Selective use of hand and forearm muscles during bone screw insertion: a natural torque meter.

PURPOSE: To compare the maximum torque produced by different muscle groups and its influence on mini-implant insertion torque and fracture prevention. MATERIALS AND METHODS: Eighty-seven professionals were evaluated for the maximum torque produced on a screwdriver by a combined action between the thumb and index finger (maximum digital torque [MDT]) and by the forearm supination movement (maximum brachial torque [MBT]). Ninety mini-implants distributed among 9 different diameters were fractured to determine the fracture torque (FT). The fracture resistance index (FRI) was obtained from: FRI_MDT = FT/MDT and FRI_MBT = FT/MBT. Analysis of variance and t tests were used to compare the groups. RESULTS: The MDT was smaller than the MBT, and the 2 measurements were smaller in female subjects. The FT increased for each 0.1-mm increment in diameter. The FRI_MDT was greater than FRI_MBT for all diameters. An FRI_MDT greater than 1 was found when the diameter was greater than or equal to 1.5 mm. An FRI_MBT greater than 1 occurred with diameters equal to or greater than 1.7 mm for female subjects and 1.8 mm for male subjects. CONCLUSIONS: The digital torque was 42% smaller than the brachial torque, and it was mechanically safer and biologically more compatible, allowing the prevention of the fracture of mini-implants with a diameter 1.5 mm or thicker owing to an insertion torque limitation at 15 N-cm.

Selective use of hand and forearm muscles during mini-implant insertion: a natural torquimeter.

OBJECTIVE: To compare maximum torque produced by different muscular groups and its influence on mini-implant insertion torque and fracture prevention. DESIGN: A prospective study involving in vivo and in vitro laboratory experiments. MATERIALS AND METHODS: Eighty-seven professionals were evaluated for maximum torque produced using a screwdriver with combined action between thumb and index fingers [maximum digital torque (MDT)] and by forearm supination movement [maximum brachial torque (MBT)]. Ninety mini-implants distributed over nine different diameters and twenty commercially available mini-implants of two different diameters and trademarks were fractured to determine the fracture torque (FT). The fracture resistance index (FRI) was obtained from: FRI_MDT = FT/MDT and FRI_MBT = FT/MBT. The analysis of variance (ANOVA) and t tests were used to compare the groups. RESULTS: MDT was smaller than MBT and both were smaller in females. FT increased for each 0·1 mm of diameter increment. FRI_MDT was greater than FRI_MBT for all diameters. FRI_MDT>1 was found when the diameter was greater than or equal to 1·5 mm. FRI_MBT>1 occurred with diameters equal or greater than 1·7 mm for females and 1·8 mm for males. The 1.5 mm and 1.6 mm diameter of commercially available and mini-implants presented FRI_MBT<1 and FRI_MDT>1. CONCLUSIONS: Digital torque was 42% smaller than brachial torque, and it was mechanically safer and biologically more compatible, allowing fracture prevention of 1·5 mm or thicker mini-implant diameter due to insertion torque limitation at 15 N/cm.

A modified orthodontic protocol for advanced periodontal disease in Class II division 1 malocclusion.

An interdisciplinary approach is often the best option for achieving a predictable outcome for an adult patient with complex clinical problems. This case report demonstrates the combined periodontal/orthodontic treatment for a 49-year-old woman presenting with a Class II Division 1 malocclusion with moderate maxillary anterior crowding, a 9-mm overjet, and moderate to severe bone loss as the main characteristics of the periodontal disease. The orthodontic treatment included 2 maxillary first premolar extractions through forced extrusion. Active orthodontic treatment was completed in 30 months. The treatment outcomes, including the periodontal condition, were stable 17 months after active orthodontic treatment. The advantages of this interdisciplinary approach are discussed. Periodontally compromised orthodontic patients can be satisfactorily treated, achieving most of the conventional orthodontic goals, if a combined orthodontic/periodontic approach is used.

Effect of mini-implant diameter on fracture risk and self-drilling efficacy.

