Biomedical subjects

W F Kimbrough

Publications and source records attributed to W F Kimbrough.

10 recordsLinked to original sources

PubMed2001

In vitro bacterial penetration of endodontically treated teeth coronally sealed with a dentin bonding agent.

This study evaluated the effectiveness of a dentin bonding agent as a barrier to prevent coronal microleakage and examined the effect of a eugenol-based sealer on the sealing ability of this resin adhesive. Fifty-one extracted human mandibular molars were incorporated in a model system using an oral streptococci as a microbial marker. Group 1 consisted of 15 teeth that were obturated with only gutta-percha and received a coronal barrier of Clearfil Liner Bond 2V. Group 2 was identical to group 1, but included the use of a eugenol-based sealer in the obturation. Group 3 consisted of 15 teeth that were obturated with gutta-percha and sealer, but did not receive a coronal barrier. Six teeth served as controls. Bacterial penetration was monitored for 90 days. Results were analyzed after 30, 60, and 90 days with Fisher's exact test (p < 0.05). All controls behaved as expected. Neither group 1 nor group 2 exhibited any bacterial leakage. Eleven of the 15 specimens in group 3 leaked between 15 and 76 days. The coronal barriers in group 1 and group 2 were significantly better in preventing coronal microleakage at 60 days (p = 0.002) and 90 days (p = 0.00005). The presence of eugenol in the sealer had no significant effect on the sealing ability of Clearfil Liner Bond 2V (p = 1).

Dental Leakage↗

PubMed2001

Effects of eugenol on resin bond strengths to root canal dentin.

The purpose of this study was to compare the regional bond strengths of C&B Metabond resin to root canal dentin, with or without treatment using a eugenol-containing endodontic sealer liquid. Eighteen extracted human canines were decoronated at the cementoenamel junction with a slow speed saw. The apical third of the root was removed leaving the cervical and middle dentin. The canal space was then enlarged with files, Gates-Glidden burs, and parapost drills. The teeth were ground on either the mesial or distal sides, permitting direct access to the entire canal. The cervical or middle third dentin was treated with Kerr Root Canal Sealer liquid, alternating between the middle and cervical thirds. Each tooth served as its own control. The adhesive resin was then luted directly to the prepared canal. Specimens, 1 x 1 x 8 mm, were prepared and mounted to a Vitrodyne testing machine enabling microtensile bond strengths to be measured. Data were analyzed using a two-way ANOVA and the least squares means test. The mean microtensile bond strengths for the cervical and middle third dentin treated with eugenol were 13.6 +/- 6.1 MPa (n = 33) and 14.8 +/- 3.9 MPa (n = 29), respectively. Without the eugenol, the mean bond strengths were 18.1 +/- 6.0 MPa (n = 31) and 17.3 +/- 4.6 MPa (n = 31) for the cervical and middle sections. The specimens treated with the eugenol liquid had significantly lower bond strengths than those without eugenol (p < 0.05) only in the cervical third. The region of the tooth tested had no effect on bond strength. That is, bond strength of the cervical third was not significantly different from bond strength on the middle third in either of the two groups (with or without eugenol) tested.

Analysis of Variance↗

PubMed2001

Measurement of endodontic file lengths: calibrated versus uncalibrated digital images.

This in vitro study compared the accuracy of file length measurements made on calibrated and uncalibrated direct digital images. Endodontic files of known lengths and ISO sizes were used in 10 single-rooted, relatively straight teeth within cadaver specimens. The crowns of the teeth were ground flat and an orthodontic wire of known length was secured to the coronal surface. This wire was placed mesiodistally and perpendicular to the root and served as the reference point for the file measurement and as a calibration reference length. A #20 file was hand-measured to a length that reached the apical third of each tooth. It was inserted and a radiographic image was secured. The instrument was remeasured three additional times at different lengths on the same tooth and reinserted before each image acquisition. Thus 40 digital images were acquired using a GE X-ray unit and a Schick Computed Dental Radiography (CDR) #2 sensor. These images were placed in random order, and an independent, blinded investigator determined the file lengths using on-screen calibrated and uncalibrated measurement of the CDR image with a straight-line and multiple-line measuring technique. The experimental measurements were compared with each other and with the known clinical measurements. A two-way analysis of variance indicated that there was a statistically significant difference showing that the calibrated measurements were more accurate than the uncalibrated measurements (p = 0.0001), and there was no significant difference between the straight-line and multiple-line measuring techniques (p = 0.14).

