Biomedical subjects

M Trope

Publications and source records attributed to M Trope.

At least 19 recordsLinked to original sources

PubMed1998

Quantitative radiographic follow-up of apical surgery: a radiometric and histologic correlation.

The objective of this study was to establish an objective method for evaluating the treatment outcome of apical periodontitis (AP). AP was induced in the mandibular premolars of beagle dogs and apicoectomies were performed with retrofilling. Standardized periapical radiographs were taken immediately after completion of treatment and at 6 months. Ten pairs of standardized radiographs of 33 treated roots were analyzed. Radiographs were digitized and subtracted after warping and gamma correction. Areas of AP and adjacent normal areas (N) in digitized original and subtraction images were analyzed using eight radiometric computations. These computations were compared with subjective histologic evaluation and objective quantitative histomorphometry of the periapical condition at 6 months. The average gray value for AP on the subtraction images was found to have significant correlation with both objective (multiple regression p < 0.01) and subjective histology (logistic regression p < 0.01). Digital subtraction may be a useful tool in endodontic apical surgery assessment.

Absorptiometry, Photon↗

PubMed1998

Strengthening immature teeth during and after apexification.

The purpose of this study was to evaluate the strengthening effect of an internal resin bonding technique. One hundred central incisors were endodontically treated and divided equally into five groups. Group 1, without any cervical preparation and with access repaired with bonded resin, served as the positive control. Teeth in groups 2 to 5 were cervically prepared to simulate the thin dentinal wall of immature teeth, and obturation material was removed to 3 mm below the cementoenamel junction (CEJ). In group 2, the negative control, the access was restored with bonded composite to the level of the CEJ. In group 3, access was restored with composite resin 3 mm apical to the CEJ using a clear post system. Group 4 was treated similarly to group 3, but an opaque post replaced the clear post. Group 5 was treated like group 3, after which a metal post was cemented into the channel left after removal of the clear post. All teeth were subjected to compression testing and the force required to fracture the teeth cervically was recorded for each group and the Kruskal-Wallis analysis performed to detect intergroup differences. All of the bonded resin techniques significantly strengthened the teeth against fracture, compared with the negative control group (p < 0.05). None of the experimental groups (3-5) were significantly different from the positive control group.

Composite Resins↗

PubMed1998

Bacterial reduction with nickel-titanium rotary instrumentation.

The purpose of this study was to compare intracanal bacterial reduction on teeth instrumented with 0.04 tapered nickel-titanium (NiTi) rotary instrumentation to bacterial reduction when using a stainless-steel K-file step-back technique using sterile saline irrigation. Forty-eight patients with apical periodontitis were randomly assigned treatment type. The canals were sampled before, during, and after instrumentation. The samples were incubated anaerobically for 7 days at 37 degrees C, colony-forming unit numbers calculated, and a log transformation performed to normalize the counts. Teeth exhibiting apical periodontitis were uniformly infected, whereas vital control teeth were not. A similar and uniform reduction occurred with progressive filing, regardless of technique (p < 0.0001). There was no detectable difference in colony-forming unit count after NiTi rotary or stainless-steel hand instrumentation (p = 0.42). Neither technique could predictably render canals free of bacteria. The results of this study indicate NiTi rotary and stainless-steel hand K-file step-back instrumentation techniques were not significantly different in their ability to reduce intracanal bacteria.

Analysis of Variance↗

PubMed1998

Nonsurgical root canal therapy treatment with apparent indications for root-end surgery.

The recent introduction of the surgical microscope to the practice of endodontics, especially for surgery, has allowed clearer visualization of the periapex during root-end resection and filling. However, despite this and other technologic advances, it has not been demonstrated that in the absence of thorough canal debridement the success rate of periapical surgery has improved over the 50% to 60% demonstrated in most long-term prognosis studies. Therefore it remains important to fully instrument and obturate the root canal system with conventional therapy before surgery is considered; this considerably improves the long-term prognosis. Each of the case reports in this article involves a situation in which conventional treatment was performed when a surgical approach might have been considered as the treatment of choice. Surgery should not be considered to be the primary treatment when root canal treatment or retreatment may be readily achieved. Indeed, the operating microscope and other technical aids will probably allow more cases to be treated and retreated conventionally that might otherwise have required surgical intervention.

