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Biomedical subjects

P A Brunton

Publications and source records attributed to P A Brunton.

At least 19 recordsLinked to original sources
PubMed2005

Oral lichenoid lesions related to dental restorative materials.

OBJECTIVES: To determine the effectiveness of replacing restorations considered to be the cause of an oral lichenoid lesion (oral lichenoid reaction)(OLL). DESIGN: Clinical intervention and nine-month follow up. SETTING: The study was carried out in the University Dental Hospital of Manchester, 1998-2002. SUBJECTS AND METHODS: A total of 51 patients, mean age 53 (SD 13) years, who had oral lesions or symptoms suspected to be related to their dental restorations were investigated. Baseline patch tests for a series of dental materials, biopsies and photographs were undertaken. Thirty-nine out of 51 (76%) of patients had their restorations replaced. RESULTS: The clinical manifestations of OLL were variable; the majority of OLL were found to be in the molar and retro molar area of the buccal mucosa and the tongue. Twenty-seven (53%) patients had positive patch test reactions to at least one material, 24 of them for one or more mercury compound. After a mean follow up period of nine months, lesions adjacent to replaced restorations completely healed in 16 (42%) patients (10 positive and 6 negative patch tests). Improvement in signs and symptoms were found in 18 (47%) patients (11 positive and 7 negative patch tests). CONCLUSION: OLLs may be elicited by some dental restorations. Replacing restorations adjacent to these lesions is associated with healing in the majority of cases particularly when lesions are in close contact with restorations. A patch test seems to be of limited benefit as a predictor of such reactions.

Dental Amalgam↗
PubMed2005

Developing dental education in primary care: the student perspective.

A pilot outreach course in restorative dentistry based in community clinics began in 2001. As part of the evaluation, 48 fourth year students completed a questionnaire about their opinions of the new course, and about restorative dentistry clinics in the dental hospital. Time management was the most frequently mentioned gain from outreach. In relation to the dental school, students most often saw the specialised teaching staff as a gain. Outreach was equally or more important for students' confidence in clinical diagnosis of dental caries, treatment planning, direct restorations, communicating with patients, and managing patients, time, and resources. The dental hospital was equally or more important for their confidence in the diagnosis of periodontal disease, root planing, crowns, bridges, dentures, and communicating effectively with laboratory staff. Patients in outreach were seen as different from those at the dental hospital because they were unselected, and had different treatment needs. Meeting course requirements was the most frequent concern about outreach. In relation to the dental hospital, students were most often concerned about the quality of teaching and support available. Outreach and the dental hospital provided complementary experiences and the new course met its educational objectives.

Dental Clinics↗
PubMed2005

Contemporary dental practice in the UK: indirect restorations and fixed prosthodontics.

OBJECTIVES: To investigate, by questionnaire, the use and selection of materials and techniques for indirect restorations and fixed prosthodontics by dental practitioners in the North West of England and Scotland. METHODS: A questionnaire was sent to 1,000 general dental practitioners selected at random from dentists in Scotland and the North West of England. Non-responders were sent another questionnaire after a period of 4 weeks had elapsed. RESULTS: A total of 701 usable questionnaires were returned, giving a response rate of 70%. When selecting a material for the core build-up of vital teeth, practitioners used the following materials (%): amalgam (60), dual and light-cured resin composite (54), glass-ionomer cements (47), compomer (29) and resin-modified glass-ionomer cements (24). Where the use of a post was indicated indirect posts of both precious (67) and non-precious (37) alloys were preferred to prefabricated posts by the majority of practitioners for the restoration of root filled teeth. Direct titanium (14) and stainless steel (14) posts were not used extensively. Impression materials used by the practitioners were as follows: addition-cured silicone (70), condensation-cured silicone (20), polyether (9) and polysulphide (2). Traditional glass-ionomer cements (59) were used for the luting of single and multiple porcelain fused to metal units, with zinc phosphate and polycarboxylate cements (33) being the preferred alternatives. CONCLUSIONS: The majority of the practitioners surveyed in this study used: amalgam for core build-ups; indirect posts; addition-cured silicone for impressions; and glass-ionomer cements for luting procedures.

Crowns↗
PubMed2005

Contemporary dental practice in the UK: demographic data and practising arrangements.

