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At least 145 records · Page 8Linked to original sources

PubMed2002

Endodontic failure caused by inadequate restorative procedures: review and treatment recommendations.

A review of the literature was performed to determine whether prompt placement of coronal restorations, including sealing and placement of posts and cores, can positively influence the long-term prognosis of teeth after root canal therapy. Both hand and MEDLINE searches were employed to identify peer-reviewed articles on radicular apical integrity after coronal restorations, especially where root canal space was used for post and core fabrication. A total of 41 articles published between 1969 and 1999 (the majority from the 1990s) were reviewed. The literature suggests that the prognosis of root canal-treated teeth can be improved by sealing the canal and minimizing the leakage of oral fluids and bacteria into the periradicular areas as soon as possible after the completion of root canal therapy.

Bacteria↗

PubMed1997

Maxillary incisor root resorption in relation to the ectopic canine: a review of 26 patients.

A retrospective study of 26 patients with maxillary incisor root resorption relating to the presence of an ectopic canine was undertaken from case records. The group consisted of nine male and 17 female patients with a mean age of 12.5 years. There was a total of 35 resorbed teeth, 26 lateral and nine central incisors, and these were related to 32 ectopic canines. The resorption tended to be extensive, 30 teeth had pulpal involvement. In two-thirds of cases the pattern of resorption involved both apical and middle thirds of the root. Despite the extensive nature of the involvement there were few clinical signs and symptoms reported by patients. 43.8 per cent of canines were lying palatal to the arch, 18.7 per cent were in the line of the arch and 37.5 per cent were buccal. Significantly 15.6 per cent were buccal and erupted. The path of canine eruption was mesio-horizontal in 21 cases. No relationship could be found between resorption and the retention or loss of the deciduous canine. The canine root formation was virtually complete in 31 of the involved canines. The study indicated that the problem is often diagnosed late both in relation to the patient's age and the extent of resorption present. It is suggested that the problem may be underestimated by dental practitioners.

Age Factors↗

PubMed1999

Histological and histochemical quantification of root resorption incident to the application of intrusive force to rat molars.

This study was conducted to investigate the nature of root resorption resulting from intrusive forces applied to the rat lower molars, by means of histological and histochemical techniques with tartrate resistant acid phosphatase (TRAP). Thirty-eight 13-week-old Wistar strain male rats were used. Intrusive force was created by a fixed appliance which was adjusted to exert an initial force of 50 g for the duration of 1, 2, and 3 weeks. The degree of root resorption and distribution of TRAP positive cells were evaluated. On the root surface, the TRAP positive scores were low in the apical regions. Significant differences in the scores were found in the inter-radicular region of the roots between the experimental and control groups for the 2- and 3-week groups. More active resorption of bone occurred during the experimental period, as denoted by greater TRAP positive scores on the bone than on the root surface. Root resorption scores in the apical root region were larger in the 2- and 3-week groups than in the 1-week group. Significant differences in the root resorption scores were also found between the 1- and 3-week groups in the inter-radicular region, indicating that intrusive force application of a longer duration may lead to a higher frequency of root resorption. It is shown that, irrespective of the level of TRAP positive cells and root resorption scores, the degree of root resorption activity is higher in the apical root region than in the inter-radicular area. These results indicate that cellular cementum may be resorbed more easily because of its richer organic components and low mineralized structure.

Acid Phosphatase↗

PubMed1999

Blood vessel response to pan-endothelium (RECA-1) antibody in normal and tooth loaded rat periodontal ligament.

