Tooth-coloured restorative materials are being used increasingly more often in Class II preparations in permanent teeth. Using a practice-based study design, we aimed to assess the survival time of Class II restorations and to identify factors relevant to their longevity. Class II restorations (n = 4,030), consisting of resin composites (81.5%), compomers (12.7%), amalgams (4.6%), and glass-ionomer cement restorations (1.2%), were placed in 1,873 patients with a median age of 15 yr. In total, 92.7% of restorations were placed due to primary caries and 5.8% were replacements. After an average follow-up period of 4.6 yr, 61.6% of the restorations were successful, 11.2% had failed, and 27.2% were not available for evaluation (owing to patient drop-out). The mean annual failure rate was 2.9% for resin-composite restorations and 1.6% for amalgams. For resin-composite restorations, secondary caries was the most common reason for replacement (73.9%), followed by loss (8.0%), fracture (5.3%), and marginal defects (2.4%). Multilevel Cox-regression analyses identified young age of the patient, high previous caries experience, deep cavities, and saucer-shaped preparation technique as predisposing to shorter longevity of resin-composite restorations. One brand of resin composite had a shorter survival time than the others.

The aim was to measure variations in threshold for operative treatment of approximal caries in permanent teeth and the use of restorative materials, compared with results from studies conducted in Norway in 1983 and 1995. In 2009, a precoded questionnaire was sent electronically to 3,654 dentists with E-mail addresses in the member register of the Norwegian Dental Association. The questions were related to caries, treatment strategies and choice of dental materials. Replies were obtained from 61% of the dentists after two reminders. Restorative treatment of approximal lesions confined to enamel, based on radiographic appearance, was proposed by 7% of the dentists, compared with 66% in 1983 and 18% in 1995. Younger dentists, significantly more often than older, would defer operative treatment of approximal lesions until the lesion was visible in dentine. While tunnel preparation most often was the preparation of choice in 1995 (47%), saucer-shaped preparation was most favoured in 2009 (69%). Tunnel preparation was only preferred by 4% of the dentists. Resin composite was the restorative material preferred by 95%, compared with 16% in 1995. The corresponding values for conventional glass ionomer cement (GIC) were 1 versus 22%, for resin-modified GIC 1 versus 7%, and for a combination of GIC and resin composite 2 versus 22%. Compomer was preferred by 1% of the respondents. The authors conclude that treatment concepts for approximal caries have changed considerably during the last 26 years. In 2009, only 7% of dentists reported that they would treat approximal caries operatively before the lesion reached dentine.

This study aimed to investigate dentists' general experience, knowledge about diagnosis, and treatment of dental erosive wear in young adults. A questionnaire was sent to 1262 Norwegian public dental health-employed dentists. The response rate was 60%. Results indicated that most dentists recorded erosive wear, half of them used a specific scoring system, and half registered lesions at the tooth surface level. Lesions were reported most often on palatal surfaces of upper anterior teeth (79% of dentists), on occlusal surfaces of lower 1st molars (74%), and on upper 1st molars (32%). Half the dentists used clinical photographs for documentation and 60% made study models. While 40% reported more erosive lesions in males, 36% reported no gender differences. High intake of carbonated beverages and acidic juices were reported as the most common cause by 97% and 72% of the dentists, respectively. Only 21% of dentists recorded the patient's dietary history, and 73% never measured saliva secretion. The majority (78%) of the dentists treated patients with erosive wear themselves. In general, the survey suggests that the dentists are relatively up to date regarding the clinical recording, diagnosis, and treatment of dental erosive wear. However, dietary and salivary analyses were not given priority, and early, preventive treatment was lacking.

Dentists' choices of restorative material indicate that the majority prefer amalgam in more challenging restorations with respect to caries activity, lesion depth, and tooth type. The findings indicate that in a period when the use of amalgam was phasing out, resin composite was the predominant material of choice for Class II restorations in children and adolescents.

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.