Effects of low-level laser therapy on the rate of orthodontic tooth movement.

OBJECTIVES: To test the hypothesis that mechanical forces combined with low-level laser therapy stimulate the rate of orthodontic tooth movement. STUDY DESIGN: This study was a double blind, randomized placebo/control matched pairs clinical trial to test the efficacy of GaAlAs low-level laser therapy (LLLT) on 12 young adult patients who required retraction of maxillary canines into first premolar extraction spaces using tension coil springs with fixed edgewise appliance. LLLT was applied on the mucosa buccally, distally and palatally to the canine on the test side and using a pseudo-application on the placebo side. Dental impressions and casts were made at the commencement of the trial and at the end of the first, second and third months after starting the trial. Measurement of tooth movements was made on each stage model using a stereo microscope. RESULTS: There was no significant difference of means of the canine distal movement between the LLLT side and the placebo side for any time periods (p-value = 0.77). CONCLUSION: The energy density of LLLT (GaAlAs) at the surface level in this study (25 J/cm(2)) was probably too low to express either stimulatory effect or inhibitory effect on the rate of orthodontic tooth movement.

Thickness of palatal masticatory mucosa associated with age.

BACKGROUND: The palatal masticatory mucosa is widely used as a donor material in periodontal plastic surgery. However, there are relatively few studies investigating the volume or thickness of the palatal mucosa. The purpose of this study was to determine the thickness of palatal masticatory mucosa in Asian subjects aged 14 to 59 years by a direct clinical technique. The associations of age and gender with the thickness of palatal mucosa were also examined. METHODS: Sixty-two systemically and periodontally healthy Asians (31 males; 31 females; age range 14 to 59 years) participated in this study. The younger age group (age 14 to 21 years) consisted of 32 subjects with a mean age of 16.8 years, whereas the older age group (age 30 to 59 years) consisted of 30 subjects with a mean age of 38.7 years. A bone-sounding method using a periodontal probe with minimal anesthesia and a prepared clear acrylic stent were utilized to assess the thickness of palatal mucosa at 15 measurement sites defined according to the gingival margin and mid-palatal line. Multiple linear regression analysis was performed to examine the associations of age and gender with the mean mucosal thickness at the subject level. The Wilcoxon test was used to determine the difference in mucosal thickness between the 2 age groups, and between gender at each measurement point. RESULTS: The mean thickness of palatal masticatory mucosa ranged from 2.0 to 3.7 mm. The younger age group had significantly thinner mucosa (mean 2.8 +/- 0.3 mm) than the older age group (mean 3.1 +/- 0.3 mm). Females had thinner mucosa than males in the same age group, but the difference was not statistically significant. Overall, the thickness of palatal mucosa increased from the canine to second molar areas and in the sites furthest from the gingival margin towards the mid-palate (with the exception of the first molar area, where significantly decreased thickness was observed). CONCLUSIONS: Within the limits of the present study, the canine and premolar areas appear to be the most appropriate donor site for grafting procedures in both young and adult individuals. The subepithelial connective tissue graft procedure can be considered as a treatment modality in young patients, since a sufficient volume of donor tissue can be obtained from the hard palate area. Other factors that may influence the thickness of palatal mucosa such as racial and genetic factors and body weight need to be further investigated.