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PubMed2001

Oral health in liver transplant children administered cyclosporin A or tacrolimus.

BACKGROUND: Immunosuppression by cyclosporin A (CsA) is associated with adverse side-effects, including nephrotoxicity, neurotoxicity and gingival overgrowth. Tacrolimus (TAC/FK506) is a new immunosuppressive agent, recently approved for use in solid-organ transplants. The mode of action of TAC is similar to that of CsA and the toxicity profile of CsA is duplicated by TAC. The effect of TAC on the gingival tissue is not yet conclusive. SAMPLE: Gingival overgrowth was assessed in 30 liver transplant children, 20 boys and 10 girls, aged 2-19 years. Seventeen children (10 boys, seven girls) were on a CsA-based immunosuppressive regimen whereas 13 children (10 boys, three girls) were on TAC for at least 1 year (mean 4.3 +/- 2.7). RESULTS: In the CsA group, 35% of children exhibited gingival overgrowth characterized by one or more units with increased sulcus probing depth (> or = 4 mm), i.e. pseudopockets. In contrast to the CsA group, none of the children in the TAC group exhibited gingival overgrowth. The occurrence of enamel hypoplasia was observed in 11 children (36%) and enamel opacities were found in 23 children (76%). Six of the 12 children (50%) with hyperbilirubinaemia biliary atresia exhibited a marked greenish discoloration of the teeth. Caries experience (dmft/DMFT) among these children was 2.0 +/- 2.8. CONCLUSION: No difference in caries experience or enamel defect was observed between the CsA and TAC group.

Adolescent↗
PubMed2000

Penetration of bacteria in bovine root dentine in vitro.

AIM: The aim of this study was to develop a test model to quantify the penetration of bacteria into dentinal tubules. METHODOLOGY: The model consisted of two compartments separated by a bovine dentine specimen with a thickness of 1.5-3.1 mm. The root cementum was removed from the root surface and the specimens were oriented in the model with the pulpal side facing the inoculated chamber of the test model. One compartment contained the test organism and the other was filled with sterile broth that was evaluated for growth of the test organism. The depth of bacterial penetration was measured in the dentine with or without a smear layer using both a histological and a quantitative recovering grinding technique, after 6 weeks of exposure to the microorganisms. RESULTS: E. faecalis penetrated dentine significantly deeper than A. israelii (P < 0.001). After removal of the smear layer with EDTA, E. faecalis penetrated significantly deeper than in dentine pretreated with saline only (P < 0.01) or with a combination of saline and sodium hypochlorite (P < 0.01). Microorganisms were found in 89% of the cultured specimens and in 80% of the specimens that were evaluated with light microscopy. Total penetration through the dentine specimen and infection of the broth in the test compartment of the model occurred in only two out of 72 specimens. CONCLUSION: Collection and immediate culturing of infected dentine dust and counting colony forming units (CFU) allowed an overview of the number of bacteria per sample and was more sensitive than microscopy. Removal of the smear layer enhanced bacterial penetration.

Actinomyces↗
PubMed2000

Effectiveness of 1 mol L-1 citric acid and 15% EDTA irrigation on smear layer removal.

AIM: The aim of this study was to evaluate in vitro the cleansing and smear layer removal capability of alternate canal irrigation with citric acid and NaOCl. METHODOLOGY: Eighty-one teeth were divided into three groups on the basis of the type of instrumentation, namely, manual stainless steel, Ni-Ti mechanized ProFile .04 taper or MACXim. The groups were further divided on the basis of irrigation protocol: 5% NaOCl alone, NaOCl alternated with 1 mol L-1 citric acid solution or a combination of 15% EDTA and Cetrimide solution. After longitudinal sectioning, dentinal walls were microphotographed with scanning electron microscopy at x300 and x1000 magnifications. Qualitative and quantitative cleansing level evaluations were performed using computerized image analysis software. Data were statistically evaluated using Kruskal-Wallis analysis and t-test. RESULTS: Qualitative evaluation at x300 and x1000 showed no statistically significant differences in cleansing ability between citric acid, EDTA and NaOCl groups. Quantitative evaluation of smear layer removal, measured as open tubules/total dentinal surface ratio, showed that 1 mol L-1 citric acid solution was comparable to EDTA (11.97% vs. 10.36%) (NS); in samples treated with ProFile .04 taper instruments citric acid was most effective (16.17%), whilst in the group treated with manual instrumentation EDTA and Cetrimide were the most effective (11.94%). Specimens irrigated with 5% NaOCl demonstrated significantly more cleansing than those obtained in the other two groups (P < 0.001). CONCLUSIONS: 1 mol L-1 citric acid solution was as effective in removing smear layer as EDTA, but was superior in specimens treated with ProFile .04 taper instruments.