OBJECTIVES: To investigate, by questionnaire, various aspects of primary dental care provision in the North West of England and Scotland. METHOD: A questionnaire containing 79 questions was sent to 1,000 practitioners, selected at random, in the North West of England and Scotland. Non-responders were sent another questionnaire after a period of 4 weeks had elapsed. RESULTS: Overall a response rate of 70% was achieved. The majority of practitioners were practice principals (65%), working in a group NHS practice (80%) located in a city or town centre (49%). On average 10-20 patients were treated each session with fewer patients treated per session under private arrangements. Many practitioners were found to lack hygienist support (44%) and to employ unqualified dental nurses (82%). Younger practitioners were more likely than senior colleagues to have access to up-to-date computers whilst 37% and 74% of respondents never used CAL programmes or magnification respectively. Contemporary cross-infection control standards were used by the majority of practitioners, although 3% of practitioners reported only autoclaving their handpiece once a day. CONCLUSIONS: The majority of practitioners, involved in this study, worked under National Health Service (NHS) regulations as principals in a group practice where the workload was greater than the private/independent sector. Contemporary cross-infection procedures were used routinely. In contrast computer-aided learning programmes and magnification were not used routinely. The practitioners in this study employed significant numbers of unqualified dental nurses.

Anesthesia, Dental↗
PubMed2004

Contemporary dental practice in the UK: aspects of direct restorations, endodontics and bleaching.

OBJECTIVES: To investigate by questionnaire, the use and selection of materials and techniques for the placement of direct restorations and the provision of endodontics and bleaching by dental practitioners in the North West of England and Scotland. METHODS: A questionnaire was sent to 1,000 general dental practitioners selected at random from dentists in Scotland and the North West of England. Non-responders were sent another questionnaire after a period of 4 weeks had elapsed. RESULTS: A total of 701 usable questionnaires were returned, giving a response rate of 70%. The most commonly used material for the restoration of Class II cavities in premolar and permanent molar teeth was amalgam (n = 605, 86%) and (n = 634, 90%) respectively. Many practitioners (n = 419, 60%) felt amalgam should continue to be used but a majority (n = 374, 66%) remained unconvinced about the merits of amalgam bonding. A minority (n = 63, 9%) of practitioners used predominantly directly placed resin composite rather than amalgam to restore Class II cavities in premolar and permanent molar teeth. Home-based vital bleaching was provided by a significant number (n = 245, 35%) of practitioners with only 18% (n = 123) providing practice-based bleaching. The most commonly used endodontic obturation technique was cold lateral condensation (n = 527, 75%) with 61% (n = 425) of respondents not using rubber dam routinely for endodontics. CONCLUSIONS: For the practitioners in this survey, amalgam was the most frequently selected direct restorative material. Few practitioners used amalgam bonding let alone direct resin composite for posterior restorations. Home-based rather than practice-based bleaching procedures were preferred, as were more traditional endodontic obturation techniques.

Dental Materials↗
PubMed2004

Healing of oral lichenoid lesions after replacing amalgam restorations: a systematic review.

OBJECTIVE: We sought to systematically review the literature related to oral lichenoid lesions (OLLs) and amalgam restorations. STUDY DESIGN: Cohort and case-controlled studies (no randomized controlled trials or controlled clinical trials available) were reviewed with respect to inclusion criteria and data on patients with OLLs, treatment interventions, and the measurement of outcomes. RESULTS: Fourteen cohort and 5 case-controlled trials met the criteria. The study population consisted of 1158 patients (27% male and 73% female; age range, 23-79 years). From 16% to 91% of patients had positive patch test results for at least 1 mercury compound. Of 1158 patients, 636 had to have their restorations replaced. The follow-up period ranged from 2 months to 9 1/2 years. Complete healing ranged from 37.5% to 100%. The greatest improvements were seen in lesions in close contact with amalgam. CONCLUSIONS: Protocols must be standardized to obtain valid results. The replacement of amalgam restorations can result in the resolution or improvement of OLLs. Patch testing seems to be of limited value. The topographic relationship between an OLL and an amalgam restoration is a useful--but not conclusive--marker.

Adult↗
PubMed2004

Resin composite monomers alter MTT and LDH activity of human gingival fibroblasts in vitro.