Immunolabelling of the normal rat molar periodontal ligament (PDL) with RECA-1 antibody, an endothelial cell surface marker, demonstrated the endothelium in the different categories of blood vessels. The intensity of immunolabelling was similar for venous capillaries (VC), post-capillary-sized venules (PCV), and collecting venules (CV). Arterial capillaries (AC) and terminal arterioles (TA) showed a different response, both having a high intensity of endothelium and smooth muscle cell labelling, whether they were located in the PDL or alveolar bone. An experimental, continuous loading of approximately 100 g was applied unilaterally to the mandibular molars for 10 minutes. In the PDL apical compression zone this load resulted in a loss of RECA-1 immunolabelling of the VC, PCV, and CV. Adjacent to the alveolar crest, where shear and tension loads were judged to have occurred, there was enhanced immunoreactivity of VC, PCV, and CV. In the loaded PDL, the AC and TA, irrespective of their location in the ligament or bone, showed strong immunofluorescence of their endothelium and the enveloping smooth muscle layer. Vessel and PDL immunofluorescence were analysed with standardized grey scale densitometry, and the data subjected to ANOVA. Comparison between individual vessel means showed significant differences (P < 0.05). Control teeth showed no immunostaining difference between the coronal and apical region vessels, whereas in the loaded teeth the overall cervical vessel endothelium had a significantly higher value than the apical vessel endothelium (P < 0.001). These findings demonstrate that the endothelium of this microvascular bed can undergo significant immunoreactivity changes when exposed to short-term, continuous, tooth loading.

Alveolar Process↗

PubMed2000

Long-term follow-up of maxillary incisors with severe apical root resorption.

The purpose of the study was to analyse the mobility of teeth with severe orthodontically induced root resorption, at follow-up several years after active treatment, and to evaluate mobility in relation to root length and alveolar bone support. Seventy-three maxillary incisors were examined in 20 patients, 10-15 years after active treatment in 13 patients (age 24-32 years) and 5-10 years after active treatment in seven patients (age 20-25 years). All had worn fixed or removable retainers; seven still had bonded twistflex retainers. Total root length and intra-alveolar root length were measured on intra-oral radiographs. Tooth mobility was assessed clinically according to Miller's Index (0-4) and the Periotest method. Crestal alveolar bone level, periodontal pocket depth, gingival, and plaque indices, occlusal contacts during occlusion and function, and dental wear were recorded. There was a significant correlation (P < 0.05) between tooth mobility, and total root length and intra-alveolar root length. No correlation was found between tooth mobility and retention with twistflex retainers. None of the variables for assessment of periodontal status, occlusion and function were related to total root length or tooth mobility. It is concluded that there is a risk of tooth mobility in a maxillary incisor that undergoes severe root resorption during orthodontic treatment, if the remaining total root length is < or = 9 mm. The risk is less if the remaining root length is > 9 mm. Follow-up of teeth with severe orthodontically induced root resorption is indicated.

Adult↗

PubMed2007

A radiographic analysis of external apical root resorption of maxillary incisors during active orthodontic treatment.

External apical root resorption (EARR) is an undesirable consequence of orthodontic treatment. The purpose of this study was to measure the amount of EARR and to examine its clinical significance in maxillary incisors, during a 12-month active treatment period. A further aim was to examine the contribution of gender, treatment technique, treatment duration, and extraction of maxillary first premolars to EARR. The sample comprised 151 maxillary incisor teeth in 40 patients (16 males, 24 females) aged 12-22 years, with different malocclusions. Standard periapical radiographs, using the long-cone paralleling technique, were obtained before and 6 and 12 months after the start of treatment. Quantitative measurements for 80 central and 71 lateral maxillary incisors were performed separately and corrected for image distortion. Root length reduction was calculated in millimetres and in terms of the percentage of the original root length. Resorption of more than 1 mm at 12 months of active treatment was considered to be clinically significant. On average, the degree of EARR for the maxillary central incisors was 0.77 +/- 0.42 and 1.67 +/- 0.64 mm, respectively, during the 6- and 12-month follow-up (P < 0.001). For the lateral incisors, the degree of EARR was 0.88 +/- 0.51 and 1.79 +/- 0.66 mm, respectively (P < 0.001). Clinically significant resorption was found for 74 per cent of the centrals and 82 per cent of the laterals. No significant correlation was observed between EARR and treatment technique. EARR was found to be correlated with gender for the lateral incisors. The effect of treatment duration (P < 0.001) and premolar extraction (P < 0.001) was statistically significant for both tooth groups.

