. Western blot and ELISA were also performed. One-way ANOVA and Scheffé test were used for statistical analysis. RESULTS: SDS-PAGE analysis identified proteins at 77, 66, 55, 50 and 26kDa. Immunoblotting did not show any differential expression pattern between control and study groups. ELISA results revealed a significant difference in the concentrations of DMP1, PP and DSP between control and root resorption groups. Concentration of PP and DSP in severe root resorption group was also statistically higher than in mild root resorption group. CONCLUSION: DSP and PP could be suitable biological markers for monitoring root resorption during orthodontic treatment, since a significant difference in the level of these dentin specific proteins is detected in all groups.

PMID: 17097600 [PubMed - indexed for MEDLINE]

Which orthodontic archwire sequence? A randomized clinical trial.

Eur J Orthod. 2006 Dec;28(6):561-6

Authors: Mandall N, Lowe C, Worthington H, Sandler J, Derwent S, Abdi-Oskouei M, Ward S

The aim of this study was to compare three orthodontic archwire sequences. One hundred and fifty-four 10- to 17-year-old patients were treated in three centres and randomly allocated to one of three groups: A = 0.016-inch nickel titanium (NiTi), 0.018 x 0.025-inch NiTi, and 0.019 x 0.025-inch stainless steel (SS); B = 0.016-inch NiTi, 0.016-inch SS, 0.020-inch SS, and 0.019 x 0.025-inch SS; and C = 0.016 x 0.022-inch copper (Cu) NiTi, 0.019 x 0.025-inch CuNiTi, and 0.019 x 0.025-inch SS. At each archwire change and for each arch, the patients completed discomfort scores on a seven-point Likert scale at 4 hours, 24 hours, 3 days, and 1 week. Time in days and the number of visits taken to reach a 0.019 x 0.025-inch SS working archwires were calculated. A periapical radiograph of the upper left central incisor was taken at the start of the treatment and after placement of the 0.019 x 0.025-inch SS wire so root resorption could be assessed. There were no statistically significant differences between archwire sequences A, B, or C for patient discomfort (P > 0.05) or root resorption (P = 0.58). The number of visits required to reach the working archwire was greater for sequence B than for A (P = 0.012) but this could not be explained by the increased number of archwires used in sequence B.

PMID: 17041083 [PubMed - indexed for MEDLINE]

RANKL increase in compressed periodontal ligament cells from root resorption.

J Dent Res. 2006 Aug;85(8):751-6

Authors: Yamaguchi M, Aihara N, Kojima T, Kasai K

The ligand receptor activator of NFkappaB (RANKL) plays an important role in osteoclast formation. However, very little is known about the relationship between external apical root resorption during orthodontic treatment and RANKL. We hypothesized that compressive force is responsible for RANKL formation and up-regulation of osteoclastogenesis in periodontal ligament (PDL) cells from patients with severe orthodontically induced external apical root resorption. RANKL and osteoprotegerin (OPG) production, TRAP-positive cells, and resorptive pits were determined. The increase of RANKL and the decrease of OPG were greater in the severe root resorption group than in the non-resorption group. The numbers of TRAP-positive cells and resorptive pits were also increased in the severe root resorption group than in the non-resorption group. These results support the hypothesis that the compressed PDL cells obtained from tissues with severe external apical root resorption may produce a large amount of RANKL and up-regulate osteoclastogenesis.

PMID: 16861294 [PubMed - indexed for MEDLINE]

Oral malodor associated with internal resorption.

J Oral Sci. 2006 Jun;48(2):89-92

Authors: Yoneda M, Naito T, Suzuki N, Yoshikane T, Hirofuji T

We report a case of oral malodor associated with internal resorption. A 39-year-old male attended our hospital complaining of oral malodor. Utilizing organoleptic measurement, the halimeter test and gas chromatography, it was diagnosed as a strong halitosis caused by oral origin. The pocket probing depth of tooth 21 was 10 mm, and X-ray examination revealed a vertical bone loss around this tooth. The patient had received periodontal treatment at two dental offices previously, but the periodontal conditions and oral malodor persisted. We performed an initial periodontal preparation, however a deep pocket remained. We therefore performed a surgical inspection including flap reflection, and found that the tooth had a large perforating defect in the distal surface. The extracted tooth had multiple perforating defects covered with granulation tissues on all root surfaces including the root apex. Taking into consideration the anamnesis and X-ray examination of the extracted tooth, internal absorption was considered to have been the cause of the multiple perforating defects. After extraction of the causative tooth, oral malodor dramatically decreased. To our knowledge, this is the first report of an oral malodor associated with internal resorption.

PMID: 16858138 [PubMed - indexed for MEDLINE]

Is mild dental invagination a risk factor for apical root resorption in orthodontic patients?

Eur J Orthod. 2006 Aug;28(4):307-12

Authors: Mavragani M, Apisariyakul J, Brudvik P, Selvig KA

The purpose of this retrospective study was to assess if dental invagination is a risk factor for root resorption during orthodontic treatment. The sample consisted of 91 patients (32 males, 59 females) with a mean age of 13.1 years (range 9.3-32.1 years) with complete orthodontic records, including periapical radiographs of the maxillary incisors before and after treatment. Forty-nine patients had at least one maxillary incisor invaginated, whilst the remaining 42 patients were free of dental invaginations. Variables recorded for each patient included gender, age, Angle classification, extraction or non-extraction therapy, ANB angle, overjet, overbite, trauma, habits, agenesis, tooth exfoliation, treatment duration, Class II elastics, body-build, general factors, impacted canines, and root form deviation. Crown and root length of the maxillary incisors were measured on pre- and post-treatment long cone periapical radiographs corrected for image distortion. The percentage of root shortening and root length loss in millimetres was then calculated. Most of the invaginated teeth were minor type 1. Statistical analysis revealed no significant difference in the severity of apical root resorption between invaginated and non-invaginated incisors in patients without dental invaginations, nor was the extent of dental invagination related to the severity of apical root resorption. However, invaginated teeth had malformed roots more often than non-invaginated teeth. Dental invagination, and particularly type 1, cannot be considered a risk factor for apical root resorption during orthodontic tooth movement.

PMID: 16763089 [PubMed - indexed for MEDLINE]

The tissue, cellular, and molecular regulation of orthodontic tooth movement: 100 years after Carl Sandstedt.

Eur J Orthod. 2006 Jun;28(3):221-40

Authors: Meikle MC

The first experimental investigation of orthodontic tooth movement was published by Sandstedt in 1904-1905. After 100 years, there is a good understanding of the sequence of events at both tissue and cellular levels and now the current focus of research is at the molecular level. The techniques of reverse transcription-polymerase chain reaction and in situ hybridization to detect mRNAs of interest have revolutionized tooth movement studies and an expanding list of antibodies and enzyme-linked immunosorbent assays directed against human and animal proteins will facilitate their identification in tissue sections and/or culture supernatants. Nevertheless, although this technology has greatly simplified research for the clinical and laboratory investigator, message is not always translated into protein, and the presence of a protein does not necessarily mean it is biologically active. In vivo and in vitro methods have been widely used in tooth movement studies. However, data from in vitro models, in which the mechanical stimulus can be carefully controlled (tension versus compression; intermittent versus continuous), should be correlated with in vivo data from animal models. The current evidence suggests that downstream from the initial mechanotransduction event at focal adhesions which link the extracellular matrix to the cytoskeleton, mechanically induced remodelling is mediated by a complex feedback mechanism involving the synthesis of cytokines such as interleukin-1 (IL-1), IL-6, and receptor activator of nuclear factor k B ligand by cells of the osteoblast and/or fibroblast lineages. These in turn act in an autocrine/paracrine fashion to regulate the expression of transcription factors, cytokines, growth factors, enzymes, and structural molecules involved in the differentiation, proliferation, and function of mesenchymal and other cell types. Contrary to the impression gained from the literature, tooth movement is not confined to events within the periodontal ligament. Orthodontic tooth movement involves two interrelated processes: (1) deflection or bending of the alveolar bone and (2) remodelling of the periodontal tissues.

PMID: 16687469 [PubMed - indexed for MEDLINE]

Changes in the physical properties of human premolar cementum after application of 4 weeks of controlled orthodontic forces.

