Facemask therapy with miniplate implant anchorage in a patient with maxillary hypoplasia.

Chin Med J (Engl). 2007 Aug 5;120(15):1372-5

Authors: Zhou YH, Ding P, Lin Y, Qiu LX

PMID: 17711747 [PubMed - indexed for MEDLINE]

Treatment effects of occipitomental anchorage appliance of maxillary protraction combined with chincup traction in children with Class III malocclusion.

J Formos Med Assoc. 2007 May;106(5):380-91

Authors: Lin HC, Chang HP, Chang HF

BACKGROUND/PURPOSE: Little information related to the treatment effects of the occipitomental anchorage (OMA) appliance of maxillary (Mx) protraction combined with chincup traction is available. The aim of this study was to investigate the treatment effects of the OMA orthopedic appliance on patients with Class III malocclusion. METHODS: Pretreatment and post-treatment cephalometric records of 20 consecutively treated patients with Class III malocclusions were evaluated and compared with a matched sample of untreated Class III control subjects. RESULTS: The OMA appliance is effective for correcting skeletal Class III malocclusion in growing children. The treatment effects of this orthopedic appliance were considered to be from both skeletal and dentoalveolar changes. The skeletal effects were mainly obtained by stimulating forward growth of the Mx complex with negligible rotation of the Mx plane and restraining forward advancement of the mandible (Mn) with backward and downward rotation of the Mn plane. The observed dentoalveolar effects were mostly due to the labial tipping movement of the Mx incisors. CONCLUSION: Our results suggest that the OMA orthopedic appliance can correct the mesial jaw relationship and negative incisal over jet. This appliance is effective for correcting skeletal Class III malocclusion with both midface deficiency and Mn prognathism in growing children.

PMID: 17561473 [PubMed - indexed for MEDLINE]

Current products and practice: bone anchorage devices in orthodontics.

J Orthod. 2006 Dec;33(4):288-307

Authors: Prabhu J, Cousley RR

Bone anchorage is a promising new field in orthodontics and already a wide variety of bone anchorage devices (BADs) are available commercially. This review aims to assist clinicians by outlining the principles of bone anchorage and the salient features of the available systems, especially those that may influence the choice of a specific BAD for anchorage reinforcement.

PMID: 17142335 [PubMed - indexed for MEDLINE]

Tapered orthodontic miniscrews induce bone-screw cohesion following immediate loading.

Eur J Orthod. 2006 Dec;28(6):541-6

Authors: Yano S, Motoyoshi M, Uemura M, Ono A, Shimizu N

The aim of this study was to investigate the initial stability of tapered orthodontic miniscrews (T-type screws) after placement, the necessity of a healing period, and the propriety of immediate loading. Twenty male Wistar rats with a mean age of 20 weeks were divided into two groups. In the immediate-loading groups, straight orthodontic miniscrews (S-type screws) and T-type screws (five rats each) underwent experimental traction force for 2 weeks (W) immediately after placement. In the healing groups (S- and T-type, five rats each), force was applied for 2 W after a 6-W healing period. The right tibia in each rat was identified as the test limb, while the left tibia in each rat was used as the control group, and underwent no experimental force during the experimental period. The screw-to-bone contact was observed histologically and the bone-screw contact ratio was calculated. Scheffe's test was performed to compare the bone-screw contact ratio in each group using statistical software package (SPSS 8.0 for Windows). In the control group, the bone-screw contact ratio improved from 34.8 +/- 16.0 to 74.8 +/- 12.0 per cent with S-type screws in proportion to the experimental period (2 to 8 W, respectively). With the T-type screws in the test group, there was no significant difference between the immediate-loading and healing groups. In the immediate-loading group, the bone-screw contact ratio with T-type screws was significantly greater (82.3 +/- 15.0 per cent) than with the S-type screws (33.3 +/- 11.8 per cent; P < 0.05), suggesting that T-type screws can be used for orthodontic anchorage immediately after placement.

PMID: 17142258 [PubMed - indexed for MEDLINE]

The benefits of aesthetic orthodontic brackets in patients requiring multiple MRI scanning.

J Orthod. 2006 Jun;33(2):90-4

Authors: Harris TM, Faridrad MR, Dickson JA

MRI scans are increasingly used diagnostically in medicine. Scans of the head and neck region can be distorted by metallic components in the vicinity. This paper discusses the consideration for aesthetic brackets (with no metal components) on all teeth including molars in patients requiring MRI scans and especially if those need to be repeated on a regular basis.

PMID: 16751430 [PubMed - indexed for MEDLINE]

The Dynamax system: a new orthopaedic appliance and case report.

J Orthod. 2006 Jun;33(2):78-89

Authors: Bass NM

The Dynamax appliance is a treatment modality for the correction of the Skeletal II malocclusion characterized by a mandibular retrusion. Progressive mandibular advancement, maxillary expansion, control of maxillary growth, incisor torque and control of vertical facial development are incorporated into a two-part appliance. The design facilitates laboratory construction, clinical handling and patient acceptability. A prefabricated spring module forms the basis of the appliance, allowing both maxillary expansion and mandibular advancement. An easily adjustable progressive forward position of the lower jaw makes a construction bite unnecessary. The spring module provides most of the structure of the appliance so that minimal acrylic is required and the appliance is fully contained within the freeway space. Contact between the upper and lower parts of the appliance occurs posteriorly in the lingual sulcus. Here the depth permits an extended vertical contact, to maintain a protrusive mandibular position throughout the range of mandibular opening, including during sleep. The lower portion of the appliance may be fixed or removable and multibracket treatment can be carried out in one or both arches at the same time as the orthopaedics.

PMID: 16751429 [PubMed - indexed for MEDLINE]

The reinforced removable retainer.

J Contemp Dent Pract. 2006 May 1;7(2):145-52

Authors: Al-Suliaman S, Hashim HA, Cordovez JL

The aim of this paper is to present a new type of orthodontic removable retainer, which is of great help to the orthodontist as well as to the patient. The procedures of fabrication are described. The Reinforced Removable Retainer (Triple "R" Retainer) is well tolerated, adaptable, and easy to fit and remove. Its main advantage is that it is not easy to break, less bulky, and very retentive.

PMID: 16685306 [PubMed - indexed for MEDLINE]

Fixed space maintainers combined with open-face stainless steel crowns.

