Long-term effect on adenoid dimensions and craniocervical angulation after maxillary expansion with fixed or functional appliances

Maxillary expansion is a common orthodontic procedure that could have a positive effect also on airway patency. The aim of the present study was to evaluate the long-term effects of rapid maxillary expansion (RME) on nasopharyngeal area and cranio-cervic

Which factors influence orthodontists in their decision to extract? A questionnaire survey

To evaluate the relative influence of different criteria in the choice between extraction and nonextraction treatment in current orthodontics, and to assess how the percentage of extractions has evolved over time. Pre-treatment records (panoramic radiograph, lateral cephalogram, study casts and photographs) of fourteen cases in permanent dentition (adult or adolescent) with class I molar relationship and moderate anterior crowding were evaluated by 28 orthodontists. For each case, each orthodontist filled out a questionnaire reporting his treatment plan proposal (extraction or nonextraction) and the importance of specific parameters in his decision-making process, using categorical scales. Orthodontists practicing for more than 15 years were also asked to compare this decision with the one they would have taken at the beginning of their professional career. The two most important factors in the decision-making were the soft tissue profile and the amount of crowding. The least important factor was the presence of third molars. In cases of nonextraction treatment, the lack of space was managed mostly by dental expansion and stripping. Twenty percent of the case evaluations revealed extraction(s) decisions. Among the orthodontists practicing for more than 15 years, the current extraction rate reached 24%, whereas the same orthodontists reported they would have extracted in 39% of the cases in the past. The present study suggests that soft tissue profile has a higher impact than traditional criteria such as cephalometric measurements in the extraction decision. This is associated with a decreased extractions rate compared to the past

Root repair after damage due to screw insertion for orthodontic miniplate placement

The aim of this investigation was to describe the healing reactions following root damage caused by placement of a miniplate anchorage system. In 4 beagle dogs, 4 titanium miniplates (2 self-tapping screws per miniplate) were placed in each maxilla, after drilling of pilot-holes. Six fixation screws were unintentionally inserted damaging the root of maxillary canines. Two weeks later, half of the miniplates were loaded with a coil spring. Two dogs were euthanized 7 weeks after placement of the miniplates, while the remaining two after 29 weeks. Histological sections were prepared, microradiographed, observed under U.V. light, then stained and analysed under ordinary light. Four screws caused direct root damage; one was damaged during the drilling process; one caused damage to the periodontal ligament only. Among these 6 screws, 2 were mobile and 4 were stable at sacrifice. Limited root damage showed some repair after 29 weeks, consisting in a thick layer of mineralized cementum including anchoring periodontal fibres. Tissue repair was not related to screw stability or loading status. Limited root damage has shown potential to heal, while extensive root damage has not. Precise position of insertion of the miniplates is thus of utmost importance

Does muscular activity related to vertical facial divergence influence the time needed for orthodontic extrusion of palatally impacted maxillary canines? A retrospective study

The aim of the present study was to evaluate if the different muscular activity correlated to different degrees of facial divergence has an effect on the time needed to extrude a palatally impacted maxillary canine. Twenty-six patients were retrospectively selected, all treated with a specific cantilever appliance that allows extrusion of the impacted canine applying a physiologic amount of force below 0.6 N in a predictable way. For all the patients, pre-treatment cephalometric tracings were used to evaluate facial divergence through the FMA angle, the angle between the maxillary and mandibular plane, and the angles between the occlusal plane and either the maxillary and mandibular plane. Linear bivariate regression was calculated to evaluate if facial divergence can predict the time needed for canine extrusion. The linear regression model was not able to predict extrusion time from variables explaining the facial divergence. Palatally impacted maxillary canines can be treated with the application of physiologic extrusion force regardless of patients? facial divergence and muscular activity

Longitudinal effects of rapid maxillary expansion on masticatory muscles activity