Cetrimonium↗
PubMed2000

Sealer distribution in root canals obturated by three techniques.

AIM: The aim of this study was to observe sealer distribution in root canals filled by different root filling techniques. METHODOLOGY: AH26 (0.05 mL) dyed with carbon black powder was placed into the prepared root canals of maxillary central incisors using a lentulo spiral. Thereafter the canals were obturated using three different gutta-percha root-filling techniques. Horizontal sections were cut in the apical and middle portions of the filled canals. Images of the cross sections were scanned and the percentage of sealer coated canal perimeter (PSCP) was measured using a computer digital imaging system. RESULTS: At 3 mm from the apex, the PSCP after lateral condensation was similar to that after vertical condensation (P > 0.05). At 6 mm from the apex, however, the PSCP was significantly higher after lateral condensation than after vertical condensation (P < 0.05). At both levels the PSCP was significantly higher after single cone (no condensation) than after the other two condensation techniques (P < 0.0001). CONCLUSIONS: Sealer may be removed from the canal wall by the condensation procedures.

Bismuth↗
PubMed2001

The efficacy of gutta-percha removal using ProFiles.

AIM: The purpose of this study was to compare the efficacy in vitro of gutta-percha removal from obturated root canals using ProFiles. METHODOLOGY: Forty-eight human root canals with curvatures ranging between 25 and 45 degrees were instrumented by a standardized method to an apical ISO size 30 and 0.04 taper. They were obturated with vertically condensed gutta-percha. Retreatment was performed with the following techniques: K-Flexofiles with chloroform; Hedstrom files with chloroform; ProFiles 0.04 taper with chloroform; ProFiles 0.04 taper alone. The time for each method was measured. A microfocal macroradiographic technique was used to evaluate the amount of debris remaining within the root canals after the retreatment procedure. Roots were divided into apical, middle and coronal parts and scored on a scale of 0 (no debris) to 3 (> 50% of walls covered with debris) by trained observers on two separate occasions. RESULTS: The scores for debris remaining within root canals for K-Flexofiles with chloroform and ProFiles with chloroform were the lowest and not significantly different at all three levels of the roots examined (P > 0.05), and Hedstrom files with chloroform and ProFiles with chloroform were not significantly different in the apical part. In general, coronal parts were cleaner than apical parts. The difference in scores at the three levels between ProFiles with chloroform and ProFiles alone were each significant (P < 0.01). Instrumentation using ProFiles with chloroform (mean 6.42 min) was significantly faster than using hand files (mean 11.67 min) (P < 0.01). CONCLUSION: The results indicated that ProFiles or hand files with chloroform produced similarly clean canals, but that ProFiles were faster.

Chloroform↗
PubMed2001

Effect of Nd:YAG laser irradiation on the apical leakage of obturated root canals: an electrochemical study.