J Contemp Dent Pract. 2006 May 1;7(2):95-103

Authors: Yilmaz Y, Kocogullari ME, Belduz N

OBJECTIVE: This study investigates the clinical performance of fixed space maintainers placed on seriously damaged abutment teeth. METHODS: Crowns were placed on damaged abutment primary teeth. Fixed space maintainers were prepared by using rectangular wire between the window in the facial surface of the crowns and other abutment teeth and were subsequently bonded with a flowable resin composite. This procedure was introduced clinically, and the cases were observed over a period of twelve months. RESULTS: Twenty-seven fixed space maintainers (25 on lower jaw, two on upper jaw) were included in this study. No clinical failure was recorded in any of the cases in the observation time, and the rate of clinical performance was 100%. CONCLUSION: The study shows the effectiveness of fixed space maintainers combined with stainless steel crowns ("open-face fixed space maintainers") which were placed on primary molar teeth used as abutments in cases with extensive caries and loss of occlusogingival dimension.

PMID: 16685300 [PubMed - indexed for MEDLINE]

Twin-block re-activation.

J Orthod. 2006 Mar;33(1):3-6

Authors: Brennan JA, Littlewood SJ

This paper briefly reviews reasons for re-activating Twin-blocks, discussing different approaches and describing a new, simple, cost effective approach, which can be undertaken at the chairside.

PMID: 16514128 [PubMed - indexed for MEDLINE]

Sagittal airway dimensions following maxillary protraction: a pilot study.

Eur J Orthod. 2006 Apr;28(2):184-9

Authors: Sayinsu K, Isik F, Arun T

The relationship between changes in the position of the maxillary structures caused by maxillary protraction therapy and airway dimensions have not been investigated as comprehensively as the accompanying skeletal changes. The purpose of this study was to examine the effects of rapid palatal expansion (RPE) used in conjunction with maxillary protraction headgear on the sagittal dimension of the airway. The treatment sample consisted of 19 Class III patients (12 girls, 7 boys) with a mean age of 10.51 +/- 1.15 years, presenting with maxillary retrognathism. A cap splint type rapid palatal expander that had hooks between the upper lateral and canine teeth was used intraorally, and a Petit type facemask device extraorally, for an average of 6.78 +/- 0.93 months. Pre- and post-treatment cephalometric radiographs were evaluated. The results of the study revealed that point A moved anteriorly. The palatal plane showed a counter-clockwise rotation matched by the clockwise rotation of the mandible and an accompanying decrease in SNB angle. The vertical parameters showed a statistically significant increase. The head was in a more extensive position in relation to the cervical vertebrae. The nasopharyngeal airway measurements (PNS-ad1, PNS-ad2) showed an increase of 2.71 +/- 3.35 and 3.03 +/- 2.37 mm, respectively. These results demonstrated that limited maxillary widening together with protraction of the maxilla, improve nasopharyngeal but not oropharyngeal airway dimensions in the short term.

PMID: 16464873 [PubMed - indexed for MEDLINE]

Effects of a segmented removable appliance in molar distalization.

Eur J Orthod. 2006 Feb;28(1):65-73

Authors: Akin E, Gurton AU, Sagdic D

The aim of the present investigation was to evaluate the skeletal and dentoalveolar treatment effects of a segmented removable appliance [removable molar distalizer (RMD)] for molar distalization. The study was conducted on 28 patients (12 females and 16 males), with a mean age of 11.8 years. All presented with a skeletal Class I malocclusion and a bilateral dental Class II molar relationship. The pre- and post-distalization records included lateral head films, study models and standard photographs. The findings were evaluated with a paired samples t-test. The average maxillary first molar distalization with the RMD was 3.98 mm, with 4.61 degrees of distal tipping. The maxillary second premolars drifted distally 2.13 mm on average with 1.54 degrees of distal tipping, while the maxillary first premolars showed 1.23 mm of mesial movement and 1.98 degrees of mesial tipping. The incisors protruded 1.09 mm with 1.27 degrees of labial tipping. The RMD was effective in distal molar movement and all patients attained a bilateral Class I molar relationship in an average period of 4.5 months. Hygiene problems and mucosal irritations, frequently found with fixed intraoral distalization techniques, were not observed during the distalization period.

PMID: 16436365 [PubMed - indexed for MEDLINE]

Observations on the use and clinical effectiveness of lacebacks.

J Orthod. 2005 Dec;32(4):294-5; author relpy 295-6

Authors: Bennett J

PMID: 16333051 [PubMed - indexed for MEDLINE]

How to ... debond Clarity brackets with ease.

J Orthod. 2005 Dec;32(4):269-71

Authors: Lee RT

Debonding ceramic brackets has been difficult due to problems with enamel fractures, enamel tears and patient discomfort. New brackets have weaker bases and the debonding technique has changed, with a recommendation that a pair of Mathieu needle holding pliers is used with Clarity brackets.

PMID: 16333049 [PubMed - indexed for MEDLINE]

Clinical pearl: clinical tips with System-R.

J Orthod. 2005 Dec;32(4):244-6

Authors: Parkin N

The article describes the versatility and ease of use of a relatively new bracket system manufactured by GAC called System-R. This system consists of two bracket types; standard width and reduced width, both of which have an active self-ligating clip. The reduced friction offered by this system allows different mechanics to be employed. Security of ligation and absence of decaying force values allows longer treatment intervals. Fast and reliable opening and closing of the clips means reduced chairside time. Difficulties experienced personally by these brackets are highlighted and some troubleshooting tips are included.

PMID: 16333045 [PubMed - indexed for MEDLINE]

Clinical pearl: LingLock--the flossable fixed retainer.

J Orthod. 2005 Dec;32(4):241-3

Authors: Amundsen OC, Wisth PJ

The present article describes a new product for long-term retention of the lower dental arch. The LingLock is a fixed bonded retainer from canine to canine in the lower front made up of separate, but co-working retention elements in the ceramic material aluminium oxide (Al2O3). The LingLock retainer enables the patient to floss the teeth in a regular manner in the actual retention area.

PMID: 16333044 [PubMed - indexed for MEDLINE]

Localized sequential use of resilient lining to generate orthodontic force in thermoformed active removable appliances.

J Orthod. 2005 Dec;32(4):235-40

Authors: Ng EW

A new modality of orthodontic treatment based on the thermoformed appliance was developed and trialled clinically. A light-cured resilient lining material commonly used for denture relining was placed locally and sequentially in thermoformed appliances to generate orthodontic forces. The new method appeared to be effective. All the presented cases showed substantial improvement in dental alignment. A number of orthodontic movements were demonstrated. Localized use of resilient lining in thermoformed orthodontic appliances appeared to be a promising alternative to other thermoformed active removable appliance (TARA) treatments. Further studies are required to optimize the procedures and explore its full potential.

PMID: 16333043 [PubMed - indexed for MEDLINE]

Essix-based molar distalization appliance.

J Orthod. 2005 Dec;32(4):229-34

Authors: Babacan H, Doruk C

A new design of molar distalization appliance and its fabrication are described in this article. This case report illustrates distal movement of mandibular molars with negligible loss of anterior anchorage. This new vacuum-formed Essix appliance can be a reasonable alternative to conventional appliances.

