17. A lot or a little at a time?

This randomised controlled clinical trial compared two techniques and materials for restoring carious teeth (n=72): bulk dentine replacement (Group A) versus incremental placement of a hybrid posterior resin composite material (Group B) in terms of patient comfort (postoperative sensitivity and tenderness on biting). Patients were followed up by way of a structured phone call at day 2 and day 7 post-operatively: those reporting discomfort at day 7 were subsequently followed up on days 14, and 30. At day 2, 18/72 restored teeth had post-operative sensitivity; this figure fell to 10/72 at day 7: at day 2 a greater level of sensitivity was reported by patients in Group A. However, at day 7 there was no statistically significant difference between the two groups in terms of sensitivity. There was no statistically significant difference between the two groups in terms of tenderness on biting at any time period. Interestingly, Class I cavities were found to be more tender on biting than Class II cavities.

Hickey D et al. Bulk dentine replacement versus incrementally placed resin composite: a randomised controlled clinical trial. J Dent 2016 46:18-22.

Q Teeth with post-operative sensitivity:
A Numbered 2 at day 2 and none at day 7
B Were reported as 18 at day 2 and 10 at day 7
C Consisted of the entire test group on days 2 and 7
D Were also the teeth with tenderness on biting

18. Dutch GDPs’ restorations

The longevity of direct restorations placed by a group of general dental practitioners (GDPs) and the effect of practice/operator, patient, and tooth/restoration related factors on restoration survival was investigated in this research project. Electronic patient files of 24 general dental practices were used for collecting the data on the longevity of 359,548 composite, amalgam, glass-ionomer and compomer restorations placed in 75,556 patients by 67 GDPs between 1996 and 2011. A wide variation in annual failure rate (AFR) existed between the dental practices (2.3% - 7.9%). Restorations in elderly people (65 years +) showed a shorter survival compared to restorations placed in patients younger than this. Restorations in molar teeth, multi-surface restorations and restorations placed in endodontically treated teeth seemed to be more at risk for re-intervention. The investigated group of GDPs placed restorations with a satisfactory longevity (mean AFR 4.6% over 10 years), although substantial differences in outcome between practitioners exist. Several potential risk factors on practice/operator, patient, and tooth/restoration level have been identified.

Laske M et al. Longevity of direct restorations in Dutch dental practices. Descriptive study out of a practice based research network. J Dent 2016 46:12-17.

Q Which restorations showed the greatest risk of failure?
A Those in molars and those in older people
B Amalgams
C Single surface restorations in younger people
D All of the above

19. Does digital point the way?

The efficiency of direct versus indirect digitalisation was assessed in a clinical trial by evaluating the marginal and internal fit of CAD/CAM fabricated zirconia crowns and three-unit fixed dental prostheses (FDPs). In 25 patients, 17 single crowns and eight three-unit FDPs were fabricated with all-ceramic zirconia using CAD/CAM technology. Each patient underwent two different impression methods; a computer-aided impression and a conventional polyether impression. Before insertion, the marginal and internal fit was recorded using silicone replicas of the frameworks. Each sample was cut into four sections and evaluated at four sites (marginal gap, mid-axial wall, axio-occlusal transition, centro-occlusal site) under x64 magnification. Although both direct and indirect digitalisation facilitated the fabrication of single crowns and three-unit FDPs with clinically acceptable marginal fit, a significantly better marginal fit was noted with direct digitalisation. Digital impressions are also less time-consuming for the dental practitioner and the patient. The results show that a direct, intraoral, digitalised impression technique is more accurate and efficient when compared with conventional impressions.

Ahrberg D et al. Evaluation of fit and efficiency of CAD/CAM fabricated all-ceramic restorations based on direct and indirect digitalization: a double-blinded, randomized clinical trial. Clin Oral Investigations 2016 20: 291-300.

Q Digital impressions are:
A Less time-consuming
B More accurate
C More efficient
D All of the above

20. Restorative caries risk

What is the risk of dentine caries developing on surfaces adjacent to newly placed composite restorations? This longitudinal study aimed to find out. Data from a practice-based study, where 4,030 posterior approximal restorations had been placed in permanent teeth were analysed where a sound surface was adjacent to a newly placed composite posterior approximal restoration. All individuals who had intact corresponding contralateral pairs of teeth in the same jaw, were included. At the end of the follow-up period, the study restorations and their adjacent surfaces were evaluated clinically and radiographically. The surfaces were followed on average for 4.8 years. Follow-up observations revealed that 41% of adjacent surfaces remained sound, compared with 67 % of the control surfaces. Caries incidence in intact approximal surfaces adjacent to newly placed composite posterior approximal restorations was significantly higher compared with the contralateral control surface without a restoration in contact. Adjacent surfaces in maxillary teeth had increased risk for dentine caries development.

Skudutyte-Rysstad R et al. Posterior composites and new caries on adjacent surfaces - any association? Longitudinal study with a split-mouth design. BMC Oral Health 2016 16: 11.

Q What is the implication of this research? That:
A There is a higher risk that interproximal surfaces adjacent to restorations will become carious
B Only patients with matching pairs of adjacent teeth will be liable to caries
C Adjacent surfaces in mandibular teeth had increased caries risk
D It is the newness of the restoration which increases the caries risk