Eur J Orthod. 2006 Aug;28(4):313-8

Authors: Chutimanutskul W, Ali Darendeliler M, Shen G, Petocz P, Swain MV

This study was performed to assess the relationship between the magnitude of orthodontic force and physical properties of individual human cementum, and to identify the sites that may be predisposed to root resorption. The findings may assist in relating physical properties of dental root cementum and its susceptibility to root resorption. Sixteen maxillary first premolar teeth were selected in eight orthodontic patients (three males and five females), mean age 14.8 years (range 11.2-17.5 years), requiring first premolar extractions. In each patient, a light orthodontic force of 25 cN was applied buccally using a sectional archwire on the first premolar on one side, while a heavy force of 225 cN was applied to the contralateral side. The teeth were extracted 4 weeks after initial force application. Hardness and elastic modulus were measured on the buccal and the lingual surfaces of the cementum at the cervical, middle, and apical third of the root. The results showed that the mean hardness and elastic modulus of cementum in the light force group were greater than in the heavy force group at all positions. There were highly significant differences in both hardness and elastic modulus between the heavy and light force groups (P < 0.01). The mean hardness and elastic modulus of cementum gradually decreased from the cervical to the apical regions for buccal as well as lingual surfaces in both groups. There was, however, an insignificant difference between hardness and elastic modulus on the buccal surface compared with the lingual surface (P < 0.05). It was concluded that the hardness and elastic modulus of cementum were affected by the application of orthodontics forces.

PMID: 16648211 [PubMed - indexed for MEDLINE]

Retrospective clinical and radiologic evaluation of nonsurgical endodontic treatment in human immunodeficiency virus (HIV) infection.

J Contemp Dent Pract. 2006 Feb 15;7(1):1-8

Authors: Suchina JA, Levine D, Flaitz CM, Nichols CM, Hicks MJ

PURPOSE: This retrospective study evaluated the clinical and radiographic status of nonsurgical endodontic treatment (ET) of anterior and posterior teeth in HIV-seropositive patients. METHODS: ET was analyzed in 26 anterior and 34 posterior teeth from 54 consecutive HIV patients (gender ratio 3 Male : 1 Female, mean age 40.2 years, mean CD4 240, CD4<500 in 88%, 12 with AIDS) over a six year period with a minimum of six months follow-up. ET was evaluated as successful, questionable, or failure based upon clinical factors (palpation, mobility, sinus tract, percussion, function, infection/swelling, occlusion, symptoms) and radiographic factors (periodontal ligament space, rarefaction, lamina dura, root resorption, obturation) during post-treatment examinations with a mean follow up of 26 months. RESULTS: Clinical evaluation at follow up found ET outcome was successful in 88%, questionable in 10% (tenderness with percussion, mobility, widened ligament), and a failure in 2% (developed lesion after ET). Periapical lesions were present in 37% of cases (mean lesion size 6.2 mm). Following ET, mean lesion size (1.8 mm) had decreased by 71%. Obturation was evaluated as optimal or acceptable in 68%. Radiographic evaluation was considered successful in 80%, no change in 15%, and a failure in 5%. CONCLUSIONS: Despite obturation deficiencies and the immunocompromised state of the patients, endodontic therapy has a relatively high degree of success in the majority of HIV/AIDS patients. HIV infection and AIDS should not be considered as a contraindication to endodontic therapy in this patient population.

PMID: 16491142 [PubMed - indexed for MEDLINE]

Adenomatoid odontogenic tumor - a rare cause of jaw swelling.

Braz Dent J. 2005;16(3):251-3

Authors: Nigam S, Gupta SK, Chaturvedi KU

Adenomatoid odontogenic tumor (AOT) is an uncommon tumor of odontogenic origin, characterized histologically by the formation of ductlike structures with amyloid-like deposits. Histogenesis of AOT is still uncertain and it is often considered as a hamartomatous lesion rather than a true neoplasm. AOT has a benign behavior and conservative surgical enucleation or curettage is sufficient. We report a case of AOT in a 15-year-old female who presented with left-sided jaw swelling with tooth resorption. Histopathology revealed intraosseus follicular variant of AOT. A brief review of literature is also discussed.

PMID: 16429194 [PubMed - in process]

Root resorption associated with orthodontic force in inbred mice: genetic contributions.

Eur J Orthod. 2006 Feb;28(1):13-9

Authors: Al-Qawasmi RA, Hartsfield JK, Everett ET, Weaver MR, Foroud TM, Faust DM, Roberts WE

Root resorption (RR) is an unwanted sequela of orthodontic treatment. Despite rigorous investigation, no single factor or group of factors that directly causes RR has been identified. The purpose of this study was to examine the effect of the genotype on susceptibility or resistance to develop RR secondary to orthodontic force. Nine-week-old male mice from eight inbred strains were used and randomly distributed into control (C) or treatment (T) groups as follows: A/J (C = 9,T = 9), C57BL/6J (C = 7,T = 8), C3H/HeJ (C = 8,T = 6), BALB/cJ (C = 8,T = 6), 129P3/J (C = 6,T = 8), DBA/2J (C = 8,T = 9), SJL/J (C = 8,T = 10), and AKR/J (C = 9,T = 8). Each of the treated mice received an orthodontic appliance to tip the maxillary left first molar mesially for 9 days. Histological sections of the tooth were used to determine RR and tartrate resistant acid phosphatase (TRAP) activity. The Wilcoxon ranked-sum non-parametric test was used to evaluate differences between the groups. The results showed that the DBA/2J, BALB/cJ, and 129P3/J inbred mouse strains are highly susceptible to RR, whereas A/J, C57BL/6J and SJL/J mice are much more resistant. The variation in the severity of RR associated with orthodontic force among different inbred strains of mice when age, gender, food, housing, and orthodontic force magnitude/duration are controlled support the hypothesis that susceptibility or resistance to RR associated with orthodontic force is a genetically influenced trait.

PMID: 16373453 [PubMed - indexed for MEDLINE]

Use of vitamin C in delayed tooth replantation.

Braz Dent J. 2005;16(1):17-22

Authors: Panzarini SR, Perri de Carvalho AC, Poi WR, Sonoda CK

This study evaluated microscopically the effects of root surface treatment with three different solutions in delayed rat teeth replantation. Central incisors from 30 rats (Rattus norvegicus, albinus Wistar) were extracted and left on a bench for 6 h. The pulps were extirpated and root canals were irrigated with 1% sodium hypochlorite. After endodontic treatment, the root surfaces of all teeth were submitted to a 10-min treatment with 1% sodium hypochlorite, changed every 5 min. The teeth were then rinsed with saline for 10 min and assigned to 3 groups with ten specimens each. Groups I, II and III were treated, respectively, with 2% acidulated-phosphate sodium fluoride, vitamin C solution and effervescent vitamin C (2 g, Redoxon. After root surface treatment, the teeth were filled with calcium hydroxide and replanted. The animals were sacrificed after 10 and 60 days. Group I (fluoride) presented the largest areas of replacement resorption and ankylosis. Comparing both vitamin C groups, Group III (effervescent vitamin C) yielded better results, showing more areas of ankylosis and replacement resorption than areas of inflammatory resorption.

PMID: 16113928 [PubMed - indexed for MEDLINE]

Validation of two-dimensional measurements of root resorption craters on human premolars after 28 days of force application.

Eur J Orthod. 2005 Aug;27(4):390-5

Authors: Chan EK, Petocz P, Darendeliler MA

The aims of this study were to develop a three-dimensional (3D) mathematical model of a typical root resorption crater and to correlate two-dimensional (2D) surface area measurements to 3D volumetric measurements of root resorption craters created under light and heavy orthodontic forces. Data were obtained from a previous study of 36 first premolars from 16 subjects requiring extraction of these teeth as part of their orthodontic treatment. Buccal tipping forces of 25 or 225 g were applied for an experimental period of 28 days. After extraction, the samples were prepared for scanning electron microscopy (SEM) imaging, image processing and analysis. Surface area (2D) and volumetric (3D) measurements of all craters were obtained. A mathematical analysis of the 2D/3D relationship enabled the determination of an appropriate digital model for the shape, type and dimensions of resorption craters, which was also able to distinguish between a 'hemispheric' model versus a 'layered' model of craters.The results demonstrated that 2D and 3D measurements were strongly correlated (r = 0.991**). Within the light and heavy force groups, the measurements were also strongly correlated (r = 0.978** and r = 0.994**, respectively). For a 28 day experimental period, 2D measurements of root resorption craters were found to be as reliable as 3D measurements.

