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PR 35 A scanning electron microscopic evaluation of human dentinal tubules and its relationship to dentin hypersensitivity
Vol. 25, No. 4, April 1 9 9 9
A scanning electron microscopic evaluation of
human dentinal tubules and its relationship to dentin hypersensitivity.
V Vig, A.K. Mickel, B. Pourjamasb* Case Western Reserve University The present study examined the surface morphology, i.e., the number and diameter of dentinal tubules, from the cervical root third of extracted human maxillary central incisors using a SEM to make a gender-based comparison. A total of eighteen (9 females and 9 males) human maxillary central incisors were obtained for this analysis. The age, sex, and race of the subjects were recorded. Within seventy-two hours after extraction, the teeth were sectioned and prepared for viewing with the use of a JEOL SEM. A well-controlled, single-blindstudy was employed, and analysis of dentin was performed using a digitizingmeasuring software program. The data collected were subjected to a Student's t-test to determine if there was a significant difference between the groups at a level of P<0.05. Analysis of the results revealed no statistical significance between average tubular diameter for females and males. Differences in the number of dentinal tubules per image between the two genders were found to be insignificant, although the greater number of dentinal tubules per image was found in females. This suggests that density, and not tubule size, may affect hypersensitivity. The subiect population showed no difference between African Americans and Caucasians in relationship to mean dentinal tubule size and the number of dentinal tubules per image. The results also showed no correlation between size or density of dentinal tubules and age.
PPRI
Reduction of intracanal bacteria using NiTi rotary instrumentation and various medicaments. G. Shuping*, A. Sigurdsson, M. Trope, University of North Carolina at Chapel Hill. Reduction or elimination of bacteria from infected root canal systems is essential for successful endodontic treatment of chronic apical periodontitis. The purpose of this study was to compare the extent of bacterial reduction using 0.04 NiTi rotary instrumentation with saline or 1.25% NaOC1 irrigation. Also, the effect of the addition of calcium hydroxide for > 1 week to 1.25% NaOC1 irrigation was tested. Forty-two subjects with radiographic and clinical signs of chronic apical periodontiti~ were recruited. The canals were sampled before treatment. during and after instrumentation, and after treatment with calcium hydroxide. The samples were incubated anaerobically for seven days at 37 o C. The initial sample confu-med infection of the canals. The bacteria from each sample were quantified and transformed to log values. There was a significantly greater reduction of bacteria when sodium hypochlorite was used as an irrigant compared to sterile saline (p=0.0001). After instrumentation with sodium hypochlorite irrigation, 61.9% of canals were rendered bacteria free. The placement of calcium hydroxide for at least one week rendered 92.5% of the canals bacteria free, a significant reduction compared to NaOC1 irrigation alone. The results of this stud,/ indicate that NaOC1 irrigation with rotary instrumentation is an important step in the reduction of canal bacteria during endodontic treatment. However, its effect could not consistentl,/render canals bacteria free. The addition of calcium hydroxide intracanal medicament should be used to more predictabl,/attain this goal.
Journal of Endodontics 4~ 307
P~] _ZZ.J
F r e q u e n c y of fourth canals in maxillary molars located when using an operating microscope: a clinical study.
N. Sempira*, G. Hartwell Virginia Commonwealth University The use of surgical microscopes has recently been introduced to facilitate treatment of surgical and nonsurgical endodontic cases. From a review of the literature, one of the reasons for endodontic failure is missed canals_ Previous studies performed by Hartwell, Bellizzi (1982, 1989) in maxillary molars showed that modifying the access preparation resulted in a significant increase of mesiolingual canals located and obturated. The aim of this study was to determine in an in vivo clinical study if the use of an operating microscope would increase the number of fourth canals located and obturated in maxillary first and second molars. Two hundred maxillary first and second molars treated with the aid of a microscope were evaluated. The number of fourth canals located and obturated was recorded. 26.4% of all maxillary molars had a negotiable fourth canal. Evaluated separately, 29.9% of first molars and 20.8% of second molars had a negotiable fourth canal. Results indicated that use of a surgical microscope did not increase the number of fourth canals located compared with those reports where access preparations were modified and the microscope was not used.
Effect of the surgical operating microscope to repair furcation perforations using two types of barriers under a resin ionomer. RC Taylor*, AK Mickel. Case Western Reserve University The purpose of the study is to evaluate the effect of two different barrier techniques, used with a surgical operating microscope (SOM), on the sealing ability of a resin ionomer against bacterial leakage, when used to non-surgically repair furcation perforations. Two hundred and sixteen extracted human molars were accessed then perforated in the furcation region. The first group consisted of 72 teeth repaired with CollaCote bioresorbable collagen packed into the defect to serve as a burner and Geristore resin ionomer placed over the defect. The second group o f 72 teeth were repaired with a mixture of 20% calcium sulfate and 80% demineralized freeze-dried bone allografl (DFDBA) as the barrier, and Geristore A third group of 72 teeth were repaired traditionally with amalgam. In each group, half (36 teeth) were repaired, using a Zeiss SOM and the other half without the SOM. The teeth were then tested for bacterial microleakage using Staphylococcus epidermidis and Proteus vulgaris and evaluations were made at 24hrs, 48hrs, and 72hrs. The results showed that teeth repaired, with both barriers (CollaCote and calcium sulfate/DFDBA) and Geristore leaked less than teeth reoaired with amalgam Also. in the amalgam ~rouo and in the CollaCote/Geristore ~rouo. teeth leaked less when they were reoaired, usine the SOM. v
v
A scanning electron microscopic evaluation of
human dentinal tubules and its relationship to dentin hypersensitivity.
