Dentofacial growth in patients with Sotos syndrome.

Bull Tokyo Dent Coll. 2007 May;48(2):73-85

Authors: Takei K, Sueishi K, Yamaguchi H, Ohtawa Y

Sotos syndrome is an overgrowth syndrome leading to peculiar facial characteristics, large hands and feet, and mental retardation. The maxillofacial characteristics are metopic protrusion, a high and narrow palate and a tapered mandible. In this study, we evaluated changes in maxillofacial growth in 2 patients with cerebral gigantism during the peripubertal period. Patient 1 was a boy aged 8 years at the first examination. The face showed midface retraction and a tapered mandible. Maxillary median diastema with an OJ of 2.5 mm and OB of 1.0 mm was observed, and the molar region showed mandibular mesial occlusion. Radiography revealed a lack of 15, 25, 37, 47, 14, 24, 34 and 44. Cephalometrics demonstrated maxillary and mandibular retrusion with an SNA of 68 degrees and an SNB of 70 degrees , and the patient had leptoprosopia with a mandibular plane of 38.0 degrees . This plane was 45 degrees at the time of re-examination when the patient was 14 years old, showing an increase in the lower facial height and decreases in facial axis and depth. Patient 2 was a boy aged 14 years at the first examination. The face showed mandibular retrusion and tapering. The occlusion was angle class II div. 1, OJ 14 mm, and OB -1 mm. Cephalometrics demonstrated maxillary and mandibular retrusion with an SNA of 74.5 degrees and an SNB of 69.5 degrees , and the patient had leptoprosopia with a mandibular plane of 37.0 degrees . At the time of re-examination, when the patient was 16 years old, the mandibular plane was 42.5 degrees , showing an increase in lower facial height and decreases in facial axis and depth. In this syndrome, excessive facial height without mandibular forward overgrowth is observed. Since the facial height tended to increase by growth during the peripubertal period, maxillofacial vertical growth is considered important in the treatment of this syndrome.

PMID: 17978548 [PubMed - indexed for MEDLINE]

Pre-operative drilling simulation method for dental implant treatment.

Bull Tokyo Dent Coll. 2007 Feb;48(1):27-35

Authors: Arataki T, Furuya Y, Ito T, Miyashita Y, Shimamura I, Yajima Y

The position, depth and direction of implant placement are often planned based on evaluation of radiographs and study casts. Insertion planned in such a manner may not be adequate for precise and safe surgery in some cases due to inadequate working clearance in the oral cavity. In order to obtain high initial stability and ensure osseointegration at the implant-bone interface, careful and precise drilling must be performed at the implant placement site. Therefore, we propose the necessity of evaluating the operability of implant treatment-devices prior to surgery. The amount of handling space needed during implant placement surgery was determined. The results showed that for implants with a length of 7-18 mm, a vertical distance of as much as 50-60 mm was required, depending on the implant platform. These results suggest the necessity of pre-operative drilling simulation in each individual. Handling space was measured with angled heads and probes fabricated on a trial basis for pre-surgical drilling simulation in the oral cavity. We believe that these instruments may be clinically useful in estimating the amount of handling space required prior to surgery and ensuring precise implant placement. Evaluation of the intra-oral environment for handling of treatment devices should be included in the pre-surgical intra-oral evaluation of dental implant cases to avoid changes in treatment planning due to intra-oral interference during the course of surgery.

PMID: 17721064 [PubMed - indexed for MEDLINE]

Importance of occlusion aspects in the completion of orthodontic treatment.

Braz Dent J. 2007;18(1):78-82

Authors: Oltramari PV, Conti AC, Navarro Rde L, Almeida MR, Almeida-Pedrin RR, Ferreira FP

The purpose of this study was to address the therapeutic goals regarding the static and functional occlusion in the completion of orthodontic treatment. For such purpose, a study population comprising 20 female treated Class II malocclusion subjects with an initial mean age of 11 years underwent a two-phase treatment (orthopedics and orthodontics). The patients were diagnosed in centric relation and were treated according to the six keys for normal occlusion and functional occlusal parameters (centric relation, vertical dimension, lateral and anterior guidances, occlusal contacts and direction of forces applied on the teeth). After removal of fixed mechanics, retainers were installed and maintained for two years. Five years after orthodontic completion, the occlusal stability of the patients was evaluated regarding molar relationship and overjet, measured in dental casts. All subjects maintained the normal molar relationship and correct overjet achieved at the end of treatment, indicating a fair level of occlusal stability. The importance of the criteria of the ideal functional occlusion to ensure a better stability after completion orthodontic treatment will be discussed in detail in this paper. In addition, some clinical situations in which localized adjustments are indicated for occlusal refinement will be described.

PMID: 17639207 [PubMed - indexed for MEDLINE]

A controlled clinical trial of the effects of the Twin Block and Dynamax appliances on the hard and soft tissues.

Eur J Orthod. 2007 Jun;29(3):272-82

Authors: Lee RT, Kyi CS, Mack GJ

The aim of this controlled trial was to identify and quantify skeletal, soft tissue and dental changes during treatment, and immediately post-treatment with Twin Block (TB) or Dynamax appliance using the techniques of three-dimensional (3D)optical surface laser scanning, cephalometric, and clinical measurements. Sixty-two Caucasian subjects, 36 males aged 11-14 years and 26 females aged 10-13 years were enrolled in the study. The patients were placed in two groups, matched for gender and age and subsequently allocated randomly for treatment with either a TB or Dynamax appliance. Active treatment lasted 9 months followed by 3 months' post-treatment observation. Laser scanning and clinical measurements were taken at 3-monthly intervals and final cephalometric records after 12 months. Statistical analysis was performed using Wilcoxon's matched-pairs signed-rank tests. The non-compliance rates were the same for both groups (9 per cent), but a greater incidence of breakages was found in the Dynamax group. The TB was found to produce slightly more antero-posterior skeletal change, median ANB reduction, TB=2 degrees, Dynamax 1.1 degree (P=0.006), and similar forward movements of the chin and was associated with larger increases in the vertical facial dimension, median total anterior face height increase; TB=3.2 mm, Dynamax = 2.8 mm (P=0.03). The soft tissue vertical cephalometric increases were 3.6 mm with the TB, 2.0 mm with the Dynamax (P=0.036), and with laser scanning 5.05 and 2.6 mm, respectively, a difference which is likely to be more clinically relevant. The median post-treatment changes in soft tissue pogonion were -0.65 mm in the TB and +0.22 mm in the Dynamax group. The optical surface scanning mark and measure system is a valid method for quantifying soft tissue changes.

PMID: 17456506 [PubMed - indexed for MEDLINE]

Bilateral TMJ disk displacement induces mandibular retrognathia.

J Dent Res. 2006 Dec;85(12):1118-23

Authors: Bryndahl F, Eriksson L, Legrell PE, Isberg A

Unilateral non-reducing TMJ disk displacement has been shown to retard mandibular growth on the ipsilateral side, with facial asymmetry a sequela. We hypothesized that bilateral affliction would impair mandibular growth bilaterally, generating mandibular retrognathia. Non-reducing TMJ disk displacement was surgically created in 10 growing New Zealand White rabbits. Ten additional rabbits served as a sham-operated control group. Facial growth was followed in serial cephalograms, with tantalum implants, during a period corresponding to childhood and adolescence in man. The results verified that bilateral non-reducing TMJ disk displacement retarded mandibular growth bilaterally, the extent corresponding to mandibular retrognathia in man. Maxillary growth was also retarded, but to a lesser degree. Growth impairment fluctuated over time, the most striking retardation occurring during periods of general growth acceleration. This should be taken into consideration when orthodontic treatment, aimed at stimulating mandibular growth, is initiated in adolescent individuals with non-reducing TMJ disk displacement.

PMID: 17122165 [PubMed - indexed for MEDLINE]

Anterior open bite treated with a palatal crib and high-pull chin cup therapy. A prospective randomized study.

