Edgewise Mechanics Research Articles

The scientific evidence for pre-adjusted edgewise attachments and mechanics.

Introduction Fixed orthodontic appliance systems continue to evolve with a wealth of evidence emerging to underpin these refinements.Aims To present the evidence from comparative prospective research informing the selection of fixed appliance design and mechanics.Design Detailed literature review.Materials and methods An electronic search to identify randomised controlled trials and clinical controlled trials was undertaken using pre-defined search terms.Results Based on high-level evidence, no one bracket system has been proven superior in terms of efficiency or outcome. Similarly, a clear advantage associated with one wire type or dimension has not been shown. The effect of lacebacks in terms of anchorage management appears to be limited, while elastomeric chain and nickel titanium closing coils are associated with similar rates of space closure.Discussion A wealth of high-quality recent evidence to support the selection of fixed appliance attachments, archwires and auxiliaries, including lacebacks and space closing mechanics, was identified.Conclusions There has been a considerable increase in the amount of high-quality evidence informing the choice of pre-adjusted edgewise mechanics in recent years. This information can be used to make evidence-based decisions in the selection and manipulation of fixed appliances during daily practice.

Cephalometric Evaluation of Maxillary Incisors Torque and Vertical Changes Utilizing Standard Edgewise Mechanics

In 1995 Gebeck & Merrifield studied a successful and unsuccessful treated Class I and Class II’s samples; they found a -1.33 mm intrusion in the former and a 0.80 mm extrusion in the latter. The purpose of this article was to perform a cephalometric evaluation of maxillary incisors torque and vertical changes. We studied a sample of 129 patients, 30 males and 99 females, taken from The Charles H. Tweed Foundation Long Term Study, at pretreatment mean age 12.93 years, posttreatment mean age 16.19 years and follow up post retention mean age 29.83 years, a 13.88 years interval. The records were collected from private practitioners across the North American continent who used Standard Edgewise Mechanics and were members of the Charles H. Tweed Foundation. All patients were Class I and II American whites treated with the extraction of 4 premolars. We found an Upper anterior incisal edge to PP vertical linear measurement 28.7 and 29.2 mm, +0.53 mm (p<0.019) from pretreatment to posttreatment. The average Upper 1 to SN angle was 103.2 ° at pretreatment and 100.1° at posttreatment, -3.2° (p<0.000), Upper 1 to PP 111.0° and 108.9°, -2.2° (p<0.000), the three of them statistically significant. Conversely, Upper 1 to commissure was not. The four measurements were also statistically significant posttreatment to follow up, upper anteriors kept losing torque after posttreatment, and less upper anteriors surface was below the commissure. Some torque loss and vertical extrusion can be expected while treating patients with extractions of four premolars, therefore, upper incisor inclination increase and vertical change by itself cannot determine the success of treatment.

A Comparative Evaluation of Accuracy of McLaughlin Bennet Trevisi Prescription of Six Commercially Available Orthodontic Metal Brackets: An In vitro Study

Introduction: While using preadjusted edgewise mechanics, tooth positioning relies on the accuracy of bracket prescription for correct expression of tip and torque when using full-size archwire, thus making accuracy of bracket prescription vital in its overall performance. This study aimed to investigate the precision offered in bracket prescription: slot dimensions, tip, and torque values. Materials and Methods: MBT prescriptions of upper left central incisor brackets manufactured by six different commercial houses were evaluated to assess the aforementioned accuracy of bracket slot dimensions as well as tip and torque values. Rapid-I Precision Measuring System was used to accurately determine slot dimensions as well as tip and torque values. Results: Results obtained in a descending order of accuracy were as follows: American Orthodontics, Ortho Organizers, 3M Unitek, Forestadent, Modern Orthodontics and JJ Orthodontics. The obtained results were evaluated statistically using one-way ANOVA test. P Conclusion: This study helps us to note the accuracy level of the inherent prescription values offered in various commercial houses and the likely effect the same may have on our expectation of a prescription finish while using attachments from any of them.

Three-dimensional evaluation of molar buccolingual inclinations after orthodontic treatment using edgewise mechanics.