AIM: The purpose of this laboratory study was to evaluate the effect of Nd:YAG laser irradiation on the apical leakage of obturated root canals using an electrochemical method. METHODOLOGY: Forty extracted single-rooted teeth were selected and the anatomic crown of each tooth was removed. The specimens were randomly divided into four groups. In group 1, the root canals were prepared with K-files and irradiated with Nd:YAG laser (5 W, 20 Hz) via a 300 microns optical fibre. Then the root canals were obturated with laterally condensed gutta-percha and Pulp Canal Sealer EWT. In group 2, the root canals were treated with the same method as those of group 1 but without laser irradiation. In group 3, the root canals were prepared with ProFiles, laser irradiated and then obturated with vertically condensed gutta-percha and Pulp Canal Sealer EWT. In group 4, the root canals were treated with the same method as those of group 3 but without laser irradiation. The electric resistance between standard and experimental electrodes in the canals was measured over a period of 10 days. RESULTS: At 2 h, groups 1 and 3 irradiated with laser had significantly less apical leakage than group 2 (P < 0.05). After 10 days, group 4 had the highest leakage, followed by groups 2, 1 and 3; the differences between the groups was statistically significant (P < 0.05). CONCLUSIONS: Laser irradiation following root canal preparation reduced apical leakage following root canal obturation.

Aluminum Silicates↗
PubMed2001

A comparative study of root canal preparation with HERO 642 and Quantec SC rotary Ni-Ti instruments.

AIM: The purpose of this study was to compare several parameters of root canal preparation using two different rotary nickel-titanium instruments: HERO 642 (Micro-Mega, Besancon, France) and Quantec SC (Tycom, Irvine, CA, USA). METHODOLOGY: Fifty extracted mandibular molars with root canal curvatures between 20 micro and 40 micro were imbedded into a muffle system. All root canals were prepared to size 45 (Quantec SC), or 40 (HERO 642), respectively. The following parameters were evaluated: straightening of curved root canals, postoperative root canal diameter, safety issues (file fractures, perforations, apical blockages, loss of working length), cleaning ability, and working time. RESULTS: Both Ni-Ti-systems maintained curvature well; the mean degree of straightening was 2.3 degrees for Quantec SC and 1.6 degrees for HERO 642. Most procedural incidents occurred with Quantec SC instruments (five fractures, three apical blockages, eight cases of loss of working length), HERO 642 preparation resulted in three blockages and one perforation. Following preparation with HERO 642, 63% of the root canals showed a round, 24% an oval, and 17% an irregular diameter; Quantec SC preparations resulted in a round diameter in 24% of the cases, oval shape in 29%, and irregular cross-section in 47% of the cases. Mean working time was shorter for HERO 642 (52 s) than for Quantec (117 s). Cleanliness of the root canal walls was investigated under the SEM using a five-score system for debris and smear layer. For debris HERO 642 achieved better results (80% scores 1 and 2) than Quantec SC (76%). The results for smear layer were similar: cleaner root canal walls were found after preparation with HERO 642 (53% scores 1 and 2), followed by Quantec SC (41%). CONCLUSIONS: Both systems respected original root canal curvature well and showed good cleaning ability; Quantec SC showed deficiencies in terms of safety.

Anti-Infective Agents, Local↗
PubMed2002

A comparative study of root canal preparation using Profile .04 and Lightspeed rotary Ni-Ti instruments.