PMID: 16333042 [PubMed - indexed for MEDLINE]

[Temporomandibular joint involvement in juvenile idiopathic arthritis: treatment with an orthodontic appliance]

Reumatismo. 2005 Jul-Sep;57(3):201-7

Authors: Bellintani C, Ghiringhelli P, Gerloni V, Gattinara M, Farronato G, Fantini F

OBJECTIVE: About 65% of children suffering from juvenile idiopathic arthritis (JIA) shows a more or less marked involvement of temporo-mandibular joint (TMJ) with altered mandibular growth, resorption of the condyles, occlusary instability, reduced chewing ability and facial dysmorphia. The purpose of our study is to prevent and to treat the progressive evolution of JIA on craniofacial growth and morphology with a functional appliance; surgery should be considered only in so far as the adequacy of TMJ movement is concerned. METHODS: From 1992 until now 72 children with proved JIA and TMJ involvement have been treated (50 females, 22 males, aged 6 to 16 years old). TMJ involvement was bilateral in 61% and unilateral in 39% of patients. A diagnostic workup was carried out involving tomograms of TMJ and cephalometric radiograph and analysis. The authors used a bimaxillary activator in the attempt to modify the unfavourable growth pattern and provide a gradual ante-rotation of the jaw. RESULTS: Almost all JIA patients showed satisfactory long term results, easing of pain, reduced skeletal discrepancy, increased function and good facial profile. CONCLUSIONS: The long term results of this study indicate that orthopaedic therapy might control the vicious circle of the malocclusion in children with JIA, preventing exacerbation of mandibular clockwise rotation. Surgical intervention for the improvement of TMJ function should be considered only if a severe restricted state is imminent.

PMID: 16258606 [PubMed - indexed for MEDLINE]

A 2-year outcome audit of a versatile orthodontic bone anchor.

J Orthod. 2005 Sep;32(3):175-81

Authors: Mommaerts MY, Michiels ML, De Pauw GA

This study examined complications leading to, or possibly leading to, treatment failure, related to the use of the orthodontic bone anchor (OBA). The OBA is a potential means of providing absolute anchorage and consists of a base-plate fixed with mono-cortical screws, a neck piercing the soft tissues, and a coronal part with conventional orthodontic hooks, tubes or slots. The investigation took the form of a single centre prospective registry at a supra-regional teaching hospital. Eighteen patients (average age 21 years) had one to four OBAs placed between January 2000 and February 2002. Altogether 35 OBAs were placed. Follow-up took place until April 2004. Reasons for placing the OBAs were noted together with any associated complications during the follow-up period. Twenty-three OBAs have been removed so far, four prematurely (one of them before it was taken into use, due to a change of treatment plan enforced by loss of the contralateral OBA). Nineteen were removed as planned after completion of the intended tooth movements. Common (but minor) complications included granulations, acute gingivitis and gingival recession. Light mobility of the OBA was also noted in some cases, but without clinical repercussions. The OBA can be loaded directly, at the level of the orthodontic archwire or more occlusally. It can be placed at any site at the circumference of the jaws, given good quality and thickness of the bony wall. Conventional biomechanical techniques can be applied. However, the failure rate (premature loss of OBA) of 8.6% is considered high, and has necessitated changes in the hardware and protocol.

PMID: 16170058 [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]

A subjective comparison of two lingual bracket systems.

Eur J Orthod. 2005 Aug;27(4):420-6

Authors: Stamm T, Hohoff A, Ehmer U

The purpose of this prospective, longitudinal study was to compare the influence of two lingual bracket systems on subjective oral comfort, speech, mastication and oral hygiene. Forty-two native speakers of standard German (32 females, 10 males; mean age 27.1 years, standard deviation 12.2) were enrolled and completed a standardized questionnaire directly before insertion of lingual brackets (T0), within 24 hours of bond-up (T1) and 3 months (+/- 1 week) later (T2). Eighteen of the patients were treated with prefabricated brackets (Ormco, seventh generation) (PB group) and 24 with customized brackets (Incognito) (CB group).While no significant intergroup differences were recorded at any of the times with respect to tongue position, conversation pattern, swallowing or oral hygiene, the CB group experienced significantly fewer tongue space restrictions, speech disturbances and impairments in chewing and biting than the PB group at T1 and T2. At T2, pressure sores, reddening or lesions to the tongue were recorded significantly less often in the CB group than in the PB group.This enhanced patient comfort in the CB group was attributed to the smaller dimensions of the customized brackets. This aspect could play a role in attracting more patients to lingual orthodontics in the future. Information given to the patient on the duration and extent of the restrictions associated with lingual orthodontics must be differentiated according to the bracket system used.

PMID: 16043479 [PubMed - indexed for MEDLINE]

Evolution of flexural rigidity according to the cross-sectional dimension of a superelastic nickel titanium orthodontic wire.

Eur J Orthod. 2005 Aug;27(4):402-7

Authors: Garrec P, Tavernier B, Jordan L

The choice of the most suitable orthodontic wire for each stage of treatment requires estimation of the forces generated. In theory, the selection of wire sequences should initially utilize a lower flexural rigidity; thus clinicians use smaller round cross-sectional dimension wires to generate lighter forces during the preliminary alignment stage. This assessment is true for conventional alloys, but not necessarily for superelastic nickel titanium (NiTi). In this case, the flexural rigidity dependence on cross-sectional dimension differs from the linear elasticity prediction because of the martensitic transformation process. It decreases with increasing deflection and this phenomenon is accentuated in the unloading process. This behaviour should lead us to consider differently the biomechanical approach to orthodontic treatment.The present study compared bending in 10 archwires made from NiTi orthodontics alloy of two cross-sectional dimensions. The results were based on microstructural and mechanical investigations. With conventional alloys, the flexural rigidity was constant for each wire and increased largely with the cross-sectional dimension for the same strain. With NiTi alloys, the flexural rigidity is not constant and the influence of size was not as important as it should be. This result can be explained by the non-constant elastic modulus during the martensite transformation process. Thus, in some cases, treatment can begin with full-size (rectangular) wires that nearly fill the bracket slot with a force application deemed to be physiologically desirable for tooth movement and compatible with patient comfort.

PMID: 16043477 [PubMed - indexed for MEDLINE]

Aesthetic orthodontic brackets.

J Orthod. 2005 Jun;32(2):146-63

Authors: Russell JS

Due to an increasing demand for superior aesthetics during fixed appliance treatment, the use of aesthetic brackets has grown in popularity over recent years. Although often requested by patients, aesthetic brackets are not without their disadvantages. This article presents the currently available plastic and ceramic brackets and discusses the potential problems associated with each. Recent advances, introduced by manufacturers in an attempt to overcome their clinical disadvantages, are described.