The purpose of this study was to measure changes in buccolingual inclination and in thickness of maxillary and mandibular buccal and lingual bone of maxillary and mandibular molars following orthodontic treatment using edgewise mechanics. Cone-beam computed tomography scans of 48 patients taken before and after completion of comprehensive orthodontic treatment were collected for this retrospective study. Buccolingual molar inclinations were reported as angular measurements using the long axis of the teeth and inferior border of the nasal floor and inferior border of the mandible, respectively. Distances between the buccal and lingual cusps of maxillary and mandibular molars, respectively, were measured to the occlusal plane to assess the change in buccolingual inclination after orthodontic treatment. The amount of buccal and lingual bone at the level of the root apex of each molar was also evaluated before and after orthodontic treatment. Orthodontic edgewise mechanics caused significant increases in mandibular first molars' inclination angle, lingual bone, and mandibular second molars' buccal bone and inclination angle. Significant decreases were noted in mandibular first molars' buccal bone, inclination distance and mandibular second molars' lingual bone and inclination distance. Maxillary teeth had fewer significant changes than the mandibular teeth. Significant decreases were found for maxillary first molars' buccal bone, inclination distance, and maxillary second molar buccal bone.

Expansion/Facemask Treatment of an Adult Class III Malocclusion

The orthodontic treatment of class III malocclusion with a maxillary deficiency is often treated with maxillary protraction with or without expansion. Skeletal and dental changes have been documented which have combined for the protraction of the maxilla and the correction of the class III malocclusion. Concerning the ideal time to treat a developing class III malocclusion, studies have reported that, although early treatment may be the most effective, face mask therapy can provide a viable option for older children as well. But what about young adults? Can the skeletal and dental changes seen in expansion/facemask therapy in children and adolescents be demonstrated in this age group as well, possibly eliminating the need for orthodontic dental camouflage treatment or orthognathic surgery? A case report is presented of an adult class III malocclusion with a Class III skeletal pattern and maxillary retrusion. Treatment was with nonextraction, comprehensive edgewise mechanics with slow maxillary expansion with a bonded expander and protraction facemask.

Ratings of profile attractiveness after functional mandibular advancement

Considerations involving orthodontic treatment and facial esthetics have directed the investigation of the optimal treatment, especially in the correction of Class II, division 1 malocclusions, both esthetically and functionally. The aim of this study is to determine whether the use of a Twin force bite corrector in combination with Edgewise mechanics yields a more esthetic facial profile than Edgewise treatment alone. Methods: The present retrospective study compared matched two groups of adolescent patients, (total n=20) The first, treated with functional orthopedic therapy using a TFBC in combination with preangulated Edgewise appliances, (n=10). The second, matched group (n=10) was treated using standard Edgewise mechanics alone. A panel of ten orthodontic graduate evaluators investigated silhouettes of lateral photographs of perceived post treatment facial esthetics of Egyptian adolescents with Class II, division 1 malocclusions treated by one of the two methods. They scored each silhouette's attractiveness on a 100% visual analogue scale (modified VAS). Independent samples t test at 0.05 level of significance was used to compare the VAS scores. Results: the evaluators showed wide range of agreement among the two treated groups in selecting the most attractive profiles. The evaluation of pre/post treatment for each group and randomized post treatment of both goups for facial attractiveness showed insignificant difference statisticaly. Conclusion: TFBC treatment in combination with Edgewise mechanics has measurable benefits.

Recidiva do apinhamento anterossuperior nas más oclusões de Classe I e Classe II tratadas ortodonticamente sem extrações

OBJETIVO: o presente estudo objetivou comparar retrospectivamente a estabilidade pós-contenção do alinhamento dos incisivos anterossuperiores em pacientes com Classe I e Classe II. MÉTODOS: a amostra consistiu de 38 pacientes de ambos os sexos, tratados sem extrações e com mecânica Edgewise, divididos em dois grupos - Grupo 1, constituído por 19 pacientes, com idade inicial média de 13,06 anos, portadores da má oclusão de Classe I com apinhamento anterossuperior inicial maior que 3mm; Grupo 2, constituído por 19 pacientes, com idade inicial de 12,54 anos, portadores da má oclusão de Classe II e, também, com apinhamento anterossuperior inicial maior que 3mm. Foram medidos nos modelos de estudo, das fases pré- e pós-tratamento e pós-contenção, o índice de irregularidade de Little, as distâncias intercaninos e entre os primeiros e segundos pré-molares, a distância intermolares e o comprimento da arcada superior. Para a comparação intragrupo nos 3 tempos de avaliação, utilizou-se os testes ANOVA e Tukey. A comparação intergrupos foi realizada pelo teste t independente. Para verificação da presença de correlação, utilizou-se o teste de correlação de Pearson. RESULTADOS: os resultados evidenciaram maior estabilidade do tratamento no Grupo 2 (Classe II), pois, durante o período pós-contenção, foi observada recidiva do apinhamento dos dentes anterossuperiores menor no Grupo 2 (0,80mm) do que no Grupo 1 (1,67mm). CONCLUSÃO: concluiu-se que o tratamento do apinhamento dos dentes anterossuperiores é mais estável na má oclusão de Classe II do que na má oclusão de Classe I.