AIM: The purpose of this Study was to compare several parameters of root canal preparation using two different rotary nickel-titanium instruments: ProFile .04 (Dentsply/ Maillefer, Ballaigues, Switzerland) and Lightspeed (Lightspeed Technology Inc., San Antonio, TX, USA). METHODOLOGY: Fifty extracted mandibular molars with root canal curvatures between 20 degrees and 40 degrees were divided into two similar groups having equal mean curvatures. The teeth were then embedded into a muffle system as described by Bramante et al. (1987) and modified by Hülsmann et al. (1999b). All root canals were prepared using ProFile .04 or Lightspeed Ni-Ti instruments to size 45 following the manufacturers' instructions. The Lightspeed system was used in a step-back technique: ProFile .04 instruments were used in a crown-down technique. The following parameters were evaluated: straightening of curved root canals (superimposition of pre- and postoperative radiographs), postoperative root canal diameter (superimposition of pre- and postoperative photographs of root canal cross-sections), safety issues (file fractures. perforations, apical blockages, loss of working length) (protocol), cleaning ability (SEM-evaluation of root canal walls using a five-score system for debris and smear layer), and working time (protocol). Statistical analysis was performed using the Wilcoxon test (P < 0.05) for straightening, and Fisher's exact-test (P < 0.05) for comparison of cross-sections, for comparison of contact between pre- and postoperative diameter, root canal cleanliness and working time. RESULTS: Both Ni-Ti systems maintained curvature well; the mean degree of straightening was less than 1 degrees for both ProFile .04 and for Lightspeed with no statistical significance between the groups. Most procedural incidents occurred with Profile .04 instruments (three fractures), Lightspeed preparation was completed without instrument fractures. Loss of working length, perforations or apical blockage did not occur with either instrument. Following preparation with Profile.04. 64.0% of the root canals had a round, 30.7% an oval, and 5.3% an irregular cross-section, Lightspeed preparation resulted in a round cross-section in 41.3% of cases, an oval shape in 45.3% of cases: 13.3% of cases had an irregular cross-section. No significant differences were found between the two systems. Lightspeed instruments enlarged the root canal more uniformly with no specimen showing 50% or more contact between pre- and postoperative diameter. The difference was statistically significant only for the coronal third of the root canals (P = 0.032). Mean working time was significantly shorter for Profile .04 (105 s) than for Lightspeed (140 s) (P = 0.02). For debris removal Lightspeed achieved the best results (68% scores 1 and 2), followed by Profile .04 (48.4%) with no significant differences between the systems. The results for remaining smear layer were similar: the lowest amount of smear layer on the root canal walls was found after preparation with Lightspeed (30.7% scores 1 and 2). followed by Profile.04 (23.1%). In the coronal third of the root canals Lightspeed performed significantly better than Profile .04 (P = 0.029): in the middle and apical third the differences were not significant. CONCLUSIONS: Both systems under investigation respected original root canal curvature and were safe to use. Both systems can be recommended for clinical use.

Dental Alloys↗
PubMed2002

Smooth flexible versus active tapered shaft design using NiTi rotary instruments.

AIM: The aim of this study was to evaluate the influence of a smooth flexible versus active tapered shaft design on canal preparation by NiTi rotary techniques. METHODOLOGY: A XMCT-scanner (SkyScan 1072) and developed software (Bergmans et al. 2001) were used to nondestructively analyze the mesial canals of 10 extracted mandibular molars in 3D with a spatial resolution of 30 microm. Specimens (n = 10 per group) were scanned before (PRE) and after (POST) preparation using Lightspeed (smooth flexible) or GT-rotary (active tapered) files. Numerical values for volumes, dentine removal (net) transportation and centring ability were obtained in addition to a visual inspection on canal aberrations. Data were analyzed by Shapiro Wilk test, multiway factorial anova, Tukey-Kramer test, Wilcoxon test and t-test. RESULTS: Results indicated that the active tapered shaft removed significantly more dentine in the middle to apical portion of the root compared to the smooth flexible design. Both groups demonstrated some straightening, but no significant differences were found with respect to instrument types. However, absolute values for net transportation and centering ratio were small and no canal aberrations could be found. CONCLUSIONS: The smooth flexible shaft design did not improve the morphological characteristics of canal preparation by NiTi rotary instruments when compared with the active tapered design. Therefore, system selection should be based upon other criteria.

Analysis of Variance↗
PubMed2002

Matrix metalloproteinase-8 (MMP-8) in pulpal and periapical inflammation and periapical root-canal exudates.