PMID: 16043475 [PubMed - indexed for MEDLINE]

Drug-induced disorders of teeth.

J Dent Res. 2005 Jul;84(7):596-602

Authors: Tredwin CJ, Scully C, Bagan-Sebastian JV

It is essential that every health care professional who is involved with the prescription or recommendation of drugs be fully aware of any resultant disorders that may arise as a side-effect. A range of drugs can affect the teeth. In this review article, drugs that have the potential to induce changes in teeth have been classified as those leading to tooth discoloration (intrinsic and extrinsic), physical damage to tooth structure (enamel, dentin, and cementum), and alteration in tooth sensitivity.

PMID: 15972585 [PubMed - indexed for MEDLINE]

Orthodontically induced root and alveolar bone resorption: inhibitory effect of systemic doxycycline administration in rats.

Eur J Orthod. 2005 Jun;27(3):215-25

Authors: Mavragani M, Brudvik P, Selvig KA

The aim of the present study was to investigate the effect of systemic administration of low-dose doxycycline (DC) on orthodontic root resorption. The effect on alveolar bone, the cell population involved, and the amount of tooth movement were also evaluated.Fifty-six 40-50-day-old male Wistar rats were used. Six animals served as untreated controls. Six animals were only administered DC for 7 days, by means of a mini-osmotic pump implanted subcutaneously. In 44 animals the maxillary first molar was mesialized by a fixed orthodontic appliance exerting 50 g force upon insertion. In 28 of these animals DC was administered at the time of appliance insertion and throughout the experiment. The animals were sacrificed 7, 10 or 14 days after force application and block sections processed for analysis. An area including the mesial aspect of the distopalatal root and the adjacent inter-radicular alveolar bone was histomorphometrically evaluated. The root resorption area, absolute alveolar bone area, distance between first and second molars, number of odontoclasts, osteoclasts, mononuclear cells on the root, tartrate-resistant acid phosphatase (TRAP)-positive cells on the root, bone, and in the periodontal ligament (PDL) were compared between DC-treated and non-DC-treated animals.The results revealed a significant reduction in root resorption, the number of odontoclasts, osteoclasts, mononuclear cells on the root surface, and TRAP-positive cells on the root and bone for the DC-administered group. The absolute alveolar bone area was greater, whereas the distance between the first and second molars did not differ between groups. In conclusion, systemic administration of low-dose DC in rats may have an inhibitory effect on orthodontically induced resorptive activity.

PMID: 15947219 [PubMed - indexed for MEDLINE]

Root resorption and ankylosis associated with guided tissue regeneration.

J Am Dent Assoc. 2005 Mar;136(3):337-41

Authors: Cury PR, Furuse C, Martins MT, Sallum EA, De Ara&#xFA;jo NS

BACKGROUND: Root resorption and ankylosis have been reported rarely as sequelae to guided tissue regeneration (GTR). The authors describe a clinical case of root resorption following GTR that involved the use of a bioabsorbable membrane. CASE DESCRIPTION: Two years after GTR was performed on a Class II furcation defect, the clinical examination revealed root resorption reaching the pulp chamber. The furcation defect was filled with epithelium and connective tissue, which contained inflammatory infiltrate and fragments of the membrane. The authors also observed areas of the tooth that exhibited points of ankylosis and root resorption. CLINICAL IMPLICATIONS: Clinical trials have reported favorable clinical and histologic results with GTR. However, this case report, along with other case reports and studies in animals, suggests a high risk of root resorption and ankylosis after GTR, which could limit the indications for this technique.

PMID: 15819347 [PubMed - indexed for MEDLINE]

Association between ectopic eruption of maxillary canines and first molars.

Eur J Orthod. 2005 Apr;27(2):186-9

Authors: Becktor KB, Steiniche K, Kjaer I

The purpose of this study was to elucidate a possible association between ectopic first molar eruption causing root resorption on the distal root of the primary maxillary second molar, and ectopic canine eruption causing root resorption on the permanent maxillary incisors.The subjects consisted of 30 patients, 22 females and eight males in the age range 8.3-15.0 years in whom root resorption of the permanent maxillary lateral and/or central incisor caused by the erupting permanent canine was diagnosed, and clinical and/or radiographic information concerning maxillary first molar eruption existed.It was found that of the 30 patients, seven (23.3 per cent) also had pathological root resorption of the second primary molar caused by ectopic molar eruption.It is suggested that patients with ectopic maxillary first molar eruption leading to pathological root resorption of the maxillary second primary molar are followed closely during the period of premolar and canine eruption, as the ectopic first molar could be an early warning of an increased risk of ectopic canine eruption leading to root resorption of the maxillary permanent incisors.

PMID: 15817627 [PubMed - indexed for MEDLINE]

Soluble cytokine receptor treatment in experimental orthodontic tooth movement in the rat.

Eur J Orthod. 2005 Feb;27(1):1-11

Authors: Jäger A, Zhang D, Kawarizadeh A, Tolba R, Braumann B, Lossdörfer S, Götz W

Pro-inflammatory cytokines, such as interleukin-1 (IL-1) and tumour necrosis factor-alpha (TNF-alpha), are believed to play a role in the biological processes involved in the course of orthodontic tooth movement and especially in root resorption. The inhibition of cytokine activity, e.g. by soluble receptors, could be beneficial in reducing this unwanted side-effect.The aim of this study was to investigate the role of cytokines IL-1 and TNF-alpha in the course of experimentally induced tooth movement. The upper left first molar was moved orthodontically in 80 male Wistar rats using a coil spring with a force of 0.5 N. Starting at day -1, three groups of 20 animals each received daily intraperitoneal injections (ip) of 2 ml of 1 mug/ml soluble receptors (a) to IL-1(sIL-RII), (b) to TNF-alpha (sTNF-alpha-RI) and (c) a combination of (a) and (b). Twenty animals served as the control. After 3, 6, 9 and 12 days, the animals were killed in groups of five. The amount of tooth movement was registered and the maxillae were prepared for histological and histomorphometric analysis. Osteoclasts and odontoclasts were identified using tartrate-resistant acid phosphatase (TRAP) histochemistry.The amount of tooth movement was reduced in all receptor-treated groups by approximately 50 per cent. At the same time, the number of TRAP-positive cells on the desmodontal bone surface and on the surface of the roots was reduced. Thus, systemic application of soluble receptors to IL-1 and TNF-alpha following experimental induction of tooth movement in the rat reduced the number of osteoclasts as well as odontoclasts.

PMID: 15743857 [PubMed - indexed for MEDLINE]

Scanning electron microscopy of root resorption of feline teeth.

J Vet Med Sci. 2004 Dec;66(12):1579-81

Authors: Ohba S, Kuwabara M, Kamata H, Yukawa M, Kiba H

Scanning electron microscopy was carried out on 10 feline extracted permanent teeth from 3 cases with root resorption. Various-sized resorption lacunae were well defined, showing an etched pattern and configuration as shown in human deciduous teeth. In cats, regardless of the shape and depth of lacunae, the resorption lacunae showed opening dentinal tubules in the wall with or without cement matrix apperring only in the deep and round lacunae of human cases. Some specific process of mineralization for repairing dental root resorption was suggested in cats.

PMID: 15644611 [PubMed - indexed for MEDLINE]

Multiple dentoalveolar traumatic lesions: report of a case and proposition of dental polytrauma as a new term.

J Contemp Dent Pract. 2004 Nov 15;5(4):139-47

Authors: Martins WD, Westphalen FH, Westphalen VP, Souza PH

Traumatic injuries to permanent teeth are common, and dramatic episodes can occur during childhood. The aim of this paper is to present a report of severe trauma to the orofacial complex of an 8-year old girl that resulted in multiple injuries. The use of the term "dental polytrauma" (concomitant different dental traumatic injuries) is advocated in this case presentation.

PMID: 15558099 [PubMed - indexed for MEDLINE]

Effects of local administration of clodronate on orthodontic tooth movement and root resorption in rats.

