Extra-oral Appliances in Orthodontic Treatment.

Extra-oral appliances are used in orthodontics to apply forces to the jaws, dentition or both and the popularity of these appliances is cyclical. Although the use of retraction headgear for the management of Class II malocclusion has declined over the last 20 years with the refinement of non-compliance approaches, including temporary anchorage devices, headgear still has a useful role in orthodontics. The use of protraction headgear has increased as more evidence of its effectiveness for the treatment of Class lIl malocclusion has become available. This paper describes the mechanics and contemporary uses of headgear in orthodontics for primary care dentists and specialist orthodontists. CPD/CLINICAL RELEVANCE: Extra-oral appliances have specific uses in orthodontic biomechanics. Clinicians using retraction headgear and protraction headgear should be familiar with their clinical indications, the potential problems and how these can be avoided.

Treating Class II malocclusion in children. Vertical skeletal effects of high-pull or low-pull headgear during comprehensive orthodontic treatment and retention.

OBJECTIVES: To evaluate, in Class II malocclusion children, vertical skeletal changes occurring with high- and low-pull headgear during non-extraction comprehensive orthodontic treatment, and retention. SETTING AND SAMPLE POPULATION: Two groups of thirty Class II malocclusion children (mean age 10.8 years) who had undergone non-extraction comprehensive orthodontic treatment with either high- or low-pull headgear and fixed appliances. MATERIAL AND METHODS: Retrospective longitudinal study, where pre-treatment, post-treatment and at least 2 year post-retention lateral cephalometric radiographs were analyzed. Comparisons were made concerning changes during treatment and retention in high- or low-pull headgear-treated children. Correlation analyses were carried out investigating changes in vertical cephalometric parameters and pre-treatment vertical facial pattern or type of headgear used. RESULTS: During treatment, sagittal relationships improved in all children and remained stable during retention. Vertically, in both high- and low-pull headgear groups, the intermaxillary angle as well as the maxillary and mandibular plane angles did not show statistically significant changes during treatment or retention, and large variation was seen between patients. When pooling the whole patient sample, change in the vertical facial pattern was independent of the pre-treatment vertical facial pattern or type of headgear used. CONCLUSION: When treating Class II malocclusion children non-extraction with high- or low-pull headgear and fixed appliances, changes in vertical skeletal relationships demonstrate wide variation, both during treatment and retention. Dentoalveolar changes brought about by these appliances may not be able to make a predictable difference in vertical skeletal patterns of growing patients.

Comparison of skeletal anchored facemask and tooth-borne facemask according to vertical skeletal pattern and growth stage.

OBJECTIVE: To compare the treatment effects between skeletal anchored facemask (SAFM) and tooth-borne facemask (TBFM) on different maturation stages and vertical skeletal patterns. MATERIALS AND METHODS: In this retrospective study, 28 patients who were treated with TBFM treatment and 19 patients who were treated with SAFM were reviewed. Cephalograms at the beginning and end of facemask application were obtained and assessed. Each treatment group was divided according to skeletal maturity and facial angle type. Nonparametric Mann-Whitney U-test was used for comparisons of maturity stage and vertical skeletal type between the treatment groups. RESULTS: SAFM produced a significant increase in the anterior-posterior position of orbitale (SNOr) and A point (N. per. to A). The high mandibular plane angle group of SAFM revealed greater anterior movement than that of TBFM without opening of the mandibular plane. In the SAFM group, the angulation of the maxillary incisors was retroclined at CVM3 compared to CVM4. In the younger group (CVM3), SAFM showed greater changes in the variables of orbitale (2.909°) and maxillary length (5.818 mm), compared to TBFM. CONCLUSIONS: Compared with the TBFM group, the findings suggest significant advantages for the SAFM group for relative skeletal maturity and vertical skeletal pattern.

Modified tandem traction bow appliance compared with facemask therapy in treating Class III malocclusions.

OBJECTIVE: To compare the effects of the modified tandem traction bow appliance (MTTBA) and the facemask in treating patients with Class III malocclusion. MATERIALS AND METHODS: The material consisted of the pre-post treatment\pre-post observation lateral cephalograms of 65 subjects with skeletal and dental Class III malocclusion. In the first group 21 patients (mean age: 10 years, 6 months) were treated with a Delaire-type facemask (FM). In the second group 22 patients treated (mean age: 10 years) with MTTBA. The remaining 22 children (mean age: 9 years, 7 months) were observed without treatment for 11 months. RESULTS: Increase in SNA, N-FH ⊥ A, and ANB angles were significantly greater in the treatment groups compared to the control group. However, ANB angle showed a significantly greater increase in the FM group (2.8 ± 0.30°) than in the MTTBA group (2.0 ± 0.18°). The overjet and molar relation increased significantly in both treatment groups, but in the FM group (5.2 ± 0.40 mm) increase in overjet was significantly greater than in the MTTBA group (4.0 ± 0.27 mm). Mesial movement of upper molar and incisor were found to be greater in the FM group compared to the modified TTBA group. CONCLUSIONS: Both appliances were found to be effective in the treatment of Class III malocclusion. Their skeletal and dental effects showed differences due to their design.