Adolescent↗

PubMed1998

Dentinogenesis imperfecta: endodontic implications. Case report.

Dentinogenesis imperfecta is a hereditary disorder resulting in defective dentin in both the primary and secondary dentitions. The complications of dentinogenesis imperfecta are difficult to manage and provide a challenge to the dentist. This case report concerns treating an African American patient with dentinogenesis imperfecta who appeared for treatment with endodontic pathosis. It illustrates the need for appropriate and timely restorative treatment to prevent pulpal pathosis. Also demonstrated is the difficulty of endodontically treating dentinogenesis imperfecta teeth because of pulpal obliteration and abnormal dentin mineralization. Early and correct diagnosis of dentinogenesis imperfecta is imperative to enable appropriate preventive interventions and optimal dental treatment. Although pulpal pathosis is rarely reported with dentinogenesis imperfecta, endodontic treatment is occasionally necessary and has a guarded prognosis if initiated after pulp canal obliteration has occurred.

Adult↗

PubMed1998

Periodontal ligament vitality and histologic healing of teeth stored for extended periods before transplantation.

A previous study evaluated the viability of dog periodontal ligament cells as indicated by tritiated thymidine uptake after extended storage in Hank's balanced salt solution and Conditioned Medium. The purpose of this study was to evaluate histologic healing following the identical storage parameters established in the earlier study. Additionally, for Conditioned Medium, matched pairs (teeth evaluated for tritiated thymidine uptake and transplanted teeth) were examined in an attempt to correlate periodontal ligament vitality and healing. Forty-six extracted endodontically treated dogs' teeth were randomly grouped and stored in Hank's balanced salt solution or Conditioned Medium for 6, 48, and 96 h and then transplanted into 6-, 48-, and 96-h sockets. The control group teeth were transplanted without storage into 6-, 48-, or 96-h sockets. After 6 months the dogs were killed and the teeth were prepared for histologic evaluation according to Andreasen. Complete healing, inflammatory root resorption, and replacement resorption were evaluated and compared. Overall, significantly better healing was observed for teeth stored in Conditioned Medium than for teeth stored in Hank's balanced salt solution. Conditioned Medium was not significantly different from controls. Additionally, there was a positive correlation between periodontal ligament viability and healing for Conditioned Medium. These results confirmed the importance of periodontal ligament viability in successful replantation and the potential of Conditioned Medium as a storage medium for avulsed teeth.

Animals↗

PubMed1998

The effect of systemic tetracycline on resorption of dried replanted dogs' teeth.

The use of systemic penicillin after an avulsion injury has been recommended to decrease the occurrence of resorption complications. Tetracycline antibiotics have been reported to possess anti-resorptive properties in addition to their anti-microbial actions. The purpose of this study was to evaluate histologically the effect of systemically administered tetracycline and amoxicillin on the inhibition of resorption due to attachment damage after replantation of dogs' teeth. Thirty-one roots from the teeth of four beagle dogs were endodontically treated to inhibit subsequent inflammatory root resorption of pulpal origin. They were then extracted and left to bench dry for 1 h to ensure severe periodontal ligament damage before replantation. For the teeth in the experimental groups, two dogs were given tetracycline hydrochloride and the other two dogs were given amoxicillin, administered orally, on the day of extraction/replantation and for the following 6 days. The control group were teeth in these animals treated in the same manner but where no antibiotics had been given. After 12-16 weeks, the dogs were sacrificed and histological sections were prepared and evaluated for complete healing, inflammatory and replacement root resorption, and the groups were compared. It was shown that healing in the amoxicillin and the control groups was poor (10.90% and 11.28%, respectively), while for the tetracycline group, 35.45% showed complete healing. Individual teeth with over 50% complete healing sites were considered as having good healing, and significantly more of these teeth were found in the tetracycline group (5 of 11 teeth) compared to the amoxicillin (1 of 11 teeth) or control group (1 of 8 teeth).

