Ryan Olley

Validation of the Basic Erosive Wear Examination

The Basic Erosive Wear Examination (BEWE) is a practical index for screening tooth wear, using a 4-point ordinal scale (0-3). The highest score is recorded in each sextant and a total score (or BEWE sextant cumulative) is calculated per subject. This study aims to investigate if the BEWE sextant cumulative score compares to one comprising a percentage score from all tooth surfaces and as a highest BEWE per subject. The aim is to assess the validity of this score. A total of 350 subjects were recruited from hospital and general practice in south-east England. Buccal, occlusal and lingual/palatal BEWE scores were collected and percentages calculated based on scores 1, 1 and above, 2 and above and 3. BEWE sextant cumulative scores and highest BEWE scores were also recorded per subject. Spearmans correlation coefficients (p values) assessed the relationship between BEWE sextant cumulative scores, BEWE percentages and BEWE highest score per subject. The BEWE sextant cumulative score correlates significantly to a BEWE score taken as a percentage score from all tooth surfaces (Spearmans r > 0.5, p < 0.001) and especially to BEWE surface scores of 1 and above and 2 and above (r > 0.8, p < 0.001) and as a highest surface score per subject (r > 0.8, p < 0.001). BEWE sextant score provides a representation of tooth wear on all tooth surfaces. This study validates a tooth wear index, which provides clinicians with risk indicators of a patients level of tooth wear and may help to guide clinical management.

A Novel Method to Quantify Dentine Tubule Occlusion Applied to in situ Model Samples

Objectives: To develop an innovative computerised routine, in conjunction with a minimally destructive imaging technique, to quantify dentine tubule occlusion. Methods: Polished human dentine samples (n = 480) were brushed during a 4-day in situ study with two occlusion-based dentifrices, a sodium fluoride control dentifrice (1,450 ppm) or water. Samples were imaged with tandem scanning microscopy (TSM) and conventional scanning electron microscopy (SEM). The level of dentine patency was then assessed using a visual ordinal scale (‘standard) or quantitatively using a specially designed computational routine. Results: The occlusion-based dentifrice resulted in significantly less patent dentine than controls for the ‘standard (p = 0.01) assessment, but not for computer analyses (p = 0.10). The correlation of the number of individual patent tubules counted visually and by the computational routine in calibrations and in the in situ study was ≥0.8. Conclusions: This study identified a new computer-based routine, capable of objectively quantifying the patency of dentine imaged by SEM and TSM.

Effects of tooth-brushing force with a desensitising dentifrice on dentine tubule patency and surface roughness

OBJECTIVESnTo investigate the effects of a 5% NovaMin containing dentifrice on dentine tubule patency and surface roughness at 100g and 400g tooth brush abrasion forces.nnnMETHODSn75 polished human dentine samples were prepared and randomly allocated into one of five groups; control (1), Na2PFO3 100g abrasion force (2), NovaMin 100g (3), Na2PFO3 400g (4) and NovaMin 400g (5). The control group underwent two 2-min cycles of artificial saliva (AS), one 2-min erosion cycle; the rest underwent two toothbrush abrasion cycles in an AS/dentifrice slurry and one 2-min erosion cycle. All samples were imaged at baseline and post intervention using Tandem Scanning Microscopy and Profilometry to analyse tubule patency and roughness.nnnRESULTSnMean tubule patency increased significantly between baseline and post intervention in groups 1,2 and 4 and decreased significantly post intervention in groups 3 and 5 (p<0.01). Post intervention, there were statistically significant differences in mean patent tubules between NovaMin and the Na2PFO3 and control groups (p<0.001). Surface roughness increased for all groups between baseline and post interventions (P<0.001); mean (SD) roughness increases for groups 1, 2, 3, 4 and 5 were 0.14 (0.05) μm, 0.18 (0.04) μm, 0.16 (0.06) μm, 0.19 (0.07) μm and 0.21 (0.02) μm respectively. Differences between group 1 and 5 were significant (p<0.01).nnnCONCLUSIONSnBrushing with NovaMin resulted in significant dentine tubule occlusion at 100g and 400g, but brushing with Na2PFO3 resulted in increased tubule patency. Surface roughness increased significantly at 400g brushing with NovaMin. There was no correlation between tubule patency and surface roughness.nnnCLINICAL SIGNIFICANCEnA NovaMin desensitising dentifrice resulted in tubule occlusion even at high brushing forces. There was minimal increase in surface roughness at the lower (100g) brushing force.

Effects of dentifrices on subsurface dentin tubule occlusion: an in situ study.