Profile changes associated with different orthopedic treatment approaches in Class III malocclusions.

The aim of this study was to evaluate and compare the soft tissue effects of chincup (CC), chincup plus bite plate (CC+P), and reverse headgear (RHg) therapies with each other and with an untreated control group (C). The material consisted of lateral cephalometric and hand-wrist films of 59 Class III cases and 20 nontreated control subjects. Thirty-one cases were treated with CC, 14 with CC+P, and 14 with RHg, and Class I relation was achieved. The mean pretreatment ages were approximately 11 years and the observation period was one year. The cephalometric films were analyzed according to the structural superimposition method of Björk. All tracings were double digitized, and the measurements were calculated by a computer program (PORDIOS). Treatment and control changes within the groups and the differences between the groups were analyzed statistically. Forward positioning of the maxilla was significant in the RHg group, whereas the mandible was positioned backward significantly in all the treatment groups. Posterior rotation of the mandible was significant in the CC+P and RHg groups. The overjet increased and the overbite decreased significantly in all the treatment groups. Forward movement of soft tissue A and upper lip was significant in all groups, whereas more pronounced in the CC+P group. The soft tissue changes in the mandibular region were significant in the CC and CC+P groups, whereas in the maxillary region more significant and similar improvements were obtained by CC+P and RHg treatments. Longterm studies are required to confirm the stability of these changes.

Distal molar movement with Kloehn headgear: is it stable?

The aim of this study was to evaluate intramaxillary molar movement after 8 months of cervical traction and posttreatment displacement 7 years later. The total molar displacements in relation to stable intraosseous reference points were compared with those observed in an untreated control group that also had intraosseous reference indicators inserted. During the headgear period, the type of molar displacement could be predicted by the direction of the force system acting on the teeth. It was noted, however, that the variation in the vertical development was related more to each patient's growth pattern than to the force system applied. After cessation of the headgear, intramaxillary displacement of the molars was noted, and the total displacement of the molars did not differ from that of the untreated group. The indication for intramaxillary displacement of the molars by means of extraoral traction is therefore questioned.

Efeitos cefalométricos do aparelho extra-bucal conjugado (Splint Maxilar) e do bionator, no tratamento da má oclusão de classe II, 1ª divisão / Comparative study of the maxillary splint and bionator appliances in the treatment of class II, division 1 malocclusion

Este estudo cefalométrico objetivou avaliar as alterações dentárias, esqueléticas e tegumentares, em jovens com má oclusão de Classe II, 1a divisão, tratados com o aparelho extrabucal conjugado (splint maxilar) e com o Bionator. Estes dois grupos experimentais foram comparados a um grupo de jovens portadores da mesma má oclusão que não receberam tratamento, pareados pelo gênero, idade, tempo de observação e grandezas cefalométricas iniciais. A amostra constou de 180 telerradiografias em norma lateral de 90 jovens, divididos em três grupos de 30, sendo 15 do gênero masculino e 15 do feminino. Os jovens do grupo 1 foram mantidos como controle e apresentaram uma idade inicial média de 10,02 anos e foram observados pelo período médio de 1,49 anos. O grupo 2, foi submetido ao tratamento utilizando o aparelho extrabucal conjugado (splint maxilar), com idade inicial média de 10,02 anos e tempo de observação de 1,78 anos. O grupo 3, foi tratado com o Bionator por um tempo médio de 1,52 anos e os jovens apresentavam idade inicial média de 10,35 anos. A comparação entre as variáveis cefalométricas iniciais evidenciou grande similaridade entre os três grupos possibilitando comparações diretas entre eles. A análise dos resultados mostrou que o tratamento da má oclusão de Classe II, 1a divisão com o AEB conjugado e com o Bionator resultou de efeitos específicos e inerentes a cada aparelho. Os resultados patentearam que o deslocamento anterior da maxila foi restringido significantemente pelo tratamento com o AEB conjugado. O Bionator promoveu um aumento significante na protrusão mandibular, enquanto que o AEB conjugado mostrou efeitos esqueléticos menos evidentes. No entanto, ambos os aparelhos estudados produziram um aumento nos comprimentos efetivo e do corpo da mandíbula, com valores maiores para o grupo 2. A relação maxilomandibular melhorou significantemente nos grupos tratados em comparação ao grupo controle. A análise do padrão de crescimento craniofacial e das alturas faciais não revelou alteração significante entre os grupos. Em relação às alterações dentoalveolares ambos aparelhos provocaram inclinação para lingual e retrusão dos incisivos superiores, porém os efeitos do AEB conjugado foram significantemente mais intensos. Os incisivos inferiores foram afetados de maneira distinta pelos aparelhos. No grupo tratado com o AEB conjugado,...

