Biomedical subjects

W P Saunders

Publications and source records attributed to W P Saunders.

At least 19 recordsLinked to original sources

PubMed2003

Fibre-based post systems: a review.

OBJECTIVES: This article presents a review of published literature examining fibre-based endodontic post systems. DATA SOURCES: A MEDLINE search was carried out for any articles in dental journals pertaining to fibre-based post systems. Wherever possible articles cited were obtained from the journals and where this was not possible abstracts were obtained. Where no abstract was available the article was not considered for evaluation. DATA EXTRACTION: Articles were reviewed by a single observer and subject to meeting inclusion criteria were included in the review. Fifty-nine articles were considered suitable for inclusion. DATA SYNTHESIS: Articles were divided into categories and a subjective description of the articles was made. CONCLUSIONS: Review indicated that (1) most published literature on fibre-based posts took the form of laboratory analyses; (2) evidence for carbon-fibre posts far exceeds that for quartz-fibre posts; (3) laboratory evidence was contradictory and could not be used to inform practice reliably; (4) few clinical studies have been carried out though these have suggested fibre based posts may be clinically appropriate for restoration of the endodontically treated tooth; and (5) controlled prospective clinical trials evaluating fibre-based posts should be undertaken to inform use for clinical practice.

Carbon↗

PubMed2002

Reduction in intracanal bacteria during root canal preparation with and without apical enlargement.

AIM: To compare in vitro intracanal bacterial reduction using nickel-titanium rotary instruments with and without apical enlargement. METHODOLOGY: Thirty-eight palatal roots of maxillary molar teeth, with mature apices were subdivided according to lengths and then randomly assigned to two experimental and one control groups. The roots were sterilized and then reinfected with Enterococcus faecalis, which served as a bacteriological marker. All roots in the experimental groups were prepared in a step-down sequence with engine-driven GT rotary files at 350 rpm. In experimental group A (n = 16) additional apical enlargement to ISO size 35 was performed. In group B (n = 16) a serial step-back technique was followed with no apical enlargement. This was combined in groups A and B with irrigation with NaOCl and EDTA. In the control group (group C, n = 6) irrigation only was carried out, with no mechanical preparation. Samples were then taken from the root canals to determine the numbers of remaining bacteria. RESULTS: In groups A and B, 15 (94%) and 13 (81%) specimens were rendered bacteria-free, respectively. In the control group C none of the specimens were bacteria-free. There was a significant difference (P < 0.001) in the antibacterial effects of experimental and control regimens. There was, however, no significant difference (P = 0.276) between the preparation methods used in the experimental groups. CONCLUSIONS: There was no significant difference in intracanal bacterial reduction when Ni-Ti GT rotary preparation with NaOCl and EDTA irrigation was used with or without apical enlargement preparation technique. It may therefore not be necessary to remove dentine in the apical part of the root canal when a suitable coronal taper is achieved to allow satisfactory irrigation of the root canal system with antimicrobial agents.

Analysis of Variance↗

PubMed2002

The effectiveness of various disinfectants used as endodontic intracanal medications: an in vitro study.

The purpose of this study was to compare in vitro the suitability of four disinfectants as intracanal medications: calcium hydroxide, chlorhexidine gel, chlorhexidine in the form of a controlled-release delivery system (PerioChip), and the combination of chlorhexidine gel with calcium hydroxide. Saline was used as the control. The disinfectants were tested at three different time periods (3, 8, and 14 days) by using human tooth specimens that had been previously contaminated with Enterococcus faecalis. Calcium hydroxide worked very efficiently in killing E. faecalis in the 3-day group and 8-day group. It was not as effective in the 14-day group. The different chlorhexidine formulations were also found to be effective for all time periods. More specifically, the combination of chlorhexidine gel with calcium hydroxide and the chlorhexidine gel worked slightly better than the PerioChip, but there was no significant difference among the medications.

Anti-Infective Agents, Local↗

PubMed2001

Funding the GDS.

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Financing, Government↗

PubMed2001

The influence of specialty training and experience on decision making in endodontic diagnosis and treatment planning.

