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Biomedical subjects

I Rotstein

Publications and source records attributed to I Rotstein.

At least 55 records · Page 3Linked to original sources
PubMed1991

In vitro determination and quantification of 30% hydrogen peroxide penetration through dentin and cementum during bleaching.

Bleaching pulpless teeth with 30% hydrogen peroxide was reported to cause external cervical root resorption. It was hypothesized that H2O2 penetrated open dentin tubules to initiate an inflammatory response that could result in root resorption. No direct experimental evidence was provided to support this theory. An in vitro model for determination and quantification of H2O2 penetration during bleaching procedures is suggested. Artificial defects of the cementum covering the cementoenamel junction were performed in 22 extracted human premolars. After 15 minutes of thermocatalytic bleaching, H2O2 could be detected in the medium surrounding all the tested teeth. Cervical root permeability to 30% H2O2 could reach up to 82% of the total amount applied.

Dental Cementum↗
PubMed1991

Effect of cementum defects on radicular penetration of 30% H2O2 during intracoronal bleaching.

Bleaching pulpless teeth with 30% hydrogen peroxide has been reported to cause external cervical root resorption. It has been hypothesized that H2O2 penetrating through open dentin tubules can initiate an inflammatory reaction which could result in root resorption. Extracted human premolars were treated endodontically and bleached intracoronally using the thermocatalytic technique. The teeth were divided into three groups; one group with no cementum defects at the cementoenamel junction, one group with artificial cementum defects at the cementoenamel junction, and another group with artificial cementum defects at the middle third of the root. The radicular penetration of 30% hydrogen peroxide in the three groups was assessed directly and compared using an in vitro model. Radicular penetration of hydrogen peroxide was found in all of the groups tested. The penetration of hydrogen peroxide was significantly higher in teeth with cementum defects at the cementoenamel junction than in those without defects.

Dental Cementum↗
PubMed1991

pH variation among materials used for intracoronal bleaching.

Intracoronal bleaching of pulpless teeth with 30% hydrogen peroxide may result in external cervical root resorption. One of several suggested etiological factors associated with this complication is the pH of the bleaching materials. Because the available data on the pH values of bleaching materials were conflicting, it was the purpose of this study to measure the pH of the materials commonly used for bleaching pulpless teeth. The pH of different concentrations of sodium perborate and 30% hydrogen peroxide, alone or in combination, were measured for a period of 14 days. Sodium perborate was confirmed to be alkaline, whereas 30% hydrogen peroxide was acidic. The pH of the materials when mixed together gradually changed from acidic to alkaline as the concentration of sodium perborate was increased. A thick clinical consistency mixture of both materials was alkaline, and its alkalinity increased with time. These results do not support the theory relating bleaching-induced root resorption to an acidic pH of the bleaching pastes.

Borates↗
PubMed1991

Dye leakage in retrofilled dog teeth and its correlation with radiographic healing.

In a previous study in beagle dogs, statistically significant differences in healing were observed radiographically 6 months after apicoectomy and retrofilling with amalgam and varnish, glass ionomer cement, or a composite resin. The purpose of this study was to compare the leakage of these retrofilling materials and to correlate leakage data with healing. After the dogs were sacrificed, 48 roots were extracted. Half of the roots had been irradiated with a CO2 laser on the bevelled root surface after retrofilling. The roots were coated with nail polish, except for their bevelled surface, and were suspended together with positive and negative controls in 2% methylene blue for 8 h. After the specimens were longitudinally split, they were ranked according to the severity of dye penetration, as observed with a dissecting microscope. The differences in dye leakage among the three retrofilling materials were not statistically significant. Consequently, dye leakage did not correlate with the previously assessed healing. Dye penetrated into the root through the bevelled root surface, regardless of CO2 laser exposure of that surface.

Animals↗
PubMed1991

Histological characterization of bleaching-induced external root resorption in dogs.

External root resorption occasionally develops after intracoronal bleaching with hydrogen peroxide. In this study, an experimental model was established to study thermocatalytic bleaching-induced root resorption in dogs. Histological examination after 6 months revealed that 18% of the teeth had root resorption lesions. The lesions could be divided into three types. In type I, root excavations were associated with a dense inflammatory cell infiltrate. Type II lesions were characterized by granulation tissue formation. In type III, the lesions were filled with reparative cementum. The three types probably represent different phases of one process. Calcium hydroxide had no effect on the occurrence or type of resorption. The instability of hydrogen peroxide and the presence of inflammatory resorption lesions 6 months postoperatively suggest hydrogen peroxide-induced toxic radicals or denaturants as potential irritants.

Animals↗
PubMed1991

In vivo efficacy of various retrofills and of CO2 laser in apical surgery.

The purpose of the present study was to radiographically assess the efficacy of various retrofilling materials and of the use of CO2 laser in apical surgery. The mandibular premolars of six beagle dogs were infected, resulting in periapical lesions. Apical surgery was performed without root canal treatment. Amalgam with cavity varnish, glass ionomer cement and a lightcured composite resin were the retrofilling materials used. In half of the material CO2 laser was used on the root surface and the bone, for occlusion of the dentinal tubuli and sterilization. The healing following surgery was observed radiographically for six months. The highest success rate (89%) was found in the roots retrofilled with amalgam and varnish, and the lowest (60%) in those retrofilled with the composite resin. The difference between these groups was statistically significant. The success rate following retrofilling with glass ionomer cement was 69%, and was not significantly different from both the other groups. Under the conditions of this study, the use of CO2 laser during surgery did not affect the treatment results.

