Guided Bone Regeneration Using Injectable Vascular Endothelial Growth Factor Delivery Gel

Background: Vascularization underlies the success of guided bone regeneration (GBR) procedures. This study evaluates the regenerative potential of GBR in combination with vascular endothelial growth factor (VEGF) delivery via an injectable hydrogel system. Methods: Critical‐sized defects were created in rat calvariae, and GBR procedures were performed with a collagen membrane alone (control), or plus bolus delivery of VEGF, or plus application of VEGF‐releasing hydrogels (VEGF–Alg). Four and 8 weeks after treatment, defect sites were evaluated with microcomputed tomographic and histomorphometric analyses for blood vessel and bone formation. Results: At 4 weeks, relative to the control condition, the bolus addition of VEGF did not affect blood vessel density within the defect site, yet the application of VEGF–Alg significantly (P <0.05) increased blood vessel density. Although there was no difference in bone regeneration at 4 weeks, at 8 weeks there was a significant (P <0.05) increase in bone regeneration in the VEGF–Alg‐treated defects. Conclusions: These data demonstrate that the application of VEGF–Alg enhanced early angiogenesis, whereas at a later time point, it enhanced bone regeneration. Controlled delivery approaches of angiogenic growth factors used adjunctively with GBR may be a promising strategy for enhancing outcomes of GBR.     

A Simplified Palatal Lift Prosthesis for Neurogenic Velopharyngeal Incompetence

Velopharyngeal incompetence is a contributing factor to speech disorders and implies the presence of hypernasality, inappropriate nasal escape, and decreased air pressure during speech. One prosthetic treatment is a rehabilitative procedure employing a palatal lift prosthesis (PLP), which reduces hypernasality by approximating the incompetent soft palate to the posterior pharyngeal wall and consists of two parts, the anterior denture base and the palatal lifting plate, which are connected with steel wires; however, it seems difficult to reproduce the mobility of the soft palate in speaking, and it is therefore likely that the palatal lifting plate stimulates or oppresses the tissue of the soft palate and hinders rather than assists articulatory function. To avoid these disturbances we devised an adjustable PLP with a flexible conjunction between the denture base and the palatal lifting plate to obtain the optimal vertical lifting angle. The palatal plate was adapted to conform in a passive manner to the soft palate with light‐cured resin. The designed PLP simplified the procedure and reduced the number of adjustments and visits.     

Socioeconomic and psychosocial predictors of dental healthcare use among Brazilian preschool children

Background

Disparities in utilization of oral healthcare services have been attributed to socioeconomic and individual behavioral factors. Parents’ socioeconomic status, demographics, schooling, and perceptions of oral health may influence their children’s use of dental services. This cross-sectional study assessed the relationships between socioeconomic and psychosocial factors and the utilization of dental health services by children aged 1–5 years.

Methods

Data were collected through clinical exams and a structured questionnaire administered during the National Day of Children’s Vaccination. A Poisson regression model was used to estimate prevalence ratios and 95% confidence intervals.

Results

Data were collected from a total of 478 children. Only 112 (23.68%) were found to have visited a dentist; 67.77% of those had seen the dentist for preventive care. Most (63.11%) used public rather than private services. The use of dental services varied according to parental socioeconomic status; children from low socioeconomic backgrounds and those whose parents rated their oral health as “poor” used dental services less frequently. The reason for visiting the dentist also varied with socioeconomic status, in that children of parents with poor socioeconomic status and who reported their child’s oral health as “fair/poor” were less likely to have visited the dentist for preventive care.

Conclusion

This study demonstrated that psychosocial and socioeconomic factors are important predictors of the utilization of dental care services.

     

β-Cell Lipotoxicity in Response to Free Fatty Acid Elevation in Prepubertal Youth: African American Versus Caucasian Contrast

Prepubertal African American (AA) youth compared with their Caucasian (C) peers have higher insulin secretion, which correlates positively with free fatty acid (FFA) concentration. In our continued efforts to explain the racial disparity in insulinemia, and because FFAs modulate insulin secretion, we hypothesized that AA youth would have a greater response to FFA-induced β-cell insulin secretion than C youth. We compared the short-term effects of FFA elevation on fasting and glucose-stimulated C-peptide–modeled insulin secretion in prepubertal normal-weight AA versus C peers during a 2-h hyperglycemic clamp (12.5 mmol/L) on two occasions: 1) infusion of normal saline and 2) infusion of 20% intralipid (IL). During IL infusion, insulin sensitivity (IS) declined comparably in AA and C youth. Glucose sensitivity of first- and second-phase insulin secretion showed a significant condition × race interaction being higher in AA youth. Disposition index, β-cell function relative to IS, declined with IL infusion in AA and C youth, with a significantly greater decrease in Cs compared with AAs. In conclusion, AA and C prepubertal youth both demonstrated a decline in β-cell function relative to IS during IL infusion, indicative of acute lipotoxicity. The greater decline in C youth compared with AAs may suggest that C youth are more susceptible to β-cell lipotoxicity than AA youth, or alternatively, that AA youth are hypersensitive to FFA stimulation of β-cell insulin secretion, consistent with our theory.Short-term exposure to elevated free fatty acid (FFA) concentrations has a stimulatory effect on β-cell function in in vitro and in vivo animal and human studies (1–8). On the other hand, chronic exposure to sustained elevations in FFAs has been shown to decrease insulin secretion and result in β-cell lipotoxicity in in vitro rat and human islet experiments (4,9,10) and in vivo human experiments (1,5,7,11,12).We previously found that prepubertal African American (AA) youth have higher insulin secretion and an upregulated β-cell function relative to insulin sensitivity (IS) compared with their Caucasian (C) peers (13). The hyperinsulinemic response in AA youth appears to be greater than the compensatory response to their lower IS, because the disposition index (DI), which is insulin secretion relative to IS, was ∼75% higher in AA than in C youth (13). Furthermore, first- and second-phase insulin concentrations during the hyperglycemic clamp correlated positively and significantly with fasting FFA levels in AAs but not Cs, despite similar plasma FFA concentrations (13). We therefore hypothesized that the higher insulin secretion in AA prepubertal youth could be driven by a greater sensitivity to the stimulatory effects of FFA on insulin secretion and β-cell function. Thus, in the present investigation we examined the effects of FFA elevation on glucose-stimulated insulin secretion in AA and C prepubertal normal-weight children, expecting to observe a heightened response in AA children.