Adolescent↗

PubMed2000

Apexification of an infected untreated immature tooth.

A case of a traumatized permanent young tooth in which apexification occurred without the benefit of endodontic treatment is reported. It illustrates how a immature incisor that underwent pulp necrosis and periapical inflammation could progress to complete apical formation.

Child↗

PubMed2000

Comparative analysis of curved root canal preparation using nickel-titanium instruments with or without EDTA.

The purpose of this study was to examine the effect of the use of EDTA as a root canal irrigant in curved root canals instrumented with nickel-titanium (Ni-Ti) instruments. Twenty extracted maxillary molars were selected. Mesiobuccal roots were used. Teeth were mounted in self-curing acrylic resin bases to allow standardized angulation of the initial and final radiographs. The preinstrumentation radiographs were made with a #15 file in the canal. The canals were instrumented with Ni-Ti instruments by the step-back technique, using or not using EDTA. The post-instrumentation radiographs were made with a #30 file in the canal. The films were projected (x10 magnification), drawn, and superimposed. Ni-Ti instruments used with EDTA were less effective in maintaining the original path of curved canals.

Chelating Agents↗

PubMed2000

Idiopathic root resorption: report of a case.

A case of multiple idiopathic apical root resorption in a 26-yr-old female patient is presented. A review of the literature revealed that extensive idiopathic root resorption is unusual. Neither local nor systemic etiological factors were found in our case. Examination of parents and siblings did not reveal a familiar tendency. Radiographs and clinical evaluation showed a very poor prognosis for most of the teeth present in the mouth of our patient.

Adult↗

PubMed2000

Efficacy of final irrigation--a scanning electron microscopic evaluation.

The purpose of this in vitro study was to determine the degree of removal of pulpal remnants and smear layer from root canals after final irrigation with three different solutions. During instrumentation the step-back preparation and 1% NaOCl were used. The final 4-min, 30-ml irrigation varied as follows: group I, 10 ml of 1% NaOCl + 10 ml of 10% citric acid + 10 ml of distilled water; group II, 15 ml of 0.5% NaOCl + 15 ml of EDTA-T; and group III, 10 ml of 5% NaOCl + 10 ml of 3% H2O2 + 10 ml of 5% NaOCl. Scanning electron microscopic photomicrographs were evaluated for the mean number of visible open dentinal tubules by three observers. The largest number of visible tubules in the three groups was in the cervical third, followed by the middle and apical thirds. There was no statistically significant difference between groups I and II when third was compared with third; however, groups I and II had significantly more visible dentinal tubules than group III.

Acid Etching, Dental↗

PubMed2000

Structure and chemical composition of an experimentally formed apical barrier after the application of calcium-glycerophosphate.

Transformation in the structure and composition of calcium-glycerophosphate (Ca-GP) was investigated using a scanning electron microscope fitted with an energy dispersive X-ray microanalysis (EDX) system. Ca-GP was packed inside roots that were subsequently implanted into the mandibles of rats to stimulate the formation of an apical barrier. Scanning electron microscopic observations of packed Ca-GP revealed three types of structures: globular aggregates, plate or flake-like aggregates, and granular aggregates. The average Ca/P molar ratios of EDX by area mode--postoperatively obtained at days 1, 3, 5, and 7--were 1.300, 1.533, 1.472, and 1.495 (analytic area: 0.01 to 0.03 mm2) and those of EDX by point mode were 1.220, 1.451, 1.487, and 1.467 (analytic point: 0.05 micron 2). The magnesium (Mg) weight percentage was found to be approximately 1.9 at days 3, 5, and 7, similar to Mg-substituted whitlockite. These findings suggest that Ca-GP are transformed, over a period of 3 days into Mg-substituted whitlockite as a result of being hydrolyzed by tissue fluid.

Analysis of Variance↗

PubMed2000

Measurement of endodontic file lengths: a density profile plot analysis.

