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Biomedical subjects

M Trope

Publications and source records attributed to M Trope.

At least 37 records · Page 2Linked to original sources
PubMed2000

Reduction of intracanal bacteria using nickel-titanium rotary instrumentation and various medications.

The purpose of this study was to evaluate the extent of bacterial reduction with nickel-titanium rotary instrumentation and 1.25% NaOCl irrigation. Also, the additional antibacterial effect of calcium hydroxide for >1 wk was tested. Forty-two subjects with radiographic and clinical signs of chronic apical periodontitis were recruited. The canals were sampled before treatment, during and after instrumentation, and after treatment with calcium hydroxide and the samples incubated anaerobically for 7 days at 37 degrees C. The bacteria from each sample were quantified and the log10 values were used for calculations and comparisons. The initial sample confirmed infection of the canals. There was a significantly greater pattern of reduction of bacteria when NaOCl was used as an irrigant, compared with sterile saline (p < 0.05). After instrumentation with NaOCl irrigation, 61.9% of canals were rendered bacteria-free. The placement of calcium hydroxide for at least 1 wk rendered 92.5% of the canals bacteria free. This was a significant reduction, compared with NaOCl irrigation alone (p = 0.0001). The results of this study indicate that NaOCl irrigation with rotary instrumentation is an important step in the reduction of canal bacteria during endodontic treatment. However this method could not consistently render canals bacteria-free. The addition of calcium hydroxide intracanal medication should be used to more predictably attain this goal.

Anaerobiosis↗
PubMed2000

Luxation injuries and external root resorption--etiology, treatment, and prognosis.

When a tooth sustains a luxation injury, attachment damage of varying degrees will occur. In addition, necrosis of the pulp might result, thereby making the pulp space susceptible to infection. These circumstances can lead to root resorption. Treatment for root resorption includes preventing it by avoiding causes of root surface injury, minimizing initial inflammation, and reversing resorption.

Anti-Bacterial Agents↗
PubMed1999

Endodontic treatment of teeth with apical periodontitis: single vs. multivisit treatment.

This study was performed to evaluate radiographic healing of teeth with apical periodontitis, treated in one visit or in two visits (a) with or (b) without calcium hydroxide as an intracanal disinfecting medicament. The patients were assigned one of the three treatment groups by the throwing of a die. The Periapical Index (PAI) Scoring Method was used to compare differences in periapical status from the beginning of treatment to a 52-wk follow-up evaluation. Overall, the periapical status of the treated teeth improved significantly after 52 wk (p < 0.0001). A PAI score of 1 or 2 was considered as representing a "good" periapical status while 3, 4, or 5 was a "bad" status. When base line PAI scores were controlled for, the calcium hydroxide group showed the most improvement in PAI score (3, 4, or 5 to 1 or 2), followed by the one-step group (74% vs. 64%). The teeth that were left empty between visits had clearly inferior healing results. Power statistics were conducted to determine the numbers required for significant differences between the groups, and it was shown that large experimental groups on the order of hundreds of patients would be required to show significant differences.

Adult↗
PubMed1999

Histological periapical repair after obturation of infected root canals in dogs.

Histological periapical healing of infected roots obturated in one-step or with prior calcium hydroxide (Ca(OH)2) disinfection was compared. Seventy-two roots of vital dog teeth were instrumented to ISO size 45. Sixty roots were infected with dental plaque and closed. Six weeks later, apical periodontitis was radiographically confirmed in the infected roots. The teeth were divided into the following groups: group 1, one-step (n = 24)-roots were irrigated with 10 ml of saline, obturated, and permanently restored; group 2, Ca(OH)2 (n = 24)-roots were treated as in group 1, except that after saline irrigation, Ca(OH)2 dressing was placed in the canal for 1 wk before obturation; group 3, positive control (n = 12)--the roots were irrigated with saline, but the canals were not obturated; and an additional group, group 4, served as a negative control (n = 12)--these teeth that were not infected with plaque were aseptically obturated. The dogs were sacrificed after 6 months. The roots and surrounding apical tissues were prepared and histologically examined by two independent evaluators blinded to the treatment groups. A two-way ANOVA test demonstrated that the four treatment groups were significantly different from one another. The positive control showed the most inflammation, the negative control the least, and the Ca(OH)2 group had significantly less inflammation than the one-step group (p < 0.05). It is concluded that Ca(OH)2 disinfection before obturation of infected root canals results in significantly less periapical inflammation than obturation alone.

Analysis of Variance↗
PubMed1999

Modulation of chronic enteric infection by distant oral infection.

This investigation determined the effects of a distant oral infection (Porphyromonas gingivalis) on a concurrent local enteric infection (Echerichia coli). A modified murine subcutaneous tissue chamber model was used. Subcutaneously implanted chambers with different microbial makeups were monitored for sloughing and their contents assayed for prostaglandin E2. Bilaterally implanted chamber experiments revealed that a distant "chronic" (immunization with heat-killed organism, followed by live challenge) P. gingivalis infection offered protection against a local chronic E. coli infection, as evidenced by delaying the time for 50% of the chambers to reject from day 19 to day 25 and a statistically significant prostaglandin E2 decrease from 529.4 +/- 176.6 ng/ml to 191.5 +/- 100.9 ng/ml (p < 0.01) (Mann-Whitney test). An acute (live challenge only) distant P. gingivalis infection or immunization with the heat-killed organism alone had no effect on "chronic" E. coli infection in this model. These data suggest that the presence of low-grade chronic oral infection may modify the responses to other infectious challenges.

Animals↗
PubMed1999

Endodontic complications of root canal therapy performed by dental students with stainless-steel K-files and nickel-titanium hand files.

Straightening of curved canals is one of the most common procedural errors in endodontic instrumentation. This problem is commonly encountered when dental students perform molar endodontics. The purpose of this study was to compare the effect of the type of instrument used by these students on the extent of straightening and on the incidence of other endodontic procedural errors. Nickel-titanium 0.02 taper hand files were compared with traditional stainless-steel 0.02 taper K-files. Sixty molar teeth comprised of maxillary and mandibular first and second molars were treated by senior dental students. Instrumentation was with either nickel-titanium hand files or stainless-steel K-files. Preoperative and postoperative radiographs of each tooth were taken using an XCP precision instrument with a customized bite block to ensure accurate reproduction of radiographic angulation. The radiographs were scanned and the images stored as TIFF files. By superimposing tracings from the preoperative over the postoperative radiographs, the degree of deviation of the apical third of the root canal filling from the original canal was measured. The presence of other errors, such as strip perforation and instrument breakage, was established by examining the radiographs. In curved canals instrumented by stainless-steel K-files, the average deviation of the apical third of the canals was 14.44 degrees (+/- 10.33 degrees). The deviation was significantly reduced when nickel-titanium hand files were used to an average of 4.39 degrees (+/- 4.53 degrees). The incidence of other procedural errors was also significantly reduced by the use of nickel-titanium hand files.

Dental Instruments↗
PubMed1999

Treatment options for the exposed vital pulp.

The exposure of dental pulp generally occurs as the result of accidental trauma or preparation techniques utilized during the restoration of carious lesions. While frank carious exposures are optimally treated with pulpectomy and root canal therapy, the ideal treatment of mechanically exposed pulps has remained controversial. This article describes the indications, clinical techniques, and prognosis for direct pulp capping and partial pulpotomy.

Anti-Infective Agents, Local↗
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↗