PMID: 15994990 [PubMed - indexed for MEDLINE]

The effects of the Twin-block appliance treatment on the skeletal and dentolaveolar changes in Class II Division 1 malocclusion.

Medicina (Kaunas). 2005;41(5):392-400

Authors: Sidlauskas A

Class II Division 1 malocclusion is the most frequent problem in the orthodontic practice. During the last ten years treatment with Twin-block functional appliance has gained popularity. The aim of the present study was to analyze the skeletal and dentoalveolar changes in Class II Division 1 malocclusions cases treated with Twin-block appliance. MATERIAL AND METHODS: Cephalometric analysis of skeletal and dentoalveolar facial structures of 34 Class II Division 1 patients treated with Twin-block appliance was performed using the same reference system before and after treatment. Longitudinal growth records of persons with excellent occlusion-Bolton standards have been used for the control in order to assess natural growth. RESULTS: Mandibular length as measured from point Articulare to point Pogonion increased by 4.6 mm in the Twin-block group compare with 2.2 mm in the control Bolton standards group. Skeletal and dentoalveolar relationship between maxillary and mandibular bases improved significantly: ANB angle reduced by 2.3 degrees, overjet reduction was 4.7 mm, postnormal molar position corrected by 3.6 mm. CONCLUSIONS: Twin-block appliance statistically significantly increases mandibular length by 2.4 mm during 12-month treatment period. With the Twin-block treatment about 40% overjet correction was achieved by skeletal and about 60% by dentoalveolar changes. Correction of postnormal buccal segments in Twin-block group was achieved by the combination of distal movement of the upper molars (0.7 mm dentoalveolar, 0.3 mm skeletal) and forward migration of lower molars (0.9 mm dentoalveolar and 1.7 mm skeletal).

PMID: 15947523 [PubMed - indexed for MEDLINE]

Archwire seating forces produced by different ligation methods and their effect on frictional resistance.

Eur J Orthod. 2005 Jun;27(3):302-8

Authors: Khambay B, Millett D, McHugh S

The aims of this study were to determine the mean tensile force of four different elastomeric modules, the archwire seating force of different ligation methods, and its effect on frictional resistance.To determine the mean tensile force, each elastomeric module (purple, grey, Alastik, and SuperSlick) was extended by 5 mm using two hooks attached to a load cell using a Nene M3000 testing machine. To assess the median archwire seating force, a maxillary premolar bracket (3M Unitek) was welded to a sheet of stainless steel (SS) and glued to a Perspex block. The bracket base was removed and the cut continued into the Perspex below. A length of test wire was taken and bent to form a "U" shape, with the middle portion 20 mm in length. The free ends of the wire were secured to the load cell of the Nene testing machine. Two wire sizes were tested, 0.017 x 0.025 and 0.019 x 0.025 inch SS. The load cell was activated and the force with which the wire was displaced into the slot by the ligation method was measured. Four types of elastomeric module were tested together with a pre-formed 0.09 inch SS ligature. The experimental method used to determine the mean frictional force of each module and wire size was carried out using a method described previously.Statistically significant differences existed in the mean tensile forces and median archwire seating forces between the elastomeric modules. Grey modules with either size wire produced the lowest median archwire seating force, whereas SS ligatures produced the highest forces. SS ligatures with either wire produced the lowest mean frictional forces, whereas grey modules produced significantly higher mean frictional force (P < 0.01). The force with which the wire was seated into the bracket did not seem to be related to the subsequent amount of mean frictional force produced.

PMID: 15947232 [PubMed - indexed for MEDLINE]

A stainless steel bracket for orthodontic application.

Eur J Orthod. 2005 Jun;27(3):237-44

Authors: Oh KT, Choo SU, Kim KM, Kim KN

Aesthetics has become an essential element when choosing orthodontic fixed appliances. Most metallic brackets used in orthodontic therapy are made from stainless steel (SS) with the appropriate physical properties and good corrosion resistance, and are available as types 304, 316 and 17-4 PH SS. However, localized corrosion of these materials can frequently occur in the oral environment. This study was undertaken to evaluate the accuracy of sizing, microstructure, hardness, corrosion resistance, frictional resistance and cytotoxicity of commercially available Mini-diamond (S17400), Archist (S30403) and experimentally manufactured SR-50A (S32050) brackets.The size accuracy of Mini-diamond was the highest at all locations except for the external horizontal width of the tie wing (P < 0.05). Micrographs of the Mini-diamond and Archist showed precipitates in the grains and around their boundaries. SR-50A showed the only austenitic phase and the highest polarization resistance of the tested samples. SR-50A also had the highest corrosion resistance [SR-50A, Mini-diamond and Archist were 0.9 x 10(-3), 3.7 x 10(-3), and 7.4 x 10(-3) mm per year (mpy), respectively], in the artificial saliva. The frictional force of SR-50A decreased over time, but that of Mini-diamond and Archist increased. Therefore, SR-50A is believed to have better frictional properties to orthodontic wire than Mini-diamond and Archist. Cytotoxic results showed that the response index of SR-50A was 0/1 (mild), Mini-diamond 1/1 (mild+), and Archist 1/2 (mild+). SR-50A showed greater biocompatibility than either Mini-diamond or Archist.It is concluded that the SR-50A bracket has good frictional property, corrosion resistance and biocompatibility with a lower probability of allergic reaction, compared with conventionally used SS brackets.

PMID: 15947222 [PubMed - indexed for MEDLINE]

An innovative adhesive procedure for connecting transpalatal arches with palatal implants.

Eur J Orthod. 2005 Jun;27(3):226-30

Authors: Crismani AG, Bernhart T, Bantleon HP, Kucher G

The aim of this presentation is to describe an innovative adhesive procedure for connecting palatal implants with transpalatal arches (TPAs). The steps required for completing the procedure, the costs involved and the requisite time were reviewed and compared with those of two alternative procedures reported in the literature. To establish the stability and reliability of the procedure in vitro, tensile stress tests were performed. The results were evaluated in view of a potential loss of anchorage and compared with reported data.The innovative adhesive procedure ensured a stable and precise connection between TPAs and palatal implants during a single visit in a chair-side time of 42 minutes. The costs incurred were euro 12.33. The composite-connected component parts resisted breakage up to a mean force of 3323.16 cN. Absolute stability of the TPA-palatal implant connection in terms of maximal anchorage was limited to a mean force of 408.05 cN at a wire strength of 0.036 inches.

PMID: 15947220 [PubMed - indexed for MEDLINE]

Advances in digital technology and orthodontics: a reference to the Invisalign method.

