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Abstracts in endodontics
ABSTRACTS IN ENDODONTICS These abstracts have been selected [rom recent issues o / O r a l R e s e a r c h A b s t r a c t s , a monthly iournal published by the American Dental Association. Selected abstracts will be published regularly as a service to the readers o/ the J o u r n a l o f E n d o d o n t i c s . More in/ormation about O R A is. available ]rom the A D A Subscription Department.
Clinicopathological study of the healing effects of human vital pulp wounds with calcium hydroxide pastes. Y o s h i o Haruyama (Tokyo Dent Coil, Tokyo, Japan). Shikwa Gakuho 75(3):331406 Mar, 1975 (Jap; summary in Eng). Ca(OH)2, Calxyl (I) and Calvital (II), were used on the exposed vital pulp of persons aged 18-35 yr. The pulp was exposed intentionally or amputated with the patient under local anesthesia, and the exposed surface was dressed with ! or II. After lining with Zn phosphate cement and amalgam and after clinical observations, the teeth were extracted. The pulps were examined histopathologically after 1-783 day in instances of pulp capping, and after 1-661 days in instances of vital pulpotomy. In instances of pulp capping, clinically, 19 of 25 patients with 1, and 23 of 25 patients with II, experienced no discomfort; the remaining 6 patients with I and 2 with II reported various uncomfortable symptoms such as spontaneous pain, disagreeable sensation, hypersensitivity to cold, and percussion discomfort. Histopathologically, 13 of 25 specimens with I were evaluated as good, 9 as fair, and 4 as bad; 24 of 25 specimens with II were evaluated as good and 1 as bad. In instances of vital pulpotomy, clinically, t7 of 25 patients, with I and 23 of 25 patients with II experienced no discomfort; the remaining 8 with I and 23 0f25 patients reported the above mentioned symptoms and hypersensitivity to heat. Histopathologically, 16 of 25 specimens with I were evaluated as good, 6 as fair, and 3 as bad; 25 of 25 specimens with II were evaluated as good. Histopathologic changes observed were: hyperemia, bleeding, round-cell infiltration, suppurative inflammation, coagulation necrosis, atrophy of the pulp, cicatrization of the pulp, formation of new dentin bridge, formation of denticles, apposition of dentin on the root canal wall, and absorbtion of dentin on the root canal wall. Tetsuo Ishiki
Clinical study on the healing of a puipectomized site under local anesthesia. Kunio Yamaguchi (Osaka Dent Univ, Osaka, Japan). J Osaka Odontol Soc 38(2): 117-35 April, 1975. After pulpectomy, 56 root canals were filled with standardized gutta-percha points and chloropercha on a single-cone method. The root canals were classified into 6 groups - - more than 1 mm, flush, 1, 2, 3, or 5 mm under filling at the apex - - and examined clinically and radiographically approximately 2 yr postoperatively. Endodontic success or failure was determined on the basis of the presence or absence of radiographic changes in periapical tissue. In the flush and more than 1 mm filling groups, many instances of failure were found at approximately 2 yr postoperatively. No difference was found in the developmental rate of failure cases between these 2 groups. The flush and 1 mm over filling groups showed a significantly higher developmental rate of successful cases than the 1, 2, 3, and 5 mm under filling groups. The 1 mm under filling group showed no significantly different developmental rate of successful cases than the 2 or 3 mm under filling group. It was strongly suggested that pulpectomy should be done at more than 1 mm under the apex. At this depth, the wound surfaces after pulp e~tirpation were easily sealed, and wound healing by means of biological reaction was expected. Masakazu Mori
Examples of healing following partial root canal filling. B. C. W. Barker (Univ Sydney, Sydney, Australia). J Brit Endodont Soc 9(1):3-10, 1976. In many instances of deficient apical seal there is frequently radiographic evidence of periapical healing or preservation of intact lamina dura, especially after vital pulpectomy. Despite reports of vital apical remnants replaced by fibrous tissue or cementum, there is little evidence related to tissue response after partial filling of the canal. Five root-filled teeth were examined; all of them had obviously inadequate root fillings and radiographically intact lamina dura but were extracted for other
reasons. Teeth were fixed in F/S and sectioned after processing. All specimens showed apical repair by. cementum and connective tissue and in 1 instance there was hard tissue formation around a poor-fitting Ag point, producing a good apical seal. This may owe its origin to ingrowth of vascular tissue from the periodontal ligament apically or to the organization of an uninfected blood clot. Rest for the vital traumatized apical tissue after pulpectomy is essential through avoidance of irritant drugs and through asepsis and immediate root filling. Rubber dam is mandatory and cautery of the exposure area before pulpectomy prevents transmission of organisms to the periapex. Canals should be prepared with a nonirritant antiseptic solution. 21 references. J . J . Messing