Eur J Orthod. 2004 Oct;26(5):469-73

Authors: Liu L, Igarashi K, Haruyama N, Saeki S, Shinoda H, Mitani H

Clodronate, a non-N-containing bisphosphonate, strongly inhibits bone resorption and also has anti-inflammatory properties. The purpose of this study was to examine the effect of the local administration of clodronate on orthodontic tooth movement. Both the right and left upper first molars of 26 7-week-old male Wistar rats were moved buccally with a standardized expansion spring. Clodronate solution was injected into the sub-periosteum area adjacent to the left upper molar every third day during the experimental period. The right first molar served as the control. Local injection of clodronate caused a significant (P < 0.001) and dose-dependent reduction in tooth movement in the rats. The number of osteoclasts on the clodronate-injected side was significantly less (P < 0.01) than on the control side. Local clodronate also inhibited root resorption incident to tooth movement. These results suggest that localized use of clodronate could be a useful therapeutic adjunct in orthodontic treatment.

PMID: 15536834 [PubMed - indexed for MEDLINE]

Cementum-like tissue deposition on the resorbed enamel surface of human deciduous teeth prior to shedding.

Anat Rec A Discov Mol Cell Evol Biol. 2004 Aug;279(2):779-91

Authors: Sahara N, Ozawa H

Prior to the shedding of human deciduous teeth, odontoclastic resorption takes place at the pulpal surface of the coronal dentin, and this resorption occasionally extends coronally from the dentinoenamel junction into the enamel. After the end of resorption, however, the resorbed enamel surface is repaired by the deposition of a cementum-like tissue. Using this phenomenon as an observation model, in this study we examined the sequence of cellular and extracellular/matrix events involved in the enamel resorption repair by light and electron microscopy. As the odontoclast terminated its resorption activity, it detached from the resorbed enamel surface; thereafter, numerous mononuclear cells were observed along the resorbed enamel surface. Most of these mononuclear cells made close contact with the resorbed enamel surface, and coated pits or patches were observed on their plasma membrane facing this surface. Furthermore, they frequently contained thin needle- or plate-like enamel crystals in their cytoplasmic vacuoles as well as secondary lysozomes. Following the disappearance of these monononuclear cells, the resorbed enamel surface now displayed a thin coat of organic matrix. Ultrastructurally, this organic layer was composed of a reticular and/or granular organic matrix, but contained no collagen fibrils. Energy-dispersive X-ray microanalysis of this thin organic layer in undecalcified sections revealed small spectral peaks of Ca and P. Cementum-like tissue initially formed along this thin organic layer, increased in width, and appeared to undergo mineralization as time progressed. The results of our observations demonstrate that regardless of type of matrix of dental hard tissues, tooth repair may be coupled to tooth resorption, and suggest that mononuclear cells and an organic thin layer found on the previously resorbed enamel surface may play an important role in the repair process initiated after resorption of the enamel.

PMID: 15278949 [PubMed - indexed for MEDLINE]

Early root alterations after orthodontic force application studied by light and scanning electron microscopy.

Eur J Orthod. 2004 Apr;26(2):119-28

Authors: Mavragani M, Amundsen OC, Selliseth NJ, Brudvik P, Selvig KA

The purpose of the study was to characterize root surface alterations in orthodontically moved teeth. Thirty-six 40-50-day-old male Wistar rats were used. The maxillary right first molar was mesialized by means of a fixed appliance, exerting 50 g of force upon insertion. One, 2 and 4 days after force application the animals were sacrificed (nine animals per observation period) and block sections processed for analysis. Nine animals served as untreated controls. In total, 20 specimens were prepared for examination of the mesial aspect of the mesiobuccal root by scanning electron microscopy (SEM). The remaining specimens were processed for light microscopy. Three morphologically distinct types of resorption defect were observed: isolated small lacunae, wide shallow resorption bays, and deep resorption lacunae. The area occupied by each resorption type varied significantly (P < 0.05) with time. Isolated small lacunae were the earliest to be observed, sometimes found in continuity with wide shallow resorption bays. Mononucleated macrophage-like cells were associated with both resorption types. Deeper lacunae extending into the dentine were found at the 4 day observation period. These always occurred within shallow resorption bays and appeared to be created by multinucleated cells. From the sequence of the different root surface defects and associated cell types observed during the development of orthodontically induced root resorption, it may be concluded that different cell types, with different resorptive potential but functionally interrelated, are involved in the successive phases of the process, and that each cell type leaves a characteristic resorption pattern on the root surface.

PMID: 15130033 [PubMed - indexed for MEDLINE]

Management of unerupted maxillary canines where no orthodontic treatment is planned; a survey of UK consultant opinion.

J Orthod. 2004 Mar;31(1):28-33; discussion 15-6

Authors: Ferguson JW, Pitt SK

OBJECTIVE: To assess current consultant opinion on the management of impacted maxillary canines in patients for whom no orthodontic treatment is planned. DESIGN: Questionnaire survey. METHOD: Questionnaires were sent to all UK consultant orthodontists identified from the Consultant Orthodontists Group database. Follow-up questionnaires were sent to those who had not replied within 6 weeks. An overall response rate of 76% was achieved. RESULTS: Most consultants were in favor of intervention, with removal of the unerupted canine, although a significant minority suggested a conservative approach. Of the latter group, nearly all recommended radiographic monitoring, but there was little agreement regarding the frequency and duration of this. The risk of root resorption was stated to be the most important factor justifying monitoring. CONCLUSIONS: Significant variation was found amongst UK consultant orthodontists with regard to the management of impacted canines, where orthodontic treatment was not planned. The clinical and radiographic features, which the respondents stated would influence their decision to remove or leave the canine, were not those that existing research suggests as being the primary risk factors. It is suggested that, once the patient has passed the peak age for initiation of resorption, a more conservative approach may be appropriate.

PMID: 15071149 [PubMed - indexed for MEDLINE]

Dentine phosphoproteins in gingival crevicular fluid during root resorption.

Eur J Orthod. 2004 Feb;26(1):25-30

Authors: Mah J, Prasad N

External apical root resorption is a common, yet unexplained, phenomenon associated with orthodontic treatment. Available methods of clinical evaluation are radiographic. Biochemical assays offer the advantage of being non-invasive, as well as being diagnostic and potentially prognostic. The hypotheses are firstly that during the process of root resorption, organic matrix proteins are released into the gingival crevicular fluid (GCF) and, secondly, that there is a difference in the levels of these proteins between a group of patients with mild root resorption and a control group. GCF was collected from the permanent central incisors of untreated subjects (controls, n = 20), primary second molars with half of the root resorbed (primary group and positive controls, n = 20) and permanent central incisors with mild root resorption in patients undergoing active orthodontic treatment (orthodontic group, n = 20). Dentine phosphoproteins (DPP) were measured in the GCF using an enzyme-linked immunosorbent assay developed with DPP isolated from human first premolars and an antibody against rat incisor DPP. The primary group showed the highest levels of DPP in the GCF compared with the orthodontic (P = 0.296) and control (P = 0.001) groups. The orthodontic group showed elevated levels relative to the control group (P = 0.046). It is concluded that root resorption can be studied using a biochemical immunoassay and that this method can provide quantitative measurement of DPP in GCF.

PMID: 14994879 [PubMed - indexed for MEDLINE]

Bone turnover rate in rats does not influence root resorption induced by orthodontic treatment.

Eur J Orthod. 2003 Aug;25(4):359-63

Authors: Verna C, Dalstra M, Melsen B

The aim of this study was to determine, in a rat model, whether a state of high or low bone turnover had an effect on the rate and type of tooth movement and on the incidence of root resorption induced by orthodontic treatment. The maxillary left first molar was moved mesially for 21 days in 52 6-month-old Wistar rats. They were divided into three groups: group 1 (n = 19) with normal bone turnover, group 2 (n = 16) with high bone turnover, and group 3 (n = 17) with low bone turnover. The contralateral side was left untreated to act as a control. The different metabolic rates were created by inducing hyper- and hypothyroidism. The amount of tooth movement was measured using an electronic calliper and the location of the centre of rotation (CRot) was determined after microcomputer tomographic scanning and subsequent three-dimensional reconstruction. Histomorphometric evaluation of root resorption was performed on undecalcified 7 microm thick sections of the maxilla and the differences between treated and untreated sides were evaluated. The results showed that high bone turnover increased the amount of tooth movement compared with the normal or low bone turnover state. There was no statistical difference in the location of the CRot. The treated side presented more root resorption than the untreated side, but this difference was not influenced by the metabolic rates. On the contrary, the untreated side in the low bone turnover group showed more root resorption, suggesting that in subjects where a decreased bone turnover rate is expected, the risk of root resorption could be increased.