Analysis of Variance↗

PubMed2000

Effect of varying the depth of heat application on the adaptability of gutta-percha during warm vertical compaction.

The purpose of this study was to compare the adaptability of gutta-percha after varying the depth of heat application in the obturation of a set of standard root canals. A split-tooth model was constructed using a human maxillary central incisor. The root canal was cleaned and shaped using a step-back preparation to a size #60 FlexOFile at the working length (WL). Five shallow depressions were produced on the root canal wall. Twenty obturations without sealer were performed for each technique (thermoplasticized injectable (TI), lateral condensation, and warm vertical compaction (WVC) with heat applications at 3, 4, 5, and 7 mm from the WL). After each obturation the model was separated and the mesial and distal sides of each obturation were examined and videotaped at x 32 magnification. The quality of the obturation was graded based on the replication to the WL, replication of the artificial depressions, surface adaptation, and homogenicity of the gutta-percha. The Kruskal-Wallis analysis and the Student-Newman-Keuls tests indicated that all the techniques were significantly different from each other (p < 0.05) except for the TI group versus the WVC group with the heat application to within 3 mm from the WL (p > 0.05). The TI technique was ranked best followed by the WVC with heat applications at 3, 4, 5, and 7 mm. The lateral condensation technique received the lowest ranking.

Analysis of Variance↗

PubMed1999

Changes in root surface temperatures with in vitro use of the system B HeatSource.

The purpose of this study was to measure root surface temperatures while using the System B HeatSource at various temperature settings. A split-tooth model of a human maxillary central incisor was prepared with 10 thermocouples to record root surface temperatures at 1-mm increments from the root apex. A System B HeatSource model 1005 was used to warm and compact gutta-percha to within 3 mm of the working length using the Buchanan technique. Twenty obturations were recorded at each of the following temperature settings: 250 degrees, 300 degrees, 350 degrees, 400 degrees, 450 degrees, 500 degrees, 550 degrees, and 600 degrees C. Examination of the mean temperatures recorded for each position and at each temperature setting revealed that the thermocouple 5 mm from the apex (T5) detected the highest increases in root surface temperatures. Only this site exceeded the 10 degrees C rise in temperature for one full minute that could cause damage to the supporting structures. The range of instantaneous temperatures at this site was 8.85 to 12.06 degrees C, with a mean of 10.62 +/- 0.93 degrees C. The results of this in vitro study indicate that any temperature setting of the System B HeatSource at or above 250 degrees C has the potential to cause the root surface temperature to rise 10 degrees C. Whether this occurs in vivo or if it does is maintained long enough to cause any tissue damage remains to be determined.

Body Temperature↗

PubMed1998

Anesthetic efficacy of the supplemental intraosseous injection for teeth with irreversible pulpitis.

The purpose of this study was to determine the efficacy of a supplemental intraosseous injection (IOI) of 2% lidocaine with 1:100,000 epinephrine using the Stabident device, after conventional anesthetic methods had failed. Patients who experienced pain during endodontic access and required a supplemental IOI using 0.45 to 0.90 ml of the local anesthetic were identified. All 37 of the patients treated had teeth diagnosed with irreversible pulpitis. Thirty-four of the teeth were mandibular posterior teeth, 2 were maxillary posterior teeth, and 1 was a maxillary anterior tooth. Patients with maxillary teeth had received infiltration anesthesia, and those with mandibular teeth had received an inferior alveolar nerve block in conjunction with long buccal infiltration. A minimum of 3.6 ml of local anesthetic was used with the conventional techniques. Modified visual analogue scales, coupled with operator evaluations, were used to measure success. The Stabident IOI was an effective supplemental anesthetic technique in 89% (+/- 5.1) or 33/37 patients evaluated. The 95% confidence interval was 74 to 97%. The IOI was successful in 91% (+/- 4.9) of the mandibular posterior teeth (31/34), and 67% of the maxillary teeth (2/3).

