Single crowns versus conventional fillings for the restoration of root-filled teeth.

BACKGROUND Endodontic treatment involves removal of the dental pulp and its replacement by a root canal filling. Restoration of root filled teeth can be challenging due to structural differences between vital and non-vital root-filled teeth. Direct restoration involves placement of a restorative material e.g. amalgam or composite, directly into the tooth. Indirect restorations consist of cast metal or ceramic (porcelain) crowns. The choice of restoration depends on the amount of remaining tooth, and may influence durability and cost. The decision to use a post and core in addition to the crown is clinician driven. The comparative clinical performance of crowns or conventional fillings used to restore root-filled teeth is unknown. This review updates the original, which was published in 2012. OBJECTIVES To assess the effects of restoration of endodontically treated teeth (with or without post and core) by crowns versus conventional filling materials. SEARCH METHODS We searched the following databases: the Cochrane Oral Health Group's Trials Register, CENTRAL, MEDLINE via OVID, EMBASE via OVID, CINAHL via EBSCO, LILACS via BIREME. We also searched the reference lists of articles and ongoing trials registries.There were no restrictions regarding language or date of publication. The search is up-to-date as of 26 March 2015. SELECTION CRITERIA Randomised controlled trials (RCTs) or quasi-randomised controlled trials in participants with permanent teeth that have undergone endodontic treatment. Single full coverage crowns compared with any type of filling materials for direct restoration or indirect partial restorations (e.g. inlays and onlays). Comparisons considered the type of post and core used (cast or prefabricated post), if any. DATA COLLECTION AND ANALYSIS Two review authors independently extracted data from the included trial and assessed its risk of bias. We carried out data analysis using the 'treatment as allocated' patient population, expressing estimates of intervention effect for dichotomous data as risk ratios, with 95% confidence intervals (CI). MAIN RESULTS We included one trial, which was judged to be at high risk of performance, detection and attrition bias. The 117 participants with a root-filled, premolar tooth restored with a carbon fibre post, were randomised to either a full coverage metal-ceramic crown or direct adhesive composite restoration. None experienced a catastrophic failure (i.e. when the restoration cannot be repaired), although only 104 teeth were included in the final, three-year assessment. There was no clear difference between the crown and composite group and the composite only group for non-catastrophic failures of the restoration (1/54 versus 3/53; RR 0.33; 95% CI 0.04 to 3.05) or failures of the post (2/54 versus 1/53; RR 1.96; 95% CI 0.18 to 21.01) at three years. The quality of the evidence for these outcomes is very low. There was no evidence available for any of our secondary outcomes: patient satisfaction and quality of life, incidence or recurrence of caries, periodontal health status, and costs. AUTHORS' CONCLUSIONS There is insufficient evidence to assess the effects of crowns compared to conventional fillings for the restoration of root-filled teeth. Until more evidence becomes available, clinicians should continue to base decisions about how to restore root-filled teeth on their own clinical experience, whilst taking into consideration the individual circumstances and preferences of their patients.

Effect of an intervertebral disk spacer on stiffness after monocortical screw/polymethylmethacrylate fixation in simulated and cadaveric canine cervical vertebral columns.

OBJECTIVE To determine the biomechanical effect of an intervertebral spacer on construct stiffness in a PVC model and cadaveric canine cervical vertebral columns stabilized with monocortical screws/polymethylmethacrylate (PMMA). STUDY DESIGN Biomechanical study. SAMPLE POPULATION PVC pipe; cadaveric canine vertebral columns. METHODS PVC model-PVC pipe was used to create a gap model mimicking vertebral endplate orientation and disk space width of large-breed canine cervical vertebrae; 6 models had a 4-mm gap with no spacer (PVC group 1); 6 had a PVC pipe ring spacer filling the gap (PCV group 2). Animals-large breed cadaveric canine cervical vertebral columns (C2-C7) from skeletally mature dogs without (cadaveric group 1, n = 6, historical data) and with an intervertebral disk spacer (cadaveric group 2, n = 6) were used. All PVC models and cadaver specimens were instrumented with monocortical titanium screws/PMMA. Stiffness of the 2 PVC groups was compared in extension, flexion, and lateral bending using non-destructive 4-point bend testing. Stiffness testing in all 3 directions was performed of the unaltered C4-C5 vertebral motion unit in cadaveric spines and repeated after placement of an intervertebral cortical allograft ring and instrumentation. Data were compared using a linear mixed model approach that also incorporated data from previously tested spines with the same screw/PMMA construct but without disk spacer (cadaveric group 1). RESULTS Addition of a spacer increased construct stiffness in both the PVC model (P < .001) and cadaveric vertebral columns (P < .001) compared to fixation without a spacer. CONCLUSIONS Addition of an intervertebral spacer significantly increased construct stiffness of monocortical screw/PMMA fixation.

Neuroanatomical correlates of tube dependency and impaired oral intake after hemispheric stroke.

BACKGROUND AND PURPOSE Acute stroke patients with severely impaired oral intake are at risk of malnutrition and dehydration. Rapid identification of these patients is necessary to establish early enteral tube feeding. Whether specific lesion location predicts early tube dependency was analysed, and the neural correlates of impaired oral intake after hemispheric ischaemic stroke were assessed. METHODS Tube dependency and functional oral intake were evaluated with a standardized comprehensive swallowing assessment within the first 48 h after magnetic resonance imaging proven first-time acute supratentorial ischaemic stroke. Voxel-based lesion symptom mapping (VLSM) was performed to compare lesion location between tube-dependent patients versus patients without tube feeding and impaired versus unimpaired oral intake. RESULTS Out of 119 included patients 43 (36%) had impaired oral intake and 12 (10%) were tube dependent. Both tube dependency and impaired oral intake were significantly associated with a higher National Institutes of Health Stroke Scale score and larger infarct volume and these patients had worse clinical outcome at discharge. Clinical characteristics did not differ between left and right hemispheric strokes. In the VLSM analysis, mildly impaired oral intake correlated with lesions of the Rolandic operculum, the insular cortex, the superior corona radiata and to a lesser extent of the putamen, the external capsule and the superior longitudinal fascicle. Tube dependency was significantly associated with affection of the anterior insular cortex. CONCLUSIONS Mild impairment of oral intake correlates with damage to a widespread operculo-insular swallowing network. However, specific lesions of the anterior insula lead to severe impairment and tube dependency and clinicians might consider early enteral tube feeding in these patients.