Serial extraction of first premolars--postretention evaluation of stability and relapse.

Case records were evaluated for 30 patients who had undergone serial extraction of deciduous teeth plus first premolars followed by comprehensive orthodontic treatment and retention. Diagnostic records were available for the following stages: pre-extraction, start of active treatment, end of active treatment, and a minimum of 10 years postretention. All cases were treated with standard edgewise mechanics and were judged clinically satisfactory by the end of active treatment. Twenty-two of the 30 cases (73%) demonstrated clinically unsatisfactory mandibular anterior alignment postretention. Intercanine width and arch length decreased in 29 of the 30 cases by the postretention stage. There was no difference between the serial extraction sample and a matched sample extracted and treated after full eruption.

Comparative study of dental arch width in plaster models, photocopies and digitized images

The aim of this study was to comparatively assess dental arch width, in the canine and molar regions, by means of direct measurements from plaster models, photocopies and digitized images of the models. The sample consisted of 130 pairs of plaster models, photocopies and digitized images of the models of white patients (n = 65), both genders, with Class I and Class II Division 1 malocclusions, treated by standard Edgewise mechanics and extraction of the four first premolars. Maxillary and mandibular intercanine and intermolar widths were measured by a calibrated examiner, prior to and after orthodontic treatment, using the three modes of reproduction of the dental arches. Dispersion of the data relative to pre- and posttreatment intra-arch linear measurements (mm) was represented as box plots. The three measuring methods were compared by one-way ANOVA for repeated measurements (alpha = 0.05). Initial / final mean values varied as follows: 33.94 to 34.29 mm / 34.49 to 34.66 mm (maxillary intercanine width); 26.23 to 26.26 mm / 26.77 to 26.84 mm (mandibular intercanine width); 49.55 to 49.66 mm / 47.28 to 47.45 mm (maxillary intermolar width) and 43.28 to 43.41 mm / 40.29 to 40.46 mm (mandibular intermolar width). There were no statistically significant differences between mean dental arch widths estimated by the three studied methods, prior to and after orthodontic treatment. It may be concluded that photocopies and digitized images of the plaster models provided reliable reproductions of the dental arches for obtaining transversal intra-arch measurements.

Prediction of Lip Response to Four First Premolar Extractions in White Female Adolescents and Adults

To develop models for predicting changes in lip position of Class I extraction patients. Pretreatment and posttreatment lateral cephalograms of 46 white female adults and 109 white female adolescents were examined. Mean pretreatment ages for the adolescent and adult groups were 12.2 +/- 1.2 years and 23.0 +/- 8.5 years, respectively. Subjects were treated with conventional edgewise mechanics. Multivariate prediction models were derived from a randomly selected sample of 119 subjects and validated on the remaining 36 subjects. Adolescents demonstrated significant vertical and horizontal skeletal growth and treatment changes, while adults showed only small increases in anterior face height. While significant retraction of the upper and lower incisors occurred in both groups, the amounts were greater in adults than in adolescents. Ratios for horizontal hard tissue to soft tissue movements ranged from 1.4:1 to 1.1:1 and 1.3:1 to 1:1 for the upper (Ls) and lower (Li) lips, respectively. There were moderate relationships between horizontal lip and underlying hard tissue movements (correlations ranged from .57 to .78 for Ls and from .58 to .86 for Li). Multiple regressions to predict lip movements showed moderately strong relationships for the upper lip (R = .79 to .81) and strong relationships for the lower lip (R = .89 to .90). Two to three variables were necessary to predict vertical lip movements (R = .82 to .87). The validation sample showed no systematic biases and similar levels of accuracy. Upper and lower lip retraction in four first premolar extraction cases can be predicted with moderately high levels of accuracy in white female adolescents and adults.