AIM: The purpose of this study was to compare the diagnostic and treatment-planning decision making of cohorts of dental surgeons with different experiences and specialty backgrounds. METHODOLOGY: Periapical radiographs of 20 teeth in patients referred for an opinion regarding the provision of endodontic surgical retreatment were taken using a paralleling technique and a film holder. The radiographs were photographed and black and white photographic prints produced to provide an image 10.5 times larger than the original radiograph. Each image was related to a clinical scenario. Each participant was asked to assess whether a periradicular lesion, as manifested by a radiolucency, was present and what clinical management would be prescribed. Ten participants in each of seven groups took part in the study. These groups were chosen to represent those dentists who were most likely to be involved in decision making in similar cases. RESULTS: In 12 out of 20 cases interobserver agreement for radiographic analysis was 'excellent' (above 90%) or 'good' (between 70 and 90%). There was less agreement for treatment decisions than for radiographic analysis and the order of agreement for cases for diagnosis was not the same as for treatment. No case achieved 'excellent' percentage interobserver agreement. The average percentage interobserver agreement of the endodontists was significantly greater than the average percentage interobserver agreement for the other groups for both radiographic assessment and treatment decisions. CONCLUSIONS: Differences in specialty backgrounds amongst the participants in this study affected both endodontic diagnostic and treatment decisions. Endodontists showed the most consistent agreement amongst the specialty groups.

Adult↗

PubMed2001

The influence of three Erbium:YAG laser energies on the in vitro microleakage of Class V compomer resin restorations.

OBJECTIVES: To investigate the influence of three Erbium:YAG pulse energies (200 mJ, 240 mJ, and 300 mJ with a 100 mJ dentine finish) on the microleakage of Class V compomer restorations (Compoglass). DESIGN: In vitro study. SAMPLE AND METHODS: Sixty-one extracted human premolar teeth were randomly allocated to three groups (according to pulse energy). Each tooth hosted one test cavity prepared with one of the three Er:YAG pulse energies using a pulse repetition rate of 5 Hz and a pulse duration of 250 microseconds, and one control cavity prepared with a conventional diamond bur in a high-speed hand piece. Both cavities were placed at the cervical margin of the tooth and were restored and finished according to the manufacturer's instructions. Each tooth was then stored in 0.12% thymol solution at 37 degrees C for three months, before being thermocycled through water baths between 5 degrees C and 55 degrees C for 240 cycles. Microleakage was assessed using a methylene blue dye penetration technique and was quantified using a score 0 (none) to 4 (to and into the axial wall). The data was analysed using the Kruskal-Wallis and Mann-Whitney U-tests. RESULTS: Leakage was seen in all groups at both the dentine and enamel margins. There were no statistically significant differences in leakage (P < 0.05) at either the enamel or dentine margins, except for the 240 mJ lased enamel margins. This group performed significantly better than the enamel margins prepared with 200 mJ (P = 0.03) and the 300/100 mJ (P = 0.01) laser energies as well as the conventionally prepared enamel margins (P < 0.001). CONCLUSION: Cavity preparation with this Erbium:YAG laser did not influence the microleakage of Compoglass restorations adversely. Different pulse energies were required for optimum cavity sealing at the enamel and dentine margins and for different materials.

Bicuspid↗

PubMed2001

Molecular identification of microorganisms from endodontic infections.

A relatively wide range of bacteria have been isolated from root canals using standard culture techniques. However, only 50% of the bacteria in the oral cavity are cultivable (S. S. Socransky et al., Arch. Oral Biol. 8:278-280, 1963); hence, bacterial diversity in endodontic infections is underestimated. This study used a PCR-based 16S rRNA gene assay, followed by cloning and sequencing of 16S rRNA amplicons from a small subset of samples to assess the diversity of bacteria present in infected root canals. A total of 41 clinical samples from 15 de novo and 26 refractory cases of endodontic infections were assessed. Of these samples, 44% were positive by culture and 68% were positive by PCR. Eight samples were selected for further analysis. Of these, the two de novo cases yielded sequences related to those of the genera Enterococcus, Lactobacillus, Propionibacterium, and Streptococcus and two clones were related to previously uncultivated bacteria, while the sinus-associated, de novo case yielded sequences related to those of the genera Lactobacillus, Pantoea, Prevotella, and Selenomonas. The five refractory cases produced clones which were related to the genera Capnocytophaga, Cytophaga, Dialister, Eubacterium, Fusobacterium, Gemella, Mogibacterium, Peptostreptococcus, Prevotella, Propionibacterium, Selenomonas, Solobacterium, Streptococcus, and Veillonella and two clones representing previously uncultivated bacteria. The phylogenetic positions of several clones associated with the Clostridiaceae and Sporomusa subgroups of the Firmicutes grouping are also shown. This study demonstrates that molecular techniques can detect the presence of bacteria in endodontic infections when culture techniques yield a negative result and can be used to identify a wider range of endodontic-infection-related bacteria including the presence of previously unidentified or unculturable bacteria.