PMID: 12938841 [PubMed - indexed for MEDLINE]

Constant versus dissipating forces in orthodontics: the effect on initial tooth movement and root resorption.

Eur J Orthod. 2003 Aug;25(4):335-42

Authors: Weiland F

The aim of this clinical and confocal laser scanning microscopic study was to compare the effects of two frequently used archwires on tooth movement and root resorption. A total of 84 premolars in 27 individuals (10 boys, 17 girls, with a mean age of 12.5 years) was moved buccally with an experimental fixed orthodontic appliance. In a split mouth experimental design the premolar on one side was activated with a stainless steel wire with a buccal offset of 1 mm, which was reactivated every four weeks and the contralateral premolar was moved with a superelastic wire with a force plateau of 0.8-1 N. This wire had an initial activation of 4.5 mm and was not reactivated during the 12-week experimental period. At the end of the experimental period the teeth were extracted. Six premolars were used as control teeth and were extracted before the experiment started. Tooth displacement was studied three-dimensionally on dental casts with a co-ordinate measuring machine. The depth, perimeter, area, and volume of the resorption lacunae was measured using three-dimensional digital images made with a confocal laser scanning microscope (CLSM). On these images the resorbed portions of the root surface were 'reconstructed' mathematically. The results show that the teeth activated with the superelastic wire moved significantly more than the teeth with the steel wire during the experimental period. The depth of the resorption lacunae did not differ significantly between the groups; however, perimeter, area, and volume of the resorption lacunae on the teeth of the 'superelastic group' were 140 per cent greater than on the teeth of the 'steel group'. It may be concluded that a greater amount of tooth movement occurred with superelastic wires, offering a force level of 0.8-1 N compared with stainless steel wires, with initially higher but rapidly declining forces in an experimental set up for a period of 12 weeks. The amount of root resorption was significantly larger in the superelastic group.

PMID: 12938838 [PubMed - indexed for MEDLINE]

Tooth bleaching--a critical review of the biological aspects.

Crit Rev Oral Biol Med. 2003;14(4):292-304

Authors: Dahl JE, Pallesen U

Present tooth-bleaching techniques are based upon hydrogen peroxide as the active agent. It is applied directly, or produced in a chemical reaction from sodium perborate or carbamide peroxide. More than 90% immediate success has been reported for intracoronal bleaching of non-vital teeth, and in the period of 1-8 years' observation time, from 10 to 40% of the initially successfully treated teeth needed re-treatment. Cervical root resorption is a possible consequence of internal bleaching and is more frequently observed in teeth treated with the thermo-catalytic procedure. When the external tooth-bleaching technique is used, the first subjective change in tooth color may be observed after 2-4 nights of tooth bleaching, and more than 90% satisfactory results have been reported. Tooth sensitivity is a common side-effect of external tooth bleaching observed in 15%-78% of the patients, but clinical studies addressing the risk of other adverse effects are lacking. Direct contact with hydrogen peroxide induced genotoxic effects in bacteria and cultured cells, whereas the effect was reduced or abolished in the presence of metabolizing enzymes. Several tumor-promoting studies, including the hamster cheek pouch model, indicated that hydrogen peroxide might act as a promoter. Multiple exposures of hydrogen peroxide have resulted in localized effects on the gastric mucosa, decreased food consumption, reduced weight gain, and blood chemistry changes in mice and rats. Our risk assessment revealed that a sufficient safety level was not reached in certain clinical situations of external tooth bleaching, such as bleaching one tooth arch with 35% carbamide peroxide, using several applications per day of 22% carbamide peroxide, and bleaching both arches simultaneously with 22% carbamide peroxide. The recommendation is to avoid using concentrations higher than 10% carbamide peroxide when one performs external bleaching. We advocate a selective use of external tooth bleaching based on high ethical standards and professional judgment.

PMID: 12907697 [PubMed - indexed for MEDLINE]

Extraction, immediate-load implants, impressions and final restorations in two patient visits.

J Am Dent Assoc. 2003 Jun;134(6):715-20

Authors: Leary JC, Hirayama M

BACKGROUND: Since the advent of immediately loaded implants, patients have experienced shorter treatment times, reduced amount of surgical therapy, preserved gingival esthetics and the comfort and security of fixed prostheses. Practitioners have experienced less expense in the form of chair time and greater patient satisfaction. CASE DESCRIPTION: The authors present two cases in which, at the first clinical visit, they extracted maxillary incisors, placed hydroxyapatite-coated implants, took impressions for final restorations and stabilized the implants immediately with a fixed interim prosthesis. At the second clinical visit, the authors placed the final restorations. All of the implants were integrated clinically, and gingival esthetics appeared to have benefited from preservation of papillary form, which was made possible with fixed interim anterior restorations. The patients expressed satisfaction with the results particularly because the treatment was accomplished in two clinical visits. CLINICAL IMPLICATIONS: The cases presented demonstrate a technique that may be of value to therapists who place immediate-load implants. The long-term effectiveness of immediate-load implants requires further evidence to ensure their long-term usefulness and safety.

PMID: 12839407 [PubMed - indexed for MEDLINE]

Root resorption related to hypofunctional periodontium in experimental tooth movement.

J Dent Res. 2003 Jun;82(6):486-90

Authors: Sringkarnboriboon S, Matsumoto Y, Soma K

Orthodontic movement of non-occluding teeth may result in undesirable apical root resorption. These teeth present with a histologically altered periodontium and are considered to be hypofunctional. The purpose of this study was to compare the amount of root resorption associated with a normal and a hypofunctional periodontium in rats during experimental tooth movement caused by heavy continuous force. The mandibular first molar was induced into a non-occluding condition in the hypofunctional periodontium group. Mesial orthodontic force was applied by means of 50-gram-force closed-coil springs for 15 days in both groups. The active root-resorption lacunae from histological sections, identified by tartrate-resistant acid phosphatase, were measured in terms of length, depth, and area. The results showed that the amount of root resorption was significantly greater in teeth with a hypofunctional periodontium than in those with a normal periodontium (p < 0.05). These results suggest that orthodontic movement of non-occluding teeth should be performed with caution.

PMID: 12766204 [PubMed - indexed for MEDLINE]

The effect of prostaglandin E2 and calcium gluconate on orthodontic tooth movement and root resorption in rats.

Eur J Orthod. 2003 Apr;25(2):199-204

Authors: Seifi M, Eslami B, Saffar AS

Possible modifications in orthodontic tooth movement (OTM) and root resorption as a result of local injections of prostaglandin E2 (PGE2) alone and with calcium gluconate (Ca) formed the aim of the present study. Twenty-four 8-week-old male Wistar rats were selected and randomly divided into three groups of eight. Both quadrants of the upper jaws of the first group of animals were used; therefore this group comprised two groups: control and normal. The upper left first molars of these eight animals were not placed under orthodontic force and received no injection, to serve as the normal group, considered for root resorption comparison only. The control group had localized submucosal injections of normal saline on the buccal side of the upper right first molar. In the third group, 0.1 ml of 1 mg/ml PGE2 was injected at the same site and the fourth group received an intraperitoneal injection of 200 mg/kg Ca (10%) in addition to the PGE2. All the injections were performed on days 0 and 7. The orthodontic appliance consisted of a closed coil spring ligated to the upper right first molar and incisor, exerting a force of 60 g during the 21-day experimental period, after which the animals were sacrificed. Palatal halves were removed for histological examination and for calculation of the amount of root resorption. Statistical analysis of data showed a significant (P < 0.05) acceleration in OTM after PGE2 injection compared with the control group. The addition of Ca reduced OTM but a significant increase (P< 0.05) was still recorded. A significant difference (P < 0.05) in root resorption was only observed between the PGE2 and normal groups. The findings show the importance of calcium ions working in association with PGE2 in stabilizing root resorption while significantly increasing OTM.

PMID: 12737218 [PubMed - indexed for MEDLINE]

Genetic predisposition to external apical root resorption in orthodontic patients: linkage of chromosome-18 marker.