OBJECTIVES: Substances such as monomers may be released from composite resin systems and may induce adverse effects in biological tissues. The aim of this study is to investigate the cytotoxic concentrations of resin composite monomers on cultures of human gingival fibroblasts. METHODS: A range of dilutions of five resin composite monomers (HEMA, HPMA, DMAEMA, TEGDMA, and Bis-GMA) were added to the culture medium of human gingival fibroblasts for 24 h. Their cytotoxic effects were measured by using two colorimetric functional assays, mitochondrial dehydrogenase activity (MTT) and lactate dehydrogenase activity (LDH) assay. The logP values (water/octanol partition) of test monomers were also calculated computationally. RESULTS: Mitochondrial reducing activity assessed with the MTT test was inhibited by all monomers and all the monomers increased the LDH release in a reproducible dose dependent manner. A wide range of TC 50 values (concentrations altering MTT and LDH activity by 50%) (0.32-5.8 mM by MTT assay and 0.36-6.7 mM by LDH assay) was observed. Ranking of composite resin monomer cytotoxicities (TC 50) were similar for both the MTT and LDH assays, (Bis-GMA>TEGDMA>DMAEMA>HPMA >HEMA). However, the MTT assay was found to be more sensitive than the LDH assay, particularly when lower doses of the tested monomers were determined. The ranking of TC 50 concentrations correlated with the calculated logP values. SIGNIFICANCE: Monomers used in dental restorative materials show a variety of toxic effects on gingival fibroblasts. A combination approach using MTT and LDH assays provides valuable information about their toxic effects.

Analysis of Variance↗
PubMed2003

Mercuric chloride: toxicity and apoptosis in a human oligodendroglial cell line MO3.13.

A human-human oligodendroglial cell line MO3.13 was chosen in this study to model the loss of oligodendrocytes that occurs during episodes of multiple sclerosis. The influence of mercuric chloride (HgCl(2)) upon cell viability specifically the mode of cell death, whether by an active apoptotic mechanism or passive necrosis was determined by morphological and biochemical analysis. Mitochondrial dehydrogenase activity MTT assay showed that HgCl(2) had toxic effects on MO3.13 cells at levels of (5-25 microM) with approximately 50% cell death observed at 58 microM. Death of cells was dependent on both time and concentrations of HgCl(2). Differentiated MO3.13 cells exposed to low concentrations (25 microM) of HgCl(2) exhibited features of apoptotic cell death, including cell shrinkage and chromatin condensation. High doses of HgCl(2) (>100 microM) induced death with characteristics of necrosis. Biochemical analysis showed that HgCl(2) activated the caspase family of proteases. This was measured directly by cleavage of fluorescent substrates and by immunoblotting assay of caspase substrate proteins; alpha-fodrin, lamin B and poly (ADP-ribose) polymerase (PARP). These results indicate that HgCl(2) is toxic at low concentrations for oligodendroglial cells and that the MO3.13 cell line dies in an apoptotic manner when exposed to low concentrations of HgCl(2). However, blood mercury concentrations in vivo in a normal population with amalgam restorations are lower by a factor of some 500 times than those causing toxicity in vitro suggesting a good safety margin in respect of environmental uptake.

Apoptosis↗
PubMed2001

The erosive effect of herbal tea on dental enamel.

OBJECTIVES: The aim of this study was to determine whether conventional black tea and a herbal tea were capable of eroding dental enamel. A further aim was to investigate whether herbal tea of the type tested eroded dental hard tissues to a greater or lesser extent than conventional black tea. METHODS: Three groups of 21 teeth were exposed to a conventional black tea Typhoo (Group A), a herbal tea Twinings Blackcurrant, Ginsing and Vanilla (Group B) and water, which acted as a control (Group C). Sequential profilometric tracings of the specimens were taken, superimposed and the degree of enamel loss calculated as the area of disparity between the tracings before and after exposure. RESULTS: Conventional black tea and herbal tea, of the type tested, both resulted in tooth surface loss. Tooth surface loss, which resulted from exposure to herbal tea (mean 0.05mm(2), s.d. 0.02), however, was significantly greater (P=0.00) than that which resulted from exposure to conventional black tea (mean 0.01mm(2), s.d. 0.00) and water (mean 0.00mm(2), s.d. 0.00). CONCLUSIONS: It was concluded that herbal tea and conventional black tea of the type tested result in erosion of dental enamel. The erosive effect of the herbal tea of the type tested was five times more severe than that of the conventional black tea tested. The cumulative effects of regular consumption of herbal tea of the type tested are likely, therefore, to be of clinical significance.

Analysis of Variance↗
PubMed2000

Tooth preparation techniques for porcelain laminate veneers.