Bacteria↗

PubMed2000

Root canal treatment and general health: a review of the literature.

REVIEW: The focal infection theory was prominent in the medical literature during the early 1900s and curtailed the progress of endodontics. This theory proposed that microorganisms, or their toxins, arising from a focus of circumscribed infection within a tissue could disseminate systemically, resulting in the initiation or exacerbation of systemic illness or the damage of a distant tissue site. For example, during the focal infection era rheumatoid arthritis (RA) was identified as having a close relationship with dental health. The theory was eventually discredited because there was only anecdotal evidence to support its claims and few scientifically controlled studies. There has been a renewed interest in the influence that foci of infection within the oral tissues may have on general health. Some current research suggests a possible relationship between dental health and cardiovascular disease and published case reports have cited dental sources as causes for several systemic illnesses. Improved laboratory procedures employing sophisticated molecular biological techniques and enhanced culturing techniques have allowed researchers to confirm that bacteria recovered from the peripheral blood during root canal treatment originated in the root canal. It has been suggested that the bacteraemia, or the associated bacterial endotoxins, subsequent to root canal treatment, may cause potential systemic complications. Further research is required, however, using current sampling and laboratory methods from scientifically controlled population groups to determine if a significant relationship between general health and periradicular infection exists.

Arthritis, Rheumatoid↗

PubMed2000

Influence of Erbium:YAG laser energies on the microleakage of Class V resin-based composite restorations.

PURPOSE: To evaluate the influence of three Erbium:YAG laser energies on the microleakage of Class V resin-based composite restorations. MATERIALS AND METHODS: 60 extracted human premolar teeth stored in 0.12% thymol solution were randomly allocated to three groups. Buccal and lingual box-shaped Class V cavities were prepared on each tooth. One cavity served as the control and was cut using a conventional diamond bur in a high-speed handpiece. The test cavity was prepared using a pulse repetition rate of 5 Hz with 1 of 3 pulse energies; 200 mJ, 240 mJ, and 300 mJ with a 100 mJ dentin finish. The cavities were restored with Scotchbond Multi-Purpose and Z100 and were finished immediately before being stored for 3 months in thymol solution at 37 degrees C. Following thermocycling between 5 degrees C and 55 degrees C for 240 cycles and a further 12 hrs storage, the teeth were immersed in a 2% aqueous solution of methylene blue for 24 hrs. They were then sectioned through the mid-point of the restorations in a bucco-lingual plane and dye penetration was scored as 0 (none) to 4 (to the axial wall) for the enamel and dentin margins of both sections. The worst score for each margin was used for statistical analysis using the Kruskal Wallis and Mann-Whitney U tests at P < 0.05. RESULTS: When the lased groups were compared, optimum sealing was achieved with energies of at least 240 mJ at the enamel margin and with energies no higher than 200 mJ to finish the dentin margin. However, while all the pulse energies compared favorably to the control group in enamel, a similar result was found only using the 300 mJ, with 100 mJ, finish at the dentin margins.

Aluminum Silicates↗

PubMed1999

Factors influencing the diagnosis and management of teeth with pulpal and periradicular disease by general dental practitioners. Part 2.