Med Sci Monit. 2005 May;11(5):PI39-42

Authors: Melkos AB

BACKGROUND: Increased aesthetic demands during orthodontic treatment resulted in several treatment alternatives. However, the need to avoid conventional fixed orthodontic appliances led, with the use of computer-aided scanning, imaging, and manufacturing technology, to the development of new therapy concepts such as Invisalign. MATERIAL/METHODS: The Invisalign orthodontic technique involves a series of clear removable appliances and has been applied to correct a variety of malocclusions. RESULTS: The Invisalign method is an aesthetic orthodontic option for many patients, but it is suited mainly to adults or adolescents who have a fully erupted dentition and it has its indications and limitations. It handles simple to moderate non-extraction alignments better than mild to moderate extraction cases. The aligners are clear and therefore aesthetically ideal for the patient; they are comfortable to wear and, as they are removable, they provide simplicity of care and better oral hygiene. They also allow the evaluation of treatment options in detail before beginning treatment by using a virtual treatment model. It is also important to point out that this method has some disadvantages, which are associated with patient compliance, limited control over specific tooth movements, and additional documentation time. CONCLUSIONS: The Invisalign concept is an aesthetic alternative in orthodontic treatment, with advantages and disadvantages. It can be utilized to treat simple to moderate alignment cases, especially in adults, and serves as an additional part of the armamentarium of the orthodontist.

PMID: 15874904 [PubMed - indexed for MEDLINE]

The variable anchorage straight wire technique compared with the straight wire technique in deep overbite correction.

Eur J Orthod. 2005 Apr;27(2):180-5

Authors: Banaie F, Parikakis K, Moberg S, Hellsing E

The aim of this retrospective study was to compare the treatment results and the number of required treatment appointments between the variable anchorage straight wire technique (VAST) and the straight wire (SW) technique. The subjects were 53 Caucasian patients of both sexes (25 males and 28 females, mean age 13.5 years at the start of treatment), with an overjet > or = 4 mm and an overbite > or = 3 mm. The patients were divided into four groups, VAST (n = 31) or SW (n = 22), extraction or non-extraction, and were treated by the same orthodontist. Variables from two lateral cephalograms obtained before and at the completion of active treatment, and the number of scheduled appointments were compared between the two techniques.The main difference between the two techniques was the bracket design. With the VAST, the bracket allowed both tipping and parallel movements with the possibility to combine double archwires. Due to the influence of the Begg technique, no extra-oral traction was needed in the VAST groups and Class II elastics were used at the start of treatment.Both techniques seemed to produce equal treatment results. However, in this study, it was shown that in deep overbite correction, the VAST required fewer scheduled appointments than the SW technique.

PMID: 15817626 [PubMed - indexed for MEDLINE]

Straight talk on braces.

FDA Consum. 2005 Jan-Feb;39(1):20-6

Authors: Bren L

PMID: 15803592 [PubMed - indexed for MEDLINE]

A randomized controlled trial comparing the quadhelix and the expansion arch for the correction of crossbite.

J Orthod. 2005 Mar;32(1):29-35

Authors: McNally MR, Spary DJ, Rock WP

OBJECTIVE: To compare the use of the quadhelix and the expansion arch for the correction of crossbite. DESIGN: A prospective randomized clinical trial supported by preliminary laboratory measurements. The null hypothesis was that there was no difference in the clinical effectiveness of the two expansion devices in terms of crossbite correction. SETTING: Queen's Hospital, Burton on Trent and The University of Birmingham, School of Dentistry.Participants: The first 60 patients on the orthodontic waiting list at Queen's Hospital who required expansion of the maxillary arch as part of the treatment plan were allocated to be treated with either a quadhelix or an expansion arch by random allocation. Twenty-eight and 27 members of each respective group completed the study. MATERIALS: Commercial quadhelix arches (3M Unitek) and custom-made expansion arches METHODS: The force produced by the type of expansion arches used in the study was measured in the laboratory to be 1.8 N at 10 mm of expansion. Quadhelix arches of sizes 2 and 3 were found to produce equivalent forces at 5 and 7 mm of expansion respectively. Either expansion device was fitted to the 60 participants according to random allocation and expanded by the standard amount. Intermolar and intercanine expansion was measured after 4, 8 and 12 weeks. Patient opinion was assessed by using a questionnaire. RESULTS: The quadhelix and the expansion arch were equally effective in producing expansion (p>0.05). After 12 weeks, the two types of archwire had produced mean intermolar expansions of 4.54 and 5.09 mm and intercanine expansions of 1.41 and 2.12 mm, respectively. Both types of arch were reported as uncomfortable by a majority of patients, the quadhelix affected mainly the tongue and the expansion arch the cheeks. The appearance of the quadhelix was disliked by 25% of participants, while 70% disliked the expansion arch. CONCLUSIONS: The null hypothesis was confirmed. However, the expansion arch had several advantages that made it a cheap alternative to the quadhelix for crossbite expansion, because it can be made and fitted at the chairside.

PMID: 15784941 [PubMed - indexed for MEDLINE]

A randomized controlled trial comparing the quadhelix and the expansion arch for the correction of crossbite.

J Orthod. 2005 Mar;32(1):26

Authors: Harrison J

PMID: 15784939 [PubMed - indexed for MEDLINE]

Mandibular incisal edge demineralization and caries associated with Twin Block appliance design.

J Orthod. 2005 Mar;32(1):3-10

Authors: Dixon M, Jones Y, Mackie IE, Derwent SK

Demineralization and caries are well documented and unwanted complications of orthodontic therapy. These are most commonly reported in relation to fixed appliance therapy. Five cases are presented of patients undergoing Twin Block appliance therapy with the appliances incorporating lower labial segment capping, illustrating a pattern of demineralization and caries of the incisal tips of the mandibular labial segment, influenced by the incisal capping and the frequent intake of carbonated soft drinks.

PMID: 15784936 [PubMed - indexed for MEDLINE]

Factors affecting friction in the pre-adjusted appliance.

Eur J Orthod. 2004 Dec;26(6):579-83

Authors: Moore MM, Harrington E, Rock WP

A jig was constructed to measure the frictional forces created by various tip and torque values in association with two types of straightwire bracket moving along tainless steel (SS) archwires. Forces were measured during translation of the bracket using an Instron machine. Steel and cobalt chromium brackets were tested in association with 0.019 x 0.025 and 0.021 x 0.025 inch steel archwires at tips from 0 to 3 degrees and torque values in 2 degree increments from 0 to 6 degrees.The mean values for static (2.2 N) and kinetic (2.1 N) friction were very similar (P = 0.71), as were the overall friction values for stainless steel (2.1 N) and chromium cobalt (2.2 N) brackets of similar dimensions (P = 0.44). Use of 0.021 x 0.025 inch wire produced three times as much friction as 0.019 x 0.025 inch wire, 3.0 N against 1.2 N (P < 0.01). Increased tip and torque were associated with highly significant increases in friction (P < 0.01). Every degree of tip produced approximately twice as much friction as comparable torque. The main conclusion of the study was that space closure should be completed on a 0.019 x 0.025 inch archwire before a 0.021 x 0.025 inch wire is used to complete tooth alignment.