Amoxicillin↗

PubMed1998

Effect of systemic tetracycline and amoxicillin on inflammatory root resorption of replanted dogs' teeth.

The use of systemic penicillin after an avulsion injury has been recommended as a way to decrease the occurrence of resorption complications. Our previous study has shown systemic tetracycline to possess anti-resorptive properties independent of potential anti-bacterial actions. The purpose of this study was to compare histologically the effectiveness of tetracycline and amoxicillin in limiting inflammatory root resorption (IR) secondary to pulpal infection, in replanted dogs' teeth. Thirty root canals in five dogs were infected with plaque. The roots were extracted, the lingual mid-roots were shaved with a fissure bur ensuring cemental damage and immediately replanted. Dogs were given either tetracycline hydrochloride or amoxicillin, administered orally, on the day of extraction and replantation and for the following 6 days. The control group was teeth in these animals treated in the same manner but where no antibiotics were given. After approximately 6 months, the dogs were sacrificed and the teeth prepared for histologic evaluation. The shaved root surface was identified in cross-sections and eight equidistant points along the cut root surface were evaluated for healing (H) or IR in eight sections per tooth. For the tetracycline group, H averaged 67.22% and IR 32.78%, which was not statistically different from the amoxicillin group with H averaging 56.88% and IR 43.12%. The tetracycline group was superior to the control group with H = 27.86% and IR = 72.14%. Since tetracycline has been shown to have anti-resorptive properties in addition to the antibacterial properties demonstrated here, it could be considered as an alternative to amoxicillin after avulsion injuries.

Amoxicillin↗

PubMed1998

Local dexamethasone improves periodontal healing of replanted dogs' teeth.

The purpose of the present investigation was to evaluate histologically the effect of dexamethasone on root resorption in stored and replanted dogs' teeth. Twenty-nine roots from three beagle dogs were endodontically treated to prevent subsequent inflammatory root resorption of pulpal origin. The teeth were extracted and randomly assigned to three groups for 48-h storage. Group 1: control group teeth (n = 13) were stored in vials containing ViaSpan only; Group 2: topical treatment teeth (n = 10) were stored in vials containing ViaSpan and dexamethasone (16 micrograms/ml); and Group 3: systemic treatment teeth (n = 6) were stored in vials containing ViaSpan without any additives. Dexamethasone was administered intramuscularly (0.5 mg/kg body weight) 2 days prior to, on the day of, and every other day after extraction and replantation for two administrations. After 12 weeks, the dogs were sacrificed, and the teeth histologically prepared and evaluated according to the analysis of Andreasen. Significant differences were found for complete healing (P = 0.0583) and inflammatory root resorption (P = 0.0568) but not for replacement resorption (P = 0.1952). In addition, comparing local to systemic administration of dexamethasone (Group 2 vs. Group 3), statistically significant differences were found for healing, 85% (Group 2) vs. 67% (Group 3) (P = 0.0125) and inflammatory root resorption, 13% (Group 2) vs. 28% (Group 3) (P = 0.0126). This study indicated that topical use of dexamethasone enhances healing and results in fewer resorption complications.

Adenosine↗

PubMed1998

Root resorption of dental and traumatic origin: classification based on etiology.

While root resorption is a relatively common complication of dental trauma, classifications of root resorption are inconsistent and confusing. All pathological root resorption of dental origin is inflammatory in nature. For root resorption to occur, the protective superficial layer must be (internally or externally) damaged or changed and an inflammatory stimulator must be present. This article attempts to classify root resorption on the basis of etiology, i.e., the cause of the protective layer loss and the cause of the inflammatory response, to facilitate more efficient treatment.

Bacterial Infections↗

PubMed1998

Subattachment inflammatory root resorption: treatment strategies.

Attempts have been made to classify root resorption according to its etiology in order to develop more efficient strategies for its treatment. This condition has been identified as resulting from damage to the protective attachment layer (predentin or precementum) of the root combined with inflammation adjacent to the root surface. This article demonstrates a series of treatment strategies focused on the reversal of each manifestation of subattachment root resorption, specifically emphasizing defects that extend apically and localized defects.

