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.

Prevalence and associated factors of periodontal conditions among 55- to 74-year-old adults in China: results from the 4th National Oral Health Survey.

OBJECTIVE: The purpose of this study was to assess periodontal health conditions among 55- to 74-year-old Chinese people and to analyze the factors associated with periodontal diseases. MATERIALS AND METHODS: In total, 9054 subjects aged 55-74 years were enrolled from all 31 provinces using a stratified multistage probability sampling method, autonomous regions and municipalities of the Chinese mainland, the response rate was 86.9%. All subjects underwent clinical examinations on the severest site for every tooth and completed a questionnaire that collected information on their sociodemographic characteristics and oral habits. T tests, chi-square tests and binary logistic regression analysis were performed to analyze the data. RESULTS: The percentage of people without bleeding on probing, probing depth ≥ 4 mm and attachment loss > 3 mm was 5.0 and 9.3% in the 55- to 64-year-old and the 65- to 74-year-old age group. The prevalence of bleeding on probing was 88.4% among 55 to 64 years old and 82.6% among 65 to 74 years old. Mean number of teeth with bleeding on probing were 13.87 among 55 to 64 years old and 11.25 among 65 to 74 years old. The prevalence of probing depth ≥ 4 mm and attachment loss > 3 mm were 69.3 and 69.9% in people aged 55-64 years and were 64.6 and 74.2% in people aged 65-74 years. Mean number of teeth with probing depth = 4-5 mm and probing depth ≥ 6 mm were 4.48 and 0.36 in 55-64 age group and 3.70 and 0.33 in 65-74 age group. And mean number of teeth with attachment loss > 3 mm were 5.17 among 55 to 64 years old and 5.63 among 65 to 74 years old. Besides, attachment loss > 3 mm was associated with age, gender, smoking, toothbrushing frequency and toothpick use. CONCLUSIONS: Periodontitis was not highly prevalent among 55- to 74-year-old Chinese adults. Age, gender, smoking, toothbrushing frequency and toothpick use could be risk factors. CLINICAL RELEVANCE: Scientific rationale for the study: The periodontal conditions among 55 to 64 and 65 to 74 years old Chinese population were not highly serious, but prevalence of bleeding on probing, periodontal pockets and attachment loss should be drawn enough attention by relevant public health administrations. PRINCIPAL FINDINGS: The prevalence of periodontal diseases was evaluated in 55- to 64-year-old and 65- to 74-year-old subjects in a nationally representative Chinese sample population. The prevalence of probing depth ≥ 4 mm and AL > 3 mm were high; these values were 69.3% and 69.9%, respectively, in the 55-64 age group and 64.6% and 74.2%, respectively, in the 65-74 age group. In addition, case percentage of AL = 4-5 mm combined with PD < 6 mm were 23.1 and 19.4% among 55- to 64-year-old and 65- to 74-year-old people. And case percentage of AL> 5 mm combined with PD ≥ 6 mm were 11.1% and 12.1% among 55- to 64-year-old and 65- to 74-year-old people, respectively. PRACTICAL IMPLICATIONS: The present study provides a reference for the epidemiological analysis of periodontal diseases. To reduce widespread inadequate treatment of periodontal diseases, clinical management should be performed in dental practices. Furthermore, oral health recommendations should be made at multiple levels.