Alguns aspectos da mecânica das alças de retração ortodôntica

As alças de retração ortodôntica são comumente empregadas em sistema Edgewise por meio de uma abordagem seccional (ex.: retração de caninos) ou por meio de uma abordagem segmentada (ex.: retração dos dentes anteriores em conjunto). Estas alças podem modular a demanda de ancoragem, dependendo dos objetivos impostos pelo plano de tratamento. Neste trabalho são discutidas as propriedades mecânicas relacionadas ao projeto de alças de retração ortodôntica, o sistema de forças decorrente de sua conformação geométrica e ativação, e os métodos empregados para testá-las. Dentre as técnicas utilizadas na análise de uma alça, o Método dos Elementos Finitos (MEF) merece destaque. Embora seja baseado em modelos matemáticos, é uma ferramenta eficaz e não onerosa para a simulação computacional de um protótipo, podendo-se assim avaliá-lo antes de sua construção física. Já os métodos experimentais se aproximam mais da condição real, porém com custo mais elevado. A utilização em diferentes estágios de ambos os métodos é aconselhável para um melhor desenvolvimento e caracterização dos protótipos.

Avaliação pelo índice PAR dos resultados do tratamento ortodôntico da má oclusão de Classe I tratada com extrações

INTRODUÇÃO: torna-se difícil, sem a utilização de um índice oclusal, uma avaliação fidedigna dos resultados e da finalização dos tratamentos ortodônticos. O índice PAR é capaz de avaliar objetivamente as alterações que ocorrem com o tratamento ortodôntico, e as melhorias conseguidas. OBJETIVO: por isto, decidiu-se, neste estudo, avaliar-se as alterações decorrentes dos tratamentos ortodônticos realizados com aparelho fixo, mecânica Edgewise e com extrações dos quatro primeiros pré-molares, bem como a qualidade de sua finalização e de seus resultados, por meio do índice de avaliação oclusal PAR. MATERIAL E MÉTODOS: foram avaliados os modelos de estudo de 94 pacientes leucodermas, com idade média de 13,46 anos, sendo 50 do gênero masculino e 44 do feminino. O tempo de tratamento médio foi de 2,09 anos. O índice PAR foi obtido dos modelos pré e pós-tratamento de cada um dos pacientes. RESULTADOS: após a realização da análise estatística descritiva, pode-se observar que o índice PAR inicial médio de 29,46 foi reduzido para 6,32 ao final do tratamento, caracterizando uma redução de 78,54% com o tratamento ortodôntico. Houve correlação do índice PAR inicial com a correção deste índice durante o tratamento. CONCLUSÃO: pode-se concluir que os casos tratados demonstraram um bom padrão de finalização ortodôntica, e quanto maior a severidade da má oclusão, maior a correção com o tratamento.

Influence of the quality of the finished occlusion on postretention occlusal relapse

In this study, we aimed to evaluate the influence of the quality of the finished occlusion on postretention occlusal stability. The sample comprised 87 patients with Class I malocclusion, treated with extraction of the 4 first premolars and edgewise mechanics; they were divided into 2 groups, according to the quality of their finished occlusions. Group 1 included 44 subjects (23 boys, 21 girls) with posttreatment peer assessment rating (PAR) scores from 0 to 5. The mean pretreatment age was 13.74 years (SD 2.14). The mean treatment time was 1.92 years (SD 0.57), the mean retention time was 1.75 years (SD 0.96), and the mean time of posttreatment evaluation was 5.17 years (SD 1.82). Group 2 included 43 subjects (22 boys, 21 girls) with posttreatment PAR scores greater than 5. The mean initial age was 13.34 years (SD 1.35). The mean treatment time was 2.20 years (SD 0.66), the mean retention time was 1.77 years (SD 0.78), and the mean posttreatment evaluation was 5.47 years (SD 1.60). The PAR and the Little irregularity indexes were measured on the dental casts at pretreatment, posttreatment, and postretention. Intergroup comparisons were made with independent t tests, and the Pearson correlation coefficient was applied to the PAR score for the whole sample at the times evaluated. Well-finished patients had lower posttreatment and postretention PAR scores and greater changes during the treatment and posttreatment periods than did the poorly finished patients. For the Little irregularity index, the only difference between the groups was at the posttreatment stage; group 1 had a smaller irregularity score than group 2. The correlation coefficients showed that the greater the treatment changes, the smaller the posttreatment PAR score and the greater the relapse. But the higher the posttreatment PAR score, the higher the postretention PAR score. It was concluded that the greater the quality of the orthodontic finished occlusion, the greater are the treatment changes and the amount of relapse and the better is the occlusal status at the postretention stage in Class I malocclusion treated with 4 premolar extractions.

