Abstract

Previous studies have shown that functional appliances can enhance mandibular growth when applied during the active growth period. However, besides patient compliance problems with bulky appliances and prolonged treatment demands, there is contradictory evidence that functional appliances have a significant long-term effect. Is there a method to enhance the growth response and improve the long-term success of functional appliances? Previous studies have also found that therapeutic ultrasound (US) can stimulate cartilage and bone growth. The objective of this study was to evaluate the effect of therapeutic US on condylar and mandibular growth in the rabbit model. Eight growing New Zealand male rabbits were chosen for this study. They received therapeutic US on one side of the mandible for 20 minutes/day for four weeks. Anthropometrical and histological evaluations revealed that US enhances mandibular growth by condylar endochondreal bone growth and consequently mandibular ramus growth. The significant results of this study support conducting a long-term study to evaluate the ultimate stability of the results obtained. Also, they suggest an extended research with a larger sample size and investigating the molecular basis of this stimulatory effect, together with forward posturing splints for optimal macroscopic and microscopic responses.

Abstract

Removable retention appliances were applied to 20 treated orthodontic patients, and their occlusal contact points were determined from occlusal registrations taken at the beginning and the end of retention. Furthermore, to determine the results at the end of retention, the occlusion of 20 treated patients was compared with a control group of another 20 subjects who had an ideal occlusion. During the retention phase the number of contacts in centric occlusion increased significantly. No significant difference was observed with regard to the location of contacts. Whereas the number of ideally located contacts was similar to that in the control group, differences were observed in actual and canine contacts between the groups. At the end of retention, the balancing side contacts in lateral movements and the posterior contacts in protrusive movements were generally determined as near contacts and showed a similarity to the control group. In order to maintain the occlusal stability that is needed for the success of orthodontic treatments, ideal occlusal contacts and localization of contacts in centric and eccentric occlusion should be considered.

Abstract

In studying the response of the glenoid fossa to mandibular protrusive appliances, apart from the condyle, much attention has been focused on what happens to the posterior wall of the fossa (postglenoid process). Remarkably, the articular eminence has been overlooked, although it is the most adaptive area of the temporomandibular joint. The purpose of this study was to explore the type of response of the articular eminence morphology to the use of mandibular propulsive appliances (activators). The study material consisted of individually corrected pre- and posttreatment lateral tomograms of 35 patients (18 boys and 17 girls) who had been diagnosed as suitable for treatment with a mandibular protrusive appliance (activator). The tomograms were scanned and digitized on screen, and points located on each tomogram and linear measurements were used to evaluate any change in glenoid fossa morphology. Paired t-tests were applied separately for the left and right sides to compare pre- and posttreatment measurements. Paired t-tests were also applied to test any difference between the left and right sides. The results of this study show that there is no statistically significant change in articular eminence morphology (height and inclination) as a result of using mandibular protrusive appliances.

Intraosseous migration of nonerupting teeth was an unknown natural phenomenon until the introduction of diagnostic roentgenography in the 1920s. Since then, clinicians have filled the literature with case reports of striking occurrences of migrating, impacted maxillary canines, mandibular canines and mandibular second premolars. Thus, today, descriptive reports of these infrequent dental anomalies are no longer so special.

Instead, we are in an era that values the collection of study samples composed of many affected individuals, not just one or several. Using statistical analysis with appropriately sized samples, we can often identify trends and significant associations for rare conditions that a

Lip incompetence resolved by active vertical control in nonsurgical treatment of a protrusion case with vertical maxillary excess

Johnny JL Liaw,

Jae Hyun Park,

Fang Fang Tsai,

Betty MY Tsai, and

Wendy WT Liao