OBJECTIVE: To identify techniques commonly used in the management of periradicular disease by general dental practitioners and to ascertain views on continuing professional education in endodontics. DESIGN: Data was collected via a postal questionnaire distributed to 617 general dental practitioners in Scotland (33% of practitioners registered with the Dental Practice Board). RESULTS: 417 (69%) questionnaires were completed and returned. Only 24.9% of respondents used rubber dam routinely. The majority of respondents used hand instruments for preparation with either sodium hypochlorite or local anaesthetic being used most frequently for irrigation. The mean time for treatment of a single rooted tooth was 71 minutes. The demand for continuing education courses was high with 340 and 197 respondents requesting endodontic and rubber dam courses, respectively. CONCLUSIONS: Traditional methods for preparing the root canal using hand instruments were favoured by most dentists. The major disincentive to the use of rotary instruments and new techniques for obturating with thermally softened gutta-percha was expense. The importance of rubber dam isolation requires reiteration and more continuing education courses are required to update clinical skills.

Dental Pulp Diseases↗

PubMed1999

Factors influencing the diagnosis and management of teeth with pulpal and periradicular disease by general dental practitioners. Part 1.

OBJECTIVE: To identify factors influencing the diagnosis and management of periradicular disease by general dental practitioners. DESIGN: The study was conducted in two stages. 1. Analysis of recent returns to the Scottish Dental Practice Board. 2. Data collection via a postal questionnaire distributed to 617 general dental practitioners in Scotland (33% of practitioners registered with the Dental Practice Board). RESULTS: 417 (69%) questionnaires were completed and returned. The majority of respondents undertook root canal treatment and the number of cases treated had increased in the last five years. The vast majority of the respondents (89.3%) were confident in their diagnosis of periradicular disease and 77.1% were confident of their treatment of the disease. A referral system for treatment was used by 31% of respondents of whom the majority used a specialist in a hospital. Over 50% of the respondents undertook surgical root canal treatment. Only 40% of respondents followed up their completed cases for longer than six months. Constraints on the provision of treatment included the time available and the low level of fees. CONCLUSIONS: Current arrangements for the treatment of periradicular disease in general dental practice are less than optimal. The fiscal arrangements for the provision of these treatments must be developed to encourage a high standard of treatment to be performed thereby maximising the likelihood of success. In addition, efforts to inform patients of the benefits of the treatment of periradicular disease should be increased.

Dental Pulp Diseases↗

PubMed1999

Three-body wear associated with three ceramics and enamel.

STATEMENT OF PROBLEM: Wear of human enamel is a clinical concern whenever opposing teeth need to be restored using ceramic restorations. PURPOSE: This in vitro study investigated wear of human enamel and 3 dental ceramics: a conventional porcelain (Vitadur Alpha), a low-fusing hydrothermal ceramic (Duceram-LFC), and a machinable ceramic (Vita Mark II) in a 3-body wear test. MATERIAL AND METHODS: Thirty pairs of tooth-ceramic specimens were tested in a dental wear machine, under a standard load (40 N), rate (80 cycles/minute), and for 25,000 cycles in a simulated food slurry medium. Amount of wear was determined by measuring the height loss of the tooth and depth of wear track of the ceramic materials. Analysis of variance (ANOVA) was used to analyze the data, followed by Bonferroni multiple comparisons method to produce sets of simultaneous 95% confidence intervals. RESULTS: ANOVA revealed significant differences between the groups for both enamel wear (P =. 002) and ceramic wear (P <.001). Further comparisons (95% CI significance level) revealed that the difference in enamel wear produced by Alpha porcelain and Duceram-LFC ceramic material was not statistically significant, whereas that produced by Vita Mark II ceramic was significantly less. Vita Mark II ceramic was significantly more resistant to wear than Alpha porcelain and Duceram-LFC ceramic. Furthermore, Alpha porcelain was significantly more resistant to wear than Duceram-LFC ceramic. CONCLUSION: The abrasiveness of Alpha porcelain and Duceram-LFC ceramic was similar, yet both were significantly more abrasive than Vita Mark II ceramic. In addition, Vita Mark II was the most wear-resistant ceramic and Duceram-LFC ceramic the least resistant.

Analysis of Variance↗

PubMed1999

Calcium hydroxide pastes: classification and clinical indications.

