The Effects of Photobiomodulation on Bone Defect Repairing in a Diabetic Rat Model.

The purpose of this study is to examine the prospective therapeutic effects of photobiomodulation on the healing of bone defects in diabetic mellitus (DM) using rat models to provide basic knowledge of photobiomodulation therapy (PBMT) during bone defect repair. For in vitro study, an Alizzarin red stain assay was used to evaluate the effect of PBMT on osteogenic differentiation. For in vivo study, micro-computed tomography (microCT) scan, H&E and IHC stain analysis were used to investigate the effect of PBMT on the healing of the experimental calvarial defect (3 mm in diameter) of a diabetic rat model. For in vitro study, the high glucose groups showed lower osteogenic differentiation in both irradiated and non-irradiated with PBMT when compared to the control groups. With the PBMT, all groups (control, osmotic control and high glucose) showed higher osteogenic differentiation when compared to the non-irradiated groups. For in vivo study, the hyperglycemic group showed significantly lower bone regeneration when compared to the control group. With the PBMT, the volume of bone regeneration was increasing and back to the similar level of the control group. The treatment of PBMT in 660 nm could improve the bone defect healing on a diabetic rat calvarial defect model.

Anti-inflammatory effects of low-level laser therapy on human periodontal ligament cells: in vitro study.

Periodontal disease is a chronic inflammatory disease that is commonly treated with surgical and nonsurgical techniques. However, both approaches have limitations. Low-level laser therapy (LLLT) has been widely applied in reducing inflammatory reactions, and research indicates that LLLT induces an anti-inflammatory effect that may enhance periodontal disease therapy. The purpose of this study was to investigate the anti-inflammatory effect of LLLT on human periodontal ligament cells (hPDLCs) in an inflammatory environment and aimed to determine the possible mechanism of action. Cells were cultured and treated with or without lipopolysaccharide (LPS) from Porphryromonas gingivalis or Escherichia coli, followed by irradiation with a gallium-aluminum-arsenide (GaAlAs) laser (660 nm) at an energy density of 8 J/cm2. Quantitative real-time polymerase chain reactions were used to assess the expression of pro-inflammatory genes, including tumor necrosis factor-α (TNF-α), interleukin (IL)-1ß, IL-6, and IL-8. The dual-luciferase reporter assay was used to examine nuclear factor-κB (NF-κB) transcriptional activity. An enzyme-linked immunosorbent assay was used to monitor the concentration of intracellular cyclic adenosine monophosphate (cAMP). Both LPS treatments significantly induced the mRNA expression of pro-inflammatory cytokines. However, LLLT inhibited the LPS-induced pro-inflammatory cytokine expression and elevated intracellular levels of cAMP. The LLLT inhibitory effect may function by downregulating NF-κB transcriptional activity and by increasing the intracellular levels of cAMP. LLLT might inhibit LPS-induced inflammation in hPDLCs through cAMP/NF-κB regulation. These results should be further studied to improve periodontal therapy.

Tongue support of complete dentures in the elderly.

This study aimed to evaluate the tongue's role in supporting maxillary denture retention (MDR), in providing additional stabilization for the mandibular denture, and the tongue's relationship with the oral health-related well being in elderly complete denture patients. Four hundred elderly individuals, 263 males and 137 females, were enrolled in this study. All were older than 65 years, and wore complete dentures. Intraoral examinations were performed in accordance with the 10 criteria embedded in the Functional Assessment of Dentures (FAD). Participants also received personal interviews and completed the Oral Health Impact Profile-14 (OHIP-14) questionnaire. The associations between MDR (tongue support) with the mean OHIP-14 sum scores and FAD categories were analyzed using the t test or analysis of variance (ANOVA). Combinations of MDR (tongue support), MDR (resistance to vertical pull), and mandibular denture stability (anterior-posterior movement) were also assessed with the remaining FAD criteria and OHIP-14 domain scores. Individuals with adequate MDR (tongue support) were significantly associated with denture articulation, denture occlusion, MDR (resistance to vertical pull), maxillary denture stability (pronounced rocking), and mandibular denture stability (anterior-posterior movement). When individuals with adequate MDR (tongue support) were analyzed in conjunction with adequate MDR (resistance to vertical pull) and adequate mandibular denture stability (anterior-posterior movement), significant associations were observed with the mean OHIP-14 sum score and three individual OHIP-14 domains: functional limitation, physical pain, and physical disability (p ＜ 0.05). The mean OHIP-14 sum score was lower among individuals with both adequate MDR (tongue support) and inadequate MDR (resistance to vertical pull) than among participants with both inadequate MDR (tongue support) and inadequate MDR (resistance to vertical pull). MDR (tongue support) demonstrated significant differences from denture occlusion, denture articulation, MDR (resistance to vertical pull), maxillary denture stability (pronounced rocking), and mandibular denture stability (anterior-posterior movement). MDR (tongue support), in conjunction with both adequate MDR (resistance to vertical pull) and adequate mandibular stability (anterior-posterior movement), were significantly associated with the individuals' oral health-related well being.

Improved denture retention in patients with retracted tongues.

BACKGROUND: Patients who wear mandibular dentures and hold their tongues in retracted positions alter the dimensions of the sublingual space and disrupt the peripheral seal that is needed for optimal denture retention. The authors studied whether retention could be improved if patients moved their tongues from a retracted resting position to an ideal resting position. METHODS: The authors observed and classified the mandibular residual ridge morphologies of 85 participants who wore complete dentures. The authors recorded and compared the retention of the mandibular denture before and after repositioning the tongue to the ideal resting position. RESULTS: When the participants' tongues were in a retracted resting position, the average retention of the mandibular denture was 75.38 gram weight (+/- 81.83 standard deviation [SD]). After participants repositioned their tongues to the ideal resting position, the average retention of the mandibular denture was 118.89 gw (+/- 93.00 SD), an increase of 57.73 percent. CONCLUSIONS: In all morphological classes, when participants held their tongues in the ideal resting position, the average mandibular denture retention increased by 57.73 percent, a statistically significant improvement compared with when participants held their tongues in a retracted resting position. CLINICAL IMPLICATIONS: Clinicians are encouraged to evaluate carefully the tongue resting position in all patients who wear dentures, help create reasonable therapeutic expectations by informing patients about the significant effect that tongue position will have on future denture retention and provide helpful neuromuscular training for patients with retracted-tongue habits.