Changes over time in canine retraction: An implant study

Introduction: The objective of this study was to analyze rates of canine movement over the first 2 months of continuous retraction, when rate changes are expected. Methods: Ten patients with bone markers placed in the maxilla and the mandible had their canines retracted over a 2-month period. Retraction was accomplished with beta-titanium alloy T-loop springs. Standardized 45 degrees oblique cephalograms where taken initially and every 28 days thereafter. The radiographs were scanned and digitized twice (the average was used for the analyses). The radiographs were superimposed by using the bone markers and oriented on the functional occlusal plane. Paired t tests were used to compare side and jaw effects. Results: There were no significant differences between sides. The maxillary cusp was retracted 3.2 mm, with less movement during the first (1.1 mm) than during the second 4 weeks (2.1 mm). The maxillary apices did not move horizontally. There were no significant vertical movements in the cusps and apices of the maxillary canines. The mandibular cusp was retracted 3.8 mm-1.1 mm during the first and 2.7 mm during the second 4 weeks. The mandibular apices were protracted 1.1 mm. The cusps and apices were intruded 0.6 and 0.7 mm, respectively. The only difference between jaws was the greater protraction of the mandibular apices during the second 4 weeks and in overall movement. Conclusions: The rate of canine cusp retraction was greater during the second than the first 4 weeks. The mandibular canines were retracted by uncontrolled tipping whereas the maxillary canines were retracted by controlled tipping. (Am J Orthod Dentofacial Orthop 2009; 136: 87-93)

Canine retraction and anchorage loss Self-ligating versus conventional brackets in a randomized split-mouth study

Objective: To evaluate the velocity of canine retraction, anchorage loss and changes on canine and first molar inclinations using self-ligating and conventional brackets.Materials and Methods: Twenty-five adults with Class I malocclusion and a treatment plan involving extractions of four first premolars were selected for this randomized split-mouth control trial. Patients had either conventional or self-ligating brackets bonded to maxillary canines randomly. Retraction was accomplished using 100-g nickel-titanium closed coil springs, which were reactivated every 4 weeks. Oblique radiographs were taken before and after canine retraction was completed, and the cephalograms were superimposed on stable structures of the maxilla. Cephalometric points were digitized twice by a blinded operator for error control, and the following landmarks were collected: canine cusp and apex horizontal changes, molar cusp and apex horizontal changes, and angulation changes in canines and molars. The blinded data, which were normally distributed, were analyzed through paired t-tests for group differences.Results: No differences were found between the two groups for all variables tested.Conclusions: Both brackets showed the same velocity of canine retraction and loss of anteroposterior anchorage of the molars. No changes were found between brackets regarding the inclination of canines and first molars.

Maxillary canine-first premolar transposition - Restoring normal tooth order with segmented mechanics

Tooth transpositions present at a relatively low incidence in the world population and primarily affect maxillary canines and premolars. Treatment of this disturbance should take into account aspects such as facial pattern, age, malocclusion, tooth-size discrepancy, stage of eruption, and magnitude of the transposition. Mechanics for correction should be entirely individualized, reducing the risks and adverse effects. Practitioners often select simpler options, indicating extraction of permanent teeth, which is an irreversible procedure that may bring about damages to the patient. This study presents a case report and treatment of unilateral transposition of maxillary canine and premolar with repositioning of affected teeth to their respective normal positions.

Maxillary canine - First premolar transposition: Restoring normal tooth order with segmented mechanics

Tooth transpositions present at a relatively low incidence in the world population and primarily affect maxillary canines and premolars. Treatment of this disturbance should take into account aspects such as facial pattern, age, malocclusion, tooth-size discrepancy, stage of eruption, and magnitude of the transposition. Mechanics for correction should be entirely individualized, reducing the risks and adverse effects. Practitioners often select simpler options, indicating extraction of permanent teeth, which is an irreversible procedure that may bring about damages to the patient. This study presents a case report and treatment of unilateral transposition of maxillary canine and premolar with repositioning of affected teeth to their respective normal positions. © 2006 by The EH Angle Education and Research Foundation, Inc.