Scientific Evidence for Pre-adjusted Edgewise Mechanics

The aim of this paper is to present scientific evidence for treatment mechanics with the pre-adjusted edgewise appliance. We have summarized findings from randomized and controlled clinical trials following a search of Medline and the Cochrane Clinical Trials Register (CCTR) 1970-June 2005. Evidence was available to support our choice of archwires, use of canine lacebacks and method of space closure, thus providing the beginning of a scientific basis for our day-to-day management of fixed appliance mechanics.

Estudo da recidiva da sobremordida relacionada com a curva de Spee, em pacientes Classe II, divisão 1, na fase pós-contenção

INTRODUÇÃO: a estabilidade dos resultados do tratamento ortodôntico é um assunto muito estudado na literatura, sem respostas conclusivas. A sobremordida, ou trespasse vertical, define-se como a relação vertical entre as bordas incisais dos incisivos superiores e inferiores, apresentando-se como um aspecto importante na avaliação dos resultados do tratamento e sua estabilidade. OBJETIVO: este estudo se propôs a avaliar a recidiva da sobremordida e sua relação com a curva de Spee. METODOLOGIA: a amostra (grupo experimental) constituiu-se de 29 pacientes, de ambos os gêneros, apresentando má oclusão de Classe II, divisão 1, e sobremordida mínima de 3,5mm, tratados com extração dos 4 primeiros pré-molares. Este grupo foi comparado a um grupo controle, com oclusão normal. A amostra faz parte do Arquivo da Disciplina de Ortodontia da FOB-USP. Avaliaram-se as telerradiografias em norma lateral e os modelos de estudo do início, final e 5 anos pós-tratamento e, para o grupo controle, as telerradiografias de dois tempos de avaliação, compatível com o tempo de tratamento do grupo experimental. Para comparação intergrupos, utilizou-se o teste t independente e, para comparação intragrupo, os testes ANOVA e Tukey. Para verificar a relação da recidiva da sobremordida com a curva de Spee, utilizou-se o coeficiente de correlação de Pearson. RESULTADOS: pela análise dos resultados obtidos, observou-se que a sobremordida apresentou uma correção significante durante o tratamento, comparando-se ao grupo controle. Porém, apresentou recidiva significante na fase pós-contenção. CONCLUSÃO: a recidiva da sobremordida apresentou uma correlação significante com a curva de Spee na fase pós-contenção.

Retrospective analysis of orthodontic treatment outcomes and its relation to postretention stability.

Objective:The present study was designed to retrospectively evaluate Class I malocclusion cases treated with extraction of the four first premolars, aiming to establish the relationship between the quality of orthodontic treatment outcomes and the long-term occlusal stability.Material and methods:The sample comprised 94 patients of both genders, presenting Class I malocclusion, treated with extractions of the four first premolars and Edgewise mechanics. All the patients selected were whites, being 50 males and 44 females. The mean pretreatment age was 13.46 years (s.d. 1.8). The mean treatment time was 2.09 years (s.d. 0.58), the mean retention time was 1.63 years (s.d. 0.73) and the mean time of postretention evaluation was 5.31 years (s.d. 1.61). The dental casts were measured at pretreatment (T1), posttreatment (T2) and postretention (T3), by the PAR index and by the Little irregularity index, and the correction due to treatment (T1-2) and the change at the postretention period (T3-2) were calculated. The descriptive statistics was performed and the Pearson correlation coefficient was applied for the PAR and the Little indices in the total sample, among the times evaluated.Results:The mean PAR reduction due to treatment was 78.54%, and 66.6%, at the postretention stage related to pretreatment stage. Significant correlations were found for the PAR index at the times evaluated, except between T1 and T2 and between T1-2 and T3. In other words, the higher the treatment correction (T1-2), the lower the posttreatment PAR index (PAR T2) will be, and the higher will be the PAR change at the postretention period (PAR T3-2). Also, the higher the posttreatment PAR score (PAR T2), the higher will be the postretention PAR score (PAR T3).Conclusion:It was concluded that the quality of orthodontic treatment outcomes is not related to the long-term occlusal stability.