A clinical evaluation of a locking orthodontic facebow.

Standard orthodontic facebows may accidentally detach from the appliance buccal tubes at night; this could reduce the effectiveness of extra oral traction and occasionally cause an injury. To try and prevent facebow detachment at night a facebow with a locking mechanism was introduced. This study assessed the ability of 706 consecutively treated patients to learn to wear and use this facebow. The facebows were fitted in 9 different practices supervised by 12 orthodontists. Data from the patients and orthodontists were collected over a 2-year period and covered approximately 166,550 nights. All the orthodontists were able to fit and adjust the facebow; a total of 697 patients successfully used the facebow. Accidental detachment of the facebow at night was reported to be less than 1%. This indicates a significant improvement in the safety of the facebow and should help to improve compliance by increasing the number of hours of wear achieved by the patients.

Effects of different vectors of forces applied by combined headgear.

The effects of various directed forces applied by combined headgear were evaluated in this study. The study material consisted of 30 patients with Class II dental relationships and steep mandibular plane angles. Three groups of 10 patients each were formed. In the first treatment group, forces of 150 gm per side were used for the high-pull component and the cervical component. In the second treatment group, forces of 200 gm per side for the high-pull component and 100 gm per side for the cervical component were applied. In the third treatment group, forces of 100 gm per side were applied for the high-pull component and 200 gm per side for the cervical component. Distal tipping of upper molar was greatest in the third treatment group. Intrusion of the upper molar in the second treatment group and extrusion of the upper molar in the third treatment group were statistically significant. Changes in occlusal and mandibular plane angles showed significant differences between the groups.

La caracterización de los arcos de alambre en el alineamiento inicial de dientes en posición irregular / Characterization of the arch wire on the initial alignment of teeth in an irregular position

La flexibilidad de una extensión de alambre depende del diámetro del alambre y de sus propiedades elásticas. La rigidez en la flexión es la fuerza requerida para doblar un alambre y la propiedad para devolverse a su forma inicial. La rigidez de un alambre puede ser medida como la rigidez de un alambre sometido a la prueba de cantiliber. La rigidez de un alambre depende del módulo elástico del alambre. La recuperación elástica es la cantidad de efecto de resorte que un alambre tiene después de haberse flexionado. La recuperación elástica se haya doblado el alambre en cilindros de diferentes diámetros. La recuperación elástica es mayor para el alambre que tuvo deformación permanente al ser flexionado sobre el cilindro con radio mínimo. El límite elástico es la propiedad de los alambres que indica la recuperación elástica. Se hace la comparación de la rigidez y de la recuperación elástica de los alambres níquel titanio, acero inoxidable, cobalto níquel, alambres trenzados de acero inoxidable y un alambre de alta resistencia a la tensión. La flexibilidad de una extensión de alambre depende de otros factores como la dimensión de los brackets y la distancia entre los brackets. Se debe tener en consideración que la incorporación de ansas se aumenta la extensión de alambre y se reduce la rigidez de la extensión de alambre.

The effects of extraction and nonextraction treatment on the mandibular position.

Decisions on extraction of teeth as an aid in orthodontic treatment depend on dental and skeletal discrepancies concerning sagittal and vertical relationships. The purpose of this study was to assess the effects of extraction and nonextraction procedures on the posterior rotation of the mandible and the position of gnathion. Forty-eight nonextraction patients and seventy-three extraction patients treated in the orthodontic department were selected. The patients were from 11 to 15 years old, with a mean age of 12 years 2 months. The lateral cephalometric radiographs taken before and after treatment were traced and measured. Eleven variables reflecting the mandibular rotation were selected on the basis of factor analysis. Before treatment, total arch circumferential discrepancy and the 11 selected measurements showed significant differences between the extraction and nonextraction groups. In the extraction group, the lower anterior facial height was larger, ramus height was smaller, and the difference between vertical position of both maxillary and mandibular first molars and posterior facial height was greater than in the nonextraction group. Consequently, the mandible showed posterior rotation and was in retruded position in the extraction group. In the nonextraction group, the type of force application had no significant effect on the changes in skeletal and dental measurements. In the extraction group, however, the type of force application had a significant effect (p less than 0.05) on the changes in total anterior facial height, the horizontal distance of the maxillary first molar to a perpendicular line to the S-N plane passing through point S, the vertical distance of the maxillary molar to the S-N plane, the vertical distance of the maxillary and mandibular first molars to the S-N plane, the difference between the vertical position of the first molars and posterior facial height, and the difference between the vertical position of the first molar and vertical height of the ramus. In the group in which high-pull face-bow headgear was used, the extraction/nonextraction procedures had a significant effect (p less than 0.05) on the changes in angle ANB, total anterior facial height, anterior lower facial height, and the difference between anterior and posterior facial height.(ABSTRACT TRUNCATED AT 400 WORDS)