Adolescent↗

PubMed1997

A comparison of thermoplastic obturation techniques: adaptation to the canal walls.

The purpose of this study was to directly compare the ability of the three types of Thermafil obturators, the Obtura II thermoplasticized injectable technique, and the lateral condensation technique to obturate a standardized root canal. A split-tooth model was constructed and the root canal was obturated 20 times with each technique. The quality of each obturation was graded according to established criteria of adaptation. Statistical analysis of the results indicated that all the techniques were significantly different from each other (p < 0.0001) except for the plastic and titanium Thermafil groups (p > 0.05), which were similar. Based on the evaluated criteria, the Obtura II injectable technique demonstrated the best adaptation to the prepared root canal. This group was followed in order by the plastic and titanium Thermafil obturators, the stainless steel Thermafil obturators, and finally by the lateral condensation technique.

Analysis of Variance↗

PubMed1996

An assessment of the ability of various materials to seal furcation canals in molar teeth.

Ninety-seven maxillary and mandibular molar teeth were evaluated for the presence of naturally occurring furcation canals using the fluid filtration method. Only one specimen demonstrated a naturally occurring patent furcation canal. An artificial furcation canal was created with a 0.33-mm drill bit in the 96 teeth lacking naturally occurring furcation canals. Fluid filtration measurements were made before and after the artificial canal was made, and these served as the negative and positive controls for each tooth. The 96 teeth were randomly divided into eight equal groups, and the floor of the pulp chambers was sealed using 3 mm of either Tytin or Dispersalloy amalgams, Vitremer, FluoroCore, gutta-percha with sealer, Tytin with Ali-Bond 2 or Amalgambond, or Dispersalloy with Ali-Bond 2. Analysis of measured microleakage at 3 months indicated that Tytin amalgam used alone had significantly more microleakage than all other materials; however, this difference did not exist when bonding agents were used with Tytin. All materials leaked significantly less than the positive controls.

Dental Leakage↗

PubMed1996

Root surface temperatures produced during post space preparation.

In vitro root surface temperatures produced during post space preparation were measured. The preparations were made using a GPX bur with rotational speeds of 6,500, 8,000, 9,500, 11,000, and 15,000 rpm. The overall mean temperature increase ranged from 0.66 degree to 4.81 degrees C and was greatest at 8,000 rpm. When speeds > 8,000 rpm were used, temperature increases also resulted, but they were significantly less than that which occurred at 8,000 rpm. Damage to the supporting structures of teeth should not occur when this bur is used, at any of the speeds evaluated, to create a post space.

Analysis of Variance↗

PubMed1994

Longitudinal evaluation of the seal of IRM root end fillings.

IRM has been recommended for root end filling during endodontic surgery. This study evaluated the seal of IRM root end fillings prepared with various powder to liquid ratios (P:L) at extended time intervals using a fluid filtration method. The P:L of IRM evaluated included 2, 3, 4, 5, and 6 g/ml and the P:L which resulted from the manufacturer's recommended scoop and dropper. Ten teeth were evaluated for microleakage for each group at 1, 2, 3, 4, 8, and 12 wk after insertion. There were no significant differences in the microleakage of any of the various P:L groups at weeks 3, 8, and 12. These results suggest that higher P:L of IRM than those previously recommended for temporary restorations and for endodontic access preparations may be acceptable for root end fillings. IRM of higher P:L has other advantages such as ease of placement and decreased setting time, toxicity, and solubility.

Analysis of Variance↗