REVIEW ARTICLE: Calcium hydroxide has been used in endodontology for many years. The aim of this paper is to review the various formulations of calcium hydroxide that have been described, with specific reference to the vehicle used to carry the compound. The requirements for a vehicle are described, and ex vivo and in vivo studies reviewed. Vehicles can be classified into aqueous, viscous and oily, the clinical properties of calcium hydroxide changing depending on the vehicle. The review also describes the use of various active components that have been added to calcium hydroxide, including antimicrobial and anti-inflammatory agents. This review will help clinicians to make informed judgements about which formulations of calcium hydroxide should be used for specific endodontic procedures.

Animals↗

PubMed1999

The effect of saliva on fluoride release by a glass-ionomer filling material.

The initial aim of this study was to investigate the effect of saliva and the formation of pellicle on the fluoride release in vitro of the glass-ionomer filling material, Chemfil Superior. For the first study glass-ionomer discs of 6 mm in diameter and 1.5 mm thick were made. Ten discs were immersed in whole stimulated saliva each day for 10 min and 10 control discs were immersed in deionized water. For the remaining 23 h and 50 min of each day, over the 20-day experimental period, both test and control discs were placed in deionized water. A considerable amount of fluoride was released on the first day (14.5 ppm F control and 13.3 ppm F test). The concentration of fluoride released on the second day fell sharply to 5.3 ppm F for controls and 4.9 ppm F for tests. This release had almost reached a plateau by day 10 and at day 20 the pellets continued to release low levels of fluoride. The concentration of fluoride released was only slightly higher for controls than for test discs when both were immersed in deionized water until day 20. However, during the 10-min period between 1.5 and 2 times as much fluoride was released into the deionized water as into saliva until day 20 when the ratio fell to 1.2:1. The second experiment assessed fluoride release when specimens were incubated for 1 h using an identical protocol. Again, less fluoride was released from the saliva-coated specimens compared with the controls (17%), which was not substantially different to the comparable 10-min samples (13%). This study indicates that saliva retards the release of fluoride from glass-ionomer and that this retarding effect is still present when discs are subsequently immersed in water compared with those that were placed in water alone. This suggests that salivary deposits have formed within minutes of immersion in saliva. This retarding effect was observed throughout the study period with the exception of the 20-day samples which had been incubated in saliva for 10 min.

Dental Deposits↗

PubMed1998

Prevalence of periradicular periodontitis associated with crowned teeth in an adult Scottish subpopulation.

OBJECTIVE: To examine the periradicular status of crowned teeth in an adult population in Scotland. DESIGN: Examination of full-mouth periapical radiographs from 319 consecutive adult patients (7596 teeth) attending Glasgow and Dundee Dental Hospitals for clinical examination. METHODS: The periradicular status of teeth with a crown present was assessed to determine the presence of a radiolucency which may indicate pulpal disease. RESULTS: 63.3% (n = 202) of patients had at least one tooth that was crowned. The total number of crowns assessed was 802, of which 458 (57.1%) were vital preparations, and 87 (19.0%) of these had radiographic signs of periradicular disease. The majority of the teeth (62.0%) had distinct widening of the periodontal membrane space which is considered to be an early sign of periapical disease. 42.9% (n = 344) of the crowned teeth had previous root canal treatment of which 50.8% (175) had evidence of a periradicular radiolucency. CONCLUSIONS: Pulpal damage may occur during procedures to provide a crown which may require subsequent root canal treatment. Radiographic follow-up of crowned teeth should be undertaken routinely.

Adult↗

PubMed1998

Polymicrobial coronal leakage of super EBA root-end fillings following two methods of root-end preparation.