INTRODUCTION: The aim of this study was to evaluate the effect of mini-implant diameter on fracture risk and self-drilling efficacy. METHODS: A sample of 405 mini-implants with 9 diameters from 1.2 to 2.0 mm was used. Ten mini-implants of each diameter were placed in artificial bone, and 25 were placed in pig iliac bone to evaluate placement torque (PT) and axial placement load (APL), which represents self-drilling efficacy. Ten mini-implants of each diameter were used to determine fracture torque (FT). The different diameters were compared regarding PT, FT, and APL. The fracture risk of each diameter was evaluated by the fracture resistance index (FT/PT × [FT-PT]). The PT and APL changes during placement were correlated. RESULTS: Only PT and FT were different for all mini-implant diameter changes. PT and FT showed a strong correlation with the mini-implant diameter, but the APL was weakly to moderately correlated. The fracture resistance index was remarkably greater for each 0.1 mm added in diameter. The PT increased significantly, whereas the APL was progressively reduced during placement. CONCLUSIONS: Increases in mini-implant diameters significantly influenced the increases of PT and FT on quantities that progressively reduced the fracture risk. The self-drilling efficacy was not strongly influenced by diameter.

Cephalometric radiographic comparison of alveolar bone height changes between adolescent and adult patients treated with premolar extractions: A retrospective study.

OBJECTIVE: In orthodontic treatment, indication of dental extractions is very common and frequently used in adult patients. This situation is a recurrent concern among orthodontists, since age and extraction treatment are factors that may increase periodontal support loss. Therefore, this study aimed to evaluate adolescent and adult patients, orthodontically treated with maxillary premolar extractions, and compare both groups regarding the changes in alveolar bone height loss, retrospectively. MATERIALS AND METHODS: Fifty-five patients were selected from the files of an Orthodontic Department and divided into 2 groups. The adolescent group comprised 30 patients with a mean age of 12.7 years (SD=1.4) and the adult group comprised 25 patients with a mean age of 25.0 years (SD=1.8). Periapical radiographs obtained at pre-treatment (T1) and posttreatment (T2) were evaluated. Wilcoxon tests were used to analyse intragroup treatment changes. Mann-Whitney tests were used to compare intergroup and inter-sex initial and final statuses and treatment changes. P<0.05 is considered to be statistically significant. RESULTS: Statistically significant increases in alveolar bone height loss of the maxillary central incisors were observed on the right and left sides of the adolescent (P=0.001 and P=0.002, respectively) and of the adult (P=0.001 and P<0.001, respectively) groups, during treatment. There were no significant differences in alveolar bone height between initial and final state, in treatment effects between adolescent and adult patients, in extraction patterns, and between males and females. CONCLUSIONS: Significant increase in alveolar bone height loss was found in both adult and adolescent patients orthodontically treated with maxillary premolar extractions. However, no significant differences were found regarding alveolar bone height changes after extraction orthodontic treatment between adolescent and adult patients.

Orthodontic-surgical treatment of Class III malocclusion with extraction of an impacted canine and multi-segmented maxillary surgery.

Establishment of a treatment plan is based on efficacy and easy application by the clinician, and acceptance by the patient. Treatment of adult patients with Class III malocclusion might require orthognathic surgery, especially when the deformity is severe, with a significant impact on facial esthetics. Impacted teeth can remarkably influence treatment planning, which should be precise and concise to allow a reasonably short treatment time with low biologic cost. We report here the case of a 20-year-old man who had a skeletal Class III malocclusion and impaction of the maxillary right canine, leading to remarkable deviation of the maxillary midline; this was his chief complaint. Because of the severely deviated position of the impacted canine, treatment included extraction of the maxillary right canine and left first premolar for midline correction followed by leveling, alignment, correction of compensatory tooth positioning, and orthognathic surgery to correct the skeletal Class III malocclusion because of the severe maxillary deficiency. This treatment approach allowed correction of the maxillary dental midline discrepancy to the midsagittal plane and establishment of good occlusion and optimal esthetics.

Long-term stability of Class II malocclusion treated with 2- and 4-premolar extraction protocols.