OBJECTIVE: The purpose of this study was to determine the effect that two guides to tooth preparation had on an operator's ability to appropriately and consistently prepare teeth for porcelain laminate veneers. STUDY DESIGN: In-vitro study. MATERIALS AND METHODS: Thirty typodont central incisor teeth were randomly allocated into three groups and a general dental practitioner was asked to prepare the teeth for porcelain laminate veneers. Group A were prepared freehand while Groups B and C were prepared with the assistance of a silicone index and depth preparation bur respectively. Images of the prepared teeth were used to calculate the mean labial depth of preparation and incisal reduction of teeth in each group. RESULTS: The mean labial reduction for Groups A, B and C was 0.37 mm (SD 0.13), 0.62 mm (SD 0.17) and 0.61 mm (SD 0.15) and the mean incisal reduction for Groups A, B and C was 1.0 mm (SD 0.28), 1.0 mm (SD 0.38) and 1.03 mm (SD 0.26) respectively. CONCLUSION: It is suggested that consideration be given to the use of a silicone index or depth gauge bur when teeth are prepared for porcelain laminate veneers.

Dental Instruments↗
PubMed2000

Resistance of two dentin-bonding agents and a dentin densensitizer to acid erosion in vitro.

OBJECTIVES: To determine the resistance of two dentin-bonding agents (DBAs) and a dentin desensitizer to simulated dental erosion. METHODS: Twenty teeth in each of three groups of selected premolars, with exposed cervical dentin, were treated with one of three dentin surface treatment systems: Gluma Desensitizer (Heraeus Kulzer (UK) Ltd), One Coat Bond (Whaledent (UK) Ltd), and Optibond FL (Kerr (UK) Ltd) and exposed to water (control) and an erosive challenge (Coca Cola) for 14 days. Sequential tracings of the specimens were taken, superimposed and the mean reduction in densensitizer or DBA thickness and or tooth loss determined. RESULTS: A mean loss of 77 microns (s.d. 14.6 microns) of tooth tissue over the untreated sites following 14 days exposure to Coca Cola was observed. The application of DBAs, as opposed to Gluma Desensistizer alone, over exposed dentin surfaces afforded substantial protection against erosion by Coca Cola over the period of study. The mean change in vertical profile of teeth treated with a DBA was 20 microns (s.d. 14.7 microns), almost four times less than that seen over untreated sites. SIGNIFICANCE: With the exception of Gluma Desensitizer, which was lost completely, One Coat Bond and Optibond FL demonstrated levels of acid dissolution resistance, which would be of potential value clinically.

Analysis of Variance↗
PubMed2000

Students' perceptions of seminar and lecture-based teaching in restorative dentistry.

In an era of self-directed learning, it is important to seek the views of dental students regarding their learning experience. Using an anonymous questionnaire, clinical dental students' perceptions of seminar and lecture-based teaching in restorative dentistry were sought. 116 of 136 questionnaires circulated were returned for analysis giving a response rate of 85%. Clinical seminars as opposed to lectures were, in the opinion of the students, a more effective way of learning, more relevant to self-development and more interactive. Seminar-based learning was considered to be more amenable to self-direction than formal didactic lectures. It is concluded that the students included in this study were found to prefer seminar-based learning opportunities as opposed to more traditional styles of learning, specifically, didactic lectures.

Attitude↗
PubMed2000

An evaluation of powder-free gloves in general dental practice.

PURPOSE OF STUDY: To evaluate the suitability of two non-sterile, powder-free gloves for routine use in general dental practice. BASIC PROCEDURES: Randomly allocated blind evaluation of two powder-free gloves by five dentists and five dental nurses in general dental practice. Each dentist and dental nurse were allocated a four-day supply of two unnamed powder-free gloves. Following glove usage a questionnaire sought their views regarding ease of donning, operator comfort, puncture and tear resistance, and tactile sensitivity. Details of procedure undertaken, time of wear and puncture and tear formation for the dentists' gloves were also recorded. The dentists' gloves were retained and subsequently tested for punctures and tears. MAIN FINDINGS: In terms of ease of donning, operator discomfort, tear resistance and tactile sensitivity neither glove was ideal, however one glove was rated higher than the other. Overall, the dentists noticed only half of the punctures and tears detected in the laboratory. One glove was more prone to punctures with the other glove more liable to tear. Time worn in excess of 20 minutes and endodontic procedures were associated with a higher incidence of punctures. PRINCIPAL CONCLUSIONS: The two powder-free gloves evaluated in this study would appear not to be suitable for routine use in general dental practice. Further developments are required before powder-free gloves of the type evaluated can be expected to receive widespread acceptance for routine use by dentists and dental nurses in general dental practice.

