Evaluation of Mandibular First Molars' Axial Inclination and Alveolar Morphology in Different Facial Patterns: A CBCT Study.

OBJECTIVE: The purpose of this study was to evaluate and compare the axial inclination of the mandibular first molars and their respective bone morphology among individuals with different facial patterns. MATERIALS AND METHODS: The sample comprised the cone beam computed tomographies (CBCTs) of 58 subjects divided into three groups according to the facial patterns: 18 brachyfacial (Group 1), with a mean age of 21.58 years; 23 mesofacial (Group 2), with a mean age of 19.14 years; and 17 dolichofacial subjects (Group 3), with a mean age of 19.09 years. Eight variables were evaluated on CBCT scans of each subject: buccal and lingual mandibular height, cervical and middle mandibular width, inclination of mandibular body, inclination of the mandibular molar buccal surface, molar width, molar angulation and tooth/bone angle. Intergroup comparisons were performed with one-way analysis of variance followed by Tukey tests. RESULTS: Buccal mandibular height presented statistically significant difference in the three facial patterns. Lingual mandibular height and mandibular inclination showed to be statistically and significantly smaller in brachyfacial subjects than in the other two groups. Mandibular width presented a statistically significant difference between brachyfacial and mesofacial groups. Negative correlations could be observed between the facial pattern and the buccal and lingual mandibular heights and inclination of the mandibular body. CONCLUSION: Buccal mandibular height was significantly and progressively larger in brachyfacial, mesofacial, and dolichofacial subjects. Lingual mandibular height was significantly smaller in brachyfacial than in mesofacial and dolichofacial subjects. Mandibular width was significantly thicker in brachyfacial than in mesofacial subjects. Brachyfacial subjects had smaller mandibular inclination than mesofacial and dolichofacial subjects.

Mesiodistal dental movement toward remodeled edentulous alveolar ridge: Digital model assessment.

INTRODUCTION: The aims of this study were to compare the changes in posterior dental inclination and angulation, and the posterior tooth crown sizes and alveolar ridge thicknesses consequent to the orthodontic procedures of closing and opening of mandibular first molar edentulous spaces. METHODS: The sample comprised 16 patients (4 men, 12 women) with an initial mean age of 34.17 years and unilateral or bilateral absence of mandibular permanent first molars. The space closure group (SCG) comprised 12 hemiarches with a mandibular first molar edentulous space varying from 2 to 7 mm, orthodontically treated with space closure. The space opening group (SOG) comprised 14 quadrants with a mandibular first molar edentulous space varying from 7.1 to 12 mm, orthodontically treated with space reopening for prosthetic replacement. Digital dental models were obtained before treatment and after space closure or opening, and posterior tooth angulation and inclination, cervico-occlusal crown height, and alveolar ridge thickness were evaluated. Interphase and intergroup comparisons were performed with dependent t tests and t tests, respectively (P <0.05). RESULTS: Mandibular second molar uprighting and changes in buccolingual inclination of the posterior teeth were similar in the groups. The second molar cervico-occlusal crown height increased in the SCG and decreased in the SOG. The alveolar ridge thickness increased in the SCG and remained stable in the SOG. CONCLUSIONS: The only significant intergroup differences were that the second molar cervico-occlusal crown height and the alveolar ridge thickness increased in the SCG, and decreased and remained stable in the SOG.

Movement of mandibular molar into edentulous alveolar ridge: A cone-beam computed tomography study.

INTRODUCTION: The purpose of this study was to evaluate the thickness and height of buccal and lingual alveolar bone of mandibular teeth moved to edentulous areas with a remodeled alveolar ridge. METHODS: The sample included 18 adult patients with unilateral or bilateral absence of mandibular permanent first molars with a mean age of 36.1 years before treatment. The mandibular hemiarches were divided into 3 groups: reopening group (15 hemiarches), closure group (12 hemiarches), and control group (9 hemiarches with no missing teeth). Cone-beam computed tomography scans with a 0.2-mm voxel size were performed 4 months after space closure or reopening. Cross sections 0.2 mm thick passing through the center of the mandibular permanent second molar and second premolar roots were used for measurements of the buccal and lingual bone plate thickness and level. Intergroup comparisons were performed with 1-way analysis of variance followed by Tukey tests (P <0.05). RESULTS: No intergroup differences were found for the alveolar bone statuses of the mandibular second premolar. For the mandibular second molar, the closing group showed significantly smaller buccal and lingual crest levels compared with the control group. CONCLUSIONS: Space closure of missing mandibular first molars caused slight buccal and lingual dehiscences at the mandibular second molar areas.

