Water jet as a novel technique for enamel drilling ex vivo.

To investigate the usage of a water jet for enamel drilling ex vivo, 210 individual extracted molars without lesions or fillings were collected. Then, the specimens were drilled by a water jet or a high-speed dental drill. The cavities of 50 teeth were reconstructed digitally by micro-computed tomography (micro-CT) to measure the height and width. The cavities of 10 teeth were longitudinally incised and their surfaces were observed by scanning electronic microscopy (SEM). After the cavities were filled, 50 fillings were vertically incised. The bonding interface between tooth and filling was observed by SEM. 50 teeth with fillings were stained in 0.1% rhodamine B solution, and then the dye penetration between tooth and filling was observed under the stereomicroscope and confocal laser scanning microscopy (CLSM). The bonding strength between enamel and filling of 50 teeth was simulated and predicted with finite element analysis (FEA). At 140-150 MPa and for 2-3 s, cavities were made with a depth of approximately 764 µm in each tooth. SEM showed the cavity surface in the water jet group had a more irregular concave and convex structure than that in the high-speed dental drill group. There was a trend that the microleakage and bonding width was smaller in the water jet group than in the high-speed dental drill group. FEA indicated that the stress on the resin surface was greater than on the enamel surface in the water jet group. Compared with the tooth drilled by a high-speed dental drill, the tooth drilled by a water jet gained better retention of the filling material and suffered less bonding strength on the enamel surface. Water jet drilling is effective for enamel drilling.

The Effect of Periodontitis on Dementia and Cognitive Impairment: A Meta-Analysis.

The association between periodontal disease and dementia/cognitive impairment continues to receive increasing attention. However, whether periodontal disease is a risk factor for dementia/cognitive impairment is still uncertain. This meta-analysis was conducted to comprehensively analyze the effect of periodontitis on dementia and cognitive impairment, and to assess the periodontal status of dementia patients at the same time. A literature search was undertaken on 19 October 2020 using PubMed, Web of Science, and Embase with different search terms. Two evaluators screened studies according to inclusion and exclusion criteria, and a third evaluator was involved if there were disagreements; this process was the same as that used for data extraction. Included studies were assessed with the Newcastle-Ottawa Scale (NOS), and results were analyzed using software Review Manager 5.2. Twenty observational studies were included. In the comparison between periodontitis and cognitive impairment, the odds ratio (OR) was 1.77 (95% confidence interval (CI), 1.31-2.38), which indicated that there was a strong relationship between periodontitis and cognitive impairment. There was no statistical significance in the effect of periodontitis on dementia (OR = 1.59; 95%CI, 0.92-2.76). The subgroup analysis revealed that moderate or severe periodontitis was significantly associated with dementia (OR = 2.13; 95%CI, 1.25-3.64). The mean difference (MD) of the community periodontal index (CPI) and clinical attachment level (CAL) was 0.25 (95%CI, 0.09-0.40) and 1.22 (95%CI, 0.61-1.83), respectively. In this meta-analysis, there was an association between periodontitis and cognitive impairment, and moderate or severe periodontitis was a risk factor for dementia. Additionally, the deterioration of periodontal status was observed among dementia patients.

A Meta-Analysis of Oral Health Status of Children with Autism.

Purpose: To present a meta-analysis whether the risks of caries and periodontal problems in autistic children are higher than those in healthy children. Study design: A literature search that included PubMed, Embase, Web of Science, Cochrane, China National Knowledge Infrastructure (CNKI), Wan fang, and Chinese Scientific and Technological Journal (VIP) databases was conducted. The primary outcomes of interest included the DMFT index, Plaque index (PI), Gingival index (GI), and Salivary pH. Quality assessment was performed in accordance with the Newcastle-Ottawa Scale (NOS). Dichotomous variables are presented as relative risk (RR), and continuous variables are presented as weighted mean difference (WMD). Results: Eight studies were included in this meta-analysis. Among these 8 studies, six studies compared the DMFT index, three studies compared PI, three studies compared GI, and three studies compared salivary pH. Meta-analysis showed that the mean DMFT index in autistic children was higher than that in healthy children, and the difference was statistically significant {MD = 0.50, 95% CI [0.04-0.96], P<0.00001}. Similarly, PI and GI in autistic children were higher than those in healthy children, and the difference between PI was statistically significant {MD = 0.59, 95%CI [0.36-0.82], P=0.02}, while the difference between GI was not statistically significant {MD = 0.52, 95%CI [0.30-0.75], P=0.08}. But the salivary pH in autistic children was lower than that in healthy children {MD = -0.28, 95%CI [-0.54--0.02], P = 0.02}, and the difference was statistically significant. Conclusion: The present analysis suggests that children with autism have poorer oral hygiene, higher risk of caries, and a lower salivary pH than healthy children.