A retrospective clinical study on the longevity of posterior Class II cast gold inlays/onlays.

OBJECTIVE: To investigate the longevity and reasons for failure of posterior cast Class II gold inlays and onlays among a group of Norwegian adults. The term inlay was used for both inlays and onlays. METHODS: A cohort of 138 patients regularly attending a general practice for check-up were examined in 2016. The patients had a total of 391 posterior gold inlays placed in the period 1970-2015. The inlays were categorized as successful, repaired or failed. Reasons for failure were classified as either "secondary caries", "fractures", "lost inlay" or "other". Participation was voluntary and no compensation was given. RESULTS: The mean age of the patients at placement was 50.8 years (SD: 12.7 yr). Most gold inlays were placed in molars (85.9%) and 14.1% in premolars; 49.4% of the inlays were in the maxilla and the 50.6% in the mandibula. Average length of follow-up was 11.6 years (range: 1-46 years, SD: 7.9); 82.9% were classified as successful, 10.7% as repaired and 6.4% as failed. Reasons for failure were secondary caries (41.3%), lost inlay (25.4%), fractures (23.8%) and other (9.5%). Mean annual failure rate (AFR) was 1.69% for repaired and failed inlays combined. However, if repaired inlays were considered as success, the AFR decreased to 0.57%. Multi-level Cox regression analyses identified low age of the patient and high number of restored surfaces as risk factors for failure. CONCLUSION: The present retrospective clinical study demonstrated an acceptable annual failure rate for Class II cast gold inlays.

Light curing procedures - performance, knowledge level and safety awareness among dentists.

OBJECTIVES: This study aimed to investigate dentists' exposure to curing light and to obtain information about the dentists' knowledge on practical use and technical features of their curing lights as well as their safety awareness. METHODS: A pre-coded questionnaire was sent electronically to all dentists (n=1313) in the Public Dental Service (PDS) in Norway in 2015. RESULTS: The Response rate was 55.8%. The dentists spent on average 57.5% of their working days placing restorations, ranging from 1 to 30 (mean 7.7, SD 3.6) restorations per day. The average length of light curing one normal layer of composite was 27s. The longest individual mean curing time per day was about 100 times higher than that of the lowest. The mean curing time for lamps of the lower reported irradiances was similar to the time representing exceedance of international guidelines for limit values for blue light to the eyes. Almost one-third of the dentists used inadequate eye protection against blue light. The odds of using adequate eye protection were significantly higher among young dentists (p<0.01). The majority of the respondents (78.3%) were unaware of the irradiance value of their curing lights, thus rendering the curing time uncertain. More dentists in this group did not perform regular maintenance of their curing lights compared with all respondents (17.1% vs. 3.3%, p<0.01). CONCLUSIONS: This study revealed considerable variations among Norwegian dentists in the Public Dental Service with respect to performance of light curing of restorations, safety awareness and technical knowledge of the curing light. CLINICAL SIGNIFICANCE: The questionnaire study identifies specific knowledge gaps among Norwegian dentists with regard to curing lights and use of personal protection. Today's dependence on technology in dentistry necessitates that the operator possesses knowledge of essential technical specifications and safe use of devices and instruments routinely used in dental treatment.

Repair of defective composite restorations. A questionnaire study among dentists in the Public Dental Service in Norway.

OBJECTIVES: This study aimed to investigate dentists' treatment choices concerning "repair or replacement" of defective restorations. METHODS: A pre-coded questionnaire was sent electronically to all dentists (n=1313) in the Public Dental Service (PDS) in Norway. Part one: The dentists were asked about age and gender, whether they performed direct restorative therapy/amount of time spent on fillings made per day due to: Primary caries, Repair of restorations or Replacement of restoration/what kind of bonding agents used and pre-treatment of the residual restoration. Part two: The dentists were asked to consider the best treatment for three patient cases with tooth/restoration fractures. RESULTS: Response rate was 55.8%, (69.6% females, 30.4% males). Respondent age varied from 25 to 77 years (mean 41.8, SD 12.4). Part one: The dentists spent on average 57.5% of the working day placing restorations, making from 1 to 30 (mean 7.7, SD 3.6) restorations per day. Reasons for treatment were; Primary caries 55.7% (SD 19.1%), repair of restorations 26.7% (SD 14.8%), replacement of fillings 18.2% (SD 11.2%). Two-step etch and rinse (ER), 3-step ER and Self-etch (SE) were used by 48.7%, 24.6% and 26.7% of the respondents, respectively. A silanising agent was used by 7.4%. Part two: Treatment choices: Repair with RC: 89.6% in case one, 86.9% in case two and 54.1% in case three. Young dentists suggested invasive treatment more often than old dentists (>38 years). CONCLUSIONS: Operative dentistry claims 57.5% of PDS dentists' working day. In addition to primary caries, repair and replacement of restorations accounted for 27% and 18% of the reasons for placing restorations. CLINICAL SIGNIFICANCE: The idea of "minimal intervention dentistry" seems to have great influence among dentists in PDS (Norway), as they seek to preserve dental hard tissue as much as possible by choosing repair before replacement. No gender differences were observed, but older dentists seem to favour repair compared with the younger dentists.