Filling of extraction sockets of feline maxillary canine teeth with autogenous bone or bioactive glass

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Complications of misdiagnosis of maxillary canine ectopic eruption

Ectopic eruption of maxillary canines can be associated with root resorption of adjacent teeth. This case report describes and discusses an interesting case of a 15-year-old girl with a Class III malocclusion and an impacted maxillary canine. Because of the unfavorable position of the ectopic canine and the severe root resorption of the maxillary left central and lateral incisors, the treatment options included extraction of the maxillary permanent canines. The mandibular first premolars were extracted to compensate for the Class III malocclusion. A panoramic radiograph taken earlier in the mixed dentition already indicated a possible eruption disturbance of the maxillary left permanent canine. The importance of early diagnosis of maxillary canine ectopic eruption is highlighted in this case report. The early identification of radiographic signs of an ectopic pathway of eruption should be followed by deciduous canine extraction to prevent canine retention and maxillary incisor root resorption. (Am J Orthod Dentofacial Orthop 2012;142:256-63)

Maxillary canine impaction in orthodontic patients with and without agenesis: A cross-sectional radiographic study

ABSTRACT Objective: To assess potential associations between maxillary canine impaction (MCI) and agenesis status as well as between MCI and gender. Materials and Methods: The records of 182 orthodontic patients with agenesis (excluding the third molars) and 630 orthodontic patients without agenesis were examined. Diagnosis of MCI was based on pretreatment panoramic radiographs. Maxillary canines that had not erupted as a result of physical barrier or deflection in the eruption path at the dental age of at least 12 years were considered impacted. Logistic regression analysis was used to test for the associations of interest. Results: MCI was detected in 5.6% (n  =  35) of the nonagenesis group (28 female and 7 male participants) and in 18.1% (n  =  33) of the agenesis group (20 female and 13 male participants). Bilateral impaction was detected in 12 patients (34.3%) of the nonagenesis group and in 11 patients (33.3%) of the agenesis group. There was evidence that maxillary lateral incisor agenesis (odds ratio  =  5.1, 95% confidence interval [CI] 2.5-10.5, P < .001) and second premolar agenesis (odds ratio  =  2.6, 95% CI 1.0-6.6, P  =  .042) were significant MCI predictors after adjusting for gender. The odds of MCI were 69% higher in female versus male subjects after adjusting for agenesis status (95% CI 0.97-2.92, P  =  .063). Conclusions: This study indicates that there is evidence that agenesis status is a strong predictor of MCI, whereas gender is a weak predictor of MCI. Caution should be exercised in interpreting the results because of the observational nature of the present study.

Influence of root parallelism on the stability of extraction-site closures

Introduction: In premolar extraction cases, root parallelism is recommended to preserve the stability of space closures. The influence of the degree of root parallelism on relapse of tooth extraction spaces has been a controversial topic in the literature. The aim of this study was to compare the angle between the long axes of the canine and the second premolarin patients with and without stability of extraction-space closures. Methods: A sample of 56 patients, treated with 4 premolar extractions, was divided into 2 groups: group 1, consisting of 25 patients with reopening of extraction spaces; and group 2, consisting of 31 patients without reopening of extraction spaces. Panoramic radiographs of each patient were analyzed at the posttreatment and 1-year posttreatment stages. The data were statistically analyzed by using chi-square tests, t tests, analysis of variance (ANOVA), and Pearson correlation coefficients. Results: The results showed that the groups did not differ regarding the angle between the canine and the second premolar, and there was no correlation between angular changes and reopening of extraction spaces, showing that dental angular changes are not determining factors for relapse, and other factors should be investigated. Conclusions: The final angle and the posttreatment changes observed in the angle between the long axes of the canine and the second premolar showed no influence on the relapse of extraction spaces. (Am J Orthod Dentofacial Orthop 2011; 139: e505-e510)

Minimplante e botão lingual como ancoragem para retração inicial de caninos superiores: estudo prospectivo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Mini-implant and Nance button for initial retraction of maxillary canines: a prospective study in cast models