A clinical comparison between nickel titanium springs and elastomeric chains

Abstract Objectives To compare the rates of maxillary canine retraction and molar anchorage loss when using either NiTi springs or elastomeric chains delivering a known force with sliding edgewise mechanics. Methods Twelve patients who required maxillary canine retraction into first premolar extraction sites as part of their orthodontic treatment were selected. In a split-mouth design, these patients received precalibrated NiTi springs (12 quadrants) and premeasured elastomeric chains (12 quadrants), all delivering initial forces of approximately 200 g and being reactivated at 28 day intervals. Space closure and forward movement of the maxillary first molars were evaluated using maxillary impressions, which were taken before the start of canine retraction and then at 28 day intervals until canine retraction was almost complete. Results Statistical analysis revealed that the mean rate of space closure with NiTi springs (1.85 mm/month) was only 0.17 mm/month greater (p = 0.011) than that produced with the elastomeric chains (1.68 mm/month). The mean rates of anchorage loss for the NiTi springs and elastomeric chain were 0.46 mm/month and 0.45 mm/month respectively. This difference was not statistically significant. These amounts of forward molar movement were calculated to be between one quarter and one third of the average space closure per month, even in the presence of a fixed transpalatal arch. Conclusion The results indicate that the rates of space closure and molar anchorage loss using either NiTi springs or elastomeric chains, if reactivated every 28 days, are likely to be similar.

Correlation between mandibular incisor crown morphologic index and postretention stability

Considering postretention stability as a result of successful orthodontic treatment, we aimed to verify the influence of mandibular-incisor-crown morphology in the relapse of mandibular anterior crowding. The sample comprised 56 white subjects of both sexes with Class I and Class II malocclusions at pretreatment, treated with extraction of 4 first premolars and edgewise mechanics. No patient underwent interproximal stripping during or after treatment. Mean pretreatment age was 13.23 years. Mean treatment time was 2.11 years, and mean posttreatment evaluation time was 5.12 years. Mandibular anterior crowding was measured with the Little irregularity index, and the mesiodistal and buccolingual proportion of the mandibular incisor crowns was measured with the Peck and Peck index. The measurements were obtained from dental casts at the pretreatment, posttreatment, and postretention stages. The Pearson correlation coefficient was calculated to determine the correlation between mandibular-incisor-crown morphology and the amount of postretention-crowding relapse. The mandibular-incisor-crown morphologic index was not significantly correlated with the amount of mandibular-anterior-crowding relapse. Mandibular-incisor-crown morphology is not correlated with the amount of mandibular-anterior-crowding relapse.

Postretention relapse of mandibular anterior crowding in patients treated without mandibular premolar extraction

Treatment stability is one of the most important objectives in orthodontics, but, despite decades of research, it is still agreed that the stability of aligned teeth is variable and largely unpredictable. This study aimed to evaluate the relapse of mandibular anterior crowding in patients treated without mandibular premolar extraction. The sample comprised 40 patients of both sexes with Class I or II malocclusions who received nonextraction treatment in the mandibular arch with edgewise mechanics. Lateral cephalograms and dental casts of each patient were obtained at pretreament, posttreatment, and 5 years postretention. Relapse of mandibular anterior crowding was assessed, and associations between this relapse and other clinical factors were also investigated. Mandibular anterior crowding was measured by the Little irregularity index, and the data were evaluated by the Mann-Whitney test. The mean relapse of mandibular anterior crowding was 1.95 mm (26.54%) over the long term. No clinical factor studied was predictive of crowding relapse in the long term.

Condylar pathway changes following different treatment modalities.

The purpose of this investigation was to evaluate the effect of extraction and non-extraction approaches on the condylar pathways in subjects treated with fixed orthodontic appliances. The study was carried out on 70 patients (47 female, 23 male) who had undergone orthodontic treatment with fixed appliances. The mean age for the total group was 16.3 years (16.5 years for the females and 16 years for the males). Forty-seven patients were treated non-extraction and 23 with extractions. None of the patients had any temporomandibular joint (TMJ) problems before orthodontic treatment and all were treated with standard edgewise mechanics. The condylar pathway recordings were taken before and after treatment with an axiograph. The maximum opening capacity was measured and the right and left condylar pathways of each patient were recorded in protrusion and during opening movements. During treatment the left opening angle (LOA) only decreased significantly in the upper premolar extraction group. The left opening distance (LOD) decreased in all groups during treatment but was only statistically significant in the non-extraction and upper and lower extraction groups. In the small overjet group (OJ < or = 4 mm), the LOA, right opening distance (ROD) and LOD decreased significantly while there was no significant change in axiographic parameters in the large overjet group (OJ > 4 mm). In the latter group, overjet and overbite decreased while mouth opening (3 mm P < 0.05) significantly increased. These results indicate that there is no difference between the effect of different treatment protocols on the condylar pathways.