Graduating dental students' ability to produce quality root canal fillings using single- or multiple-cone obturation techniques.

The primary purposes of this study were to compare the quality (length and density) and efficiency (time to completion) of obturation when single- or multiple-cone obturation techniques were used by graduating dental school students on previously instrumented single-canalled teeth using simulated clinical conditions in vitro. Five students took part in the study, each of whom obturated thirty-six teeth using six obturation techniques. The multiple-cone techniques included lateral condensation of gutta-percha, the technique the students had used in their laboratory and clinical courses, and two similar variations: lateral condensation of Epiphany and mechanical lateral condensation of gutta-percha. These three methods were compared to three single-cone techniques: Thermafil, Activ GP, and GuttaFlow. The students had no experience with single-cone techniques except for a brief introduction and demonstration. All obturations were timed, and post-obturation radiographs were taken in the clinical and proximal views (CV and PV). The radiographs were read by two endodontic faculty members who were blinded to technique, student, and fellow faculty member's results. Data were also separated by operator experience with individual techniques: the first three obturations/techniques were compared to the final three obturations/techniques. Data were analyzed using chi-square tests. The quality produced or time required rarely differed within multiple-cone or single-cone groups, but statistical differences did occur between the two groups. Multiple-cone obturation was more likely to produce adequate length (p=0.0042), density in the CV (p=0.0056), and density in the PV (p=0.0003). Conversely, the single-cone techniques were significantly faster (mean 350 seconds) than the multiple-cone techniques (mean 464 seconds) (p=0.0020). Quality did not improve significantly with the experienced groups versus the inexperienced with any of the six techniques, but the mean time for obturation decreased from 449 seconds to 362 seconds. These preliminary findings suggest that further training and experience are needed to improve the quality of obturation produced when single-cone techniques are used. Further research is needed to determine how much training and/or experience will be needed.

Incidence of endodontic implantitis and implant endodontitis occurring with single-tooth implants: a retrospective study.

The purposes of this study were to determine success and survival rates for implants and teeth adjacent to implants and the incidence of endodontic implantitis (E-I) (endodontic involvement in adjacent teeth causing implant failure) and implant endodontitis (I-E) (implant placement causing endodontic failure). The data were from 233 single-tooth implants placed in 116 subjects by postgraduate periodontal students with recall radiographs taken >or=9 months after implant placement. Three groups were analyzed: group A, implants with no adjacent teeth (n = 90); group B, implants with nonendodontically treated adjacent teeth (n = 123); and group C, implants with endodontically treated adjacent teeth (n = 20). The success and survival rates for implants were both 92.2% in group A, 98.4% and 99.2% for group B, and 85% and 95% for group C, respectively. For adjacent teeth, they were both 99.4% in group B compared with 75% and 90% in group C. However, after case review, none of the implants or adjacent teeth in group B were considered to have E-I or I-E, and one (5%) of the implants in group C had E-I and two (10%) of the adjacent teeth may have had I-E. The results of the present study agree with previous research, which suggests that endodontically treated teeth adjacent to single-tooth implants are usually successful and should be maintained.

Pulp responses to precise thermal stimuli in dentin-sensitive teeth.

The purpose of this study was to determine whether pulpal responses to cold temperatures applied to enamel, using a method that precisely controls the intensity of the cold stimulus or measures the response time, could distinguish dentin-sensitive teeth from nonsensitive teeth. Eighteen human subjects were stimulated with cold temperatures decreasing in 5 degree C intervals (and with tetrafluoroethane) on exposed root and enamel of a dentin-sensitive tooth and enamel of a contralateral nonsensitive tooth. Pain threshold, intensity of pain, time to pain onset, and duration of pain at baseline, 4 h, 8 h, and 1 week were measured. Responses to enamel stimulation of sensitive teeth compared with the nonsensitive teeth usually were highly correlated and not significantly different. The exception was a longer duration of pain in the dentin-sensitive teeth (4.62 +/- 0.47 s) compared with nonsensitive teeth (2.92 +/- 0.49 s; p = 0.016) after enamel stimulation with tetrafluoroethane. Longitudinal studies are necessary to determine whether these slight increases in pain duration indicate an increased probability of pulpal degeneration or need for dentin protection.

Nonsurgical management of a dilacerated maxillary lateral incisor with type III dens invaginatus: a case report.

Type III dens invaginatus is a developmental anomaly characterized by an enamel-lined channel that originates on the coronal surface and passes apically through part or all of the root and exits into the periodontal ligament. In this case report, a 13-yr-old male had a Type III dens that exited at the midroot level of tooth #7. At that same level, the root dilacerated severely to the mesial, and a periradicular radiolucency was present on the distal. A 12-mm periodontal defect was present on tooth #6 and a sinus tract was present. All maxillary anterior teeth responded normally to pulp vitality testing, and no other abnormal probing depths were present. The channel opening in the crown was located, and the channel was negotiated, enlarged, and filled with calcium hydroxide. Thirteen weeks later, the probing was normal and the canal was obturated with gutta-percha and restored. Two- and 6-yr recalls showed complete healing of the bony defects and continued normal responses to vitality testing.