Chi-Square Distribution↗
PubMed1999

Procera all-ceramic crowns: a new approach to an old problem?

Increasing patient expectations regarding the appearance of restorations continue to test the ingenuity and skill of the dental team. To this end the quest for sufficiently strong, metal-free, all-ceramic restorations to function in all areas of the mouth continues apace. We report on a possible solution to this problem that uses computer-aided design/computer-aided milling (CAD/CAM) technology coupled with a novel, densely sintered, ceramic material. In this article we offer suggestions for case selection, preparation design, and luting procedures, and in addition illustrate these with a number of completed cases.

Adult↗
PubMed1999

Fracture resistance of teeth restored with onlays of three contemporary tooth-colored resin-bonded restorative materials.

STATEMENT OF PROBLEM: There are uncertainties regarding the use of large indirect composites and ceramics in the restoration of posterior teeth. PURPOSE: This study investigated the fracture resistance of teeth restored with restorations of 3 contemporary resin-bonded tooth-colored materials placed in a standardized onlay preparation. MATERIAL AND METHODS: A random sample of preparations for tooth-colored onlays was obtained from a full service dental laboratory. A preparation was then duplicated in 30 natural teeth by copy milling. An additional 10 teeth were not prepared, and acted as a control. Ten onlays of each of the 3 materials (Belle Glass, SR Isosit, and Empress) were produced and resin bonded into place according to the manufacturers' instructions. The restorations were compressively loaded to fracture and the mode of failure recorded. RESULTS: The fracture resistances obtained for the teeth restored with the composite material (mean 1.56 kN; SD 0.54) were greater than those obtained for the teeth restored with the ceramic material (mean 0.99 kN; SD 0.49) and the fiber-reinforced composite material (mean 0.99 kN; SD 0.56). CONCLUSION: Teeth restored with composite onlay restorations demonstrated a higher fracture resistance than equivalent sized onlay restorations produced from fiber-reinforced composite or a ceramic material. Failure under compressive loading may be found to be less catastrophic when a fiber-reinforced composite rather than a composite or ceramic material is used.

Acrylic Resins↗
PubMed1999

A three-year evaluation of restorations placed with a smear-layer-mediated dentin bonding agent in non-carious cervical lesions.

PURPOSE: To evaluate the handling characteristics, clinical behavior, and effectiveness of Coltene ART Bond/Brilliant restorations in mixed Class V preparations in maxillary premolar and canine teeth of adult patients over a three-year period. MATERIALS AND METHODS: Single-center, uncontrolled, clinical evaluation of 50 restorations in 26 patients extending over 36 months. RESULTS: At three years, 34 restorations, or 68% of those originally placed, in 20 patients were available for review. One of the 34 restorations had been lost 15 months after placement. In terms of marginal integrity and staining, anatomic form, surface texture and staining, and postoperative sensitivity, over 90% of the restorations reviewed at three years were rated alpha. Following difficulties in obtaining excellent color match in relation to 14 (28%) of the restorations at the time of placement, only 44% of the restorations were rated alpha at three years. CONCLUSION: It was concluded that with the possible exception of excellent color match, ART Bond/Brilliant restorations may be found to perform favorably in mixed Class V lesions in selected adult patients over a period of at least three years. The findings indicate that resin composite restorations placed with a smear-layer mediated dentin bonding agent may be found to have a favorable clinical outcome in non-carious cervical lesions.

Adult↗
PubMed1998

Preparations for porcelain laminate veneers in general dental practice.

OBJECTIVE: To investigate variations in preparations for porcelain laminate veneers (PLVs) in general dental practice. DESIGN: Laboratory-based retrospective analysis of dies for PLVs. SETTING: General dental practice in England and Wales (1994). METHODS: A sample (95 cases) of laboratory models from general dental practice featuring preparations for PLVs was randomly selected from a full service commercial dental laboratory. Aspects of the preparations were quantified and compared with accepted preparation criteria distilled from a review of the literature. RESULTS: The teeth found to be most frequently prepared for PLVs were maxillary incisors (48%). The majority of cases investigated were for one veneer only (56%). The margins of the preparations were variably positioned with more than half of the preparations (55%) having no clear margin. In accordance with current guidelines the incisal edge tended to have been reduced during preparation (47%). In contrast, most teeth were underprepared with an average depth of preparation of 0.16 mm (SD 0.60 mm, 95% CI-0.1, 0.42). CONCLUSIONS: There was little evidence that established guidelines for the preparation of teeth for PLVs had been applied in full.

Dental Porcelain↗