V Vig, A.K. Mickel, B. Pourjamasb* Case Western Reserve University The present study examined the surface morphology, i.e., the number and diameter of dentinal tubules, from the cervical root third of extracted human maxillary central incisors using a SEM to make a gender-based comparison. A total of eighteen (9 females and 9 males) human maxillary central incisors were obtained for this analysis. The age, sex, and race of the subjects were recorded. Within seventy-two hours after extraction, the teeth were sectioned and prepared for viewing with the use of a JEOL SEM. A well-controlled, single-blindstudy was employed, and analysis of dentin was performed using a digitizingmeasuring software program. The data collected were subjected to a Student's t-test to determine if there was a significant difference between the groups at a level of P<0.05. Analysis of the results revealed no statistical significance between average tubular diameter for females and males. Differences in the number of dentinal tubules per image between the two genders were found to be insignificant, although the greater number of dentinal tubules per image was found in females. This suggests that density, and not tubule size, may affect hypersensitivity. The subiect population showed no difference between African Americans and Caucasians in relationship to mean dentinal tubule size and the number of dentinal tubules per image. The results also showed no correlation between size or density of dentinal tubules and age.
PPRI
Reduction of intracanal bacteria using NiTi rotary instrumentation and various medicaments. G. Shuping*, A. Sigurdsson, M. Trope, University of North Carolina at Chapel Hill. Reduction or elimination of bacteria from infected root canal systems is essential for successful endodontic treatment of chronic apical periodontitis. The purpose of this study was to compare the extent of bacterial reduction using 0.04 NiTi rotary instrumentation with saline or 1.25% NaOC1 irrigation. Also, the effect of the addition of calcium hydroxide for > 1 week to 1.25% NaOC1 irrigation was tested. Forty-two subjects with radiographic and clinical signs of chronic apical periodontiti~ were recruited. The canals were sampled before treatment. during and after instrumentation, and after treatment with calcium hydroxide. The samples were incubated anaerobically for seven days at 37 o C. The initial sample confu-med infection of the canals. The bacteria from each sample were quantified and transformed to log values. There was a significantly greater reduction of bacteria when sodium hypochlorite was used as an irrigant compared to sterile saline (p=0.0001). After instrumentation with sodium hypochlorite irrigation, 61.9% of canals were rendered bacteria free. The placement of calcium hydroxide for at least one week rendered 92.5% of the canals bacteria free, a significant reduction compared to NaOC1 irrigation alone. The results of this stud,/ indicate that NaOC1 irrigation with rotary instrumentation is an important step in the reduction of canal bacteria during endodontic treatment. However, its effect could not consistentl,/render canals bacteria free. The addition of calcium hydroxide intracanal medicament should be used to more predictabl,/attain this goal.
Journal of Endodontics 4~ 307
P~] _ZZ.J
F r e q u e n c y of fourth canals in maxillary molars located when using an operating microscope: a clinical study.
N. Sempira*, G. Hartwell Virginia Commonwealth University The use of surgical microscopes has recently been introduced to facilitate treatment of surgical and nonsurgical endodontic cases. From a review of the literature, one of the reasons for endodontic failure is missed canals_ Previous studies performed by Hartwell, Bellizzi (1982, 1989) in maxillary molars showed that modifying the access preparation resulted in a significant increase of mesiolingual canals located and obturated. The aim of this study was to determine in an in vivo clinical study if the use of an operating microscope would increase the number of fourth canals located and obturated in maxillary first and second molars. Two hundred maxillary first and second molars treated with the aid of a microscope were evaluated. The number of fourth canals located and obturated was recorded. 26.4% of all maxillary molars had a negotiable fourth canal. Evaluated separately, 29.9% of first molars and 20.8% of second molars had a negotiable fourth canal. Results indicated that use of a surgical microscope did not increase the number of fourth canals located compared with those reports where access preparations were modified and the microscope was not used.
Effect of the surgical operating microscope to repair furcation perforations using two types of barriers under a resin ionomer. RC Taylor*, AK Mickel. Case Western Reserve University The purpose of the study is to evaluate the effect of two different barrier techniques, used with a surgical operating microscope (SOM), on the sealing ability of a resin ionomer against bacterial leakage, when used to non-surgically repair furcation perforations. Two hundred and sixteen extracted human molars were accessed then perforated in the furcation region. The first group consisted of 72 teeth repaired with CollaCote bioresorbable collagen packed into the defect to serve as a burner and Geristore resin ionomer placed over the defect. The second group o f 72 teeth were repaired with a mixture of 20% calcium sulfate and 80% demineralized freeze-dried bone allografl (DFDBA) as the barrier, and Geristore A third group of 72 teeth were repaired traditionally with amalgam. In each group, half (36 teeth) were repaired, using a Zeiss SOM and the other half without the SOM. The teeth were then tested for bacterial microleakage using Staphylococcus epidermidis and Proteus vulgaris and evaluations were made at 24hrs, 48hrs, and 72hrs. The results showed that teeth repaired, with both barriers (CollaCote and calcium sulfate/DFDBA) and Geristore leaked less than teeth reoaired with amalgam Also. in the amalgam ~rouo and in the CollaCote/Geristore ~rouo. teeth leaked less when they were reoaired, usine the SOM. v
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