Eur J Orthod. 2006 Dec;28(6):610-7

Authors: Torres F, Almeida RR, de Almeida MR, Almeida-Pedrin RR, Pedrin F, Henriques JF

The aim of this prospective randomized clinical study was to cephalometrically investigate the dentoalveolar and soft tissue changes produced by a removable appliance with a palatal crib associated with high-pull chin cup therapy in children with an Angle Class I anterior open bite (AOB) malocclusion. Thirty children (8 males and 22 females) with an initial mean age of 8.3 years and a mean AOB of 4.1 mm were treated with a removable appliance composed of a palatal crib associated with chin cup therapy for 12 months. A control group of 30 individuals (7 males and 23 females) closely matched for age, initial mean age 8.6 years, gender, and ethnicity with a mean AOB of 4.6 mm was followed without treatment. The measurements (means and standard deviations) were statistically analysed using a paired t-test. The results showed no significant differences in the level of molar eruption or in lower anterior face height, suggesting that the vertical control expected from the chin cup therapy did not occur. Dentoalveolar changes at the anterior region were evident, with statistically significant extrusion, retrusion, and lingual tipping of the maxillary and mandibular incisors (P < or = 0.05). However, these hard tissue changes did not imply soft tissue changes and the variables related to the soft profile were not statistically significantly different between the groups. The dentoalveolar changes at the anterior region of the dental arches were mainly responsible for closure of the AOB in patients treated in the mixed dentition.

PMID: 17101701 [PubMed - indexed for MEDLINE]

Functional adaptability of jaw-muscle spindles after bite-raising.

J Dent Res. 2006 Sep;85(9):849-53

Authors: Yabushita T, Zeredo JL, Fujita K, Toda K, Soma K

In a previous experiment, we found that masseter muscle spindles show functional plasticity after 5 to 15 days under increased occlusal vertical dimension (iOVD). In the present study, we hypothesized that spindle function would eventually recover if longer observation periods were allowed. Therefore, in this study we investigated changes in masseter muscle spindle function over periods of 1 day to 8 weeks. Masseter muscle-spindle responses to ramp-and-hold jaw stretches were recorded from the mesencephalic trigeminal nucleus in 35 barbiturate-anesthetized female Wistar rats. The rats were previously divided into Control and iOVD groups, and those in the iOVD group received a 2.0-mm composite resin build-up to the maxillary molars. In this condition, there were no statistically significant differences in masseter muscle spindle sensitivity between Control and iOVD in the six- and eight-week subgroups. Our results further indicate a high degree of adaptability in masseter muscle spindle function following changes in OVD.

PMID: 16931870 [PubMed - indexed for MEDLINE]

Normal torque of the buccal surface of mandibular teeth and its relationship with bracket positioning: a study in normal occlusion.

Braz Dent J. 2006;17(2):155-60

Authors: Mestriner MA, Enoki C, Mucha JN

This study evaluated the degree of buccolingual inclination of mandibular tooth crowns relative to torque. For such purpose, mandibular and maxillary stone casts from 31 Caucasian Brazilian adults with normal occlusion, pleasant facial aspect and no history of previous orthodontic treatment were examined. A custom device was developed for measuring the degree of inclination (torque) of bracket slots of orthodontic appliances relative to the occlusion plane, at three bonding height: standard (center of clinical crown), occlusal (0.5 mm occlusally from standard) and cervical (0.5 mm cervically from standard). Except for the mandibular incisors, which presented a small difference in torque from one another (lingual root torque for central incisors and buccal root torque for lateral incisors), the remaining average values are close to those found in the literature. Due to the convexity of the buccal surface, the 1-mm vertical shift of the brackets from occlusal to cervical affected the values corresponding to the normal torque, in approximately 2 degrees in central and lateral incisors, 3 degrees in canines and 8 degrees in premolars and molars.

PMID: 16924345 [PubMed - indexed for MEDLINE]

Primary canine and molar relationships in centric occlusion in three to six year-old Turkish children: a cross-sectional study.

J Contemp Dent Pract. 2006 Jul 1;7(3):59-66

Authors: Yilmaz Y, G&#xFC;rbüz T, Simşek S, Dalmiş A

This cross-sectional study aimed to evaluate the primary canine and the primary molar relationship in 205 (90 girls and 115 boys) three to six year-old Turkish children with the primary dentition in centric occlusion according to gender and age. In terms of the molar relationship, Class I was represented by 88.29% of all children who agreed to participate in the study, followed by Class II (7.31%), and Class III (4.4%). In terms of the canine relationship, Class I was represented by 87.8% of the sample, followed by Class II (7.8%), and Class III (4.4%). A statistically significant difference was found between age and both the canine and molar relationships (p<0.005), and a positive correlation was confirmed among them. However, the difference and correlation between the gender and the canine and molar relationships were not significant.

PMID: 16820808 [PubMed - indexed for MEDLINE]

The effect of periodontal surgery on bite force, occlusal contact area and bite pressure.

J Am Dent Assoc. 2006 Jul;137(7):978-83; quiz 1028

Authors: Alkan A, Keskiner I, Arici S, Sato S

BACKGROUND: Tooth mobility resulting from the loss of periodontal support or trauma induced by periodontal surgery may change the amount of bite force (BF) and bite pressure (BP) and number of occlusal contact areas (OCAs). The aim of the authors' study was to compare BF, BP and OCA of teeth with periodontal disease before and after periodontal surgery with similar values of healthy teeth. METHODS: The authors performed quantitative analysis of BF, BP and OCA using a pressure measurement film. Ten patients with periodontitis who needed periodontal surgery served as the test group. The authors took measurements of BF, BP, OCA and mobility (using Miller's Mobility Index) just before surgery and at one, four and 12 weeks after surgery. They also measured clinical attachment levels (CAL) before surgery and 12 weeks after surgery. Ten subjects without periodontitis served as the control group. RESULTS: Although BF and OCA increased the first week after periodontal surgery, analysis of variance (ANOVA) showed no statistically significant differences at a 95 percent confidence interval. There were statistically significant differences between first-week mobility and that at four and 12 weeks (P = .001). A factorial ANOVA showed significant interaction between BF and mobility (P < .05). CONCLUSIONS: The authors' findings suggest that changes in BF, BP and OCA were not affected by periodontal surgery. However, mean mobility values and BF are correlated. Further investigations of this measurement method involving larger study populations and a longer follow-up period are needed. CLINICAL IMPLICATIONS: It seems to be helpful to follow occlusal changes after periodontal surgery using a pressure measurement film. It also may be suggested that this measurement method could be used to evaluate the treatment prognosis.

PMID: 16803824 [PubMed - indexed for MEDLINE]

Pharyngeal airway changes following mandibular setback surgery.

Indian J Dent Res. 2005 Oct-Dec;16(4):147-50

Authors: Ramesh BV, Vinod N, Murugesan K

Treatment of dentofacial deformities with jaw osteotomies has an effect on airway anatomy and therefore mandibular setback surgery has the potential to diminish airway size. The purpose of this study was to evaluate the effect of mandibular setback surgery on airway size. 8 consecutive patients were examined prospectively. All patients underwent mandibular setback surgery. Cephalometric analysis was performed preoperatively and 3 months post operatively with particular attention to pharyngeal airway changes. Pharyngeal airway size decreased considerably in all, patients thus predisposing to development of obstructive sleep apnea. Therefore, large anteroposterior discrepancies should be corrected by combined maxillary and mandibular osteotomies.

PMID: 16761707 [PubMed - indexed for MEDLINE]

Size and orientation of masticatory muscles in patients with mandibular laterognathism.

J Dent Res. 2006 Jun;85(6):552-6

Authors: Goto TK, Nishida S, Yahagi M, Langenbach GE, Nakamura Y, Tokumori K, Sakai S, Yabuuchi H, Yoshiura K

Size measurements of jaw muscles reflect their force capabilities and correlate with facial morphology. Using MRI, we examined the size and orientation of jaw muscles in patients with mandibular laterognathism in comparison with a control group. We hypothesized that the muscles of the deviated side would be smaller than those of the non-deviated side, and that the muscles of both sides would be smaller than in controls. In patients, a comparison of deviated and non-deviated sides showed, in orientation, differences for masseter and medial pterygoid muscles, but, in size, differences only for the masseter muscle. Nevertheless, muscle sizes in patients were much smaller than in controls. Lateral displacement of the mandible can explain the orientation differences, but not the smaller muscle size, in patients. It is possible that the laterodeviation initiates an adaptive process in the entire jaw system, resulting in extensive atrophy of the jaw muscles.

PMID: 16723654 [PubMed - indexed for MEDLINE]

Evaluation of the centroid method of occlusion for studying mandibular and maxillary growth.