OBJETIVO: a ancoragem óssea é fundamental para o sucesso do tratamento de algumas más oclusões, pois permite a aplicação de forças contínuas, diminui o tempo de tratamento e independe da colaboração do paciente. MÉTODOS: o propósito desse trabalho foi comparar, por meio de modelos dentários, a perda de ancoragem após a retração inicial de caninos superiores entre dois grupos. O grupo A utilizou o mini-implante enquanto o grupo B utilizou o Botão de Nance. Para todos os pacientes foram realizados dois modelos (M1 e M2). Os primeiros modelos foram realizados ao início (M1), e os outros ao final da retração inicial de canino (M2). RESULTADOS: todas as medidas foram tabuladas e submetidas à análise estatística. Para verificar o erro sistemático intraexaminador foi utilizado o teste t pareado. Na determinação do erro casual utilizou-se o cálculo de erro proposto por Dahlberg. Para comparação entre as fases Início e Após, foi utilizado o teste t pareado. Para a comparação entre os grupos de mini-implante e Botão de Nance, foi utilizado o teste t de Student para medidas independentes. em todos os testes foi adotado nível de significância de 5% (p<0,05). CONCLUSÃO: ao se medir e comparar em modelos dentários a perda de ancoragem dos molares após a retração inicial de canino utilizando-se dois sistemas de ancoragem distintos (Mini-implante e Botão de Nance), pôde-se observar a inexistência de diferença estatisticamente significativa entre os dois grupos.

Predictable drill-free screw positioning with a graduated 3-dimensional radiographic-surgical guide: A preliminary report

Introduction: Mini-implants are placed in restricted sites, requiring an accurate surgical technique. However, no systematic study has quantified technique accuracy to reliably predict the surgical risks. Therefore, a graduated 3-dimensional radiographic-surgical guide (G-RSG) was proposed, and its inaccuracy and risk index (RI) were estimated. Methods: The sample consisted of 6 subjects (4 male, 2 female), who used mini-implant anchorage. Ten drill-free screws (DFS) were placed by using the G-RSG. The central point of the mesiodistal septum width (SW) was the selected implant site on the presurgical radiograph. The distances between DFS and the adjacent teeth (5-DFS and 6-DFS) were measured to evaluate screw centralization and inaccuracy degree (ID). These distances were statistically compared by independent t tests, and inaccuracy was determined by the expression ID = (5-DFS-6-DFS)/2, which represents deviation of the mini-implant`s final position regarding the central point initially selected. Then SW, ID, and screw diameter (SO) were combined to estimate the surgical risk with RI expressed by RI = SO/SW-ID. Results: The 5-DFS and 6-DFS distances were not significantly different. The ID of the G-RSG was 0.17 mm. The low ID ensured a safe RI (<1) in spite of the restricted SW. Conclusions: The G-RSG accuracy allowed fine prediction of the final DFS position in the inter-radicular septum, with a low RI, which is a helpful tool to estimate surgical risks. (Am J Orthod Dentofacial Orthop 2009; 136: 722-35)

Gingival recession in maxillary canines and central incisors of individuals with clefts

Background. Mucogingival alterations are inherent to clefts and may be worsened by the several plastic surgeries required in these individuals. Objective. The aim of this study was to evaluate the prevalence, severity, and some possible etiologic factors of gingival recessions in teeth adjacent to the cleft. Study design. A total of 641 teeth ( maxillary canines and central incisors) of 193 individuals with cleft lip and/or palate were examined. A generalized linear model was used, and the Wilcoxon test was used to compare the recession with cleft types. Results. Comparison among cleft types as to the presence of recession revealed a statistically significant positive relationship for the maxillary right and left central incisors only in the group with left cleft lip, alveolus, and palate (P = .034). The most frequently affected tooth was the right maxillary canine (26.16%). Conclusion. The prevalence of recession in teeth close to the cleft was higher, although it was not very severe. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010; 109: 37-45)

Group A T-loop for differential moment mechanics: An implant study

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Compensatory canine angulation in angle class II and III patients

Abstract: The aim of this study was to evaluate the occurence of compensation in mesiodistal axial inclinations of canines in skeletal malocclusions patients. The sample consisted of 25 Angle Class II, division 1 malocclusion (group 1) and 19 Angle Class III malocclusion patients (group 2). After measurement of dental angulations through a method that associates plaster model photography and AutoCad software, comparisons between the groups were performed by T-test for independent samples. Results showed that there was no statistically significant difference (p ≤ 0.05) between groups, when maxillary canine angulations were compared. Regarding the mandibular canines, there was a statistically significant difference in dental angulation, expressed by 3.2° for group 1 and 0.15° for group 2. An upright position tendency for mandibular canines was observed in the Angle Class III sample. This configures a pattern of compensatory coronary positioning, since the angulation of these teeth makes them occupy less space in the dental arch and consequently mandibular incisors can be in a more retracted position in the sagittal plane.