Humans↗

PubMed1997

TNF-alpha release in monocytes after exposure to calcium hydroxide treated Escherichia coli LPS.

Lipopolysaccharide (LPS), a cell wall component of Gram negative anaerobic bacteria, has been implicated in the pathogenesis of periapical disease resulting from infected root canals. Calcium hydroxide [Ca(OH)2] has been shown to be an effective medicament in such infections, reducing the microbial titre within the canal. It has been proposed that the therapeutic effect of Ca(OH)2 may also be the result of direct inactivation of LPS. The aim of this study was to investigate whether the toxic potential of an Escherichia coli LPS could be reduced or eliminated by Ca(OH)2. Four concentrations of E. coli LPS ranging from 1-1000 ng/ml sterile water were incubated in duplicate either with 25 mg Ca(OH)2 or sterile water alone. Controls consisted of Ca(OH)2 without LPS or sterile water only. Monocytes were collected from peripheral blood by centrifuging through a gradient and plated to a specific density. Adherent monocytes were incubated for 4 days at 37 degrees C with 5% CO2 in M199 medium with 10% autologous serum. The different LPS solutions were added to the wells on day 5. After 4 h the supernatants were collected and quantitatively assayed for TNF-alpha using a commercial ELISA kit. Statistical analysis was performed with ANOVA. Results indicated that Ca(OH)2 is able to eliminate the ability of an E. coli LPS to stimulate TNF-alpha production in peripheral blood monocytes (P < 0.0001).

Calcium Hydroxide↗

PubMed1997

Comparison of two laser Doppler systems on the measurement of blood flow of premolar teeth under different pulpal conditions.

An in vivo investigation was conducted to assess the ability of two laser Doppler flowmeters (DRT4, Moor Instruments Ltd; Laserflo BPM2, Vasamedics) to differentiate between vital pulp, ischaemically necrosed pulp, and an empty pulp chamber in premolar teeth in children. Sixteen intact, vital teeth in need of extraction for orthodontic purposes were identified. Laser Doppler blood flow readings were taken prior to (T1) and after the administration of adrenaline-free local anaesthetic (T2), after extraction and replantation of the teeth (T3), and after broaching the pulp tissue and replanting the teeth (T4). The data collected (flux values) for both instruments were analysed using a repeated measures ANOVA. Significant differences were found for vital pulp (T1, T2) versus ischaemically necrosed pulp (T3), and for vital pulp (T1, T2) versus an empty pulp chamber (T4), with the Moor DRT4 instrument. This instrument also detected a significant difference in pulpal blood flow to the vital pulp, before and after the administration of local anaesthetic. No other significant differences were found.

Analysis of Variance↗

PubMed1997

Revascularization of traumatized teeth assessed by laser Doppler flowmetry: case report.

Infection of the pulp space in addition to the attachment damage of a traumatic injury to a tooth, results in serious complications and often tooth loss. Therefore, the prevention or treatment of root canal infection is a major consideration in these cases. In immature teeth, revascularization of a necrotic pulp is possible and highly desirable. Unfortunately, current sensitivity tests are poor indicators of revascularization, with the result that many pulps are removed unnecessarily. Laser Doppler flowmetry is an objective test of the presence of moving red blood cells within a tissue, which has been reported to be effective in the detection of tooth pulp vitality as well. A case is presented where an eight year old child severely luxated both maxillary central incisors. While only one of the incisors was weakly responsive to CO2 ice at 76 days after replantation, the laser Doppler flowmeter indicated that revascularization was occurring in both teeth at a much earlier time. Because of the laser Doppler readings, endodontic treatment was not initiated and the teeth developed normally.

Child↗

PubMed1997

Periodontal healing of extracted dogs' teeth air-dried for extended periods and soaked in various media.