PMID: 15650066 [PubMed - indexed for MEDLINE]

The effectiveness of laceback ligatures: a randomized controlled clinical trial.

J Orthod. 2004 Dec;31(4):303-11; discussion 300

Authors: Irvine R, Power S, McDonald F

OBJECTIVE: To evaluate the effects of laceback ligatures on the anteroposterior and vertical position of lower incisors and the mesial position of the lower first molars. DESIGN: Randomized controlled trial. SETTINGS: Patients under treatment in the Department of Orthodontics, Royal Bournemouth Hospital, Dorset, during a 6 month period from November 1999 to March 2000. SUBJECTS: Sixty-two adolescents (mean 13.7 years, range 11.2-16.8 years) with similar malocclusions, requiring extraction of all first premolars, were randomly assigned to experimental (laceback: 30; 12 male, 18 female) and control (non-laceback: 32; 14 male, 18 female) groups. INTERVENTIONS: Treatment using upper and lower fixed appliances following extraction of four premolars. One group had lacebacks placed, whilst the control group had no lacebacks. MAIN OUTCOME MEASURES: The participants were examined clinically and radiographically, and lateral cephalograms with radio-opaque tooth markers and lower study casts records were taken when lower fixed appliances were placed (T1) and following sufficient leveling with a 0.018 inch stainless steel round wire (T2). Linear measurements were recorded following digitization of the lateral cephalograms and using a vernier caliper on the study casts. A Student t-test was used to examine differences between the two groups following assessment for normality. RESULTS: In both groups the lower incisors retroclined during T1-T2; (Mean+/-SD: Experimental -0.53+/-1.9 mm, Control -0.44+/-1.29 mm). There was no statistical significance between the two groups (p = 0.84). The lower incisors extruded in both groups; 0.47+/-0.98 mm in the experimental group and 0.44+/-0.87 mm in the control group. There was no statistical difference between the groups (p = 0.9). The lower first molars showed 0.83 mm greater mesial movement in the experimental group, which was statistically significant (p < 0.05). Labial segment crowding decreased in both groups (experimental -3+/-1.6 mm, control -2.67+/-2.28 mm), the difference between the groups being non-significant (p = 0.51). Arch length decreased in both groups (experimental -2.08+/-2.82 mm , control -2.9+/-3.06 mm), but the difference between them was not significant (p = 0.28) CONCLUSIONS: In first premolar extraction cases, the lower labial segment does not procline during the leveling stage with the pre-adjusted edgewise appliance and the use of laceback ligatures conveys no difference in the anteroposterior or vertical position of the lower labial segment. Furthermore, the use of laceback ligatures creates a statistically and clinically significant increase in the loss of posterior anchorage.

PMID: 15608345 [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]

Clinical management in extraction cases using palatal implant for anchorage.

J Orthod. 2004 Dec;31(4):288-94

Authors: Giancotti A, Greco M, Mampieri G, Arcuri C

This case report presents a Class I extraction treatment in an adult patient with bimaxillary crowding using a palatal implant for anchorage control. The implant (pure titanium 6 mm SLA) is inserted in the middle of the palate, after a careful radiological assessment on a lateral cephalogram. At the end of the healing period (13 weeks), an anchorage device, such as a squared trans-palatal bar connecting the maxillary molars to the palatal implant, is projected and placed in order to obtain the posterior anchorage control. The orthodontic treatment was performed according to the bidimensional technique.

PMID: 15608343 [PubMed - indexed for MEDLINE]

A modified monobloc for the treatment of obstructive sleep apnoea in paediatric patients.

Eur J Orthod. 2004 Oct;26(5):523-30

Authors: Cozza P, Polimeni A, Ballanti F

The aims of this study were to determine the differences in craniofacial morphology between children with obstructive sleep apnoea (OSA) and control subjects, and to investigate the effects of modified monobloc (MM) appliance treatment in OSA children. The treatment group consisted of 20 OSA Caucasian subjects (10 boys and 10 girls) with ages ranging from 4 to 8 years (mean 5.91 years). The control group comprised 20 healthy Caucasian subjects without OSA (10 boys and 10 girls) with ages ranging from 5 to 7 years (mean 6 years). Polysomnography was used to establish the diagnosis of OSA and to evaluate the effects of MM treatment in the test group. Cephalometric radiographs and study models were obtained for all subjects. A number of statistically significant differences were detected in craniofacial morphology between the treatment group and controls. The treatment group demonstrated a skeletal Class II pattern (P= 0.04), with a reduced mandibular length (P= 0.03) and a corresponding increase in overbite. The hyoid bone was located superiorly in the OSA group (P = 0.04). Analysis of the dental arches demonstrated a significantly smaller distance between the first and second inter-molar primary mandibular regions (P = 0.03 and P = 0.04, respectively) in OSA patients. Repeat polysomnography, with the MM in situ, after 6 months of wear, revealed a significant reduction in the apnoea-hypopnoea index in children with OSA (P= 0.0003). The MM was found to reduce daytime sleepiness and to subjectively improve assessed sleep quality. The patients and their parents reported good compliance with MM treatment.

PMID: 15536841 [PubMed - indexed for MEDLINE]

The rat as a model for orthodontic tooth movement--a critical review and a proposed solution.

Eur J Orthod. 2004 Oct;26(5):483-90

Authors: Ren Y, Maltha JC, Kuijpers-Jagtman AM

The aims of this study were to perform a systematic review of the use of rats as a model for experimental tooth movement, to give a critical evaluation of the use of elastics as a force delivery system, and to describe a newly designed well-defined model for tooth movement in rats. The literature from 1981 to 2002 indicates that in 57 per cent of animal studies on orthodontic tooth movement, rats were used, but in many of these investigations the experimental set-up was poorly documented. Only three of the 159 studies fulfilled the inclusion criteria for a good model: a force magnitude of less than 20 cN; moving molar(s) mesially; an experimental duration longer than 2 weeks; and no extra experimental condition such as drug intervention. As more than one-quarter of the studies on tooth movement in rats used elastics to produce an orthodontic force, and as the forces they produced and their force decay during decompression are unknown, their mechanical characteristics on decompression were tested. Elastics stored under dry conditions or in water showed significant force decay from around 45 N to almost 0 N within the first 0.2 mm of decompression. With regard to the above-mentioned shortcomings of using rats as a model for tooth movement, a newly designed experimental appliance for tooth movement in rats was evaluated. It proved to be stable and simple and able to deliver a continuous and constant force as low as 10 cN on all three molars together during an experimental period of 12 weeks without interference in animal welfare, and was able to compensate for the effects of molar distal drift and continuous incisor eruption.

