Tooth loss, denture wearing and implants: Findings from the National Study of Adult Oral Health 2017-18

Feasibility study and material selection for powder-bed fusion process in printing of denture clasps

BACKGROUND AND OBJECTIVE

The retention of selective laser melting (SLM)-built denture clasps is inferior to that of cast cobalt-chromium (Co-Cr) clasps engaging 0.01-in undercuts, which are commonly used in clinical practice. Either the clasps engage in excessively deep undercuts or inappropriate printing process parameters are applied. With appropriate undercut engagement and levels of process parameters, the retention of SLM-built clasps (including Co-Cr, commercially pure titanium [CP Ti], and Ti alloy [Ti-6Al-4V] ones) may be comparable to that of cast Co-Cr clasps. Therefore, this feasibility study aimed to evaluate their retention to guide dentists during material selection for the powder-bed fusion process during the printing of denture clasps.

METHODS

We engaged the clasp arm at an appropriate undercut depth (0.01 or 0.02 in), built clasps at the orientation of their longitudinal axes approximately parallel to the build platform, generated square prism support structures at a critical overhang angle of 30°, applied optimized laser parameters (laser power, scan speed, and hatch space), and adopted annealing treatment for Co-Cr, CP Ti, and Ti-6Al-4V clasps. After postprocessing and accuracy measurement, an insertion/removal test of the clasps for 15,000 cycles was performed to simulate 10 years of clinical use, and the retentive force was recorded every 1500 cycles. Permanent deformation of the retentive arms of the clasps was measured. Cast Co-Cr clasps engaging 0.01-in undercuts were designated the control group.

RESULTS

The initial retentive forces of the SLM-built Co-Cr clasps engaging 0.01-in undercuts and CP Ti and Ti-6Al-4V clasps engaging 0.02-in undercuts were comparable to those of the control group. SLM-built Co-Cr clasps engaging 0.01-in undercuts and Ti-6Al-4V clasps engaging 0.02-in undercuts had similar final retentive force and less permanent deformation compared with those of the control group; SLM-built CP Ti clasps engaging 0.02-in undercuts had lower final retentive force and greater permanent deformation.

CONCLUSIONS

Considering the long-term retention and permanent deformation of the retentive arms, Co-Cr and Ti-6Al-4V alloys, except CP Ti, are recommended for printing denture clasps. SLM-built Co-Cr clasps should engage 0.01-in undercuts, and Ti-6Al-4V clasps should engage 0.02-in undercuts.

Effects of Denture Cleaning Regimens on the Quantity of Candida on Dentures: A Cross-Sectional Survey on Nursing Home Residents

Oral care involving a denture cleaning regimen is important for reducing the incidence of systemic diseases. However, limited information is currently available on denture cleaning frequencies and regimens. Therefore, the present study investigated the relationship between the number of Candida spp. present on the complete dentures of nursing home residents and cleaning regimens. Residents were surveyed to assess their denture cleaning methods. Plaque was collected by applying a sterile swab to the mucosal surface of each examined complete denture worn by 77 residents, and the Candida spp. collected were cultured, identified, and quantified. The relationship between denture cleaning regimens and the quantity of Candida spp. was investigated. Correlation and multivariable analyses revealed that the strongest factor influencing the number of Candida spp. on dentures was the frequency of use of denture cleansers. The number of Candida spp. was the lowest on dentures cleaned daily with a denture cleanser. The present results demonstrated that the daily use of a denture cleanser effectively controlled the adherence of Candida spp. to dentures. Oral and other healthcare providers need to provide instructions on and assist nursing home residents with the daily care of dentures, using denture cleansers, including the environment where cleaning is performed.

A Longitudinal Study of Chronic Periodontitis in Two Cohorts of Community-Dwelling Elderly Australians

Background: The study aimed to estimate and compare the incidence and progression of chronic periodontitis among two generations of older Australian adults. Methods: Data were from two population-based cohort studies of Australian older adults aged 60+ years South Australian Dental Longitudinal Studies (SADLS), SADLS I (1991-1992) and SADLS II (2013-2014). American Academy of Periodontology/the U.S. Centres for Disease Control and Prevention (CDC/AAP), and the 2018 European Federation of Periodontology classification (EFP/AAP) case definitions were used to define and calculate the incidence and progression of chronic periodontitis. Multivariable Poisson regression models were used to estimate incidence risk ratios (IRRs) of periodontitis. Results: A total 567 and 201 dentate respondents had periodontal exams in SADLS I and II, respectively. The incidence rate was greater in SADLS II than in SADLS I, approximately 200 vs. 100/1000 person years, respectively. Current smokers had more than two times higher IRRs, 2.38 (1.30-4.34) and 2.30 (1.24-4.26), than their non-smoking counterparts in the previous generation under the CDC/AAP and EFP/AAP, respectively. Conclusions: The most recent generation of older adults has greater incidence and progression of periodontitis than the previous generation. Being a current tobacco smoker was a significant risk factor for both the incidence and progression of periodontitis.

Global Perspectives of Oral Health Policies and Oral Healthcare Schemes for Older Adult Populations

The aim of this study was to present a concise summary of the oral health policies and oral healthcare schemes for older adult populations in a number of selected countries around the world. In this paper, the current and planned national/regional oral health policies and oral healthcare schemes of nine countries (Australia, Brazil, China including Hong Kong, India, Japan, Switzerland, Thailand, the United Kingdom, and the United States) are reported. Barriers and challenges in oral health promotion in terms of devising oral health policies, implementing oral health schemes, and educating the future dental workforce are discussed. In response to the aging of population, individual countries have initiated or reformed their healthcare systems and developed innovative approaches to deliver oral health services for older adults. There is a global shortage of dentists trained in geriatric dentistry. In many countries, geriatric dentistry is not formally recognized as a specialty. Education and training in geriatric dentistry is needed to produce responsive and competent dental professionals to serve the increasing number of older adults. It is expected that oral health policies and oral healthcare services will be changing and reforming in the coming decades to tackle the enduring oral health challenges of aging societies worldwide.

Trend and distribution of coronal dental caries in Australians adults

AIMS

To report the experience of coronal dental caries in the Australian adult population.

METHODS

Dentate people aged 15 years and over were online or telephone interviewed, and dental examined (n = 5022). The number of decay, missing and filled surfaces (DMFS) were recorded. Independent variables were demographic, socioeconomic conditions and dental care characteristics. Proportions of DMFS >0, average DMFS and its components were calculated.

RESULTS

Overall, 32.1% had decayed surfaces, with a higher proportion found in males (34.7%) and 40% higher in those living in remote areas than in those living in major city and regional areas. The prevalence of decayed surfaces varied from 37.4% (lowest income group) to 25.0% (highest income group). The mean number of decayed surfaces was three times higher in the lowest income group compared to the highest one. Uninsured people had a higher prevalence of decayed surfaces and lower mean of filling surfaces than insured group. Participants with an unfavourable pattern of dental visiting had two times higher prevalence of decay than their counterparts. Overall, three quarters (77.4%) had at least one filling in their permanent dentition. This percentage increased from 61.6% among 15-34 year olds, to 88.0% among those aged 55-74 years.

CONCLUSION

Socioeconomic inequalities in caries experience persist in Australia.