Eur J Orthod. 2006 Aug;28(4):345-51

Authors: Murata S, Nakamura S, Nagahara K

The aim of this study was to evaluate the centroid method of occlusion for studying mandibular growth and development. This novel technique comparatively expresses the direction of growth of the maxilla and mandible as a single unit. The centroid 'G' was geometrically calculated from the triangle Deltaabc, which comprised the palatal, articulare-gnathion (Ar-Gn), and A-B planes. The plane angles and positional relationship of the centroid with the upper first molar was investigated, focusing on differences between genders and malocclusions. Lateral cephalograms were obtained of 26 males and 51 females with a 'normal' Class I occlusion, 216 females with a Class III incisor relationship, and 230 females, all aged >18 years, with a Class II incisor relationship. Bolton standards and Sakamoto's data were used to determine changes in the angle of the palatal plane to the Ar-Gn plane. Non-significant levels of variation were observed in the angle of the palatal plane to the Ar-Gn plane during the developmental period from childhood to adulthood. Among Class I adult subjects, Deltaabc was similar between genders and the centroid G was located near the occlusal surface of the upper first molar. There was no difference in the area of Deltaabc between malocclusion types. The positional relationship of the centroid G with the upper first molar revealed a shift of the centroid mesially and cervically during the transition from Class III to Class I to Class II. These findings indicate that the centroid method can contribute to orthopaedic diagnosis and the planning of treatment strategies.

PMID: 16644852 [PubMed - indexed for MEDLINE]

Centric relation: A historical and contemporary orthodontic perspective.

J Am Dent Assoc. 2006 Apr;137(4):494-501

Authors: Rinchuse DJ, Kandasamy S

BACKGROUND: Centric relation (CR) has been a controversial subject in dentistry for more than a century. For at least the past four decades, issues involving CR have been of interest to orthodontists. The definition of CR has changed over the past half-century from a retruded, posterior and, for the most part, superior condyle position to an anterior-superior condyle position. TYPE OF STUDIES REVIEWED: The authors addressed the historical and contemporary orthodontic perspective of CR. The source material for this review came mainly from literature and searches the lead author accumulated over the last 30 years. As there is no evidence-based (EB) model level 3 (systemic) review on the topic of CR, the best evidence on this subject was gleaned only from a thorough examination and evaluation at EB model level 2 (experience plus best available sample studies). There was, however, enough high-quality EB model level 2 information on the topic of CR for the authors to draw conclusions on the basis of a scientific appraisal of relevant research. RESULTS: Although the reliability of CR records has been substantiated, the records' validity has little to no evidentiary support. In addition, population-based sample studies and consensus statements from national conferences support the view that the positions of the temporomandibular joint (TMJ) condyles in relation to the glenoid fossa or CR position are not diagnostic of temporomandiblar disorders. There appears to be little to no benefit of using gnathologic records and articulator-mounted dental casts to discern discrepancies in maximum intercuspation of the teeth coincident with TMJ condyles in an anterior-superior CR position in orthodontic patients. CLINICAL IMPLICATIONS: The benefit of using gnathologic CR records and articulators in orthodontics has not been substantiated by scientific evidence.

PMID: 16637479 [PubMed - indexed for MEDLINE]

Model surgery technique for Le Fort I osteotomy--alteration in occlusal plane associated with upward transposition of posterior maxilla.

Bull Tokyo Dent Coll. 2005 Aug;46(3):67-78

Authors: Yosano A, Yamamoto M, Shouno T, Shiiki S, Hamase M, Kasahara K, Takaki T, Takano N, Uchiyama T, Shibahara T

It is difficult to translate analytical values into accurate model surgery by traditional methods, especially when moving the posterior maxilla. This is because cephalometric radiographic analysis generated information on movement of the posterior nasal spine (PNS) can not be recreated in model surgery. Therefore, we propose a method that accurately reflects such analysis and simulation of movement using Quick Ceph 2000 (Orthodontic Processing Corporation, USA). This will allow the enrichment of model surgery prior to actual surgery in cases where upward movement of the posterior maxilla is involved. All patients who participated in this study had skeletal mandibular prognathism characterized by a small occlusal plane angle in respect to the S-N plane. Cephalometric radiographs were taken and analyzed with the Quick Ceph 2000. Pre- and post-surgical evaluations were performed using Sassouni arc analysis and Ricketts analysis. Prior to transposition, we then prepared an anterior occlusal bite record on a model mounted on an articulator. This bite was then used as a reference when the molar parts were to be transposed upwards. The use of a occlusal bite permitted an accurate translation of the preoperative computer simulation into model surgery, thus facilitating favorable surgical results.

PMID: 16598183 [PubMed - indexed for MEDLINE]

Long term results of mandibular distraction.

J Indian Soc Pedod Prev Dent. 2006 Mar;24(1):30-9

Authors: Batra P, Ryan FS, Witherow H, Calvert ML

Mandibular distraction osteogenesis has become a popular surgical modality due to its many advantages over conventional orthognathic surgical procedures. However, in spite of the technique having been used for over 15 years, no concrete long term results are available regarding the stability of results. We discuss the various studies which have reported either in favour or against the stablility of results after distraction. We report a series of 6 cases (3 unilateral and 3 bilateral distraction) where distraction was carried out before puberty and followed them up to seven years after removal of distractors. This case series shows that results achieved by distraction osteogenesis are unstable or best unpredictable with respect to producing a permanent size increase in the mandible. The role of the distraction osteogenesis in overcoming the pterygomassetric sling is questionable. We suggest a multicenter study with adequate patient numbers treated with a similar protocol and documented after growth cessation to have meaningful conclusions on the debate of distraction osteogenesis versus orthognathic surgery.

PMID: 16582529 [PubMed - indexed for MEDLINE]

Cephalometric correction factors for bite opening--a dry skull study.

Eur J Orthod. 2006 Aug;28(4):378-82

Authors: Lam E, Quick AN, Herbison P

The lateral cephalometric radiograph supplies the clinician with valuable information regarding the facial skeletal morphology of the patient, provided that it is taken correctly. These radiographs should be taken while the patient is occluding in maximum intercuspation, failing which the exposure is often repeated, leading to an increase in patient radiation dose as well as added cost in time and materials. This study investigated the relationship between limited bite opening and selected cephalometric variables. Thirty-one dry skulls were used and five splints were constructed for each skull giving increments of bite opening from 0 to 5 mm. Six lateral radiographs per skull were taken at each increment of bite opening. The radiographs were traced and the points plotted using a reflex metrograph. A linear relationship was found between bite opening and SNB, ANB, SN-mandibular plane, and SN-Y-axis angles. Errors in digitization, superimposition, and landmark identification were determined and found to be acceptable. Regression analysis produced a highly significant (P < 0.001) gradient for each of these angular relationships, allowing a set of correction factors to be produced, which can be applied to bite openings up to 5 mm.

PMID: 16495373 [PubMed - indexed for MEDLINE]

Making fixed prostheses that are not too high.

J Am Dent Assoc. 2006 Jan;137(1):96-8

Authors: Christensen GJ

It has been observed that a high percentage of multiple crowns or FPDs arrive from laboratories too "high." This article suggests methods to create accurate alginate impressions, opposing casts and IORs. If dentists use these techniques, it is anticipated that fewer FPDs will be too high as dentists attempt to seat them in the mouth.

PMID: 16457005 [PubMed - indexed for MEDLINE]

Meta-analysis of immediate changes with rapid maxillary expansion treatment.

J Am Dent Assoc. 2006 Jan;137(1):44-53

Authors: Lagrav&#xE8;re MO, Heo G, Major PW, Flores-Mir C

BACKGROUND: The authors conducted a literature review to evaluate immediate transverse, anteroposterior, and vertical dental and skeletal changes produced by rapid maxillary expansion (RME). TYPES OF STUDIES REVIEWED: The authors reviewed clinical trials that assessed immediate dental and/or skeletal changes after RME using cephalometric analysis, model casts or both. No surgical or other simultaneous treatment was accepted during the evaluation period. RESULTS: The authors searched electronic databases and found 31 articles that met the initial inclusion criteria. The authors later rejected 12 of these articles because they did not report immediate changes, three because they lacked detailed descriptions of their results and two because of their nonconventional appliance designs. Fourteen articles satisfied th final inclusion criteria; however, they had methodological deficiencies. CLINICAL IMPLICATIONS: The greatest changes resulting from RME in the studies analyzed were dental and skeletal transverse changes. Few vertical and anteroposterior immediate changes were statistically significant, though they probably are not clinically important.