J Dent Res. 2003 May;82(5):356-60

Authors: Al-Qawasmi RA, Hartsfield JK, Everett ET, Flury L, Liu L, Foroud TM, Macri JV, Roberts WE

External apical root resorption (EARR) is a common orthodontic treatment sequela. Previous studies implicate a substantial genetic component for EARR. Using a candidate gene approach, we investigated possible linkage of EARR associated with orthodontic treatment with the TNSALP, TNFalpha, and TNFRSF11A gene loci. The sample was comprised of 38 American Caucasian families with a total of 79 siblings who completed comprehensive orthodontic treatment. EARR was assessed by means of pre- and post-treatment radiographs. Buccal swab cells were collected for extraction and analysis of DNA. No evidence of linkage was found with EARR and the TNFalpha and TNSALP genes. Non-parametric sibling pair linkage analysis identified evidence of linkage (LOD = 2.5; p = 0.02) of EARR affecting the maxillary central incisor with the microsatellite marker D18S64 (tightly linked to TNFRSF11A). This indicates that the TNFRSF11A locus, or another tightly linked gene, is associated with EARR.

PMID: 12709501 [PubMed - indexed for MEDLINE]

Inactivated periods of constant orthodontic forces related to desirable tooth movement in rats.

J Orthod. 2003 Mar;30(1):31-7; discussion 21-2

Authors: Kameyama T, Matsumoto Y, Warita H, Soma K

AIM: To examine the effects of inactive periods of force on the amount of tooth displacement and root resorption during experimental tooth movement in rats. SAMPLE: Sixty 11-week-old male Sprague-Dawley rats. METHOD: The maxillary first molar (M1) was moved mesially using a removable titanium-nickel alloy closed coil spring for 14 days. The rats were divided into four groups with, 0, 1, 4, and 9 hours of inactivation per day. RESULTS: Tooth displacement in the 0- and 1-hour groups was significantly greater than that in the 9-hour group. The area of root resorption in the 4- and 9-hour groups was significantly less than that in the 0- and 1-hour groups. There was no significant difference in root resorption between 0- and 1-hour groups, and also between 4- and 9-hour groups. CONCLUSION: The distance of tooth displacement gradually decreased as the inactive period increased, whereas root resorption suddenly decreased between 1 and 4 hours of inactive orthodontic force.

PMID: 12644605 [PubMed - indexed for MEDLINE]

Further observations on tertiary dentin in human deciduous teeth.

Adv Dent Res. 2001 Aug;15:76-9

Authors: Klinge RF

The structure of reparative tertiary dentin in human deciduous teeth has been studied. Reparative dentin is secreted by a new generation of odontoblast-like cells which have been subject to strong stimuli, e.g., trauma or deep active caries lesions with associated pulp inflammation. Ground sections of 25 teeth were prepared, and contact microradiographs were produced. Another 30 teeth were demineralized, embedded in paraffin, sectioned, and stained with hematoxylin and eosin. Some demineralized sections from each tooth were also studied in the scanning electron microscope. Most of the teeth showed some type of tertiary dentin formation. Mineralized tissue with a varied morphology was observed. In teeth which had been subject to trauma, the entire pulp chamber was sometimes obliterated. Mineralization seemed to start in the incisal region, and the central part of the pulp was the last part to be obliterated. Radiolucent voids and canals were seen. The organic matrix was dense and fibrous. In the pulp chamber and especially in the root canals, resorption had often occurred, indicating that signals giving rise to odontoclasts were also present. Resorption was often followed by deposition of various amounts of cementum-like repair tissue. The cells responsible for the formation of reparative dentin are believed to be subodontoblasts or undifferentiated ectomesenchymal cells. The varied morphology of the reparative dentin, observed in the pulp of the teeth examined, indicates that different stimuli lead to induction of hard-tissue-forming cells which produce different types of hard tissue.

PMID: 12640746 [PubMed - indexed for MEDLINE]

The Kabuki syndrome: four patients with oral abnormalities.

Eur J Orthod. 2003 Feb;25(1):13-9

Authors: Petzold D, Kratzsch E, Opitz Ch, Tinschert S

The aim of this paper is to report the oral signs and symptoms of four patients with Kabuki syndrome. All had oral abnormalities affecting the palate, teeth, and/or lips, including wide spacing between the teeth, screwdriver-shaped upper incisors, hypodontia, delayed tooth eruption, narrow spacing in the upper canine area, large pulp chambers of the upper incisors and permanent molars, external root resorption of the upper central incisors and permanent molars, a division of the lower third of the root canal in normally one-rooted teeth, tooth retention, retrognathia of the upper jaw, a high palate or cleft lip/palate, and microforms of lower lip fistula.

PMID: 12608719 [PubMed - indexed for MEDLINE]

In vivo killing of Porphyromonas gingivalis by toluidine blue-mediated photosensitization in an animal model.

Antimicrob Agents Chemother. 2003 Mar;47(3):932-40

Authors: K&#xF6;merik N, Nakanishi H, MacRobert AJ, Henderson B, Speight P, Wilson M

Porphyromonas gingivalis is one of the major causative organisms of periodontitis and has been shown to be susceptible to toluidine blue-mediated photosensitization in vitro. The aims of the present study were to determine whether this technique could be used to kill the organism in the oral cavities of rats and whether this would result in a reduction in the alveolar bone loss characteristic of periodontitis. The maxillary molars of rats were inoculated with P. gingivalis and exposed to up to 48 J of 630-nm laser light in the presence of toluidine blue. The number of surviving bacteria was then determined, and the periodontal structures were examined for evidence of any damage. When toluidine blue was used together with laser light there was a significant reduction in the number of viable P. gingivalis organisms. No viable bacteria could be detected when 1 mg of toluidine blue per ml was used in conjunction with all light doses used. On histological examination, no adverse effect of photosensitization on the adjacent tissues was observed. In a further group of animals, after time was allowed for the disease to develop in controls, the rats were killed and the level of maxillary molar alveolar bone was assessed. The bone loss in the animals treated with light and toluidine blue was found to be significantly less than that in the control groups. The results of this study show that toluidine blue-mediated lethal photosensitization of P. gingivalis is possible in vivo and that this results in decreased bone loss. These findings suggest that photodynamic therapy may be useful as an alternative approach for the antimicrobial treatment of periodontitis.

PMID: 12604524 [PubMed - indexed for MEDLINE]

[Evaluation of pH variation and cervical dentin permeability in teeth submitted to bleaching treatment]

Pesqui Odontol Bras. 2002 Jul-Sep;16(3):263-8

Authors: Dezotti MS, Souza MH, Nishiyama CK

External cervical root resorption is one of the disadvantages of the bleaching procedure. There are several mechanisms that may be responsible for causing resorption, such as the chemical and physical action of the utilized materials and the morphology of the cementoenamel junction. The purpose of this study was to investigate the presence of a communication between the pulp chamber and the external root surface. The investigation was carried out by means of pH tests and measurement of dye infiltration into cervical dentin after the bleaching procedure. Thirty-four human permanent incisors were submitted to endodontic treatment. The teeth were assigned to three experimental groups, according to the level at which the filling was cut, and to the sealing of the root canal entrance with glass ionomer cement. Sodium perborate and 30% hydrogen peroxide were utilized for bleaching. pH readings were carried out after 30 minutes, 24 h, 48 h and 72 h from the beginning of the procedure. The teeth were immersed in 0.5% basic fuchsin for 24 h in order to determine possible differences in the permeability of cervical dentin. The results revealed that pH tended to change when the root filling was cut at the entrance of the canal, when 2 mm of the filling were removed, and when the canal entrance was sealed with glass ionomer. Dentinal permeability increased in the three experimental groups, in comparison with the control group. These slight differences may suggest a communication between the pulp chamber and the external root surface.

PMID: 12386690 [PubMed - indexed for MEDLINE]

Periodontal 5'-deiodination on forced-induced root resorption--the protective effect of thyroid hormone administration.

Eur J Orthod. 2002 Aug;24(4):363-9

Authors: V&#xE1;zquez-Landaverde LA, Rojas-Huidobro R, Alonso Gallegos-Corona M, Aceves C

The present investigation was designed to study the protective effect given by thyroid hormone (TH) on root resorption: (1) whether intra-peritoneal versus oral TH administration had the same efficiency; and (2) whether this effect involved local or systemic mechanisms. For this purpose, circulating T3 levels, systemic alkaline phosphatase (APase) activity, and 5'deiodinase (5'D) activity were evaluated in the periodontal area of 80 Sprague-Dawley rats, 8 weeks of age, in which orthodontic appliances had been inserted. The results showed that TH-treated animals (intra-peritoneal or oral) had significantly less force-induced root resorptive lesions compared with a control group, without apparent changes in T3 or APase levels, and that periodontal remodelling was accompanied by a significant increase in local T3 generation as a result of T4 deiodination. This 5'D activity was higher in those animals that received exogenous TH. These results suggest that this protective TH mechanism may be achieved at a local level and that administration of low doses of TH may play a protective role on the root surface either during orthodontic treatment or in those patients that present spontaneous root resorptive lesions.