Class II malocclusion treatment using Jasper Jumper appliance associated to intermaxillary elastics: a case report.

INTRODUCTION: Skeletal, dental and profile discrepancies can be amended by using functional orthodontic appliances. OBJECTIVE: This study is a report of the treatment of a patient, 11 years and 4 months old, with Class II, division 1, malocclusion, convex profile, protrusion of upper incisors, pronounced overjet and overbite, and mild crowding. METHODS: The patient was treated with a Jasper Jumper associated to fixed appliances for 6 months and Class II intermaxillary elastics (3/16-in) during the last 4 months. After debonding, a Hawley retainer was used during daytime and a modified Bionator for night use during one year. In the lower dental arch a bonded lingual retainer was used. This treatment combination improved the profile, as well as the overjet, overbite and molar relation. RESULTS: There was clockwise mandibular rotation and increase of lower anterior facial height. The lower incisors were protruded and extruded and the lower molars were extruded. The centric occlusal relation was checked and it was coincident to the maximum usual intercuspation. CONCLUSIONS: It was demonstrated that the Jasper Jumper is an efficient alternative to Class II malocclusion treatment, providing improvement in the facial profile, although the changes are more dentoalveolar than skeletal.

Class II malocclusion treatment using Jasper Jumper appliance associated to intermaxillary elastics: a case report

INTRODUCTION: Skeletal, dental and profile discrepancies can be amended by using functional orthodontic appliances. OBJECTIVE: This study is a report of the treatment of a patient, 11 years and 4 months old, with Class II, division 1, malocclusion, convex profile, protrusion of upper incisors, pronounced overjet and overbite, and mild crowding. METHODS: The patient was treated with a Jasper Jumper associated to fixed appliances for 6 months and Class II intermaxillary elastics (3/16in) during the last 4 months. After debonding, a Hawley retainer was used during daytime and a modified Bionator for night use during one year. In the lower dental arch a bonded lingual retainer was used. This treatment combination improved the profile, as well as the overjet, overbite and molar relation. RESULTS: There was clockwise mandibular rotation and increase of lower anterior facial height. The lower incisors were protruded and extruded and the lower molars were extruded. The centric occlusal relation was checked and it was coincident to the maximum usual intercuspation. CONCLUSION: It was demonstrated that the Jasper Jumper is an efficient alternative to Class II malocclusion treatment, providing improvement in the facial profile, although the changes are more dentoalveolar than skeletal.

INTRODUÇÃO: discrepâncias esqueléticas, dentárias e de perfil podem ser melhoradas com a utilização de aparelhos ortopédicos funcionais. OBJETIVO: esse artigo tem o objetivo de relatar o tratamento de um paciente de 11 anos e 4 meses de idade com má oclusão de Classe II divisão 1, ½ cúspide bilateral, alteração de perfil, protrusão dos incisivos superiores, overjet e overbite acentuados e apinhamento suave. MÉTODOS: o paciente foi tratado por meio do Jasper Jumper associado ao aparelho fixo por 6 meses e elásticos intermaxilares de Classe II (3/16") nos últimos 4 meses. Após a remoção do aparelho fixo, foram utilizadas as contenções, a placa de Hawley para uso diurno e o Bionator modificado para uso noturno, por um ano. No arcada inferior, foi utilizada contenção 3x3 fixa colada de canino a canino. Essa combinação de tratamento melhorou o perfil, bem como os trespasses horizontal e vertical, além da relação molar. RESULTADOS: houve rotação mandibular no sentido horário e aumento da altura facial anteroinferior. Os incisivos inferiores foram protruídos e extruídos, e os molares inferiores sofreram extrusão. A relação cêntrica oclusal foi checada e era coincidente com a máxima intercuspidação habitual. CONCLUSÃO: comprovou-se que o Jasper Jumper é uma alternativa eficiente para o tratamento da Classe II, proporcionando melhoras no perfil facial, embora as alterações sejam mais dentoalveolares do que esqueléticas.