The purpose of this study was to evaluate measurements of endodontic files of known length and diameter using a density profile plot analysis of digital images. Ten single-rooted teeth with relatively straight roots in cadaver specimens were used. The crowns of the teeth were removed and a rectangular orthodontic wire, 5.13 mm in length, was placed horizontally on the occlusal surface to serve as a calibration reference point. The #8, #10, #15, and #20 FlexOFiles were measured to the nearest 0.5 mm and then placed to four working lengths that terminated within the apical third of each root. A GE X-ray unit and a Schick CDR #2 sensor were used to digitally acquire 160 images. The digital images were placed in random order and an independent, blinded investigator determined the file length using a density profile plot analysis. The measurements generated by the histogram analysis (experimental) were compared with the original clinical measurements. The paired t test, intraclass correlation coefficient, and the Bradley-Blackwood test were used to assess reliability. The results revealed that the means of the experimental measurements of all file sizes were within 0.5 mm of the known lengths and were always shorter than the known lengths. Also, the larger the file size the less deviation from the known lengths: #20, -0.16 mm (p = 0.0001); #15, -0.21 mm (p = 0.0001); #10, -0.34 mm (p = 0.0001); and #8, -0.45 mm (p = 0.0001). This study demonstrated that the density profile plot analysis might be a useful adjunct for the measurement of endodontic file lengths on a digital image.

Analysis of Variance↗

PubMed2000

A comparative study of smear layer removal using different salts of EDTA.

Three solutions of EDTA--a 15% concentration of the alkaline salt, a 15% concentration of the acid salt, and a 25% concentration of the alkaline salt--were evaluated for smear layer removal in root canal systems. All solutions were adjusted to pH 7.1 using either NaOH or HCl. When the EDTA solutions were alternately used for root canal irrigation with 5.25% NaOCl, they completely removed the smear layer in the middle and coronal thirds of canal preparations, but were less effective in the apical third. None of the EDTA solutions by themselves were effective at completely removing the smear layer at any level. The alkaline tetrasodium salt, pH adjusted with HCl, is more cost effective and performed equally as well as the more commonly used disodium salt.

Acids↗

PubMed2001

PH changes at the surface of root dentin after intracanal dressing with calcium oxide and calcium hydroxide.

This study was designed to compare pH changes at the cervical and apical surfaces of root dentin after canal obturation with calcium oxide or calcium hydroxide pastes. The effect of the exposure to CO2 on the pH at the root surface also was assessed for both materials. Thirty-six extracted human canines were selected and instrumented. Wells 1 mm deep x 1.5 mm in diameter were drilled in the cervical and apical regions of the buccal root surface. The teeth were randomly divided into two groups and obturated with either calcium hydroxide or calcium oxide. pH was measured in the cervical and apical wells at varying time intervals until 48 days posttreatment. After pH measurement on day 48 the vials were flushed with CO2 and the pH measured again at days 53 and 68. The results indicated a similar pattern of pH increase after treatment with either calcium oxide or calcium hydroxide. pH dropped significantly after exposure to CO2 in both groups. This study demonstrated that hydroxyl ions produced when calcium oxide reacts with water diffuse through the dentinal tubules to the surface of the root in a manner similar to hydroxyl ions from calcium hydroxide.

Analysis of Variance↗

PubMed2001

Effectiveness of three endodontic irrigants at various tubular depths in human dentin.

Bacteria from infected root canals can invade dentinal tubules, thus dentin disinfection is an important aspect of endodontic therapy. This study compares three endodontic irrigants for efficiency in killing bacteria established within human dentinal tubules. Root canals in extracted teeth were prepared and sterilized. Broth cultures of Enterococcus faecalis were allowed to grow within the canals to penetrate dentinal tubules. The infected canals were exposed individually to each of the irrigants for 1 min. Irrigants were 0.525% sodium hypochlorite, Tubulicid (0.2% EDTA), and 0.12% chlorhexidine (Peridex). Sterile water was the control. Viable bacteria were analyzed by drilling incrementally into dentin from the cementum toward the canal. Smaller diameter drills were used for each depth. Shavings were cultured at three depths, for each of three root levels: coronal, midroot, and apical. Although considerable variation occurred between roots, sodium hypochlorite seemed to be superior. Tubulicid and Peridex were better than water. More bacteria remained viable at greater distances from the pulp. These observations apparently apply to all levels in the canal.