To investigate the modifications induced by rapid maxillary expansion (RME) on the electromyographic (EMG) activities of the anterior temporal and superficial masseter muscles, in patients without pre-treatment EMG alterations. Twenty-one patients with unilateral posterior cross-bite selected from the orthodontic department of the University of L?Aquila (Italy), were enrolled. There was no control group in this study since each subject acted as a control of her/himself. Two surface EMG recordings were taken: T0 (before RME) and at T1 (3 month after the end of expansion). To verify the neuromuscular equilibrium, the EMG activities of both right and left masseter and anterior temporal muscles were recorded during a test of maximum clench. EMG indexes were compared by paired Student?s t-test. In both occasions, all indices showed a good symmetry between the right and left side masticatory muscles. No statistically significant differences were found between the two recordings. In children without pre-treatment EMG alterations, no variations in standardized muscular activity after RME were found. The treatment did not alter the equilibrium of the masseter and temporal muscles

Effects of the functional orthopaedic therapy on masticatory muscles activity

The purpose of this study was to examine surface electromyographic (sEMG) activity of masticatory muscles before and after functional orthopaedic therapy with Sander appliance. Ten adolescents (5 girls, 5 boys) with an Angle Class II, division I malocclusion, 9-13 years old, were submitted to sEMG before and after functional orthopaedic therapy. To verify the neuromuscular equilibrium, the standardized EMG activities of right and left masseter and anterior temporal muscles were recorded during maximum voluntary clench, and analysed calculating: POC (index of the symmetric distribution of the muscular activity determined by the occlusion); TC (index of presence of mandibular torque) and Ac (index suggesting the position of occlusal barycentre). The total muscular activity was also calculated. Pre- and post- functional therapy data were compared with Wilcoxon Signed-Rank Test. Before treatment, all subjects had a good neuromuscular equilibrium, which was not altered by treatment. sEMG evaluations allow to quantify the impact of occlusion on masticatory muscle activity and to control that the functional orthopaedic therapy maintain a good muscular coordination

Expansion of permanent first molars with rapid maxillary expansion appliance anchored on primary second molars

To evaluate how the amount of expansion of the primary second molars, the patient?s age, and the skeletal maturation stage influence the amount of expansion at the level of the permanent first molars. Fifty-five patients aged between 6 and 11 years with a cervical vertebral maturation stage of CS1 or CS2 were retrospectively selected. The intermolar width was measured before and after expansion to evaluate the amount of expansion achieved at the level of the primary second molars and the permanent first molars. Stepwise multiple linear regression was used to evaluate how the amount of primary molars expansion, the patient?s age, and the cervical vertebral maturation stage predict the amount of permanent molar expansion. A significant regression equation was found, and for every 1 mm of primary molar expansion, 0.91 mm of permanent molar expansion can be expected. An age between 6 and 11 years and the CS1 or CS2 skeletal maturation stage were not significant predictors of permanent molar expansion. A rapid maxillary expansion appliance anchored on primary second molars is effective in expanding the permanent molars to correct a transverse maxillary deficiency in prepubertal patients, transferring the risks associated with the large forces used to the primary teeth

Dentoskeletal effects of the bitejumping appliance and the twin-block appliance in the treatment of skeletal class ii malocclusion: A retrospective controlled clinical trial

The current retrospective controlled trial aimed to compare the dentoskeletal effects of the Bite-Jumping (BJ) and the Twin- Block Appliance (TB) in the treatment of skeletal Class II malocclusion. The sample was screened for eligibility criteria including skeletal and dental Class II malocclusion; Cervical Vertebral Maturation at Stage 3 at treatment start, and Func- tional orthopedic treatment with either a TB or BJ appliances. Twenty-three patients treated with TB, and twenty-three treated with BJ were included. Cephalometric data were compared with a control group of 15 untreated subjects retrieved from the American Association of Orthodontists Foundation Craniofacial Growth Legacy Collection. Baseline character- istics were similar between groups. A significant increase for the AO-BO dimension, and a significant decrease in the over- jet, were registered for both study groups respect to controls. TB was more effective than BJ in increasing the mandibu- lar length (Co-Gn), in reducing the ANB angle and changing the SNB angle. The resulting differences between the two groups could be attributed to the different appliances. In conclusion, both appliances demonstrated a clinical efficacy in treating Class II. TB seems therefore better indicated, respect to BJ, in Class II cases with a predominant component of mandibular hypoplasia

Efecto de la prolongación de la máscara facial en el desarrollo de los caninos maxilares impactados: un estudio retrospectivo.