Biological study on the tissue reactions of some root canal filling materials. Jiann-Nan Chen (Osaka Dent Univ, Osaka, Japan). J Osaka Odontol Soc 38(6):574-98 Dec, 1975. Gutta-percha, AH26, Kri 1, Tubli-~;eal, N2, andHydrex root canal filling materials were loaded into polyethylene tubes and embedded into the dorsal subcutaneous tissue of rats. The specimens remained implanted for periods of 1 day, 3 days, I wk, 2 wk, 4 wk, and 2 months. Animals were killed and the implants, together with surrounding tissues, were excised. Immediately after the dissection, serial sections were prepared in the cryostat (-20~ and studied histochemically by various enzymes and also by hematoxylin and eosin staining. Gutta-percha and Kri 1 are less irritating to the surrounding tissues. 2 wk postoperatively, the fibrous tissue was proliferating as covering materials. AH26 provoked such severe responses that in 2 wk either infiltrating cells were evident or the tissue had necrosed. One month postoperatively, the fibrous tissue appeared at the end of the material. Tubli-seal and N2 created the greatest inflammatory reaction to the surrounding tissues for a prolonged time. Hydrex caused considerable initial and persisting inflammatory responses in the surrounding tissues. As soon as reparation commenced, Hydrex promoted progressive healing. The histochemical changes in alkaline phosphatase (ALP), acid phosphatase (ACP), succinate dehydrogenase (SDH), and lactate dehydrogenase (LDH) were studied in proliferating connective and inflammatory tissue. The wounds caused by the irritating materials showed a decrease in ALP or LDH activity; an increase in ALP caused proliferation of fibroblastic tissues, infiltration of inflammatory cells, and newly-formed capillaries. In addition, ACP activity had increased. The proliferation of fibrous tissue is considered directly proportional to the presence of ALP, ACP, SDH, and LDH. The inflammatory reaction also seems to have the same proliferation with the presence of ALP enzymes. Masakazu Mori
Assessment of the "Aspir" endodontic irrigator/aspirator. A H. R. Rowe (Guy's Hosp Dent Sch, London, United Kingdom). J Brit Endodont Soc 9(1): 23-4, 1976. The Aspir machine acts as an irrigation and aspiration device to effect removal of debris during endodontic treatment: It consists of a handpiece plus 3 containers for irrigating solutions and a compressor, all mounted in a unit. Lifting the handpiece from its holder activates the compressor. A foot switch with 4 positions directs compressed air into a preselected irrigant container, expelling irrigant through a fine needle in the handpiece, which is adjustable to the length of the canal. The type of irrigant and the pressure at which it is expelled are easily changed. An aspirator tip in the handpiece simultaneously evacuates the fluid. The machine is easy to operate and permits irrigation of fine canals; however, the needle blocks easily and requires constant replacement. It is time consuming to adjust for the required volume of solution, and the compressor is noisy. J . J . Messing
Clinicopathological study of the healing effects of human vital pulp wounds with calcium hydroxide pastes. Y o s h i o Haruyama (Tokyo Dent Coil, Tokyo, Japan). Shikwa Gakuho 75(3):331406 Mar, 1975 (Jap; summary in Eng). Ca(OH)2, Calxyl (I) and Calvital (II), were used on the exposed vital pulp of persons aged 18-35 yr. The pulp was exposed intentionally or amputated with the patient under local anesthesia, and the exposed surface was dressed with ! or II. After lining with Zn phosphate cement and amalgam and after clinical observations, the teeth were extracted. The pulps were examined histopathologically after 1-783 day in instances of pulp capping, and after 1-661 days in instances of vital pulpotomy. In instances of pulp capping, clinically, 19 of 25 patients with 1, and 23 of 25 patients with II, experienced no discomfort; the remaining 6 patients with I and 2 with II reported various uncomfortable symptoms such as spontaneous pain, disagreeable sensation, hypersensitivity to cold, and percussion discomfort. Histopathologically, 13 of 25 specimens with I were evaluated as good, 9 as fair, and 4 as bad; 24 of 25 specimens with II were evaluated as good and 1 as bad. In instances of vital pulpotomy, clinically, t7 of 25 patients, with I and 23 of 25 patients with II experienced no discomfort; the remaining 8 with I and 23 0f25 patients reported the above mentioned symptoms and hypersensitivity to heat. Histopathologically, 16 of 25 specimens with I were evaluated as good, 6 as fair, and 3 as bad; 25 of 25 specimens with II were evaluated as good. Histopathologic changes observed were: hyperemia, bleeding, round-cell infiltration, suppurative inflammation, coagulation necrosis, atrophy of the pulp, cicatrization of the pulp, formation of new dentin bridge, formation of denticles, apposition of dentin on the root canal wall, and absorbtion of dentin on the root canal wall. Tetsuo Ishiki