Analysis of Variance↗

PubMed2002

Root-end fracture during retropreparation: a comparison between zirconium nitride-coated and stainless steel microsurgical ultrasonic instruments.

The purpose of this study was to evaluate a stainless steel (CT-5) and zirconium nitride coated (KiS) microsurgical ultrasonic instrument with regard to possible root-end fracture production during retropreparation. Forty extracted human central incisors were prepared in a crown-down fashion. Canals were obturated with gutta-percha by lateral condensation. Root-ends were resected. Teeth were placed in methylene blue for 48 h and evaluated by three independent evaluators under microscope. Teeth with existing fractures were eliminated from the study. The remaining teeth were randomly divided into two equal groups. Group A was prepared with the CT-5 tip and Group B with the KiS tip. Preparation time was recorded for all roots. The teeth were again immersed in methylene blue for 48 h and reevaluated. No root-end fractures were produced by either the KiS or CT-5 microsurgical ultrasonic instruments.

Apicoectomy↗

PubMed2002

Participation of bacterial biofilms in refractory and chronic periapical periodontitis.

The aim of this study was to examine morphologically the participation of extraradicular biofilm in refractory periapical periodontitis. Six teeth and five extruded root filling gutta-percha points associated with refractory periapical periodontitis were investigated by scanning electron microscope. In nine of 11 samples examined, bacterial biofilms were seen at the extraradicular area. The gutta-percha surface was covered with glycocalyx-like structures, and filaments, long rods, and spirochete-shaped bacteria were predominant in the extraradicular sites. Planktonic cells, which were filaments and spirochete-shaped bacteria, emigrated from the glycocalyx structures in some spots. In the extracted teeth, biofilm consisting of both bacteria and glycocalyx-like structures were observed on the periapical root surfaces. Next to the residual periodontal ligament, a few filaments, rods, and fusiforms were attached on the healthy cementum surface. The present findings suggested that bacterial biofilms formed in the extraradicular areas were related to refractory periapical periodontitis.

Adolescent↗

PubMed2003

Identification of resected root-end dentinal cracks: a comparative study of visual magnification.

The purpose of this in vitro study was to evaluate and compare the effectiveness of visual enhancements as aids in identifying artificially created dentinal cracks in resected root ends. Fifty human maxillary central incisors were decoronated, and the root canals were instrumented to ISO size 50 at the working length. The apical 3 mm of the roots were resected, and cracks were artificially created in the apical dentin with an average load of 5.6 kg using a cylindrical wedge in a miniature drill press. A video microscope at x65 magnification was used to observe the cracks as they developed. Four independent examiners evaluated the root specimens using unaided/corrected vision (group 1), loupes at x3.3 magnification (group 2), a surgical operating microscope at x10 magnification (group 3), and the Orascope at x35 magnification (group 4). The examiners' proficiency at correctly identifying root ends with and without cracks was evaluated. The data were compared to the predetermined standard (27 cracked, 23 not cracked) with a one-tailed Fisher's exact test (alpha = 0.05). Statistically, the Orascope (p = 0.02) was significantly superior, whereas using unaided/corrected vision (p = 0.99), loupes (p = 0.88), or the microscope (p = 0.14) was not significantly better than guessing. The accuracy of correct identification for unaided/ corrected vision, loupes, the microscope, and the Orascope was 39%, 45%, 53%, and 58%, respectively. A two-way analysis of variance of the accuracy of crack identification showed a significant difference among the four visualization techniques (p = 0.0007) and also among the four evaluators (p = 0.006).

Analysis of Variance↗