PURPOSEnTo evaluate, in situ, the penetration of deposits formed within the subsurface of dentin samples treated with desensitizing dentifrices designed to occlude dentin tubules compared to two controls.nnnMATERIALS AND METHODSnTwenty-eight healthy participants wore left and right intraoral appliances, each retaining four human dentin samples, for two periods of 4 days. Samples were power-brushed, outside the mouth, twice daily with test products (dentifrices containing 8% strontium or 8% arginine) or control (1,450 ppm NaF or water) and subjected to an agitated grapefruit juice acid challenge on days 3 and 4. Eighteen dentin samples were randomly selected from each treatment group and were dry fractured for scanning electron microscopy and energy-dispersive x-ray spectroscopy analysis.nnnRESULTSnThe proportion of cross-sectioned dentin tubules with subsurface occlusion (occluded to a mean of 5 ± 2 μm, range: 1 to 9 μm below the surface) for the 8% strontium group on days 1 and 2 (pre-acid) was 82% (SD: 9%, 95% confidence interval [CI] = 78% to 86%) and on days 3 and 4 (post-acid) was 88% (SD: 10%, CI = 83% to 93%). For 8% arginine on days 3 and 4 (post-acid), the proportion was 78% (SD: 8%, CI = 74% to 82%). These results were statistically significant compared to those for controls (P < .01). The 8% arginine on days 1 and 2 (pre-acid) and water and control paste on all days revealed no subsurface deposit.nnnCONCLUSIONSnWithin the limitations of this study, cross-sectional SEM analysis suggested strontium and arginine dentifrices occlude tubules subsurface in dentin compared to negative controls following acid challenge. The desensitizing dentifrices elicit subsurface changes that may potentiate their effects for the management of dentin hypersensitivity, particularly for patients who consume acidic beverages.

Observational study investigating tooth extraction and the shortened dental arch approach

The shortened dental arch (SDA) provides a cost-effective dentition, considering the population is ageing and retaining teeth for longer. The aims were to observe the reasons and sites of tooth extraction and assess the functional dentition over 15xa0years in dental practice. Subjects were recruited who required permanent tooth extractions between 2000 and 2015. The reasons for extractions were chosen from twelve extraction codes. Data were also collected for demographics, tooth position, root treated teeth and functional pairs remaining. Patient-centred factors on reasons for tooth extraction and comments on chewing ability and aesthetics following extractions were recorded. Nine hundred and fifty-one teeth were extracted in 900 patients. The mean age was 60xa0years (SD 20, SE 7, 95% CI 46, 74). Reasons for extraction were periodontal disease (nxa0=xa0361, 38%), periapical infection (nxa0=xa0288, 34%) or tooth and tooth-root fractures (15%). Extractions included 201 (21%) second molars, 179 (19%) first molars, 152 (16%) second premolars, 95 (10%) first incisors, 86 (9%) second incisors, 76 (8%) canines and 67 (7%) first premolars. Following extractions, median functional pairs were 12, interquartile range (IQR) 19-7. Individuals with ≥10 functional pairs including anterior teeth (60%, nxa0=xa0571) had no complaints with chewing ability or aesthetics. They did not require additional prostheses. Periodontal disease and periapical infection were the main causes for the extraction. First and second molars followed by second premolars were the most commonly extracted teeth. This study supports the SDA in creating a cost effective, functional dentition in an aging population, provided remaining teeth and restorations are preserved/maintained, oral health is promoted, and anterior aesthetic tooth replacement is ensured.

An up to 50-year follow-up of crown and veneer survival in a dental practice

Statement of problem. Indirect restorations are an important treatment in dental practice, but long‐term survival studies are lacking. Purpose. The purpose of this retrospective study was to report on the outcome of indirect restorations, which were followed up annually for up to 50 years in a dental practice. Material and methods. A retrospective survival study was undertaken at a mixed National Health Service (NHS)/private dental practice in London, UK. Data were collected for restorations placed between 1966 and 1996 by 1 experienced operator. It was a requirement that patients had been followed up annually with clinical and radiographic examinations for up to 50 years. Patients were enrolled on a strict preventive policy and had excellent oral hygiene. Oral hygiene, restoration location, sensitivity, occlusion, and other details (preparation design, taper, cement used) were recorded. Restoration outcome was recorded as successful and surviving, unknown, or failed. The data were described descriptively. Kaplan‐Meier survival curves and hazard curves were used to assess the survival of crowns and the probability of failure over time. Results. A total of 223 restorations were placed in 47 patients between 1966 and 1996 and reviewed annually for up to 50 years (until 2016). These restorations included 154 metal‐ceramic crowns (101 posterior and 53 anterior), 25 posterior gold crowns, 22 anterior ceramic veneers, and 22 anterior ceramic crowns. Restorations were in occlusion. The mean survival for metal‐ceramic crowns was estimated as 47.53 years (95% confidence interval [CI]: 45.59‐49.47 years). Failures in metal‐ceramic crowns (n=6, 3.9%) were due to periapical periodontitis. The remaining restoration types had 100% survival at 50 years. Conclusions. This study showed that the survival of crowns and veneers is high over 50 years in clinical practice with annual follow‐up and good oral hygiene. The proportion of teeth with loss of vitality, confirmed clinically and with radiographs, was minimal.