PMID: 15536836 [PubMed - indexed for MEDLINE]

How to effectively use a 2 x 4 appliance.

J Orthod. 2004 Sep;31(3):248-58

Authors: Dowsing P, Sandler PJ

A mixed dentition treatment can efficiently and effectively be provided using a 2 x 4 appliance. The indications for early treatment are discussed and advantages of fixed appliances over traditionally used removable appliances illustrated using four case reports.

PMID: 15489369 [PubMed - indexed for MEDLINE]

A comparison of three light curing units for bonding adhesive pre-coated brackets.

J Orthod. 2004 Sep;31(3):243-7; discussion 202-3

Authors: Ip TB, Rock WP

OBJECTIVE: To compare the effectiveness of three curing lights of different types. DESIGN: Prospective randomized laboratory investigations. MATERIALS AND METHOD: Adhesive pre-coated orthodontic brackets were bonded to 9 groups of extracted premolars and the adhesive was cured using three different curing lights, each at three different times. Bond strength was tested using a shear/peel method. RESULTS: The plasma light had 3 times the light intensity of the standard quartz halogen light. The curing times recommended by the manufacturers were 2 seconds for the plasma light, 10 seconds for the high intensity quartz halogen light and 20 seconds for the standard one. Mean debond stresses with these cure times were 9.36, 11.77 and 12.00 MPa, respectively, p<0.04. Increasing the plasma light cure to 4 seconds increased the mean debond stress to 11.19 MPa, similar to that for the other lights, p=0.62. CONCLUSIONS: Use of a plasma light confers worthwhile time savings when bonding orthodontic brackets, whilst producing bonds of equivalent strength to those found with quartz halogen lights.

PMID: 15489368 [PubMed - indexed for MEDLINE]

Interdisciplinary management of dental implant patient: a case report.

Kaohsiung J Med Sci. 2004 Aug;20(8):415-8

Authors: Chen CM, Tseng YC, Huang IY, Yang CF, Shen YS, Lee HE, Chen CH

Maxillary molars can over-erupt when their antagonists are lost and there are no replacements. When the opposing molars severely extrude into the edentulous space, it is difficult to replace the missing teeth with either fixed or removable prostheses. We present the following case report, providing a solution for this type of problem. A two-stage posterior subapical osteotomy was used to reestablish the intermaxillary space. Following orthodontic treatment and implant placement, the patient regained occlusal harmony and normal masticatory function.

PMID: 15473654 [PubMed - indexed for MEDLINE]

Torque capacity of metal and polycarbonate brackets with and without a metal slot.

Eur J Orthod. 2004 Aug;26(4):435-41

Authors: Harzer W, Bourauel C, Gmyrek H

The aim of the present study was to investigate slot deformation and the equivalent torque capacity of polycarbonate brackets with and without a metal slot in comparison with those of a metal bracket. For this purpose, the expansion characteristics and, in a further investigation, the labial crown torque of an upper central incisor, were measured in a simulated intra-oral clinical situation, using the orthodontic measuring and simulation system (OMSS). Three types of bracket with a 0.018 inch slot were tested: polycarbonate Brillant without a metal slot, Elegance with a metal slot and the metal bracket, Mini-Mono. For testing purposes the brackets were torqued with 0.016 x 0.022 inch (0.41 x 0.56 mm) and 0.018 x 0.022 inch (0.46 x 0.56 mm) ideal stainless steel archwires. In the activating experiments, significantly higher torque losses and lower torquing moments were registered with both rectangular archwires with the polycarbonate brackets than with the metal bracket. In the simulation tests, significantly higher torquing moments were registered with the metal bracket than with the polycarbonate brackets. The values for the Elegance bracket were between those of the Mini-Mono and Brillant brackets. The OMSS model approximates the clinical situation, with the torque loss being notably higher than in the in vitro activating experiments. This is due to the adjacent teeth giving the archwire additional play. In addition, the torquing process may twist the archwire, resulting in subsidiary forces. On the basis of the present results, all three brackets can be recommended for torquing. However, in view of the high torque losses, the torques programmed in the straightwire technique must be seen as questionable. Data should be provided by the manufacturer on the bending to be expected in polycarbonate brackets, which has to be offset by additional torque, or the bracket torque should be omitted from the technical specifications.

PMID: 15366389 [PubMed - indexed for MEDLINE]

A clinical comparison of the quadhelix appliance and the nickel titanium (tandem loop) palatal expander: a preliminary, prospective investigation.

Eur J Orthod. 2004 Aug;26(4):411-20

Authors: Donohue VE, Marshman LA, Winchester LJ

Maxillary expansion using either a quadhelix appliance (Qx) or a nickel titanium palatal expander (Nt) was prospectively compared in 28 consecutive new patients (19 female, nine male) presenting with posterior buccal segment crossbites. Study models taken at each activation were measured to determine the mean maxillary expansion efficacy (Emax) and the mean expansion rate (m(max)) across the first molars and first premolars. Patient discomfort was assessed using visual analogue scores, and cost-effectiveness was also considered. Neither Emax nor m(max) differed significantly between Qx and Nt across either the first molars or the first premolars. However, both Emax and m(max) were significantly greater across the first molars than across the first premolars only with Qx (Emax: 8.4 +/- 0.7 mm versus 5.1 +/- 0.6 mm, P = 0.001; m(max): 0.09 +/- 0.005 mm/day versus 0.05 +/- 0.006 mm/day, P = 0.0001). In addition, greater variance was apparent in m(max) with Nt than with Qx across both the first molars and the first premolars. Overall, Qx and Nt elicited similar discomfort. However, significantly less was reported with Nt on days 6 (P = 0.04) and 7 (P= 0.03) following the second 'activation'. These preliminary results suggest that Qx and Nt are equally efficacious maxillary expanders. However, Qx expansion appeared significantly more controlled, as well as more individually predictable in expansion rate. Overall, Qx and Nt probably elicit similar discomfort, but significantly less discomfort may be seen with Nt following the second activation. Finally, because more than one appliance is invariably required with Nt, Qx expansion is potentially less costly.

PMID: 15366386 [PubMed - indexed for MEDLINE]

Evaluation of nasal airway resistance during rapid maxillary expansion using acoustic rhinometry.