AIM: To study the presence, levels and molecular forms of matrix metalloproteinase (MMP) -8 (collage-nase-2) in pulpal and periapical inflammation, and the changes in MMP-8 levels in root-canal exudates during root-canal treatment. METHODOLOGY: Periapical exudate samples were collected from 11 necrotic teeth with radiographically verified periapical periodontitis during three root-canal treatment visits with interappointment calcium hydroxide (Ca(OH)2) medication. MMP-8 levels and molecular forms were analyzed with immunofluorescent assay (IFMA) and Western immunoblot. Inflamed pulp tissue and periapical granuloma tissue (n = 10 for both) were obtained from other patients and used for MMP-8 immunohistochemical (IHC) staining. RESULTS: The periapical exudate samples demonstrated marked differences in MMP-8 levels between the teeth in the first visit and significant decrease in MMP-8 levels during the root-canal treatment (P = 0.0107). One specimen failed to show a decrease in MMP-8 below 1000 ng mL(-1) a vertical root fracture was later diagnosed and the tooth extracted. IHC staining showed that in addition to PMN-leucocytes, macrophages and plasma cells produced MMP-8 in pulp and periapical granulomas. CONCLUSIONS: The findings demonstrate the presence of MMP-8 in the inflamed pulp and periapical tissue, indicating that MMP-8 has a role in pulpal and periapical inflammation, most likely participating in tissue extracellular matrix degradation. They further indicate that MMP analysis from periapical exudate could be used to indicate and monitor inflammatory activity and the success of treatment in teeth with periapical lesions.

Analysis of Variance↗
PubMed2000

Oral health in children undergoing liver transplantation.

AIMS: To determine the prevalence of dental caries in children undergoing liver transplantation and to compare the plaque, gingivitis, and gingival overgrowth indices and oral mucosal lesions in children before and after liver transplantation. PATIENTS AND METHODS: Patients undergoing liver transplantation at King's College Hospital were examined before transplantation, at 3 and 106 days post-transplantation. Healthy children from the Greenwich Health District, south-east London, were matched to the liver transplant patients by age, gender, socio-economic factors and the presence or absence of active dental caries. RESULTS: Twenty-seven liver transplant patients (mean age: 7 years and 10 months; SD 3 years and 5 months) and 27 controls (mean age: 8 years and 6 months; SD 3 years and 7 months) were examined. The mean dmft and DMFT scores were 2.3 (SD 4.1) and 0.8 (SD 1.4), respectively, in the liver transplant patients, and 1.2 (SD 2.2) and 0.9 (SD 1.5), respectively, in the controls. There were no significant differences between either the mean plaque or gingivitis indices for the primary and permanent teeth in patients before and after transplantation. There were no significant differences between the liver transplant patients and the controls for either mean plaque or gingivitis indices at each examination time. Gingival overgrowth was present in 41% of liver recipients receiving cyclosporin with or without nifedipine, but not in the majority receiving tacrolimus at the final examination. Oral mucosal lesions were absent in both the patients and controls at each examination time. CONCLUSIONS: The oral health of the children undergoing liver transplantation was inadequate. Funding and implementation of an oral health care programme must become a priority for all children before and after liver transplantation.

Adolescent↗
PubMed2001

The use of the transmandibular implant system in extreme atrophy of the mandible; a retrospective study of the results in two different hospital situations.

This retrospective study aims to investigate and compare the results obtained with the transmandibular implant (TMI) in two different hospital situations. Group I were patients treated in a teaching hospital since 1984 by a varying group of surgeons and prosthodontists with a varying degree of experience with the TMI. Group II were patients treated in 1993 and 1994 by experienced surgeons and prosthodontists in the hospital where the TMI was originally developed. In group I, a relatively high frequency of reversible (45.4%) and irreversible--i.e. implant loss--(15.2%) complications occurred. In group II, no implants were lost and reversible complications were reported in 10.8% of the patients. In general, the patients of both groups were quite satisfied with the result of the treatment. In both groups, limited bone loss around the implant posts could be observed. An increase in the height of the mandibular bone distal of the lateral posts was frequently observed, especially in group II. It is concluded that both very favourable and less favourable results can be obtained with the TMI. In this study the best results are found in a highly specialized TMI centre, where patients are treated--with only uncompromised implant-posts--by a small group of experienced surgeons and prosthodontics with accurate application of the existing guidelines.