PMID: 12198866 [PubMed - indexed for MEDLINE]

[Clinical evaluation of external radicular resorption in non-vital teeth submitted to bleaching]

Pesqui Odontol Bras. 2002 Apr-Jun;16(2):131-5

Authors: Loguercio AD, Souza D, Floor AS, Mesko M, Barbosa AN, Busato AL

The purpose of this study was to evaluate the presence of external resorption in non-vital teeth submitted to bleaching. The evaluated patients had at least one non-vital tooth, which had been bleached between 1986 and 1996. All teeth were submitted to bleaching with hydrogen peroxide and sodium perborate, as described by Busato et al.5,6. From 193 patients recalled for clinical and radiographic evaluation of bleached teeth, only 43 attended (54 teeth). The average time elapsed after bleaching was 3.5 years. The results revealed that none of the examined teeth had any degree of external cervical resorption.

PMID: 12131986 [PubMed - indexed for MEDLINE]

Experimental tooth movement under light orthodontic forces: rates of tooth movement and changes of the periodontium.

J Orthod. 2002 Jun;29(2):129-35

Authors: Kohno T, Matsumoto Y, Kanno Z, Warita H, Soma K

AIM: To investigate light forces for experimental tooth movement. METHOD: Light orthodontic forces of 1.2, 3.6, 6.5, and 10 g force (gf) were applied for 14 days to move rat molars, and the effects of the forces on the rate of tooth movement and changes of the periodontium were examined. RESULTS: In the early period, despite the different levels of force used in each group, there were no significant differences in tooth displacement. From hour 56 to day 14, the tooth displacement in the 1.2 gf group was significantly smaller than that in the other groups and the rate was nearly constant. The rates of tooth displacement in the 3.6, 6.5, and 10 gf groups fluctuated repeatedly, while the orthodontic forces gradually decreased. CONCLUSION: Experimental tooth movement in rats, tipping without friction under light forces, were either constant or fluctuated in cycles of several days' duration. This is in contradiction to the three-phases-theory of tooth movement described in previous investigations using heavy forces.

PMID: 12114463 [PubMed - indexed for MEDLINE]

SEM observations of resected root canal ends following apicoectomy.

Bull Tokyo Dent Coll. 2002 Feb;43(1):7-12

Authors: Furusawa M, Asai Y

The purpose of this study was to examine the apical foramen of root apices extracted during apicotomies. A total of 25 teeth extracted from 25 patients admitted to the Department of Conservative Dentistry at Tokyo Dental College's Chiba Hospital were used for the study. All patients were between 22 to 56 years of age at the time of the study, and each of the 25 cases was determined clinically on radiographs to be chronic apical suppurative periodontitis. Microsurgery was performed on all cases, and the extracted root apices were then observed using SEM. The results demonstrated a wide opening, greater than 350 microns as measured along the major axis, of the apical foramen in 80% of the cases. Various characteristics indicative of resorption were observed around the apical foramen. These features included those believed to have been caused by overinstrumentation during root canal treatment as well as irregularly shaped areas presumed to be apical lesions that had enlarged and eroded. We observed a high frequency of manifestations of cementum resorption surrounding the root apices of teeth with apical lesions. Furthermore, we concluded that in the majority of cases in the present study, due to the fact that the apical foramen exceeded normal opening dimensions as a result of overinstrumentation during root canal treatment or resorption around the root apex, prolongation of the lesions had occurred in response to direct contact of microbial infectious matter and tissues surrounding the root apex over a large area. The above finding suggested that, in cases in which the apical foramen is destroyed through overinstrumentation larger than #35 or in which the apical foramen opens up to dimensions greater than 350 microns due to pathologic resorption, surgical intervention may be indicated. On the other hand, in 64% of the cases, an accessory canal was observed in the root apical lesion. Based on this observation, the presence of an accessory canal in the root apex may contribute to some degree to the prolongation of the lesion.

PMID: 12013825 [PubMed - indexed for MEDLINE]

Idiopathic external root resorption associated to hypercalciuria.

Med Oral. 2002 May-Jun;7(3):192-9

Authors: Llena-Puy MC, Amengual-Lorenzo J, Forner-Navarro L

Although external root resorption (ERR) is a physiological process in deciduous dentition, it is very infrequent in permanent dentition - where the phenomenon is related to the existence of inadequate occlusal forces, periodontal pathology and microtraumatisms, etc. However, in many cases root resorption cannot be attributed to any concrete cause; such cases are defined as idiopathic external root resorption (IERR). Epidemiological studies have found that the underlying cause can only be established in 5% of all ERR. The present study describes three cases of IERR with different degrees of involvement and associated to mild calciuria and a history of nephrolithiasis. Hypercalciuria with normal blood calcium levels is usually idiopathic and exhibits a familial trait, with a prevalence of 20-40 cases per 1,000 individuals in adults. A form of hypercalciuria associated to nephrolithiasis with a mutation of the CLCN5 gene has been identified, involving low molecular weight proteinuria - though this mutation has not been uniformly demonstrated in most cases of idiopathic hypercalciuria. The peculiarity of the cases described in the present study is attributable to the coexistence of IERR with normocalcemic hypercalciuria and nephrolithiasis - thus pointing to the need for in-depth evaluation of the possible association of these three clinical situations.

PMID: 11984501 [PubMed - indexed for MEDLINE]

Tissue reaction to orthodontic tooth movement--a new paradigm.

Eur J Orthod. 2001 Dec;23(6):671-81

Authors: Melsen B

Direct or indirect resorption are both perceived as a reaction to an applied force. This is in contrast to orthopaedic surgeons who describe apposition as 'the reaction to loading of bone'. The article reviews the literature on intrusion of teeth with periodontal breakdown, and on the basis of clinical and experimental studies. The conclusion is reached that intrusion can lead to an improved attachment level, and that forces have to be to low and continuous. The tissue reaction to a force system generating translation of premolars and molars in the five Macaca fascicularis monkeys is described. Three force levels, 100, 200, and 300 cN were applied for a period of 11 weeks. Undecalcified serial sections were cut parallel to the occlusal plane and a grid consisting of three concentric outlines of the root intersected by six radii was placed on each section so that areas anticipated to be subject to differing stress/strain distributions were isolated. A posteriori tests were utilized in order to separate areas that differed with regard to parameters reflecting bone turnover. Based on these results and a finite element model simulating the loading, a new hypothesis regarding tissue reaction to change in the stress strain distribution generated by orthodontic forces is suggested. The direct resorption could be perceived as a result of lowering of the normal strain from the functioning periodontal ligament (PDL) and as such as a start of remodelling, in the bone biological sense of the word. Indirect remodelling could be perceived as sterile inflammation attempting to remove ischaemic bone under the hyalinized tissue. At a distance from the alveolus, dense woven bone was observed as a sign of a regional acceleratory phenomena (RAP). The results of the intrusion could, according to the new hypothesis, be perceived as bending of the alveolar wall produced by the pull from Sharpey's fibres.

PMID: 11890063 [PubMed - indexed for MEDLINE]

Changes in root length during orthodontic treatment: advantages for immature teeth.

Eur J Orthod. 2002 Feb;24(1):91-7

Authors: Mavragani M, B&#xF8;e OE, Wisth PJ, Selvig KA

The purpose of the study was to investigate root lengthening during orthodontic treatment in relation to the age of the patient, the developmental stage of the root, and the anticipated growth. Specifically, the potential benefit of treating young teeth was addressed. The sample consisted of 80 patients with Angle Class II division 1 malocclusions, treated with extraction of at least two maxillary first premolars, and edgewise technique with 0.018-inch slot brackets. Additionally, a cross-sectional control group of 66 untreated individuals matched to gender, and pre- and post-treatment age of the experimental group was included. Crown and root lengths of the maxillary incisors were measured on peri-apical radiographs before and after treatment, and corrected for image distortion. The stage of root development before treatment was recorded. Root elongation during treatment was found for 50 out of the 280 examined teeth. Age at treatment start was significantly higher among the patients showing root shortening of the lateral incisors during treatment than among those showing root elongation (P < 0.05). The stage of root development was significantly related to the direction of root length change, i.e. shortening or elongation. Roots elongated during treatment did not differ in length from untreated teeth of similarly aged individuals. There was no significant difference in the extent of root lengthening between the roots elongated during treatment and the normal root lengthening in age-matched untreated individuals. Post-treatment root length was significantly related to pre-treatment age. Roots that were incompletely developed before treatment reached a significantly greater length than those that were fully developed at the start of treatment. The results of this study show a definite advantage for younger teeth with regard to post-treatment root length. This finding may influence treatment planning strategy.