The aim of this study was to compose in vitro coronal leakage of a super EBA root-end filling material after two root-end cavity preparation techniques. A mixed anaerobic microbial marker was used. Forty-five extracted human teeth with straight, single root canals were prepared chemo-mechanically to a size 40 master apical file. The teeth were divided into experimental groups (35 teeth) and control groups (10 teeth). Forty teeth (35 experimental teeth and five negative control teeth) were obturated by lateral condensation of cold gutta-percha with Tubliseal EWT sealer. The remaining five teeth were not obturated and served as positive controls. These teeth were stored for 6 months in artificial saliva. The apical 3-4 mm of each root was resected perpendicular to the long axis of the root and a root-end cavity prepared to a depth of 3 mm using either a size 008 rosehead burr or an ultrasonic retroprep tip. Freshly mixed EBA cement was placed into the root-end cavity. The entire root surface of each tooth, except the cutting surface of the apical end, was sealed with nail varnish. The coronal part of each root canal was sealed with the cut end of a tube and placed in a bottle containing sterile Brain Heart Infusion Broth (BHIB). A marker consisting of Anaerobic streptococci and Fusobacterium nucleatum in BHIB was placed in each coronal chamber at 7-day intervals and daily observations were made for bacterial growth in the apical chamber for 60 days. All positive control teeth exhibited bacterial leakage within 48 h, whilst the apical chamber of negative control teeth remained uncontaminated throughout the test period. Fifty-nine percent (n = 10) of the specimens prepared with a burr showed leakage after 90 days, whilst only 22% (n = 4) of the ultrasonically prepared group showed leakage after the same time. The group prepared with ultrasonic tips showed statistically significant less specimens with leakage (P < 0.05) than the group prepared with burrs.

Dental Leakage↗

PubMed1998

The effect of a carbonated beverage on the wear of human enamel and dental ceramics.

PURPOSE: This study was performed to investigate the effect of a carbonated beverage on the wear of human enamel and three dental ceramics: a conventional porcelain (Vitadur Alpha), a hydrothermal low-fusing ceramic (Duceram-LFC), and a machinable ceramic (Vita Mark II). MATERIALS AND METHODS: Tooth-against-ceramic specimens (10 per group) were tested in a wear machine under a load of 40 N, at a rate of 80 cycles per minute, and for a total of 25,000 cycles. The test was performed in distilled water or with intermittent exposure to a carbonated beverage (Coca-Cola). Wear was determined by measuring the height reduction of the tooth specimens and the depth of wear track in the ceramic specimens. RESULTS: ANOVA revealed a significant difference among the groups for both enamel and ceramic wear (p < .001). When tested in water, Alpha porcelain caused significantly more enamel wear and also exhibited greater wear than Duceram-LFC and Vita Mark II. However, with exposure to the carbonated beverage, the enamel wear produced by Duceram-LFC did not differ significantly from that produced by Alpha porcelain, and Vita Mark II produced the least amount of enamel wear. Overall, exposure to the carbonated beverage significantly increased the enamel wear. The wear of Duceram-LFC and Vita Mark II increased with exposure to the carbonated beverage. CONCLUSIONS: It was concluded that exposure to the carbonated beverage accelerated the enamel wear and decreased the wear resistance of Duceram-LFC and Vita Mark II ceramics. Overall, Vita Mark II was shown to be the most resistant to wear and also significantly less abrasive than conventional Alpha porcelain.

Analysis of Variance↗

PubMed1997

Technical standard of root canal treatment in an adult Scottish sub-population.

OBJECTIVE: To examine the periapical status, technical standard and frequency of root canal treatment in an adult population in Scotland. DESIGN: Examination of full-mouth periapical radiographs from 340 consecutive adult patients (8420 teeth) attending Glasgow and Dundee Dental Hospitals for clinical examination. METHODS: Position and quality of the root fillings were assessed together with signs of periradicular radiolucencies. The influence of the type of coronal restoration was also assessed. MAIN OUTCOME MEASURES: Pathologies associated with impacted third molars and outcomes following surgical removal of third molars. RESULTS: 54% of the patient sample had root filled teeth. 5.6% of the teeth examined radiographically had root fillings, and of these, 58.1% had radiographic signs of periapical disease. 41% of the patients had at least one non-root canal treated tooth with periapical disease. 77% of teeth with post-retained crowns had evidence of periapical pathology. CONCLUSIONS: Root fillings judged to be adequate radiographically had a reduced incidence of radiolucencies. Teeth obturated beyond the apex had more radiolucencies than those obturated flush with or within 2 mm of the radiographic apex. A high proportion of post-retained crowns were associated with periapical pathology. There is a substantial future need both for root canal treatment and for standardised treatment methods.

Adult↗