Atrophy↗
PubMed2001

Effect of gutta-percha solvents at different temperatures on the calcium, phosphorus and magnesium levels of human root dentin.

The aim of this study in vitro investigation was to evaluate the alterations caused by warmed gutta-percha solvents on the calcium, phosphorus and magnesium levels of root dentin. Extracted human anterior teeth, whose crowns and apical root thirds had been removed were used as root dentin specimens. The roots were sectioned longitudinally into two segments, cleaned and dried. Segments were divided into 12 groups (n=12). In 6 groups, the specimens received treatment with the following solvents at room temperature (22 degrees C): Chloroform, xylene, eucalyptol, orange oil, halothane and saline (control). Within each group, the specimens were further subgrouped into two to be incubated (100% humidity at 37 degrees C) for 5 and 10 min, respectively, following treatment with the solvents. The remaining six groups were treated with the same solvents which had been previously warmed to body temperature (37 degrees C) and received the same experimental procedures. The levels of calcium, phosphorus and magnesium in each specimen were analysed using energy dispersive spectrometric microanalysis. Statistical analysis of the readings showed that neither warming of the solvents nor prolonged incubation (treatment) time was capable of altering the histochemical composition of cut root dentin surfaces.

Body Temperature↗
PubMed2001

Survival rate and fracture strength of incisors restored with different post and core systems after exposure in the artificial mouth.

The survival rate and fracture resistance of 40 decapitated endodontically treated maxillary central incisors using four different post and core systems covered with all-ceramic copings was evaluated after exposure in the artificial mouth. Ten samples of the following post and core systems were investigated: high precious metal post (Permador) and core (Olympia) (A), zirconia post (Cerapost) with a pre-fabricated bonded ceramic core (Ceracap) (B), resin-ceramic post (experimental) with a pre-fabricated bonded ceramic core (Ceracap(R)) (C) and a zirconia post (Cerapost) with a custom made ceramic core (Cosmo Ingots) (D). The all-ceramic copings (Procera) were cemented using Panavia TC. The survival rates after 1 200 000 cycles in the artificial mouth are as follows: 90% (A), 80% (B), 60% (C) and 100% (D). The results of the means and standard deviations (s.d.) of the fracture resistance during static loading are: 1270 +/- 312.5 (A), 1494.5 +/- 333.5 (B), 1146.7 +/- 182.6 (C) and 463.3 +/- 46.2 (D). There are statistically significant differences between all groups with the exception of A and B, and A and C (Wilcoxon test). None of the zirconia posts with custom made ceramic cores covered with all-ceramic copings fractured during dynamic loading in the artificial mouth. The mean fracture strength during static loading was less favourable than that of groups A, B and C but above the clinical necessary level.

Cementation↗
PubMed2001

Handling characteristics of a palladium-free gallium-based alloy compared with a high copper dental amalgam in a simulated clinical trial.

The aim of the current study was to compare the handling characteristics of a palladium-free gallium-based alloys (Galloy) with those of a high-copper amalgam (Permite C). The study had a particular interest in the evaluation of the direct placement delivery system used with both alloys. Ten dentists participated in the current study. Each placed two amalgam and two gallium-based alloy restorations in conventional class II cavities prepared in acrylic typodont teeth. None of the participating dentists had used the direct placement delivery system or had any previous experience with gallium-based alloy and no practice was allowed beforehand. The restorations were evaluated according to the following criteria: ease of loading the cavity (delivery system), ease of condensation, capacity to produce and sustain contact area, ease of carving, resistance to damage during removal of the matrix band, overall quality of the restoration and the available working time. Each criterion was given a score on a scale of 1-5 (1: very poor, 2: poor, 3: fair, 4: good, 5: very good). The results showed no statistically significant difference in the evaluated criteria between the two alloys (P > 0.05) except for criterion number 2 (ease of condensation, P=0.0005).

Acrylic Resins↗