Assessment of Dental Arch Changes and Buccal Bone Thickness in Patients treated with Self-ligating Brackets.

AIMS: To evaluate changes in transverse dimensions of upper arch and thickness of the buccal bone plate in patients undergoing orthodontic treatment during the leveling phase. MATERIALS AND METHODS: Sixteen patients aged between 11 and 30 years, presenting with class I and II malocclusion, with minimum of 2 mm crowding treated without extraction, were divided into two groups: GI (n = 8), self-ligating brackets (Easyclip Aditek), and GII (n = 8), conventional preadjusted brackets (3M Unitek). The intercanines, interpremolar, and intermolar widths were measured in dental casts using a digital caliper, before (T1) and after 6 months of treatment (T2). Measurements of the thickness of the bone plate were performed by using cone-beam computed tomography (CBCT) scans and Dolphin three-dimensional program. Paired and nonpaired t tests were applied to analyze the results in and between the groups for the changes in the transversal arch dimensions and buccal bone thickness. RESULTS: In all statistical tests, the significance level was set at 5%. A nonsignificant increase in transverse dimensions and a slight reduction on thickness of the buccal bone plate were observed in both groups. CONCLUSION: The dimensional changes of transverse and thickness of the bone plate during the initial phase of treatment were similar, regardless of the bracket design. CLINICAL SIGNIFICANCE: It should be noted that the bracket design does not influence the treatment course regarding transversal dimensions and buccal bone thickness.

Anti-inflammatory and analgesic effects of low-level laser therapy on the postoperative healing process.

[Purpose] This study aimed to evaluate the anti-inflammatory and analgesic effects of intraoral application of low-level laser therapy (660 nm) to control pain, swelling and interincisal opening following the extraction of mandibular third molars. [Subjects and Methods] Ten patients underwent removal of lower third molars using the same surgical protocol and pharmacological approach. In the postoperative period, all patients received four consecutive daily sessions of low-level laser therapy, beginning 24 hours after the surgery. Intraoral applications using the diode laser with 660 nm wavelength in the continuous scan mode were performed covering the entire surgical area, which was divided into four quadrants, each of 1 cm(2) area at a distance of 1 cm. The energy applied at each point was 5 J/cm(2) during 8 seconds. [Results] The swelling and interincisal opening returned to normal 24 hours after the first low-level laser therapy application (Friedman test). Moreover, the pain intensity was reduced on the third postoperative day, according to the Friedman test. [Conclusion] Low-level laser therapy (660 nm), at the dosimetry used in this study, was effective in reducing postoperative pain and swelling following oral surgery.

The impact of healing time before loading on orthodontic mini-implant stability: a histomorphometric study in minipigs.

OBJECTIVE: To evaluate healing time before loading, areas compression and tension and location of insertion on mini-implant stability. DESIGN: Six minipigs were used. Each animal received 3 mini-implants in each quadrant: 1 mini-implant was used as an unloaded control (G1, n=24); the other 2 were loaded with 150g-force at three time intervals (G2: immediate loading, G3: after 15 days and G4: after 30 days), with 16 mini-implant in each experimental group. After 120 days, tissue blocks of the areas of interest were harvested. Clinical analysis (exact Fisher test) determined the survival rate. Histological analysis (Kontron KS 300™, Zeiss) quantified the fractional bone-to-implant contact (%BIC) and bone area (%BA) at each healing time point, areas of interest, and insertion site (ANOVA and t tests for dependent and independent samples). RESULTS: The mini-implant survival rates were G1: 71%, G2: 50%, G3: 75% and G4: 63%, with no statistical differences between them. The groups presented similar %BIC and %BA. There were no differences between the compression and tension sides or maxillary and mandibular insertion sites. CONCLUSIONS: These results suggest that low-intensity immediate or early orthodontic loading does not affect mini-implant stability, because similar histomorphometric results were observed for all the groups, with partial osseointegration of the mini-implants present.

Radiographic techniques for medical-dental research with minipigs.

Techniques were developed to obtain standardised intra- and extra-oral radiographs in minipigs for use in medical-dental research. Twelve male minipigs (BR-1 Minipigs) were chosen at random. Two animals each at 3, 5, 7, 9, 12 and 15 months of age were anaesthetised and subjected to radiographic examinations to assess six techniques. Three intra-oral and three extra-oral techniques, standardised for humans, were used with variations of the angle of incidence of the X-ray beams, focus-film distance and exposure time. Two film positioners were developed for the intra-oral techniques. Two examiners then chose the radiographs with the least image distortion, greatest clarity and least superimposition of images. For each technique, the suitable angle of incidence of the X-ray beams, the focus-film distance and exposure time that produced the highest quality radiographs were standardised.

Dental and skeletal characterization of the BR-1 minipig.

This study was designed to characterize the development of oral structures in the BR-1 minipig and to compare these data with literature reports on domestic swine and other minipig lineages. Twelve male minipigs were anesthetized and given physical and radiographic examinations. The presence and chronology of tooth eruption from 3 to 15 months of age were assessed, and the radiographic results were interpreted by two certified researchers, who obtained a high index of agreement (kappa>0.81). The eruption chronology was similar to that reported for domestic swine and other minipig lineages. The results indicate that it is possible to use the BR-1 minipig in dental research.