The present study was designed to compare the stress distributions in two restoration types of implants and the surrounding bone. The first restoration type was a conventional cement-retained zirconia crown, and the second was a novel cementless screw-retained zirconia crown with a base abutment. A three-dimensional finite element method was used to model the implants, restorations, and supporting bone. A comparative study of the two implants was performed under two masticatory loads: a vertical load of 100 N and a 30-degree oblique load of 100 N. Under both loading conditions, the maximum von Mises stress and strain values in the implant and supporting bone were higher in the conventional cement-retained restoration model than in the cementless screw-retained model. In terms of stress distribution, the cementless screw-retained zirconia crown with base abutment may be considered a superior restoration option compared to the conventional cement-retained zirconia crown.

Effects of implant angulation on digital implant impression accuracy remain controversial. Therefore, this in vitro study aimed to compare the digital implant impression trueness among models with different implant angulations and scan body materials. Six partially edentulous mandibular models with dental implants on the right second premolar and second molar areas were categorized according to the implant angulation of the distal implant (parallel, or 15° mesially or lingually tilted compared to the mesial implant) and scan body materials (polyetheretherketone or titanium). After scanning each model with intraoral scanners, the root mean square and within-tolerance values were calculated with respect to the reference, and nonparametric statistical tests were performed (α = .05). Scan data from models with the mesially tilted distal implant showed better trueness than the corresponding parallel and lingually tilted groups in terms of root mean square values (p < .017). The root mean square value in the titanium scan body group was lower than that in the polyetheretherketone scan body group (p < .001). However, the percentage within a tolerance of ± .1 mm was higher in the polyetheretherketone scan body group than in the titanium scan body group (p = .001). Intraoral scan data of models where the terminal implant was mesially tilted showed better trueness.

Objective: This cross-sectional study investigated the relationship between handgrip strength and oral health behaviours among Koreans. Methods: The data of 7589 individuals (3384 men and 4205 women) aged ≥19 years who participated in the Korea National Health and Nutrition Examination Survey 2014–2015 were analyzed. Oral health behaviour was assessed based on the number of daily toothbrushing sessions and the use of secondary oral-care products. The association between oral-health behaviour and handgrip strength was investigated adjusting for confounders. Multivariable logistic regression analysis was performed (α = 0.05). Results: The proportion of participants diagnosed with sarcopenia was significantly higher in the group with poor oral-health behaviours. After adjusting for confounders including age, the adjusted odds ratios and 95% confidence intervals of female participants with low handgrip strength in groups toothbrushing thrice or more per day, twice per day, and once or less per day were 1 (reference), 1.18 (0.99–1.4), and 1.24 (0.89–1.71), respectively. There were significantly more participants with low handgrip strength in the group that did not use secondary oral products for both sexes. Conclusions: Oral health behaviour is associated with handgrip strength among adults. Poor oral self-care habits may constitute a risk indicator for low muscle strength.

This study examined the prevalence of self-perceived chewing discomfort depending on the type of dental prosthesis used in South Korean adults. The subjects were 12,802 people over 20 years of age who participated in a health interview and dental examination. Chewing discomfort was examined using a self-assessed report with a structured questionnaire. Using multivariable logistic regression analysis, adjusted odds ratios were evaluated along with their 95% confidence intervals (α = 0.05). After adjusting for covariates, including age, gender, smoking, drinking, hypertension, diabetes, body mass index, education, income, and toothbrushing frequency, the odds ratios (95% confidence intervals) for chewing discomfort in groups without a dental prosthesis, with fixed dental prostheses, with removable partial dentures, and with removable complete dentures were 1 (reference), 1.363 (1.213–1.532), 2.275 (1.879–2.753), and 2.483 (1.929–3.197), respectively. The association between the prevalence of chewing discomfort and the type of dental prosthesis used was statistically significant even after adjusting for various confounders (p < 0.0001). The type of dental prosthesis was related to chewing discomfort among South Korean adults.

Lee JH, et al. J Korean Med Sci. 2019 Sep;34(41):e262. https://doi.org/10.3346/jkms.2019.34.e262