Eur J Orthod. 2004 Aug;26(4):397-401

Authors: Doruk C, S&#xF6;kücü O, Sezer H, Canbay EI

The purpose of this study was to evaluate nasal airway resistance (NAR) during rapid maxillary expansion (RME) using acoustic rhinometry (AR). The sample comprised 22 children (13 girls and nine boys) with maxillary constriction. The mean age was 12.9 +/- 1.54 years and all patients were found to have normal nasal cavities following anterior rhinoscopic examination. A modified bonded splint type RME appliance was used for expansion. AR was used to measure NAR before (T1), during (T2) and after (T3) expansion, and at the end of retention (T4). Each AR recording was performed, for each patient, with and without the use of a decongestant. Subjective evaluation of reported changes in nasal breathing were also undertaken at T3. The results showed that NAR was significantly reduced with the use of RME, with the main decrease observed during expansion (P < 0.05). The use of a decongestant was not found to have any effect on the results. Subjective evaluation showed that 59 per cent of patients considered that their nasal breathing had improved following RME.

PMID: 15366384 [PubMed - indexed for MEDLINE]

Evaluation of methods of archwire ligation on frictional resistance.

Eur J Orthod. 2004 Jun;26(3):327-32

Authors: Khambay B, Millett D, McHugh S

The aim of the study was to investigate the effect of elastomeric type and stainless steel (SS) ligation on frictional resistance using a validated method. To assess the validity of the new test system to measure mean frictional forces, SS and TMA wires, each with dimensions of 0.017 x 0.025 and 0.019 x 0.025 inches, were used in combination with a self-ligating Damon II bracket or a conventional preadjusted edgewise premolar SS bracket without ligation. Four types of elastomeric module, purple, grey, Alastik or SuperSlick, and a pre-formed 0.09 inch SS ligature were then assessed as methods of ligation using preadjusted edgewise premolar SS brackets. The specimens were tested on a Nene M3000 testing machine, with a crosshead speed of 5 mm/minute and each test run lasted for 4 minutes. Each bracket/wire combination with each method of ligation was tested 10 times in the presence of human saliva and the mean frictional force was recorded. The mean frictional forces were compared using three-way analysis of variance. The Damon II self-ligating bracket and unligated conventional SS bracket produced negligible mean frictional forces with any of the wires tested. For the 0.017 x 0.025 SS, 0.019 x 0.025 SS or 0.019 x 0.025 inch TMA wires, SS ligatures produced the lowest mean frictional forces. With the 0.017 x 0.025 TMA wire, purple modules produced the lowest mean frictional force. There was no consistent pattern in the mean frictional forces across the various combinations of wire type, size and ligation method. Under the conditions of this experiment, the use of passive self-ligating brackets is the only method of almost eliminating friction.

PMID: 15222719 [PubMed - indexed for MEDLINE]

Applications of 3D imaging in orthodontics: part II.

J Orthod. 2004 Jun;31(2):154-62

Authors: Hajeer MY, Millett DT, Ayoub AF, Siebert JP

PMID: 15210932 [PubMed - indexed for MEDLINE]

An ex vivo assessment of gingivally offset lower premolar brackets.

J Orthod. 2004 Mar;31(1):34-40; discussion 16

Authors: Thind BS, Larmour CJ, Stirrups DR, Lloyd CH

OBJECTIVES: To compare the force to failure of standard premolar brackets to that of gingivally offset brackets and evaluate the site of bond failure between the two bracket types through the use of the Adhesive Remnant Index (ARI). DESIGN: An ex vivo study. SETTING: Dental Materials Science Laboratory, Dundee Dental School, Dundee. MATERIALS AND METHODS: Forty extracted lower premolar teeth (caries free, extracted as part of orthodontic treatment, all donors living in a non-fluoridated area), divided into two equal size sample groups, as follows: Group 1: Victory Series (3M Unitek, Monrovia CA, USA) lower premolar brackets bonded to buccal surfaces with Transbond XT (3M Unitek, Monrovia CA). Group 2: Victory Series Gingivally Offset Bicuspid Brackets (3M Unitek, Monrovia CA) bonded to buccal surfaces with Transbond XT (3M Unitek, Monrovia CA). Force was applied in the occluso-gingival direction using an Instron Model 4469 Universal Testing Machine (Instron Ltd, High Wycombe, UK) operating at a cross-head speed of 0.5 mm/min and its value at failure determined. Following debond, the site of bond failure and ARI were recorded. OUTCOME: Force to failure, site of bond failure and adhesive remnant index. RESULTS: The Weibull analysis gave higher values for the force to failure at 5% level (200 v. 159 N) and at all other levels of probability of failure for the gingivally offset bracket. The non-parametric survival analysis using Gehan-Wilcoxon tests with Breslow's algorithm (p < 0.0001) showed significant difference in force to failure between bracket types. Chi-square tests showed no significant (p = 0.55) relationship between the site of bond failure and the bracket types. CONCLUSION: Ex vivo testing suggests that there is a significant difference in the force to failure between gingivally offset and standard lower premolar brackets when force application is from an occluso-gingival direction. The site of failure (as given by the ARI) is insensitive to bracket types and force to failure.

PMID: 15071150 [PubMed - indexed for MEDLINE]

Orthodontic palatal implants: clinical technique.

J Orthod. 2004 Mar;31(1):3-8

Authors: Tinsley D, O'Dwyer JJ, Benson PE, Doyle PT, Sandler J

The aim of this paper is to familiarize the readers with some of the clinical considerations necessary to ensure successful use of mid-palatal implants. Both surgical and technical aspects will be discussed along with a description of impression techniques used.

PMID: 15071143 [PubMed - indexed for MEDLINE]

Perception of pain during orthodontic treatment with fixed appliances.

Eur J Orthod. 2004 Feb;26(1):79-85

Authors: Erdin&#xE7; AM, Dinçer B

The aims of this study were to investigate the initial time at which pain occurs after insertion of two initial wires of different sizes, the duration of the pain, the areas affected within the mouth, the level of self-medication, the effect of this pain on daily life, and whether gender is important in the perception of pain. The study group consisted of 109 patients (52 boys, 57 girls) with a mean chronological age of 13.6 years for boys and 14.7 years for girls. Insertion of either a 0.014 or 0.016 inch wire was by random selection. Following insertion of the archwires, a questionnaire comprising a total of 49 questions was given to the patients. They described the time of initial pain in the first question, answered the next 24 questions as 'yes' or 'no', and used a visual analogue scale for the final 24 questions. No significant differences were found in terms of gender, in the perception period of initial pain as regards the areas affected within the mouth or the effect of pain on daily living when the 0.014 and 0.016 inch wire groups were compared at 6 hours, 1, 2, 3, 4, 5, 6 and 7 days. At 24 hours, which was found to be statistically significant, more pain relief was used in the 0.014 inch archwire group. The results show that in both groups, initial pain was perceived at 2 hours, peaked at 24 hours and had decreased by day 3.

PMID: 14994886 [PubMed - indexed for MEDLINE]