The aim of this study was to determine the periodontal healing of replanted dogs' teeth which, after extended extra-oral dry times, had been soaked in various media before replantation. Incisors and premolars of beagle dogs were root canal treated, extracted and bench dried. The teeth were grouped according to dry times of 30, 45 and 60 minutes. Each group of teeth was soaked in one of three media, Hank's balanced salt solution, ViaSpan (Belzer UW-CSS, Dupont Pharmaceuticals), or Conditioned Medium (supernatant of confluent culture of human gingival fibroblasts) for 30 minutes before replantation. Controls consisted of teeth extracted and replanted without drying on soaking (negative control), and bench-dried teeth replanted without soaking in the media (positive control). The dogs were killed 6 months after replantation of the teeth, which were prepared for histologic evaluation. Five microns cross-sections (every 70 microns) of the root and surrounding tissue were evaluated for healing/resorption according to Andreasen's criteria. The best healing occurred for the roots which had been immediately replanted. Healing in the positive control groups decreased with increased dry time. For the 30-minute dry time groups, soaking in media had no beneficial effect on periodontal healing compared with the controls. Soaking in ViaSpan resulted in an increased healing incidence for both the 45- and 60-minute bench-dried groups while soaking in the other media had no consistent beneficial effect. It appears from this study that an avulsed tooth that has been left dry for 30 minutes should be replanted immediately without soaking. However, teeth that have been dry for 45 or 60 minutes would benefit from soaking for 30 minutes in ViaSpan.

Adenosine↗

PubMed1997

The role of the socket in the periodontal healing of replanted dogs' teeth stored in ViaSpan for extended periods.

In a previous study on the extended storage of extracted dogs' teeth, it was hypothesized that changes in the socket environment might play a role in the periodontal healing of these teeth. The purpose of this study was to evaluate the role of the socket in the periodontal healing of replanted dogs' teeth. Extracted endodontically treated dogs' teeth were stored in ViaSpan for 6 hours and replanted into sockets after 6, 48 or 96 hours. Controls included teeth extracted and replanted immediately, 48-hour stored teeth replanted into 48-hour sockets and 96-hour stored teeth replanted into 96-hour sockets. After 6 months the dogs were killed and the teeth prepared for histologic evaluation according to Andreasen. Overall healing for the groups and healing for teeth within the groups were evaluated and compared. The best results were obtained when the teeth were replanted immediately. For the teeth stored in ViaSpan for 6 hours, complete healing decreased significantly as the age of the socket increased. In addition, the rate of replacement resorption increased significantly with increasing socket age for the 6-hour stored teeth. Forty-eight-hour stored teeth replanted into 48-hour sockets had the lowest healing rate with levels of inflammatory resorption not seen in the other groups. According to the results of this study, the socket environment plays an important role in the healing of replanted teeth in dogs.

Adenosine↗

PubMed1997

Tritiated thymidine uptake in periodontal ligament cells of dogs' teeth stored in various media for extended time periods.

The purpose of this study was to evaluate a new storage solution, Conditioned Medium, vs Hank's balanced salt solution and ViaSpan with respect to the viability of periodontal ligament cells of exarticulated teeth. Teeth were stored for periods of 6, 48, and 96 hours in Hank's balanced salt solution, ViaSpan (Dupont Pharmaceuticals), or Conditioned Medium. Teeth were cultured for 24 hours in Dulbecco's medium supplemented with tritiated thymidine. The cultured teeth were sectioned and evaluated with autoradiography. Control teeth were extracted and immediately treated as above without storage. Mitotic activity was indicated by clusters of five or more grains over the nuclei of fibroblasts in the remaining periodontal membrane. The ratio of labeled to unlabeled cells (labeling index) was calculated for each treatment group. When storage time was compared across all groups, 96 hours was significantly different from 6 and 48 hours (P < 0.001 and P < 0.012 respectively). Storage time of 6 hours was not significantly different from 48 hours (P > 0.10). After comparison of the nine experimental groups with the control group, only Hank's balanced salt solution at 96 hours was significantly different (P < 0.004).

Adenosine↗

PubMed1997

Cervical root resorption.

This article describes cervical root resorption, an external inflammatory root resorption arising immediately below the attachment level of the root. The pathogenesis is not fully understood, although many theories have been presented. Clinically, cervical root resorption is usually asymptomatic. The radiographic appearance is variable and is easily mistaken for that of internal root resorption. Histologically, the presentation is identical to that of other inflammatory root resorptions.

Humans↗