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Biomedical subjects

Richard E Walton

Publications and source records attributed to Richard E Walton.

10 recordsLinked to original sources
PubMed2005

Determining the optimal obturation length: a meta-analysis of literature.

The purpose was to aid in determining termination of instrumentation and obturation. A meta-analysis was conducted as to success/failure of different obturation lengths. Inclusion criteria were (a) minimum follow-up of 2 yr, (b) data on obturation length, (c) definition of success/failure, (d) available data on success/failure, (e) radiographic evaluation. Correlations were made as to success/failure as related to length of obturation from the apex. When comparing group A (obturated 0-1 mm from apex) versus group C (obturated past apex) using the DerSimonian and Laird estimates, group A showed a marginally better (p < 0.10) success rate than group C by 28.8%. Group A had better success than group B (obturated >1 mm short); the difference was insignificant. The results were similar after controlling for study quality using a single random effects regression model. In conclusion, the meta-analysis indicated that a better success rate is achieved when treatment includes obturation short of the apex.

Dental Pulp Cavity↗
PubMed2005

Effect of root canal filling/sealer systems on apical endotoxin penetration: a coronal leakage evaluation.

Endotoxin, elaborated by gram-negative organisms, is an important factor in apical periodontitis. The objective of this study was to evaluate the magnitude of endotoxin penetration through root canal treated teeth using a dual chamber model system. Forty-four maxillary anterior teeth were prepared endodontically and canals filled either by lateral condensation or a warm thermoplasticized technique in combination with either Roth's 801 or AH 26 sealer. Teeth were suspended in the model system with a mixed anaerobic bacterial suspension in the upper chamber and HBSS in the lower chamber. The QCL-1000 LAL assay was used to measure endotoxin at 0, 1, 7, 14, and 21 days. Response feature analysis using trapezoidal area under the curve was performed; the four treatment groups were compared using nonparametric methods. Groups differed (p = 0.028), with thermoplasticized root canal filling/Roth's 801 sealer permitting the least apical endotoxin penetration. Results suggest that Roth's 801 sealer may have a role in inhibiting endotoxin penetration.

Analysis of Variance↗
PubMed2005

Evaluation of intracanal sealer distribution with 5 different obturation techniques.

OBJECTIVE: The aim of this study was to determine the distribution patterns of sealer relative to the gutta-percha and the canal wall following the use of different obturation techniques: vertical condensation, Obtura II, System B, SimpliFill, and Thermafil Plus; lateral condensation was used as a comparison. METHODS AND MATERIALS: One hundred five extracted single-rooted teeth were divided into 5 groups of 20 according to obturation technique, with 5 in the lateral condensation group. Instrumentation technique and sealer selection were based on the manufacturer's recommendations. Following obturation, teeth were stored for 4 months at 37 degrees C in 100% humidity. Roots were split longitudinally and halves were examined under a stereomicroscope (x 10) to determine the amount of sealer coverage between the gutta-percha and canal wall. Coverage was categorized as slight (0 to 1/3), low partial (1/3 to 2/3), high partial (2/3 to 9/10), and complete (9/10 to 10/10). RESULTS: Different techniques showed different patterns, but no obturation technique had sealer forming a continuous layer between the gutta-percha and canal wall. The vertical condensation group generally had low partial coverage. Obtura II was the only group to have slight coverage, which occurred in the coronal half. Coronal and apical halves in both the System B and Thermafil Plus groups had the most samples with high partial coverage. SimpliFill had the most samples with complete coverage in both the coronal and the apical portions. All lateral condensation samples showed low partial coverage. CONCLUSION: Sealer distribution patterns were incomplete and inconsistent, regardless of the obturation technique. No technique had sealer forming a continuous layer between the gutta-percha and canal wall.

Gutta-Percha↗
PubMed2003

Calcium hydroxide as an intracanal medication: effect on posttreatment pain.

Calcium hydroxide is advocated as an intracanal medication for various purposes, including prevention of posttreatment symptoms. This study assessed whether calcium hydroxide had a pain-controlling effect at different times when compared with no intracanal medication. One hundred forty patients participated. Conditions diagnosed were pulp/periapical pathosis with or without symptoms. At least partial cleaning and shaping was completed. At random, either Ca(OH)2 plus H2O paste or a dry cotton pellet was placed in the canals of half the teeth, respectively. All teeth were temporized with Intermediate Restorative Material. Patients assessed posttreatment pain up to 48 h as none, mild, moderate, or severe. The pain levels in each test group [Ca(OH)2 versus cotton pellet] at each time period were compared statistically with a multiple-regression analysis. There was no significant difference in posttreatment pain between the two groups at any time period or with any diagnosis or symptom. The use of calcium hydroxide as an intracanal medication was unrelated to the incidence and/or severity of posttreatment pain.