PMID: 16456998 [PubMed - indexed for MEDLINE]

A comparative study of cephalometric and arch width characteristics of Class II division 1 and division 2 malocclusions.

Eur J Orthod. 2006 Apr;28(2):179-83

Authors: Isik F, Nalbantgil D, Sayinsu K, Arun T

The aim of this compound cephalometric and arch-width study was to determine any dental and/or skeletal differences between subjects with Class II division 1 and Class II division 2 malocclusions. The dento-skeletal characteristics of Class II subjects were evaluated using lateral cephalometric radiographs and dental casts of 90 untreated patients. The sample included 46 Class II division 1 patients (19 girls and 27 boys) with a mean age of 15.27 +/- 2.48 years, and 44 Class II division 2 patients (27 girls and 17 boys) with a mean age of 15.95 +/- 3.25 years. The intermolar, interpremolar and intercanine measurements were carried out on study models. The radiographs were digitized and processed using Dolphin Imaging software. In addition to standard descriptive statistical calculations, an independent samples t-test was carried out in order to compare the two groups. The non-parametric Mann-Whitney U test was utilized for the parameters for the data which were not normally distributed. The only statistically significant difference between the groups for the study model measurements was mandibular intercanine width. The cephalometric results revealed that SNB angle was responsible for the skeletal sagittal difference between the two groups. In addition, the Class II division 1 group had higher vertical proportions and the Class II division 2 group a more concave profile with a prominent chin. The sagittal skeletal pattern of Class II division 2 subjects was found to be very similar to the Class I skeletal relationship, with no evidence of any mandibular restriction.

PMID: 16431898 [PubMed - indexed for MEDLINE]

A computerized photographic assessment of the relationship between skeletal discrepancy and mandibular outline asymmetry.

Eur J Orthod. 2006 Apr;28(2):97-102

Authors: Good S, Edler R, Wertheim D, Greenhill D

The aim of this study was to investigate the relationship between mandibular outline asymmetry and skeletal discrepancy in a sample of orthodontic patients (33 females, 33 males) aged from 8 to 19 years. Skeletal discrepancy was assessed in both the anteroposterior and vertical planes, using standard cephalometric analyses. All were photographed under standardized conditions and the photographs were then digitized for analysis using a computerized system to assess differences in four variables (area, perimeter, compactness and moment-ratio) between the right and left sides of the mandibular outline. The results showed good repeatability of the photographic, cephalometric and digitization methods. A statistically significant relationship was found between mandibular outline asymmetry and both anteroposterior and vertical skeletal discrepancy in this sample, when compared with patients with an average skeletal pattern. There appeared to be a statistically significant relationship between a reduced ANB angle (< 3 degrees) and mandibular outline asymmetry (P = 0.051), as well as between an increase in lower face height and mandibular asymmetry (P = 0.023).

PMID: 16431897 [PubMed - indexed for MEDLINE]

Assessment of open and incomplete bite correction by incisor overlap and optical density of polyvinyl siloxane bite registration.

Eur J Orthod. 2006 Apr;28(2):166-72

Authors: Shpack N, Einy S, Beni L, Vardimon AD

Open bite (OB) is a generalized term, which could incorporate subgroups that react differently to vertical correction. The objectives of the present study were to detect vertical treatment changes in incomplete bite (IB: inter-incisor overlap with no lower incisor contact with teeth or palate) and OB (no inter-incisor overlap) groups compared with a complete bite (CB: inter-incisor overlap with full lower incisor contact with teeth or palate) control group, to evaluate treatment response of the central and lateral incisors, and to study the vertico-sagittal interaction. Dental casts were taken at three time points, pre-treatment, post-treatment, and after one year of retention, from 54 Class II patients (22 males and 32 females with a mean age of 11 years 6 months) divided into three groups: CB (n = 21), IB (n = 18) and OB (n = 15). Measurements included incisor overlap (mm) and optical density (OD/mm2) of occlusal bite registration made of polyvinl siloxane. Both CB and IB groups demonstrated post-retention bite opening. However, bite opening in the CB group was three times greater than that in the IB group (e.g. lower lateral = -1.42 mm, 118 OD/mm2 versus -0.40 mm, 107 OD/mm2). Conversely, the OB group showed a significant (P < 0.001) bite closure (e.g. lower lateral = 1.30 mm, -377 OD/mm2). Overjet changes affected OD measurements, causing diversity in OD and millimetric measurements of the lateral incisors in the IB group. In conclusion, the OB group demonstrated a significant stable vertical correction; a post-treatment non-contact inter-incisor relationship was determined by a vertico-sagittal relapse; and full compensation of an IB was not possible.

PMID: 16267127 [PubMed - indexed for MEDLINE]

Craniofacial morphology in Chinese female twins: a semi-longitudinal cephalometric study.

Eur J Orthod. 2005 Dec;27(6):556-61

Authors: Peng J, Deng H, Cao C, Ishikawa M

It would be of benefit to have a better understanding of the relative effects of genetics and environmental factors on craniofacial parameters when undertaking orthodontic therapy and treatment planning. However, there is a lack of such information in pre-adolescents. The aim of this study was to verify the degree of genetic and environmental contribution to the growth of the facial skeleton in twins aged 6 to 12 years. The material comprised the lateral cephalograms of 89 pairs of female twins in Beijing, China, of whom 61 pairs were diagnosed by DNA analysis as monozygotic (MZ) and 28 pairs as dizygotic (DZ). Four main groups (with a starting age of 6, 7, 9 and 11 years) were studied in a semi-longitudinal manner, with a sub-group further investigated for 2-4 consecutive years. The total sample therefore consisted of 183 pairs (MZ 110, DZ 73) aged from 6 to 12 years. The depths of the cranial base, mid and lower face were measured, as well as anterior and posterior face height. A two-tailed t-test showed significant environmental effects on lower face depth (P < 0.01), whilst genetic effects on face height were also significant (P < 0.01). The results suggest that early orthodontic intervention would have a greater influence on the antero-posterior rather than on the vertical plane of growth.

PMID: 16257991 [PubMed - indexed for MEDLINE]

Temporomandibular joint internal derangement in mandibular asymmetry. What is the relationship?

Eur J Orthod. 2006 Feb;28(1):83-8

Authors: Buranastidporn B, Hisano M, Soma K

The purpose of this study was to clarify the contributing factors and their influences on temporomandibular joint internal derangement (TMJ ID) symptoms in subjects with mandibular asymmetry. Postero-anterior (PA) cephalograms of 187 pre-orthodontic treatment subjects (aged 18-45 years, mean 23.9 years) were used to investigate the inclination of the frontal occlusal (FOP) and frontal mandibular (FMP) planes to determine vertical asymmetry. Mandibular dental midline shift (DMS) and mandibular midline shift (MMS) were studied to determine transverse asymmetry. The degree of asymmetry was analysed in conjunction with the results from self-administered TMJ ID history forms. A prevalence of TMJ ID was most related to the inclination of the FMP (P < 0.01), with the symptoms being notably higher when the cant was greater than 3 degrees. The symptomatic side was related only to the inclination of the FOP and FMP. Symptoms confined to the ipsilateral side were primarily found in subjects with mild asymmetry, whereas symptoms on both sides and those on the contralateral side were greater in those with moderate and severe asymmetry, respectively. No significant correlation was found for DMS and MMS. The results suggest that the degree of asymmetry in the vertical dimension is significantly correlated with TMJ ID symptoms.

PMID: 16257990 [PubMed - indexed for MEDLINE]

Cephalometric standards for Slovenians in the mixed dentition period.

Eur J Orthod. 2006 Feb;28(1):51-7

Authors: Drevensek M, Farcnik F, Vidmar G

The aim of this study was to develop standard cephalometric values for Slovenians in the period of the mixed dentition. Eighty-eight children were included in the study (46 girls and 42 boys, mean age 9.31 +/- 1.52 years). The selection criteria were: in the mixed dentition, a score of the modified Eismann method for an objective assessment of malocclusion of less than 15 points, the absence of aplasia and supernumerary teeth, no congential anomalies and no previous orthodontic treatment. Twenty-five cephalometric measurements were performed twice to analyse the size and shape of the craniofacial complex. The reliability of the measurements was assessed by correlation coefficients, regression, and analysis of inter-subject differences; satisfactory results were obtained. The differences between boys and girls and between those in the early and late mixed dentition period were tested with a two-way analysis of variance. The most pronounced changes between the early and late mixed dentition were observed in the vertical skeletal relationships: a decrease in mandibular inclination, interbasal angle and gonial angle, and an increase in anterior and posterior face height. Sagittal skeletal relationships remained constant from the early to the late mixed dentition. No significant differences were found between the observed developmental stages. Significant differences between genders were found only for anterior and posterior face height, with boys showing larger values (P </= 0.001). As there were no significant differences between the early and late mixed dentition, the mean measurement values of the total sample can be used as cephalometric standards for Slovenians in the mixed dentition period.