INTRODUCTION: The objective of this study was to cephalometrically compare the stability of complete Class II malocclusion treatment with 2 or 4 premolar extractions after a mean period of 9.35 years. METHODS: A sample of 57 records from patients with complete Class II malocclusion was selected and divided into 2 groups. Group 1 consisted of 30 patients with an initial mean age of 12.87 years treated with extraction of 2 maxillary premolars. Group 2 consisted of 27 patients with an initial mean age of 13.72 years treated with extraction of 4 premolars. T tests were used to compare the groups' initial cephalometric characteristics and posttreatment changes. Pearson correlation coefficients were calculated to determine the correlation between treatment and posttreatment dental-relationship changes. RESULTS: During the posttreatment period, both groups had similar behavior, except that group 1 had a statistically greater maxillary forward displacement and a greater increase in the apical-base relationship than group 2. On the other hand, group 2 had a statistically greater molar-relationship relapse toward Class II. There were significant positive correlations between the amounts of treatment and posttreatment dentoalveolar-relationship changes. CONCLUSIONS: Treatment of complete Class II malocclusions with 2 maxillary premolar extractions or 4 premolar extractions had similar long-term posttreatment stability.

Orthognathic treatment for a patient with Class III malocclusion and surgically restricted mandible.

This case report describes the orthodontic-surgical treatment of an adult with Down syndrome and a Class III skeletal malocclusion with posterior open bite, horizontal facial pattern, missing mandibular posterior teeth, and surgical restriction of the mandible.

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 (SØ) were combined to estimate the surgical risk with RI expressed by RI = SØ/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 interradicular septum, with a low RI, which is a helpful tool to estimate surgical risks.

Influence of cephalometric characteristics on the occlusal success rate of Class II malocclusions treated with 2- and 4-premolar extraction protocols.

INTRODUCTION: The objectives of this investigation were to compare the initial cephalometric characteristics of complete Class II Division 1 malocclusions treated with 2 or 4 premolar extractions and to verify their influence on the occlusal success rate of these treatment protocols. METHODS: A sample of 98 records from patients with complete Class II Division 1 malocclusion was divided into 2 groups with the following characteristics: group 1 consisted of 55 patients treated with 2 maxillary first premolar extractions at an initial mean age of 13.07 years; group 2 included 43 patients treated with 4 premolar extractions, with an initial mean age of 12.92 years. Initial and final occlusal statuses were evaluated on dental casts with Grainger's treatment priority index (TPI), and the initial cephalometric characteristics were obtained from the pretreatment cephalograms. The initial cephalometric characteristics and the initial and final occlusal statuses of the groups were compared with the t test. A multiple regression analysis was used to evaluate the influence of all variables in the final TPI. RESULTS: The 2-premolar extraction protocol provided a statistically smaller TPI and consequently a better occlusal success rate than the 4-premolar extraction protocol. The 4-premolar extraction group had statistically smaller apical base lengths, more vertical facial growth patterns, and greater hard- and soft-tissue convexities at pretreatment than the 2-premolar extraction group. However, the multiple regression analysis showed that only the extraction protocol was significantly associated with the final occlusal status. CONCLUSIONS: The initial cephalometric characteristics of the groups did not influence the occlusal success rate of these 2 treatment protocols.

Interdisciplinary treatment of localized juvenile periodontitis: a new perspective to an old problem.

What can be done for a 17-year-old girl with localized juvenile periodontitis, a Class II malocclusion, and flared teeth? Is it possible to regain epithelial attachment and rebuild the bone architecture? Is it possible to achieve good esthetics and occlusion with conventional orthodontic treatment, or is an interdisciplinary approach needed? What sequence should be followed? What is the prognosis for the affected teeth in the long term? Our aim in this article was to review the literature and present a clinical case to shed more light on the subject.

Relationship between maxillary and mandibular base lengths and dental crowding in patients with complete Class II malocclusions.

OBJECTIVE: To verify the relationship between maxillary and mandibular effective lengths and dental crowding in patients with Class II malocclusions. MATERIALS AND METHODS: The sample comprised 80 orthodontic patients with complete Class II malocclusions in the permanent dentition (47 male, 33 female) who were divided into two groups according to the amount of mandibular tooth-arch size discrepancy. The maxillary and mandibular effective lengths (Co-A and Co-Gn) and tooth-arch size discrepancies were measured on the initial cephalograms and dental casts, respectively. Intergroup comparisons of apical base lengths were performed with independent t-tests. Correlation between base length and dental crowding was examined by means of Pearson's correlation coefficient (P < .05). RESULTS: Patients with Class II malocclusion and moderate to severe crowding had significantly smaller maxillary and mandibular effective lengths than subjects with the same malocclusion and slight mandibular crowding. A weak inverse correlation was also found between maxillary and mandibular effective lengths and the severity of dental crowding. CONCLUSION: Decreased maxillary and mandibular effective lengths constitute an important factor associated with dental crowding in patients with complete Class II malocclusion.

