Comparative assessment of two-phase class II treatment with Activator or Bionator followed by fixed appliances: A retrospective controlled before-and-after study.

AIM: Two-phase treatment for children with Class II malocclusion with several functional appliances is still performed by many orthodontists, while the Activator and the Bionator appliances are two of the most popular ones. Aim of this study was to compare the skeletal and dentoalveolar effects of treatment with these two appliances. METHODS: Class II children treated with Activator or Bionator in the first phase, followed by a phase of fixed appliances were included. Skeletal and dentoalveolar parameters were assessed from lateral cephalograms and analysed with linear regressions at 5%. RESULTS: A total of 89 patients (mean age 10.0 years; 47% female) were included. During the first phase, Bionator increased less the SNB (difference in mean treatment-induced changes [MD] -0.7°; 95% confidence interval [CI] -1.3 to -0.2°; P=0.01) and decreased less the ANB angle (MD 0.6°; 95% CI 0 to 1.1°; P=0.03) compared to Activator. Activator slightly increased the facial axis and Bionator reduced it (MD -1.6°; 95% CI -2.3 to -0.8°; P<0.001). Compared to Activator, the Bionator retroclined more the upper incisors (MD -2.4°; 95% CI -4.6 to -0.2°; P=0.03) and increased more the interincisal angle (MD 2.9°; 95% CI 0.5 to 5.4°; P=0.02). After the second phase (6.2 years after baseline), the only differences were a reduced facial axis (MD -1.3°; 95% CI -2.2 to -0.3°; P=0.008) and an increased maxillary rotation (MD 0.9°; 95% CI 0 to 1.8°; P=0.04) with Bionator compared to Activator. CONCLUSION: Similar dentoalveolar effects were seen overall with two-phase treatment with either appliance, with Bionator being associated with more vertical increase compared to Activator.

Incidence of incisor root resorption associated with the position of the impacted maxillary canines: A cone-beam computed tomographic study.

INTRODUCTION: The purpose of this study was to examine the incidence and position of lateral and central incisor root resorption owing to the impaction of maxillary canines by means of cone-beam computed tomography and to investigate parameters associated with the respective resorption. METHODS: Sixty-one patients presenting with unilateral or bilateral impacted maxillary canines were evaluated in a university clinic in Athens, Greece, using cone-beam computed tomography scan. No patient had undergone any type of orthodontic treatment in the past. Eleven different parameters related to the existence, grade, and localization of resorption were examined. Logistic regression analysis was used to evaluate potential associations. RESULTS: In our study, canine impaction caused lateral root resorption in 18.5% of the cases examined. Age was associated with localization of the impacted maxillary left canine in a palatal-buccal direction. More specifically, in younger patients, the impacted left canine was more likely to be located in the middle of the maxillary bone, whereas in older patients, it was more likely to be located in the palatal or buccal side of the bone. Lateral root resorption in the apical or middle third was more common in the younger ages, whereas lateral root resorption in the incisal third more common in the older ages. Lateral root resorption increased as the angle between the longitudinal axis of the impacted canine and the adjacent lateral incisor also increased. CONCLUSIONS: Incidence of lateral root resorption was 18.5% in this study population. In younger patients, the impacted canines appear more often in the middle of the maxillary bone, whereas in older patients, the canines are located more often in the palatal or buccal side of the maxilla.

Reliability of different radiographic methods for the localization of displaced maxillary canines.

INTRODUCTION: The purpose of this study was to evaluate the reliability of the radiographic images of the main conventional x-ray techniques compared with the information from cone-beam computed tomography (CBCT). METHODS: Twenty patients with unilateral or bilateral impaction of the maxillary canines had radiographic examinations by means of periapical x-rays, occlusal x-rays, panoramic x-rays, and CBCT scans. Three experienced orthodontists examined all x-rays from each patient and evaluated the radiographic images of the impacted canines. The examiners were asked to detect resorption in adjacent teeth and the buccal-palatal position of the impacted canines. Agreement between examiners was statistically tested. RESULTS: Different diagnoses were produced by the 3 examiners regarding localization of the impacted canines and the presence or absence of root resorption of the adjacent teeth in conventional radiographic images. It appears that whereas panoramic x-ray is more sensitive in detecting resorption and tooth position, occlusal and periapical imaging have higher specificity and positive predictive value. The examiners were in good or excellent agreement when occlusal and periapicals were used for the definite diagnosis of resorption and tooth position. There was no disagreement of the examiners in CBCT images, which were used as the gold standard. CONCLUSIONS: Conventional radiographic methods demonstrated a more subjective diagnostic procedure compared with CBCT images. CBCT is a more accurate and precise examination method compared with conventional radiography for the localization of impacted teeth and root resorption of the adjacent teeth.

Dental arch and cephalometric changes following treatment for class III malocclusion by means of the function regulator (FR-3) appliance.

AIM: The aim of this retrospective clinical study was to evaluate dental arch, skeletal, dentoalveolar, and soft tissue profile changes following treatment of Class III malocclusion by means of the Function Regulator (FR-3) appliance. SUBJECTS AND METHODS: The study sample consisted of 14 growing patients (seven boys and seven girls) with a mean age of 9.7 +/- 1.1 years presenting Class III malocclusion. They were treated with an FR-3 appliance exclusively for a period of 2.4 +/- 0.6 years. Dental casts and lateral cephalometric radiographs were obtained immediately before initiation and after completion of treatment with the FR-3 appliance. Thirteen variables were used for the dental cast analysis and 61 variables for the cephalometric analysis. The paired t-test was utilized to evaluate the presence of significant changes (p < 0.05). RESULTS: The evaluation of the dental casts revealed that there was a significant increase in intermolar, interpremolar, and intercanine width of the maxilla and of palatal height after treatment. Concerning the mandible, an increase in intermolar and intercanine width and a decrease in lower arch depth were observed. Cephalometric evaluation revealed a significant decrease in SNB angle and an increase in ANB angle, overjet, facial convexity, nose prominence, and lower soft tissue face height. There was an increase in upper lip thickness and a decrease in lower lip convexity observed after treatment. CONCLUSIONS: The results of this study confirm a favorable functional and esthetic maxillary and mandibular position following treatment by means of the function regulator (FR-3) appliance.