PMID: 16230328 [PubMed - indexed for MEDLINE]

Craniofacial changes in Icelandic children between 6 and 16 years of age - a longitudinal study.

Eur J Orthod. 2006 Apr;28(2):152-65

Authors: Thordarson A, Johannsdottir B, Magnusson TE

The aim of the present study was to describe the craniofacial changes between 6 and 16 years of age in a sample of Icelandic children. Complete sets of lateral cephalometric radiographs were available from 95 males and 87 females. Twenty-two reference points were digitized and processed by standard methods, using the Dentofacial Planner computer software program. Thirty-three angular and linear variables were calculated, including: basal sagittal and vertical measurements, facial ratio, and dental, cranial base and mandibular measurements. For the angular measurements, gender differences were not statistically different for any of the measurements, in either age group, except for the variable s-n-na, which was larger in the 16-year-old boys (P < or = 0.001). Linear variables were consistently larger in the boys compared with the girls at both age levels. During the observation period mandibular prognathism increased but the basal sagittal jaw relationship, the jaw angle, the mandibular plane angle and cranial base flexure (n-s-ba) decreased in both genders (P < or = 0.001). Maxillary prognathism increased only in the boys from 6 to 16 years. Inclination of the lower incisors and all the cranial base dimensions increased in both genders during the observation period. When the Icelandic sample was compared with a similar Norwegian sample, small differences could be noted in the maxillary prognathism, mandibular plane angle and in the inclination of the maxilla. Larger differences were identified in the inclination of the lower incisors. These findings could be used as normative cephalometric standards for 6- and 16-year-old Icelandic children.

PMID: 16230326 [PubMed - indexed for MEDLINE]

Changes in natural head position observed immediately and one year after rapid maxillary expansion.

Eur J Orthod. 2006 Apr;28(2):126-34

Authors: McGuinness NJ, McDonald JP

Rapid maxillary expansion (RME) has been shown to increase nasal permeability and reduce nasal airway resistance. A number of studies have examined the relationship between RME and the change in airway resistance, or the relationship between airway resistance and natural head position (NHP). Few studies, to date, have examined the relationship between RME and the change in NHP resulting from the consequent change in airway resistance. A sample of 43 adolescent patients with uni- or bilateral crossbite in the permanent dentition underwent RME as part of normal orthodontic treatment. Cephalograms in NHP were taken before, immediately after expansion, and one year after RME. No significant changes in the craniofacial angles were observed immediately after expansion. One year post-expansion, however, NSL/VER had reduced by 3.14 degrees (P < 0.01), OPT/HOR by 2.13 degrees (P < 0.05), and CVT/HOR by 2.55 degrees (P < 0.05). The results of this study suggest an ongoing change in head posture possibly due to a change in the mode of breathing from oral to nasal as a result of RME, thereby contributing to a change in craniofacial development, supporting and adding to the soft tissue stretching hypothesis.

PMID: 16157633 [PubMed - indexed for MEDLINE]

Comparative data on facial morphology and muscle thickness using ultrasonography.

Eur J Orthod. 2005 Dec;27(6):562-7

Authors: Satiro&#x11F;lu F, Arun T, Işik F

The purpose of this investigation was to measure the thickness of the masseter, levator labii superioris, and zygomaticus major muscles; to examine the reproducibility of ultrasonographically measured muscle thickness; to evaluate the association between facial and masticatory muscle thickness and vertical facial pattern; and to test whether the variation in muscle thickness is related to the variation in the body mass index (BMI) of different individuals. The thickness of the masseter, levator labii superioris and zygomaticus major muscles was measured bilaterally by ultrasonography in 47 (23 females, 24 males) healthy, fully-dentate young adults who volunteered for the study. The measurements for each individual were performed twice for the masseter muscle: during relaxation and during maximal clenching. Standardized lateral cephalograms of the subjects were traced to determine their facial morphology. The data obtained from the lateral cephalograms were used to divide the subjects into three groups according to their vertical facial pattern: low angle (n = 14), high angle (n = 17) and normal (n = 16). In the low angle group, the mean masseter muscle thickness was 15.20 (+/- 1.90) mm under relaxed conditions and 16.31 (+/- 2.18) mm during maximal clenching. In the high angle group, the respective measurements were 13.29 (+/- 2.52) mm and 14.72 (+/- 2.63) mm. In the vertically normal group, they were 13.56 (+/- 1.95) mm and 14.57 (+/- 1.83) mm. There was no relationship between vertical growth of the face and the thickness of the investigated muscles of facial expression. Masseter muscle thickness was found to be significantly correlated to vertical facial pattern and BMI, showing that individuals with a thick masseter had a vertically shorter facial pattern, whereas the muscles of facial expression showed no relationship with vertical facial pattern.

PMID: 16135538 [PubMed - indexed for MEDLINE]

Prediction of post-treatment outcome after combined treatment with maxillary protraction and chincap appliances.

Eur J Orthod. 2006 Feb;28(1):89-96

Authors: Yoshida I, Yamaguchi N, Mizoguchi I

The aims of this study were to identify differences in the initial skeletal morphology between successful and unsuccessful groups and to establish a novel method for predicting the final outcome of treatment with a maxillary protraction appliance (MPA) and chincap. The cephalograms used in this study were taken from 32 Japanese girls (mean age 10.2 years) with a Class III malocclusion at the beginning of treatment with an MPA and chincap (T1), at removal of the appliance (T2), and during the final post-treatment period (T3). The subjects were divided into two groups according to the treatment outcome at T3. Lower face height (ANS-Me), total face height (N-Me), ratio of face height (ANS-Me/N-ANS), maxillary position, mandibular plane and gonial angle at T1 were all significantly larger in the unsuccessful group, compared with the successful group. Discriminant analysis indicated that lower face height and gonial angle were significant determinants for distinguishing between the two groups at T1. From T1 to T2, while the anterior displacement of the maxilla was almost the same in the two groups, SNB decreased by 1.6 degrees in the successful group and 0.4 degrees in the unsuccessful group. After orthopaedic treatment, a second phase of treatment with a multibracket system was performed (T2 to T3). From T2 to T3, SNA increased by 0.4 degrees in the successful group and decreased by 0.7 degrees in the unsuccessful group. These results indicate that the vertical dimensions of the craniofacial skeleton are important for predicting the prognosis of skeletal Class III patients treated with a MPA and chincap and that the discriminant formula established in this study is effective in predicting the final treatment outcome.

PMID: 16113036 [PubMed - indexed for MEDLINE]

Effects of activator and activator headgear treatment: comparison with untreated Class II subjects.

Eur J Orthod. 2006 Feb;28(1):27-34

Authors: T&#xFC;rkkahraman H, Sayin MO

The aims of this study were to determine whether the activator and activator headgear encourage mandibular growth, and whether there is any superiority of one appliance over the other or if the resultant changes are due to normal growth. Forty-nine skeletal Class II division 1 patients were selected. Thirty-three (13 females, 20 males; mean age 12.52 +/- 1.42 years) were treated with an Andresen activator and the remaining 16 (7 females, 9 males; mean age 13.04 +/- 1.47 years) with an activator headgear combination. Twenty Class II subjects (9 females, 11 males; mean age 12.57 +/- 1.11 years) who had previously refused treatment served as a control group. Cephalometric landmarks were marked and digitized by one author to avoid inter-observer variability. Nine angular and 12 linear measurements were established and measured using Vistadent AT software. A paired-sample t-test and an ANOVA test were used to statistically evaluate the findings. The results revealed that both the activator and the activator headgear combination significantly (P < 0.001) encouraged mandibular growth, but had little restraining effect on the maxilla. The mandibular incisors were more controlled in the activator headgear combination group. The resultant skeletal, dentoalveolar and soft tissue changes differed significantly from those due to growth.