Hybrid fixation in the bilateral sagittal split osteotomy for lower jaw advancement.

Miniplate and screw fixation has been widely used in bilateral sagittal split osteotomy, but some issues remain unclear concerning its lack of rigidity when compared to Spiessl's bicortical technique. This paper demonstrates the hybrid fixation technique in a case report. A 34-year-old female patient underwent a double jaw surgery with counter-clockwise rotation of the mandible fixed using the hybrid fixation technique. The patient evolved well in the postoperative period and is still under follow up after 14 months, reporting satisfaction with the results and no significant deviation from the treatment plan up to now. No damage to tooth roots was done, maxillomandibular range of motion was within normality and regression of the inferior alveolar nerve paresthesia was observed bilaterally. The hybrid mandibular fixation is clearly visible in the panoramic and cephalometric control radiographs. It seems that the hybrid fixation can sum the advantages of both monocortical and bicortical techniques in lower jaw advancement, increasing fixation stability without significant damage to the mandibular articulation and the inferior alveolar nerve. A statistical investigation seems necessary to prove its efficacy.

Influence of the cephalometric characteristics on the occlusal success rate of Class II malocclusions treated with nonextraction or with two maxillary premolar extraction protocols.

AIM: To compare the initial cephalometric characteristics of complete Class II malocclusions treated with nonextraction or with two maxillary premolar extractions and to verify their degree of influence on the occlusal success rate. METHODS: A sample of 84 records from patients with complete Class II malocclusions was divided into two groups. Group 1 consisted of 31 patients treated with nonextraction at an initial mean age of 12.95 years, while group 2 included 53 patients treated with two maxillary premolar extractions at an initial mean age of 13.3 years. Initial and final occlusal statuses were evaluated on dental casts with Grainger's Treatment Priority Index (TPI); the initial cephalometric characteristics were obtained on the pretreatment cephalograms. The initial cephalometric characteristics of the groups were compared by t test. A multiple linear regression analysis was used to evaluate the influence of all variables in the percentage of TPI reduction. RESULTS: The pretreatment cephalometric characteristics of the two maxillary premolar extraction cases were a greater vertical growth pattern, greater max illary and mandibular incisor protrusion, greater maxillary incisor and molar dentoalveolar heights, and greater upper and lower lip protrusion than the nonextraction group. However, the regression analysis demonstrated that only the extraction protocol was significantly associated with the occlusal success rate in the groups. CONCLUSIONS: It was concluded that the initial cephalometric characteristics of the groups did not influence the occlusal success rate of the two treatment protocols investigated.

Open-bite orthodontic-surgical treatment in the Klippel-Trenaunay-Weber syndrome: a case report.

We describe the orthodontic treatment of a patient with Klippel-Trenaunay-Weber syndrome (KTWS) who received orthodontic treatment that included rapid palatal expansion and orthognathic surgery. There is no report in the literature with this orthodontic treatment protocol, that was considered successful. The pros and cons of this approach as well as the risks involved are discussed.

An orthodontic-surgical approach to Class II subdivision malocclusion treatment.

Despite the different orthodontic approaches to Class II subdivision malocclusions one has also to consider the skeletal components before undertaking any treatment protocol. Significant involvement of the skeletal structures may require a combined surgical orthodontic treatment, which has remained stable for more than four years, as illustrated in this case report.

Segmental LeFort I osteotomy for treatment of a Class III malocclusion with temporomandibular disorder.

