Trueness, 3D Deviation, Time and Cost Comparisons Between Milled and 3D-Printed Resin Single Crowns.

The purpose of this in-vitro study was to compare trueness, 3D deviation, production time and costs of milled and 3D-printed resin single crowns. A total of 20 CAD-CAM resin single crowns were fabricated from 10 digital wax patterns designed on 10 tooth preparations available in a reference model. Standardized control linear measurements were performed with a CAD software. Each STL file was then used to fabricate two resins crowns - one milled and one 3D-printed. All crowns underwent physical linear measurements using a digital caliper. The crowns were then scanned using an intraoral scanner for assessing 3D deviation. Finally, time to produce a single crown, as well as costs and production rates of both methods were also compared. Both CAM methods did not present statistically significant differences in linear measurements, as compared to controls (P⟩.05). Furthermore, 3D-printed crowns had significantly greater deviations in cervical margins (P=.032) and occlusal surfaces (P=.041), as compared with milled crowns. Finally, 3D-printing took significantly longer to produce one single crown (P=.001), but with a cheaper and higher production rate than milling. These findings suggest that milling devices produce resin single crowns with smaller 3D deviations but more expensive costs, as compared with low-cost 3D printers.

Dental Public Health in Action: Experiences and Responses of Oral Health Care Professionals during the First Wave of the COVID-19 Pandemic in Malta.

Initial impetus for action: Maltese Oral Health Care Professionals (OHCP) experienced changes to clinical practice and redeployment during the COVID-19 pandemic. In the early stages, there were few data on the resultant changes to the provision of dental services or their impact on the wellbeing of dental professionals. Solutions Suggested: Two questionnaires were designed to explore different domains in OHCP working on the frontline of the COVID-19 pandemic as well as in other areas/sectors. The findings were intended to inform guidance documents and to better support the profession. Findings: Anxiety-provoking factors, challenges, and areas of concern of OHCP were identified and practical recommendations to support transitioning to the 'new normal' were presented. OHCP expressed anxiety about contracting COVID-19 from their workplace and passing infection to other family members, friends, or patients. As a result, OHCP expressed the need for better protective clothing, workplace ventilation, and air filtration systems. Future implications: Provision of adequate PPE for OHCP was a priority. New guidelines for dental practice were informed by the experiences of the particpating OHCP. University modules to enhance the resilience of OHCP were among the recommendations to support practitioners.

Erosive wear of the primary dentition: who is aware of it?

AIM: To determine the influence of erosive tooth wear in the primary dentition on parental perceptions of oral health. METHODS: This cross-sectional study involved a standardised clinical examination of 775 preschool aged children and a parent-administered questionnaire. Erosive tooth wear was measured using the Basic Erosive Wear Examination Index. RESULTS: 71% and 81% of 3 (n = 256) and 5 year-old children (n = 337) respectively exhibited signs of erosive tooth wear. Prevalence was influenced by region (p = 0.049) (p = 0.007) in both age cohorts (χ2, p < 0.05) respectively and by parental level of education (p = 0.012) in the 5-year-old cohort. Parental perception of oral health was significantly associated (χ2, p < 0.05) with parental level of education in the 5-year-old cohort and with the presence of dental caries, reports of pain and dental appearance of the child in both age cohorts. Parental perceptions were unaffected by the degree of erosive tooth wear their child exhibited (p = 0.0564), (p = 0.739) in both age cohorts respectively. CONCLUSIONS: Erosive dental tooth wear is increasingly observed in the primary dentition however is not perceived as an oral health issue by parents. Its diagnosis and management therefore, fall heavily within the remit of the dental practitioner.

Undergraduate students' evaluation and reflections on a gerodontology programme.