PMID: 16093256 [PubMed - indexed for MEDLINE]

Comparative cephalometric study of Class III malocclusion in Saudi and Japanese adult females.

J Oral Sci. 2005 Jun;47(2):83-90

Authors: Bukhary MT

The cephalometric features of class III malocclusion in Saudi adult females were investigated and compared with reference data for Japanese females. The sample consisted of 30 standardized pre-treatment cephalometric radiographs of adult Saudi females diagnosed as having skeletal class III malocclusion. The radiographs were traced and digitized. Linear and angular variables were obtained for comparison of cranial base, maxilla, mandible, intermaxillary and dentoalveolar measurements. The method error in identifying and locating the anatomical landmarks was small and acceptable. Student's t-test was used for comparing the measurements. The results showed that Saudi females had a larger anterior cranial base, a smaller posterior cranial base, a smaller cranial base angle, smaller anterior and posterior facial heights, downward tipping of the maxilla, a retruded chin, a less steep mandibular plane, an increased joint angle, a smaller ramus, body and total mandibular length, and less retroclined mandibular incisors. The null hypothesis of no difference between the two groups was rejected. These results appear to suggest real differences in skeletal features between Saudi and Japanese adult females.

PMID: 16050488 [PubMed - indexed for MEDLINE]

Roentgen-cephalometric standards for a Swedish population. A longitudinal study between the ages of 5 and 31 years.

Eur J Orthod. 2005 Aug;27(4):370-89

Authors: Thilander B, Persson M, Adolfsson U

This study was performed to establish age- and gender-specific cephalometric normative data for a Swedish population. The material comprised 469 lateral cephalograms from two groups of subjects of Swedish origin between 5 and 31 years of age. All subjects (males and females) were diagnosed as 'normal' according to specified criteria and with no history of orthodontic treatment. Lateral cephalograms and body height measurements were taken at 5, 7, 10 and 13 years of age in one group (group E) (longitudinal follow-up). The same registrations were made in the other group (group U) at 7, 10 and13 years of age (mixed longitudinal type). Those 13 year olds were re-examined at 16, 19 and 31 years of age (longitudinal follow-up). No significant differences between age groups in the two samples were found. Therefore, subjects of the same age were combined. The study is hence regarded as a longitudinal follow-up from 5 to 31 years of age. The subjects were also grouped into dental development stages to widen the applicability of the cephalometric data.The craniofacial distances were constantly larger in males than in females, while no statistical differences as regards angular measurements were seen between genders. Distances as well as angular measurements varied with the different developmental periods. The results clearly verify that facial pattern changes existed during the observation period, with a growth acceleration of most distances between the 13 and 16 year recordings.

PMID: 16043474 [PubMed - indexed for MEDLINE]

Soft tissue facial angles in Down's syndrome subjects: a three-dimensional non-invasive study.

Eur J Orthod. 2005 Aug;27(4):355-62

Authors: Ferrario VF, Dellavia C, Serrao G, Sforza C

The aim of the present study was to obtain quantitative information concerning the three-dimensional (3D) arrangement of the facial soft tissues of subjects with Down's syndrome. The 3D co-ordinates of 50 soft tissue facial landmarks were recorded by an electromechanical digitizer in 17 male and 11 female subjects with Down's syndrome aged 12-45 years, and in 429 healthy individuals of the same age, ethnicity and gender. From the landmark co-ordinates, geometric calculations were obtained of several 3D facial angles: facial convexity in the horizontal plane (upper facial convexity, mid facial convexity including the nose, and lower facial convexity), mandibular corpus convexity in the horizontal plane, facial convexity including the nose, facial convexity excluding the nose, interlabial angle, nasolabial angle, angle of nasal convexity, left and right soft tissue gonial angles. Data were compared with that collected for the normal subjects by computing the z-scores.Facial convexity in the horizontal plane (both in the upper and mid facial third), facial convexity in the sagittal plane and the angle of nasal convexity were significantly (P < 0.05) increased (flatter) in subjects with Down's syndrome than in the normal controls. Both left and right soft tissue gonial angles were significantly reduced (more acute) in the Down's syndrome subjects. Subjects with Down's syndrome had a more hypoplastic facial middle third with reduced nasal protrusion, and a reduced lower facial third (mandible) than reference, normal subjects.

PMID: 16043473 [PubMed - indexed for MEDLINE]

Ranking facial attractiveness.

Eur J Orthod. 2005 Aug;27(4):340-8

Authors: Knight H, Keith O

The first aim of this investigation was to assemble a group of photographs of 30 male and 30 female faces representing a standardized spectrum of facial attractiveness, against which orthognathic treatment outcomes could be compared. The second aim was to investigate the influence of the relationship between ANB differences and anterior lower face height (ALFH) percentages on facial attractiveness. The initial sample comprised standardized photographs of 41 female and 35 male Caucasian subjects. From these, the photographs of two groups of 30 male and 30 female subjects were compiled. A panel of six clinicians and six non-clinicians ranked the photographs.The results showed there to be a good level of reliability for each assessor when ranking the photographs on two occasions, particularly for the clinicians (female subjects r = 0.76-0.97, male subjects r = 0.72-0.94). Agreement among individuals within each group was also high, particularly when ranking facial attractiveness in male subjects (female subjects r = 0.57-0.84, male subjects r = 0.91-0.94). Antero-posterior (AP) discrepancies, as measured by soft tissue ANB, showed minimal correlation with facial attractiveness. However, a trend emerged that would suggest that in faces where the ANB varies widely from 5 degrees, the face is considered less attractive. The ALFH percentage also showed minimal correlation with facial attractiveness. However, there was a trend that suggested that greater ALFH percentages are considered less attractive in female faces, while in males the opposite trend was seen.Either of the two series of ranked photographs as judged by clinicians and non-clinicians could be used as a standard against which facial attractiveness could be assessed, as both were in total agreement about the most attractive faces. However, to judge the outcome of orthognathic treatment, the series of ranked photographs produced by the non-clinician group should be used as the 'standard' to reflect lay opinion.

PMID: 16043472 [PubMed - indexed for MEDLINE]

Craniofacial development in obese adolescents.

Eur J Orthod. 2005 Dec;27(6):550-5

Authors: Sadeghianrizi A, Forsberg CM, Marcus C, Dahll&#xF6;f G

The purpose of this study was to investigate craniofacial morphology in obese adolescents and to compare the morphological data with those of normal adolescents. The study was based on measurements of lateral cephalometric roentgenograms of adolescents who had been diagnosed as obese. Linear and angular measurements were obtained from cephalometric tracings of 27 females (mean age 15.6 +/- 0.83 years) and 23 males (mean age 13.9 +/- 0.98 years). The data were compared with corresponding measurements of gender and age matched controls. The results showed that both males and females in the obesity group exhibited significantly larger mandibular and maxillary dimensions than the controls. On average, mandibular length (Cd-Pgn) was 10 mm greater in males and 8 mm greater in females. Maxillary length (Pm-A) was 3.5 mm greater in males and 3 mm greater in females. When considering vertical dimensions, lower anterior (Ans-Gn) and posterior (S-Go) face height were 4 and 5 mm greater in the obese males, respectively, while in the obese females both these distances were 4 mm greater compared with the controls. Both maxillary (SNA) and mandibular (SNB, SNPg) prognathism were more pronounced in the obesity group than in the control group. This also influenced the average soft tissue profile, which was less convex in the obesity groups. The mandibular plane angle (ML/SN) was smaller in the obesity group than in the control group. Craniofacial morphology differs between obese and normal adolescents. In general, obesity was associated with bimaxillary prognathism and relatively greater facial measurements.

PMID: 16009667 [PubMed - indexed for MEDLINE]

The influence of lower face vertical proportion on facial attractiveness.

Eur J Orthod. 2005 Aug;27(4):349-54

Authors: Johnston DJ, Hunt O, Johnston CD, Burden DJ, Stevenson M, Hepper P

This study investigated the influence of changing lower face vertical proportion on the attractiveness ratings scored by lay people.Ninety-two social science students rated the attractiveness of a series of silhouettes with normal, reduced or increased lower face proportions. The random sequences of 10 images included an image with the Eastman normal lower face height relative to total face height [lower anterior face height/total anterior face height (LAFH/TAFH) of 55 per cent], and images with LAFH/TAFH increased or decreased by up to four standard deviations (SD) from the Eastman norm. All the images had a skeletal Class I antero-posterior (AP) relationship. A duplicate image in each sequence assessed repeatability. The participants scored each image using a 10 point numerical scale and also indicated whether they would seek treatment if the image was their own profile.The profile image with normal vertical facial proportions was rated by the lay people as the most attractive. Attractiveness scores reduced as the vertical facial proportions diverged from the normal value. Images with a reduced lower face proportion were rated as significantly more attractive than the corresponding images with an increased lower face proportion. Images with a reduced lower face proportion were also significantly less likely to be judged as needing treatment than the corresponding images with an increased lower face proportion.