This article reports the case of a 19-year-old young man with Class III malocclusion and posterior crossbite with concerns about temporomandibular disorder (TMD), esthetics and functional problems. Surgical-orthodontic treatment was carried out by decompensation of the mandibular incisors and segmentation of the maxilla in 4 pieces, which allowed expansion and advancement. Remission of the signs and symptoms occurred after surgical-orthodontic intervention. The maxillary dental arch presented normal transverse dimension. Satisfactory static and functional occlusion and esthetic results were achieved and remained stable. Three years after the surgical-orthodontic treatment, no TMD sign or symptom was observed and the occlusal results had not changed. When vertical or horizontal movements of the maxilla in the presence of moderate maxillary constriction are necessary, segmental LeFort I osteotomy can be an important part of treatment planning.

Determinantes do tratamento ortodôntico-cirúrgico / Determinants of orthodontic-surgical treatment

Em algumas situações o ortodontista se depara com o dilema entre indicar apenas o tratamento ortodôntico ou o ortodôntico cirúrgico e muitos critérios devem ser considerados antes de uma decisão final ser tomada. O objetivo deste artigo é apresentar o tratamento ortodôntico-cirúrgico de um paciente com má oclusão de Classe I e discutir quais fatores são relevantes durante a escolha do melhor tipo de tratamento para cada caso.(AU)

In some situations, the orthodontist faces the dilemma of indicating only an orthodontic treatment or a surgical-orthodontic treatment and many criteria must be considered before a final decision is taken. The objective of this article is to present the orthodontic-surgical treatment of a Class I malocclusion patient and discuss which factors are relevant when deciding the best treatment approach for each case (AU)

Influência da classe II, subdivisão, tipo 1, e das extrações assimétricas no posicionamento dos terceiros molares inferiores – relato de caso / Influence of Type 1 class II subdivision malocclusion and asymmetric extractions on mandibular third molar positioning – a case report

Este relato de caso teve como objetivo exemplificar e discutir, à luz da literatura científica, a influência da Classe II, subdivisão, tipo 1, sobre a posição dos terceiros molares inferiores, bem como avaliar o impacto das extrações assimétricas de 3 pré-molares sobre a erupção destes dentes. Previamente ao tratamento, a paciente apresentava os terceiros molares inferiores impactados, sendo que no lado da relação molar de Classe II a impacção era mais severa, provavelmente em decorrência da característica dentoalveolar determinante desta má oclusão, que é a posição mais distal do primeiro molar inferior no lado da Classe II. Após o tratamento observou-se a desimpacção do terceiro molar inferior no lado da Classe I, onde foi realizada a extração de um pré-molar. Porém, no lado oposto, onde nenhuma extração foi realizada, o terceiro molar inferior permaneceu impactado. Concluiu-se que o profissional deve atentar para a propensão da Classe II, subdivisão, tipo 1, apresentar o terceiro molar inferior no lado da Classe II em condição mais desfavorável à erupção, e que este fato, por si, não justificaria a realização de extrações simétricas de 4 pré-molares em razão da menor proporção de sucesso deste protocolo, quando aplicado à Classe II, subdivisão, tipo 1. A extração assimétrica de 2 pré-molares superiores e um pré-molar inferior no lado da Classe I pode favorecer a erupção e/ou desimpacção do terceiro molar inferior neste lado, indicando a necessidade de postergar a decisão da extração.

This case report aimed to illustrate and discuss, in the light of scientific literature, the influence of Type 1 Class II subdivision malocclusion on the positioning of the mandibular third molar and to evaluate the impact of the asymmetric extraction of 3 premolars on the eruption of that tooth. Before treatment, the patient had impacted mandibular third molars. The Class II side showed more severe impaction, probably due to the main dentoalveolar feature of this malocclusion, which is the mandibular first molar more distally positioned on the Class II side. After treatment, mandibular third molar were disimpacted on the Class I side, where premolar extraction was performed. However, in the opposite side, where no extraction was performed, the impaction of the mandibular third molar was kept unchanged. It was concluded that the professional should be aware that the Type 1 Class II subdivision malocclusion is prone to present less favorable condition for eruption of the mandibular third molar on the Class II side. Nevertheless, this fact itself could not justify making symmetric extraction of 4 premolars because this protocol presents a smaller occlusal success rate when applied to the Type 1 Class II subdivision malocclusion. In addition, asymmetric extraction of 2-maxillary premolars and a mandibular premolar on the Class I side can benefit the eruption and/or disimpaction of the mandibular third molar in this side, indicating the need to postpone the extraction decision.