INTRODUCTION: Many societies have observed a steady increase of many older adults living longer due to advancements in health and standard of living. The dental team requires specialised training in gerodontology to better prepare for the future needs of the elderly patients. It is the aim of this study to report the undergraduate students' activities and perspectives on their work experience in a geriatric residence. MATERIALS AND METHODS: An anonymous online questionnaire on the theoretical and practical aspects of training was sent to students in dentistry and dental hygiene (DH) undergraduate courses. Students were also invited to discuss their experiences. Data of clinical treatment performed by the students were collected. The number of clinical hours of student exposure to patients was measured. RESULTS: Completion of the questionnaire was high (90%). Both DH and dentistry students have in excess of 100 hours/y of clinical practice. Overall students rate their experience as a positive one that enriches patients' well-being. However they identify barriers to oral health and experience challenges related to their clinical work and level of competence (Kruskal-Wallis Test P < .05). CONCLUSIONS: study participants were strongly motivated towards the management of frail older adults and cognisant of the barriers and constraints of achieving a reasonable level of oral health. Gerodontology programmes should be adaptable in order to create the appropriate environment and address socio-emotional challenges experienced by students.

Reversal of UVA skin photosensitivity and DNA damage in kidney transplant recipients by replacing azathioprine.

Azathioprine is associated with enhanced skin photosensitivity to ultraviolet A (UVA) and leads to incorporation of 6-thioguanine (6-TG) into DNA of dividing cells. Unlike canonical DNA, 6-TG DNA is damaged by UVA, which comprises more than 90% of the ultraviolet reaching earth. Skin photosensitivity to UVA and UVB was measured in 48 kidney transplant patients immunosuppressed either by azathioprine (n = 32) or mycophenolate (n = 16). In 23 patients, azathioprine was subsequently replaced by mycophenolate and skin photosensitivity, DNA 6-TG content in peripheral blood mononuclear cells, and susceptibility to UVA-induced DNA damage were monitored for up to 2 years. The mean minimal erythema dose to UVA on azathioprine was twofold lower than on mycophenolate. Three months after replacing azathioprine by mycophenolate mofetil, the minimal erythema dose to UVA had increased from 15 to 25 J/cm(2) (p < 0.001) accompanied by reduced DNA 6-TG content. P53 protein expression in irradiated skin indicated reduced susceptibility to UVA-induced DNA damage. 6-TG DNA in peripheral blood mononuclear cells remained measurable for over 2 years. Replacing azathioprine selectively reduced the skin photosensitivity to UVA, attenuated UVA-induced skin DNA damage, and is likely based on incorporated 6-TG in DNA.

PTCH mutations in basal cell carcinomas from azathioprine-treated organ transplant recipients.

The immunosuppressant azathioprine is used to prevent graft rejection after organ transplantation. To investigate whether azathioprine-associated mutagenesis contributes to the high incidence of skin tumours in organ transplant recipients (OTRs), we analysed PTCH gene mutations in 60 basal cell carcinomas (BCC); 39 from OTRs receiving azathioprine and 21 from individuals never exposed to azathioprine. PTCH was mutated in 55% of all tumours, independent of azathioprine treatment. In both the azathioprine and non-azathioprine groups, transitions at dipyrimidine sequences, considered to indicate mutation by ultraviolet-B radiation, occurred frequently in tumours from chronically sun-exposed skin. In BCC from non-sun-exposed skin of azathioprine-treated patients, there was an over-representation of unusual G:C to A:T transitions at non-dipyrimidine sites. These were exclusive to the azathioprine-exposed group and all in the same TGTC sequence context at different positions within PTCH. Meta-analysis of 247 BCCs from published studies indicated that these mutations are rare in sporadic BCC and had never previously been reported in this specific sequence context. This study of post-transplant BCC provides the first indication that azathioprine exposure may be associated with PTCH mutations, particularly in tumours from non-sun-exposed skin.

An unusual cutaneous-polyposis syndrome stabilized with acitretin.

We present a patient with an unusual enterocutaneous syndrome. Long-term, low-dose acitretin treatment has stabilized the development of gastrointestinal lesions while synchronously reducing cutaneous morbidity.