Animals↗
PubMed1991

In vitro efficacy of sodium perborate preparations used for intracoronal bleaching of discolored non-vital teeth.

Bleaching materials containing 30% hydrogen peroxide have been used successfully for the treatment of discolored non-vital teeth. Intracoronal application of these materials was occasionally associated with the development of external root resorption. Extracted human teeth with intact crowns were discolored in vitro and bleached with three preparations of sodium perborate. These preparations included: sodium perborate with 30% hydrogen peroxide, sodium perborate with 3% hydrogen peroxide and sodium perborate with water. The bleaching materials were placed in the pulp chamber of the discolored teeth and sealed with IRM for 14 days. They were replaced with fresh preparations after 3 and 7 days. The coronal tooth shades were evaluated after 3, 7 and 14 days and a comparison of the bleaching success of the groups was made at each interval. It was found that after 14 days and three bleachings there was no significant difference in success between the groups. It is therefore recommended that sodium perborate be used in combination with water rather than with hydrogen peroxide to reduce the risk of post-bleaching external root resorption.

Borates↗
PubMed1991

Conservative management of a combined endodontic-orthodontic lesion.

Pulp injury may occur during orthodontic tooth movement particularly in previously traumatized teeth. Therefore the management of such cases requires specific therapeutic considerations. An extensive periradicular lesion was detected in an orthodontically treated maxillary incisor with an uncertain history of a previous traumatic incident. Conservative endodontic therapy resolved the periradicular lesion thus enabling the orthodontic treatment to continue uneventfully. It is essential to closely monitor the patients undergoing orthodontic treatment and those who are in retention, particularly if a history of trauma is suspected.

Adolescent↗
PubMed1991

Effect of bleaching time and temperature on the radicular penetration of hydrogen peroxide.

Extracted human premolars were treated endodontically and bleached intracoronally. The teeth were bleached with 30% hydrogen peroxide for periods of 5, 20, 40 and 60 min at temperatures of 24 degrees C, 37 degrees C and 47 degrees C. A correlation for both bleaching time and temperature and the radicular penetration of hydrogen peroxide was found. No penetration was found after 5 min bleaching at any of the temperatures tested. Prolonging the bleaching time after 5 min increased the hydrogen peroxide penetration at each of the temperatures tested. A rise in the bleaching temperature also increased the hydrogen peroxide penetration although not significantly for all tested periods. It is therefore suggested to minimize the bleaching time and temperature when hydrogen peroxide is used as the oxidizing agent. Bleaching should be limited to separate 5-min periods rather than being performed over a long continuous period.

Adult↗
PubMed1990

Apical closure of mature molar roots with the use of calcium hydroxide.

Calcium hydroxide may induce apical root closure in affected mature teeth as well as in immature teeth. Once an apical hard tissue barrier is formed, a permanent root canal filling can be safely condensed. Two cases are described in which calcium hydroxide induced apical root closure in mature molar teeth where the apical constriction was lost because of chronic inflammatory process.

Adult↗
PubMed1989

Incidence of four-rooted maxillary second molars: literature review and radiographic survey of 1,200 teeth.

A study of 1,200 teeth was carried out in order to determine the occurrence of four-rooted maxillary second molars. One-thousand untreated teeth were examined radiographically. Two-hundred teeth were evaluated radiographically following endodontic treatment. The results indicated that only 0.4% of the teeth presented with four separate roots. Endodontic therapy in such a tooth is described.

Adult↗
PubMed1989

A persistent oronasal sinus tract of endodontic origin.

Extraoral sinus tracts of endodontic origin may be confused with a wide variety of diseases. Although they may be located in a variety of sites on the face and neck, once diagnosed the treatment is relatively simple and successful. Endodontic therapy is the treatment of choice in these cases; however, periapical surgery may occasionally be required. A case of persistent oronasal sinus is described in which healing occurred only after surgical removal of the involved lesion.

Adult↗
PubMed1989

Bypassing gutta-percha root fillings with an automated device.

Endodontic retreatment using Canal Finder K files and chloroform was performed in 106 gutta-percha-obturated, curved root canals, 71 in vitro and 35 in vivo. The minimum time taken to bypass the obturation in a single root canal was 3 s and the maximum time 95 s. The mean times were 19 and 27 s in the two in vitro groups and 32 s in the in vivo group. Eighty-nine percent of the root canals which had been obturated short were bypassed apically in vivo. Root canal curvature was well maintained in all but two root canals. In these two cases apical transportation occurred. Breakage of files occurred three times in vitro, but this did not prevent the completion of bypassing with new files. These results are attributed to the mode of action of the Canal Finder system, which makes it an efficient root canal pathfinder. The advantages of the suggested technique are discussed in light of the clinical considerations of endodontic retreatment.

Gutta-Percha↗
PubMed1988

Lichen planus evoked by periodontal surgery.

A case of Lichen Planus (LP) following periodontal surgery in a patient previously free of the disease is described. Genetic predisposition and lymphokine secretion stimulated by local trauma are suggested as a possible mechanism of the phenomenon. It is recommended that LP patients, especially those suffering from the erosive type, should be treated as conservatively as possible, minimizing the possibility of trauma to the oral tissues where local immunity may have been altered by a pathological process.

Adult↗