Adult↗
PubMed2003

Intracanal distribution patterns of sealers after lateral condensation.

The purpose of this study was to examine coverage patterns of sealer on canal walls and between gutta-percha cones after lateral condensation. Ninety extracted teeth with single canals were evenly and randomly divided into three sealer groups (Roth's, Sealapex, AH 26). Canals were cleaned and shaped, then coated with one of the three sealers followed by lateral condensation of gutta-percha. The teeth were placed into 100% humidity at 37 degrees C. After 4 months the roots were notched and fractured longitudinally and the dentin lifted to expose the gutta-percha sealer and dentin walls. Qualitative assessment was in the apical and coronal as to the amount and the pattern of sealer coverage. Coverage was categorized by the amount and location as follows: (a) no sealer; (b) slight-partial; (c) moderate-partial; or (d) complete coverage. Sealer was frequently absent between gutta-percha cones and the canal wall and at times absent between cones, with a general moderate-partial coverage. No sealer group demonstrated complete coverage; however, AH 26 showed more consistent moderate-partial distribution. Coverage was better in the coronal. In conclusion, none of the three sealers showed a continuous layer between the primary gutta-percha obturant and the canal wall or in spaces between cones.

Bismuth↗
PubMed2002

Sealer distribution in coronal dentin.

A major cause of tooth discoloration is sealer remnants in the pulp chamber after root canal treatment. The purpose of this study was to assess coronal distribution and color changes of four commonly used sealers placed in the pulp chamber after 2 yr. Fifty extracted premolars were cross-sectioned in the coronal third of the root. The chamber contents were removed, and instrumentation was via the canal; then freshly mixed sealer was placed in each chamber. Sealers evaluated were: AH 26, Kerr Pulp Canal Sealer, Roth 801, and Sealapex. The apical access was sealed with white sticky wax, and the tooth was maintained in a moist environment at 37 degrees C for 2 yr. Teeth were split longitudinally, and digital images of the exposed dentin were made, scrambled, and evaluated blindly by trained evaluators for color changes and for presence of sealer in dentin. There was no measurable penetration of sealer into dentin for all groups and no dentin discoloration occurred. The sealers displayed marked discoloration. At 2 yr, the sealers discolored and remained confined primarily to the pulp chamber.

Bismuth↗
PubMed2002

Straight line access and coronal flaring: effect on canal length.

The object of this study was to determine if canal length is altered as a result of straight-line access (SLA) and coronal flaring (CF). Selected were 86 canals of extracted molars and premolars from two groups: straight or severely curved (Schneider curvature <5 degrees and >20 degrees). The reference cusp tip and root-end were flattened to produce reproducible measurements. A #10 file was placed such that the tip extended slightly beyond the apex, with the handle on the referenced cusp. The amount of file protrusion was measured with a stereomicroscope. Then, SLA and CF were performed and the corresponding file replaced to the same coronal reference position. Apical file protrusion was measured again. The change in canal length was determined by the difference in the pre- and post-SLA/CF measurements. A Wilcoxon signed rank test statistically verified that there was a measurable, significant (p < 0.001) change in canal length after SLA and CF. The mean change overall was slight, with a decrease of 0.17 mm. Severe curvature had a slightly greater, significant effect on the amount of change. Tooth type had no significant effect. Changes in working length from SLA and CF, although statistically significant, were very small and clinically unimportant.

Bicuspid↗
PubMed2002

Comparison of carbon dioxide versus refrigerant spray to determine pulpal responsiveness.

There is little evidence for which cold delivery method is most accurate in determining pulp responsiveness. This study compared carbon dioxide dry ice sticks (CO2) versus refrigerant spray (RS) to generate a patient response from different types of teeth restored to varying degrees. Fifteen human patients were selected. In each quadrant, three teeth were identified and the restoration type recorded. Blindfolded patients were randomly tested with either CO2 or RS in a crossover design at two different sessions. Responsiveness was recorded as yes/no and the interval (in seconds) from application to response was determined. Results showed that (a) CO2 and RS were equivalent in producing a pulpal response regardless of tooth and presence of restoration, and (b) CO2 took significantly (p < 0.05) longer to evoke a response than RS using paired t tests. In conclusion, RS and CO2 were equivalent in determining pulpal responsiveness, but the elicited response from RS was faster.

Adult↗