PMID: 15961569 [PubMed - indexed for MEDLINE]

Perceptions of facial aesthetics in two and three dimensions.

Eur J Orthod. 2005 Aug;27(4):363-9

Authors: Todd SA, Hammond P, Hutton T, Cochrane S, Cunningham S

The aims of this study were to investigate whether the preferred facial relationship chosen by professionals and the general public is Class I and to ascertain whether viewing two-dimensional (2D) or three-dimensional (3D) images had any effect on the ranking of facial attractiveness. Orthodontists (n = 47), maxillofacial surgeons (n = 25) and members of the general public (n = 78) assessed 2D and 3D facial scans of two males and two females that had been morphed to produce five images reflecting different skeletal patterns: Class I, mild and moderate Class II, and mild and moderate Class III. Each assessor placed the images in rank order of preference, after viewing alternate 2D and 3D image formats for each face. The data were analysed using logistic regression.In 2D, professionals (orthodontists and maxillofacial surgeons) chose Class I as the preferred facial image more frequently than the general public for only one of the four faces. However, in 3D format they chose Class I as the preferred facial image for some subject faces more, and others less, frequently when compared with the general public. The gender of the assessor was not significant when assessing the preferred facial relationship for Class I images in either 2D or 3D formats. The oldest assessors (56+ years) were significantly less likely than the younger age groups to select Class I as the preferred facial relationship in both 2D and 3D. In summary, there was too great a degree of variation to say that a difference between 2D and 3D facial images was evident.

PMID: 15961568 [PubMed - indexed for MEDLINE]

Change in cranio-cervical angulation following orthognathic surgery.

Eur J Orthod. 2005 Jun;27(3):268-73

Authors: Savjani D, Wertheim D, Edler R

Changes in natural head posture (NHP) were investigated in 33 patients (10 males, 23 females) with an age range of 16-40 years (median 21 years) following orthognathic surgery to change vertical face height. The reproducibility of the radiographer's technique of taking radiographs in NHP was investigated using a photographic method and found to be acceptable. The patients were divided into two groups: group 1, patients who had more than 3 mm of vertical change in anterior total face height (ATFH) and group 2, those who had less than 3 mm vertical change.For group 1 there was a significant relationship between ATFH change and cranio-cervical angulation (NSL/OPT) change (r = 0.532, P = 0.023), compared with group 2 (r = -0.247, P = 0.376). A similar relationship was revealed between lower anterior face height (LAFH)/ATFH ratio and NSL/OPT, where the correlation was also higher in group 1 (r = -0.635, P = 0.005) compared with group 2 (r = -0.182, P = 0.515). The correlation between cranio-vertical angulation (NSL/VER) and ATFH was not significant for group 1 (r = 0.406) or group 2 (r = 0.239) patients. Additionally, NSL/VER and LAFH/ATFH correlation for the two groups was not significant (r = -0.392 and -0.338, respectively).There appears to be a relationship between the reduction in vertical face height following orthognathic surgery and neck posture (as indicated by NSL/OPT). As no significant relationship was found between the reduction in face height and head posture (as indicated by NSL/VER) this suggests that neck posture, rather than head posture, had changed.

PMID: 15947227 [PubMed - indexed for MEDLINE]

Effect of mandibular position on upper airway collapsibility and resistance.

J Dent Res. 2005 Jun;84(6):554-8

Authors: Inazawa T, Ayuse T, Kurata S, Okayasu I, Sakamoto E, Oi K, Schneider H, Schwartz AR

It has been proposed that advancement of the mandible is a useful method for decreasing upper airway collapsibility. We carried out this study to test the hypothesis that mandibular advancement induces changes in upper airway patency during midazolam sedation. To explore its effect, we examined upper airway pressure-flow relationships in each of 4 conditions of mouth position in normal, healthy subjects (n = 9). In the neutral position, Pcrit (i.e., critical closing pressure, an index of upper airway collapsibility) was -4.2 cm H(2)O, and upstream resistance (Rua) was 21.2 cm H(2)O/L/sec. In the centric occlusal position, Pcrit was -7.1 cm H(2)O, and Rua was 16.6 cm H(2)O/L/sec. In the incisor position, Pcrit was significantly reduced to -10.7 cm H(2)O, and Rua was significantly reduced to 14.0 cm H(2)O/L/sec. Mandibular advancement significantly decreased Pcrit to -13.3 cm H(2)O, but did not significantly influence Rua (22.1 cm H(2)O/L/sec). We conclude that the mandibular incisors' position improved airway patency and decreased resistance during midazolam sedation.

PMID: 15914594 [PubMed - indexed for MEDLINE]

Molar bite force in relation to occlusion, craniofacial dimensions, and head posture in pre-orthodontic children.

Eur J Orthod. 2005 Feb;27(1):58-63

Authors: Sonnesen L, Bakke M

The present study examined bite force in relation to occlusion, craniofacial dimensions, and head posture. The sample comprised 88 children (48 girls, 40 boys) aged 7-13 years, sequentially admitted for orthodontic treatment of malocclusions entiling health risks. Bite force was measured in the molar region by means of a pressure transducer. Angle classification, number of teeth and contact in the intercuspal position (ICP) were recorded and dental arch widths were measured on plaster casts. Craniofacial dimensions and head posture were recorded from lateral cephalometric radiographs taken with the subject standing with their head in a standardized posture (mirror position). Associations were assessed by Spearman correlations and multiple stepwise regression analyses.The maximum bite force increased significantly with age in girls, with teeth in occlusal contact in boys, and with increasing number of erupted teeth in both genders. Bite force did not vary significantly between the Angle malocclusion types. Only in boys was there a clear correlation between bite force and craniofacial morphology: cranial base length (n-ba, n-ar), posterior face height (s-tgo, ar-tgo), vertical jaw relationship (NL-ML), mandibular inclination (NSL-ML), form (ML-RL) and length (pg-tgo), and inclination of the lower incisors (Ili-ML). Multiple regression analysis showed that the vertical jaw relationship (P < 0.001) and the number of teeth present (P < 0.01) were the most important factors for the magnitude of bite force in boys. In girls, the most important factor was the number of teeth present (P < 0.001). No correlations between bite force and head posture were found.

PMID: 15743864 [PubMed - indexed for MEDLINE]

Role of occlusal vertical dimension in spindle function.

J Dent Res. 2005 Mar;84(3):245-9

Authors: Yabushita T, Zeredo JL, Toda K, Soma K

Several studies have suggested the jaw-muscle spindle as the receptor responsible for regulating and maintaining the occlusal vertical dimension (OVD). However, to challenge this assumption, we hypothesized that long-term changes in OVD could affect the sensory inputs from jaw-muscle spindles. In this study, we investigated changes in masseter muscle spindle function under an increased OVD (iOVD) condition. Responses of primary and secondary endings of masseter muscle spindles to cyclic sinusoidal stretches were investigated. Twenty barbiturate-anesthetized female Wistar rats were divided into control and iOVD groups. Rats in the iOVD group received a 2.0-mm composite resin build-up to the maxillary molars. After iOVD, masseter muscle spindle sensitivity gradually decreased. Primary and secondary spindle endings were affected differently. We conclude that iOVD caused reduction in masseter muscle spindle sensitivity. This result suggests that peripheral sensory plasticity may occur following changes in OVD. Such changes may provide a basis for physiological adaptation to clinical occlusal adjustments.

PMID: 15723864 [PubMed - indexed for MEDLINE]

A clinical evaluation of the clinical remount procedure.