Objective: The aim of the present study was to evaluate if maxillary protraction with facemask increases the risk of maxillary canine impaction. Materials and method: The records of 76 skeletal Class III subjects with a cervical vertebral maturation stage between CS1 and CS3 and a displaced maxillary canine were retrospectively collected. Intraoral photographs, orthopantomography and lateral cephalograms were collected, and patients were divided into three groups depending on the type of treatment received – a Rapid Palatal Expander (RPE), a RPE in conjunction with a facemask (RPE-FM), or a Class III functional appliance (FA). The patient’s records were used to determine if the maxillary canines were correctly erupted after that phase of treatment. A binary logistic regression was used to evaluate the effect of treatment modality and skeletal maturation stage on the chance of maxillary canine impaction. Results: No effect of the three different treatment modalities and of the skeletal maturation stage on the risk of canine impaction was observed. Conclusions: The protraction facemask can be used in growing skeletal Class III subjects without increasing the risks of maxillary canine displacement.El objetivo del presente estudio fue evaluar si la protracción maxilar con mascarilla aumenta el riesgo de impactación canina maxilar. Materiales y método: se recogieron retrospectivamente los registros de 76 sujetos esqueléticos de Clase III con una etapa de maduración vertebral cervical entre CS1 y CS3 y un canino maxilar desplazado. Se recogieron fotografías intraorales, ortopantomografía y cefalogramas laterales, y los pacientes se dividieron en tres grupos según el tipo de tratamiento recibido: un expansor palatino rápido (RPE), un RPE junto con una máscara facial (RPE-FM) o un aparato funcional (FA) clase III. Los registros del paciente se usaron para determinar si los caninos maxilares entraron en erupción correctamente después de esa fase del tratamiento. Se utilizó una regresión logística binaria para evaluar el efecto de la modalidad de tratamiento y la etapa de maduración esquelética sobre la posibilidad de impactación canina maxilar. Resultados: no se observó ningún efecto de las tres modalidades de tratamiento diferentes y de la etapa de maduración esquelética sobre el riesgo de impactación canina. Conclusiones: la mascarilla de protracción se puede usar en sujetos esqueléticos clase III en crecimiento sin aumentar los riesgos de desplazamiento canino maxilar

Condylar Asymmetry in Children with Unilateral Posterior Crossbite Malocclusion: A Comparative Cross-Sectional Study

Unilateral posterior crossbite (UXB) is a common, severely asymmetric malocclusion, characterized by maxillary hypoplasia and masticatory dysfunction. The aim of this research is to evaluate the asymmetry of mandibular condyles and rami in children with UXB. This comparative cross-sectional study included 33 children with UXB (girls = 15, boys = 18; mean age ± SD = 8.0 ± 1.3 years.months]) and 33 age- and gender-matched controls (girls = 15, boys = 18; mean age ± SD = 8.4 ± 1.3 years.months]). Pre-treatment OPGs were analyzed by comparing the height of condyles and rami between the sides using the method by Habets et al. (1988); the result was considered significant if the degree of asymmetry was >6%. Children with UXB showed a significantly increased asymmetry of mandibular condyles (mean ± SD = 10.7% ± 9, p < 0.001), but not of rami (mean ± SD = 1.9% ± 2.3), compared to controls. The rami did not show significant asymmetry in either group. The presence of an increased condylar asymmetry index in a developing patient with unilateral posterior crossbite is a sign of altered skeletal growth and should be considered in the diagnostic process and treatment plan