Efficacy of erbium-doped yttrium aluminum garnet laser with casein phosphopeptide amorphous calcium phosphate with and without fluoride for remineralization of white spot lesions around orthodontic brackets

Objective

This study aimed to assess the efficacy of erbium-doped yttrium aluminum garnet (Er:YAG) laser, pastes containing casein phosphopeptide amorphous calcium phosphate (CPP-ACP) with and without fluoride and their combination for prevention of white spot lesions in the enamel.

Materials and Methods

This in vitro experimental study was conducted on 90 extracted sound premolars. The teeth were then randomly divided into six groups of 15: (1) Control, (2) laser, (3) CPP-ACP with fluoride (GC MI Paste, Recaldent™ 900 ppm as NaF), (4) CPP-ACP without fluoride (GC Tooth Mousse Recaldent™), (5) laser + CPP-ACP with fluoride, and (6) laser + CPP-ACP without fluoride. In each group, enamel surface was exposed to the remineralizing agent. The teeth were then subjected to pH cycling for 14 days. The teeth were then sectioned, polished, and underwent cross-sectional microhardness testing at 20-160 μ depth quantitatively. Using the Simpson's rule, the amount of mineral loss was calculated in each group. Statistical Analysis Used: ANOVA was used for the comparisons, and Tukey's test was applied for pairwise comparisons.

Results

The highest mean volume percentage of microhardness at 20-60 μ depth belonged to the group laser + CPP-ACP with fluoride and the lowest belonged to the control group (P = 0.001). The differences were not significant at 80-120 μ depth (P > 0.05). These finding are confirmed according to △Z (mineral loss).

Conclusion

Based on these results, Er: YAG laser was able to decrease demineralization and was a potential alternative to preventive dentistry and was more effective when combined with CPP-ACP products.

Effect of Carbon Dioxide Laser on Increasing Vestibular Depth in Cleft Lip and Palate Patients

BACKGROUND

Shallow upper buccal sulcus deformity in cleft lip and palate patients is one of the common secondary deformities after primary cleft lip and palate repair; this deformity may prevent or complicate orthodontic and prosthodontic procedures causing aesthetic and functional problems. A number of methods are described to increase the anterior maxillary sulcus in these patients.

PURPOSE

This study assessed the use of a carbon dioxide laser (CO₂) to increase the sulcus depth.

METHOD

Fifteen patients with cleft lip and palate (eight unilateral and seven bilateral) were studied. The surgical procedure was performed using CO₂ laser. The vestibular depth and lip length were measured at three time points namely before surgery (T0), 1 week following surgery (T1), and 4 months following surgery (T2). After data collection, statistical analyses were done using PASW^® version 18 SPSS.

RESULTS

The mean values of vestibular depth were 9.46 ± 1.92, 13.83 ± 1.88, and 13.23 ± 1.76 mm for T0, T1, and T2, respectively. The vestibular depth significantly increased after 4 months of follow-up (p = 0.001). The mean amount of vestibular depth gain was not significantly different in unilateral and bilateral cleft groups (p = 0.908). The mean value of upper lip length increased by a mean of 1.23 mm and was statistically significant (p = 0.001).

CONCLUSIONS

Upper buccal sulcus reconstruction with CO₂ laser provides successful and stable results. CO₂ laser application is suggested as an alternative to conventional vestibuloplasty.

New evidence on hypoglycemic effect of quinolinic acid in diabetic rats

In the present study, the effects of administrating 4 mM and 300 mg kg(-1) b.wt. of quinolinic acid were studied, in vitro and in vivo, respectively, to evaluate its inhibitory activity on phosphoenolpyruvate carboxykinase in diabetic rats. The results of in vitro studies have clearly indicated the inhibitory effect of quinolinic acid on enzyme activity. The hill plot showed the binding stoichiometry of quinolinic acid per enzyme to be 4:1. The in vivo studies showed that intra peritoneal injection of 300 mg kg(-1) b.wt. initiates reduction of blood glucose level in 1 h after injection, restoring the blood glucose to its normal level at 2 h post injection and keeping it constant for at least further 4 h. Based on present results we concluded that quinolinic acid and hence its precursor tryptophan having induced obvious hypoglycemic effects in normal and diabetic rats at high enough concentrations, they are worthy of further study and research for their hyperglycemic effect in other diabetic animal models.