J Contemp Dent Pract. 2005 Feb 15;6(1):48-55

Authors: Al-Quran FA

One hundred patients were treated with complete dentures. The patients were divided into two equal groups; the first group (50 patients) received complete dentures and a clinical remount procedure was performed, while the second group received complete dentures without a clinical remount. A four point, nine scale Patient Denture Satisfaction questionnaire was used to evaluate the patients' satisfaction with their dentures. When the clinical remount procedure was used, results have shown a highly significant improvement in the comfort of the upper dentures and in the fit and comfort of the lower dentures. There was a significant improvement in the chewing ability as well. In conclusion it is highly recommended the clinical remount procedure be used because it improves the patient's satisfaction with their dentures in many important aspects as shown in this study.

PMID: 15719076 [PubMed - indexed for MEDLINE]

Chrome cobalt mandibular advancement appliances for managing snoring and obstructive sleep apnea.

J Orthod. 2004 Dec;31(4):295-9

Authors: Ash SP, Smith AM

Snoring and sleep apnea are chronic conditions. This article describes the use of cobalt chrome mandibular advancement appliances as a long-term, robust addition to the appliances used to treat these conditions. The clinical indications, appliance design, construction stages and special features of using cast alloy bases are described.

PMID: 15608344 [PubMed - indexed for MEDLINE]

Occlusion confusion.

J Am Dent Assoc. 2004 Sep;135(9):1228-30; author reply 1230-1232

Authors: Rinchuse DJ, Rinchuse DJ

PMID: 15493387 [PubMed - indexed for MEDLINE]

Occlusion confusion.

J Am Dent Assoc. 2004 Aug;135(8):1086

Authors: Greenberg M

PMID: 15387045 [PubMed - indexed for MEDLINE]

Axiographic findings in patients undergoing orthodontic treatment with and without premolar extractions.

Eur J Orthod. 2004 Aug;26(4):427-33

Authors: Heiser W, Stainer M, Reichegger H, Niederwanger A, Kulmer S

Mechanical axiography was performed on 49 (37 female, 12 male) patients prior to orthodontic treatment, after removal of the fixed appliance, and at the end of retention. Twenty-five subjects (mean age 12.8 years) underwent orthodontic treatment without premolar extractions (group 1) and 24 subjects (mean age 13.5 years) with premolar extractions (group 2). The axiographic tracings of the protrusive movements were analysed using a digitizer and specially designed software. A statistically significant increase (P < 0.05) in the values for horizontal condylar inclination (HCI) was found for both groups over the entire observation period. Group 1 showed a higher increase (P < 0.05) between the beginning of treatment and removal of the brackets, and group 2 between bracket removal and the end of retention. At the end of retention, a similar increase in HCI values was found for both groups. Over the observation period, the frequency of pathological axiographic findings decreased, which seems to be a positive effect of orthodontic treatment.

PMID: 15366388 [PubMed - indexed for MEDLINE]

Can temporomandibular dysfunction signs be predicted by early morphological or functional variables?

Eur J Orthod. 2004 Aug;26(4):367-73

Authors: Pahkala R, Qvarnstr&#xF6;m M

The aim of the present study was to establish whether the early signs of various orofacial dysfunctions, malocclusions, or occlusal interferences can predict the development of temporomandibular dysfunction (TMD) in young adults. Forty-eight subjects referred for speech therapy and 49 controls participated in all four stages of this longitudinal study. The subjects were examined at the ages of 7, 10, 15, and 19 years. The phoniatrician diagnosed errors in place of articulation and problems in the movement and co-ordination of the speech articulators. Occlusion, TMD signs (palpatory tenderness of the masticatory muscles, and of temporomandibular joints (TMJ), jaw deviation on opening, and clicking), mandibular movement capacity and occlusal interferences were registered by the orthodontist. Multiple logistic regression models were applied in order to evaluate whether single signs of TMD at the age of 19 years were related to previous/present malocclusions or interferences, to misarticulations of speech, problems in oral motor skills, or other signs of TMD. The effect of gender was also considered. The results showed that excessive overjet was the only variable which seemed to consistently increase the risk of TMD. In addition, girls seemed to be more prone to the development of TMD than boys. Although, during growth, there were both local and central factors associated occasionally with TMD development, the predictive value of those variables in the estimation of the individual risk of TMD was rather small.

PMID: 15366380 [PubMed - indexed for MEDLINE]

Dentoskeletal effects and facial profile changes during activator therapy.

Eur J Orthod. 2004 Jun;26(3):293-302

Authors: Cozza P, De Toffol L, Colagrossi S

The aim of this retrospective study was to investigate cephalometrically the skeletal, dental, and soft tissue modifications induced by activator treatment in patients with Class II malocclusions caused by mandibular retrognathism. The subjects, all in the mixed dentition, were selected from a single centre and were divided into two groups: 40 patients treated with an incisor double capping activator (20 girls, 20 boys with a mean age of 10 years) and a control group of 30 subjects (15 girls, 15 boys with a mean age of 10 years). The dentoskeletal and aesthetic changes that occurred were compared on lateral cephalograms taken before treatment (T0) and after 18-24 months, when the activator was removed (T1). In the control group the radiographs were obtained before (T0) and after (T1) 21 months (standard deviation +/- 3 months). Activator treatment in these growing patients resulted in a correction of the Class II relationship (ANB -2.14 degrees), a restriction of maxillary growth (SNA -0.5 degrees), an advancement of the mandibular structures (SNB +1.64 degrees, FH--NPg +3.39 degrees; OLp-B +5.17 mm, OLp-Pg +5.14 mm, OLp-Go +2.44 mm), a correction of the overjet (-5.03 mm), an improvement in overbite (-1.17 mm) and uprighting of the maxillary incisors (1--FH -5.64 degrees). The activator appliance was effective in treating growing patients with mandibular deficiency: activator therapy corrected Class II malocclusions by a combination of skeletal and dental changes and improved the soft tissue facial profile.

PMID: 15222715 [PubMed - indexed for MEDLINE]

Kinesiographic study of complete denture movement related to mucosa displacement in edentulous patients.

Pesqui Odontol Bras. 2003 Oct-Dec;17(4):356-61

Authors: Compagnoni MA, de Souza RF, Leles CR

The mucosa that covers the residual ridges of edentulous patients may present some distortion or displacement when occlusal loading is applied in complete dentures. This distortion and movement of the denture can result in acceleration of residual ridge resorption and loss of retention and stability. The aim of this study was to analyze the pattern of upper complete denture movement related to underlying mucosa displacement. A sample of 10 complete denture wearers was randomly selected, which had acceptable upper and lower dentures and normal volume and resilience of residual ridges. The kinesiographic instrument K6-I Diagnostic System was used to measure denture movements, according to the method proposed by Maeda et al.7, 1984. Denture movements were measured under the following experimental conditions: (A) 3 maximum voluntary clenching cycles and (B) unilateral chewing for 20 seconds. The results showed that under physiological load, oral mucosa distortion has two distinct phases: a fast initial displacement as load is applied and a slower and incomplete recovery when load is removed. Intermittent loading such as chewing progressively reduces the magnitude of the denture displacement and the recovery of the mucosa is gradually more incomplete.

PMID: 15107919 [PubMed - indexed for MEDLINE]

[APDI and ODI estimated from substitute palate plane]

Shanghai Kou Qiang Yi Xue. 2004 Feb;13(1):13-6

Authors: Chen ZQ, Qian YF, Shen G, Wang GM

PURPOSE: The substitute palate plane was defined at the cephalometrics of noncleft patients. APDI and ODI were estimated from substitute PP. It is expected that the APDI and ODI estimated from PP (APDI',ODI')can be extended to the cleft patients to illustrate the anteroposterior and vertical relationship between maxilla and mandible. METHODS: The cephalometrics of 30 patients of C-I,C-II and C-III were traced and so were in 30 patients of normal overbite,deep overbite and open bite. The substitute palate plane(PP') was defined. The inclination of the PP to the FH, APDI and ODI, the inclination of the substitute PP to the FH,APDI' and ODI' were measured. The APDI and APDI' of C-I, C-II and C-III patients were compared,The ODI and ODI' of normal overbite, deep overbite and open bite patients were also compared by group t test. RESULTS: There was no significant difference between APDI and APDI' in C-I, C-II and C-III patients and also no significant difference between ODI and ODI' in normal overbite,deep overbite and open bite patients. It is showed the higher the ODI',the deeper the overbite. And the higher the APDI', the more mesial the molar relationship. CONCLUSIONS: The APDI and ODI estimated from substitute PP can be used as an important criterion to judge the vertical and anteroposterior development of the the maxilla, especially in palate clefts patients.

PMID: 15007472 [PubMed - indexed for MEDLINE]