PMID: 11887384 [PubMed - indexed for MEDLINE]

Restoration and retention of maxillary anteriors with severe root resorption.

J Am Dent Assoc. 2002 Jan;133(1):67-71

Authors: Savage RR, Kokich VG

BACKGROUND: The authors describe the treatment of three patients who had severe apical root resorption of maxillary lateral incisors caused by ectopically erupting canines. Ectopically erupting canines derive from a normal path of eruption and may cause resorption of the adjacent teeth. CASE DESCRIPTION: The authors present the three cases of severe root resorption caused by ectopically erupting canines. They then discuss various prosthetic options; the indications, advantages and disadvantages of various treatment modalities; the long-term retention and esthetic concerns of the patients; and the inherent limitations of restorative treatment. CLINICAL IMPLICATIONS: Increased tooth mobility and long-term retention are significant concerns in cases of patients who have severe root resorption. Attaining stability with lingual splinting can cause esthetic problems. An interdisciplinary approach is necessary to provide optimal care for the patient.

PMID: 11811745 [PubMed - indexed for MEDLINE]

Cellular events at the onset of physiological root resorption in rabbit deciduous teeth.

Anat Rec. 2001 Dec 1;264(4):387-96

Authors: Sahara N

For elucidation of how physiological root resorption of deciduous teeth is initiated, the cellular events that occur surrounding the root of rabbit deciduous teeth before and at the onset of physiological root resorption were observed by means of light and electron microscopy. In addition, the cytodifferentiation of odontoclasts during the initial phase of this root resorption was evaluated by histochemical staining of tartrate-resistant acid phosphatase (TRAP) activity as a marker odontoclasts and their precursors. The present investigation was focused on the physiological root resorption of the deciduous lower second molar of rabbits from Day 0-5 postnatally. At birth, the deciduous molar had not erupted yet, and no TRAP-positive cell could be found surrounding the tissue adjacent to the root of the deciduous tooth. TRAP-positive mononuclear cells were initially detected in the coronal portion of the dental follicle of the permanent tooth at Day 1 postnatally. Ultrastructurally, these mononuclear cells had moderate numbers of mitochondria and short-strand rough endoplasmic reticulum, as well as scattered free ribosomes throughout their cytoplasm. TRAP-positive mononuclear cells then appeared in the cementoblast layer immediately adjacent to the surface of the deciduous roots. These mononuclear cells projected cytoplasmic extensions between the cementoblasts and made contact with the cementum. At that time, cell-cell contact was frequently observed between these mononuclear cells and cementoblasts. During 3-5 days postnatally, the number of TRAP-positive multinucleate odontoclasts on the root surface gradually increased. They had well-developed ruffled borders and made typical resorption lacunae on the root surface of the deciduous tooth. During this early postnatal period, neither inflammatory cells nor necrotic tissue could be observed surrounding the deciduous root. This study demonstrates that the dental follicle of the permanent tooth as well as the connective tissue adjacent to the deciduous root might play important role in site- and time-specific recruitment, development, and activation of odontoclasts before and at the onset of physiological root resorption.

PMID: 11745094 [PubMed - indexed for MEDLINE]

Immunolocalization of vacuolar-type H+-ATPase, cathepsin K, matrix metalloproteinase-9, and receptor activator of NFkappaB ligand in odontoclasts during physiological root resorption of human deciduous teeth.

Anat Rec. 2001 Nov 1;264(3):305-11

Authors: Oshiro T, Shibasaki Y, Martin TJ, Sasaki T

To investigate the cellular mechanisms of physiological root resorption in human deciduous teeth, the authors examined the immunocytochemical localization of vacuolar-type H+-ATPase, a lysosomal cysteine proteinase, cathepsin K, matrix metalloproteinase-9 (MMP-9), and receptor activator of NFKB ligand (RANKL) in odontoclasts. H+-ATPase, cathepsin K, and MMP-9 are the most important enzymes for decalcification of apatite crystals and degradation of type-I collagen. In addition, RANKL is one of the key regulatory molecules in osteoclast formation and functions. Odontoclasts developed extensive ruffled borders and clear zones apposed to the resorbing root dentine surfaces. On immunoelectron microscopy, the expression of vacuolar-type H+-ATPase was detected along the limiting membranes of pale vacuoles and the ruffled border membranes of odontoclasts. Cathepsin K in odontoclasts was localized within pale vacuoles, lysosomes, the extracellular canals of ruffled borders, and the underlying resorbing dentine surfaces. MMP-9 localization in odontoclasts was similar to those of cathepsin K. RANKL was detected in both mononuclear stromal cells and odontoclasts located on resorbing dentine surfaces. These results suggest that (1) odontoclasts are directly involved in decalcification of apatite crystals by active extrusion of proton ions mediated by H+-ATPase and (2) extracellular degradation of dentine type-I collagen by both cathepsin K and MMP-9, and (3) odontoclast differentiation and activity are regulated, at least in part, by RANKL, possibly produced by mononuclear stromal cells and odontoclasts themselves in the resorbing tissues. Thus, the cellular mechanisms of physiological root resorption appear to be quite similar to those of osteoclastic bone resorption.

PMID: 11596012 [PubMed - indexed for MEDLINE]

Tooth movement and changes in periodontal tissue in response to orthodontic force in rats vary depending on the time of day the force is applied.

Eur J Orthod. 2001 Aug;23(4):329-38

Authors: Miyoshi K, Igarashi K, Saeki S, Shinoda H, Mitani H

The purpose of this study was to investigate whether there are any differences in tooth movement or in the response of periodontal tissue to orthodontic force when the force is applied at different times of the day. One hundred 6-week-old male Wistar rats were divided into one control group without force application and three experimental groups based on the time of day the force was applied to the upper first molars. Animals in the whole-day group received force continuously throughout the experimental period, while animals in the light- and dark-period groups received force only during the light (07:00-19:00) or dark period (19:00-07:00), respectively. Tooth movement was measured using the occlusal view of a precise plaster model with a profile projector. Periodontal tissues were evaluated histologically. The time course of tooth movement varied among the groups. Tooth movement over 21 days in the whole-day and light-period groups was about twice that as in the dark-period group. The formation of new bone on the tension side in the whole-day and light-period groups was more than twice that as in the dark-period group. On the pressure side, more osteoclasts appeared on the alveolar bone in the whole-day and light-period groups than in the dark-period group. The light-period group showed less extensive hyalinization of the periodontal ligament (PDL) than the whole-day group. The area of root resorption on day 21 also varied among the groups. Interference by masticatory forces did not seem to be a principal cause of the decreased tooth movement in the dark-period group. These results indicate that there are considerable variations in tooth movement and in the response of periodontal tissue to orthodontic force when the force is applied at different times of the day in rats. The results suggest that diurnal rhythms in bone metabolism have important implications in orthodontic treatment.

PMID: 11544782 [PubMed - indexed for MEDLINE]

The labiogingival notch: an anatomical variation of clinical importance.

J Am Dent Assoc. 2001 Jul;132(7):919-21

Authors: Ben-Bassat Y, Brin I

BACKGROUND: The labiogingival notch is a developmental phenomenon affecting the maxillary central incisors. Clinically, it can be easily misdiagnosed and improperly treated. Thus, it is important for dentists to recognize this condition. CASE DESCRIPTIONS: The authors describe two cases of misdiagnosed labiogingival notch on a maxillary central incisor. In one case, the notch was misinterpreted as a carious lesion and placement of a restoration was advised. In the second case, external resorption was suspected and forced eruption of the incisor was requested. In both cases, no treatment was needed. CLINICAL IMPLICATIONS: Misdiagnosis of this developmental phenomenon may lead to unnecessary invasive interventions. Because of this, clinicians need to be aware of this clinical variant.

PMID: 11480645 [PubMed - indexed for MEDLINE]