Clinical study on the healing of a puipectomized site under local anesthesia. Kunio Yamaguchi (Osaka Dent Univ, Osaka, Japan). J Osaka Odontol Soc 38(2): 117-35 April, 1975. After pulpectomy, 56 root canals were filled with standardized gutta-percha points and chloropercha on a single-cone method. The root canals were classified into 6 groups - - more than 1 mm, flush, 1, 2, 3, or 5 mm under filling at the apex - - and examined clinically and radiographically approximately 2 yr postoperatively. Endodontic success or failure was determined on the basis of the presence or absence of radiographic changes in periapical tissue. In the flush and more than 1 mm filling groups, many instances of failure were found at approximately 2 yr postoperatively. No difference was found in the developmental rate of failure cases between these 2 groups. The flush and 1 mm over filling groups showed a significantly higher developmental rate of successful cases than the 1, 2, 3, and 5 mm under filling groups. The 1 mm under filling group showed no significantly different developmental rate of successful cases than the 2 or 3 mm under filling group. It was strongly suggested that pulpectomy should be done at more than 1 mm under the apex. At this depth, the wound surfaces after pulp e~tirpation were easily sealed, and wound healing by means of biological reaction was expected. Masakazu Mori
Examples of healing following partial root canal filling. B. C. W. Barker (Univ Sydney, Sydney, Australia). J Brit Endodont Soc 9(1):3-10, 1976. In many instances of deficient apical seal there is frequently radiographic evidence of periapical healing or preservation of intact lamina dura, especially after vital pulpectomy. Despite reports of vital apical remnants replaced by fibrous tissue or cementum, there is little evidence related to tissue response after partial filling of the canal. Five root-filled teeth were examined; all of them had obviously inadequate root fillings and radiographically intact lamina dura but were extracted for other
reasons. Teeth were fixed in F/S and sectioned after processing. All specimens showed apical repair by. cementum and connective tissue and in 1 instance there was hard tissue formation around a poor-fitting Ag point, producing a good apical seal. This may owe its origin to ingrowth of vascular tissue from the periodontal ligament apically or to the organization of an uninfected blood clot. Rest for the vital traumatized apical tissue after pulpectomy is essential through avoidance of irritant drugs and through asepsis and immediate root filling. Rubber dam is mandatory and cautery of the exposure area before pulpectomy prevents transmission of organisms to the periapex. Canals should be prepared with a nonirritant antiseptic solution. 21 references. J . J . Messing
Biological study on the tissue reactions of some root canal filling materials. Jiann-Nan Chen (Osaka Dent Univ, Osaka, Japan). J Osaka Odontol Soc 38(6):574-98 Dec, 1975. Gutta-percha, AH26, Kri 1, Tubli-~;eal, N2, andHydrex root canal filling materials were loaded into polyethylene tubes and embedded into the dorsal subcutaneous tissue of rats. The specimens remained implanted for periods of 1 day, 3 days, I wk, 2 wk, 4 wk, and 2 months. Animals were killed and the implants, together with surrounding tissues, were excised. Immediately after the dissection, serial sections were prepared in the cryostat (-20~ and studied histochemically by various enzymes and also by hematoxylin and eosin staining. Gutta-percha and Kri 1 are less irritating to the surrounding tissues. 2 wk postoperatively, the fibrous tissue was proliferating as covering materials. AH26 provoked such severe responses that in 2 wk either infiltrating cells were evident or the tissue had necrosed. One month postoperatively, the fibrous tissue appeared at the end of the material. Tubli-seal and N2 created the greatest inflammatory reaction to the surrounding tissues for a prolonged time. Hydrex caused considerable initial and persisting inflammatory responses in the surrounding tissues. As soon as reparation commenced, Hydrex promoted progressive healing. The histochemical changes in alkaline phosphatase (ALP), acid phosphatase (ACP), succinate dehydrogenase (SDH), and lactate dehydrogenase (LDH) were studied in proliferating connective and inflammatory tissue. The wounds caused by the irritating materials showed a decrease in ALP or LDH activity; an increase in ALP caused proliferation of fibroblastic tissues, infiltration of inflammatory cells, and newly-formed capillaries. In addition, ACP activity had increased. The proliferation of fibrous tissue is considered directly proportional to the presence of ALP, ACP, SDH, and LDH. The inflammatory reaction also seems to have the same proliferation with the presence of ALP enzymes. Masakazu Mori
Assessment of the "Aspir" endodontic irrigator/aspirator. A H. R. Rowe (Guy's Hosp Dent Sch, London, United Kingdom). J Brit Endodont Soc 9(1): 23-4, 1976. The Aspir machine acts as an irrigation and aspiration device to effect removal of debris during endodontic treatment: It consists of a handpiece plus 3 containers for irrigating solutions and a compressor, all mounted in a unit. Lifting the handpiece from its holder activates the compressor. A foot switch with 4 positions directs compressed air into a preselected irrigant container, expelling irrigant through a fine needle in the handpiece, which is adjustable to the length of the canal. The type of irrigant and the pressure at which it is expelled are easily changed. An aspirator tip in the handpiece simultaneously evacuates the fluid. The machine is easy to operate and permits irrigation of fine canals; however, the needle blocks easily and requires constant replacement. It is time consuming to adjust for the required volume of solution, and the compressor is noisy. J . J . Messing