Incidence of flare-ups and evaluation of quality after retreatment of resorcinol-formaldehyde resin ("Russian Red Cement") endodontic therapy.

The purpose of this retrospective study was to evaluate the quality of treatment and incidence of flare-ups when teeth with resorcinol-formaldehyde resin are retreated in a postgraduate endodontic clinic. Fifty-eight cases were included in this study. Obturated and unfilled canal space was measured on radiographs. Forty-eight percent of the total canal space was filled before retreatment; 90% was filled after retreatment. After retreatment, obturations were rated as optimal in 59%, improved in 33%, unchanged in 6%, and worse in 2%. Seven patients (12%) had postretreatment flare-ups. Data were statistically analyzed using the Cochran-Armitage Test for Discrete Variables. No statistical difference in the incidence of flare-ups was found in teeth that before treatment had more than half the canal space filled compared to teeth with less than half, cases with pre-existing periradicular radiolucencies compared to cases with normal periradicular appearance, symptomatic cases compared to asymptomatic cases, or cases with optimal fillings after retreatment compared to less than optimal cases. It was concluded that teeth with resorcinol-formaldehyde fillings might be retreated with a good prognosis for improving the radiographic quality, but a higher than normal incidence of flare-ups may occur.

Resorcinol-formaldehyde resin "Russian Red" endodontic therapy.

Resorcinol-formaldehyde resin is a material used in endodontic therapy in many foreign countries. With immigration to the United States increasing, American dentists need to become familiar with resorcinol-formaldehyde therapy. It contains two potentially toxic components, formaldehyde (liquid) and resorcinol (powder). Zinc oxide or barium sulfate may be used for radiopacity. When 10% sodium hydroxide is added to the mixture, polymerization occurs, which can form a brick-hard red material that has no known solvent. Several variations in technique exist. The catalyst can be mixed in before insertion into the tooth, added after the mixture is inserted, or not used. Providers believe pulp tissue will be fixed and bacteria destroyed apical to the level of resorcinol-formaldehyde resin placement. Canals are frequently not instrumented or obturated to their full length. Few success-failure studies have been published and results are contradictory. Consequently, providers have little guidance regarding when to retreat or for predicting the difficulty of retreatment.

A survey of endodontic residents' attitudes about a career in dental education.

There is an increasing demand for qualified educators throughout American dental schools. A survey designed to identify reasons for interest or lack of interest in education as a career was sent to all first and second year endodontic residents enrolled in the United States in 1999. Seventy-four percent of the 392 students responded (224 men and 65 women). The survey results were analyzed using descriptive statistics and Chi-square tests. Ninety-three percent of the respondents reported an interest in teaching on a part time basis, and of those, 51% were willing to teach 1.5 days/week, but only 16% were willing to teach more than 1.5 days/week. The survey included a list of eight potential reasons for not being interested in a career in education and respondents were asked to mark their top three. Low salaries for teachers was the most frequently chosen reason (70%), 51% listed educational debt, and 31% listed desire to be their own boss or lack of interest in research. Students were also asked to choose the top three reasons for interest in dental education from a list of seven reasons. Enjoyment of clinical teaching was the most frequently selected reason (41%): 32% included enjoying working with others in the field and 24% listed enjoyment of the university atmosphere.

Hereditary pattern for dentinal dysplasia type Id: a case report.

Generalized pulpal calcifications arouse suspicion of diseases or conditions of systemic or hereditary origin. This case report describes a 45-year-old patient with generalized pulpal calcifications and bulging of the roots in areas corresponding to the pulp chambers in otherwise normal teeth. Similar findings were present in the patient's daughters and brother. This pattern of pulpal calcifications is consistent with the hereditary condition of dentinal dysplasia type Id.

Effect of narcotic pain reliever on pulp tests in women.

The purpose of this study was to determine the effect of one dose of a common narcotic-based pain reliever (Vicodin) on a battery of oral sensitivity tests across time in women. Fifteen Caucasian women randomly were given an oral dose of 10 mg of hydrocodone/1000 mg of acetaminophen or placebo in a double-blind, cross-over design. At baseline (before drug) and after 2, 4, and 8 h each subject was evaluated for sensitivity thresholds with four tests around an experimental tooth: (a) electric pulp tester applied to exposed root; (b) electric pulp tester on adjacent mucosa; (c) increasing probe pressure (grams) on adjacent mucosa; and (d) decreasing cold probe (degrees C) on the exposed root. The outcomes of all tests were not statistically different between drug and placebo treatments at any time point (p > 0.05). These results suggest that a systemic dose of hydrocodone/acetaminophen has little impact on healthy pulp or mucosa sensitivity in women as measured by common diagnostic tests.