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PubMedDate not supplied

Influence of the spatulation of two zinc oxide-eugenol-based sealers on the obturation of lateral canals.

The objective of this research was to evaluate, in vitro, the importance of the correct manipulation of endodontic sealers, correlating it with flow rate and with the consequent obturation of root canals. Twenty-four human canines were prepared, 1 mm from the apex, with K-files up to size 50, by means of the step-back technique. Six lateral canals were then drilled in each tooth, with size 10 file fixed to a low-speed handpiece. The teeth were randomly divided into 4 groups, and root canals were obturated either with the Endométhasoneregister mark or target sealer or Grossman sealer, prepared at ideal or incorrect clinical consistency. After obturation by means of the lateral condensation technique, the teeth were radiographed and evaluated as to the number of sealed lateral canals. Statistical analysis revealed significant differences (p < 0.001) between the tested sealers, and indicated the higher capacity of the well-manipulated Grossman sealer to fill lateral canals. It can be concluded that the flow rate of a sealer and its correct manipulation are very important for the satisfactory obturation of lateral canals.

Administration, Topical↗
PubMed2000

Treating internal resorption using a syringeable composite resin.

BACKGROUND: Internal resorption is a pathological process initiated within the pulp space with the loss of dentin. It often is described as an oval shaped enlargement of the root canal space and usually is asymptomatic and detectable by routine radiographs. Treatment of internal resorption has included several materials--gutta-percha, zinc oxide eugenol and amalgam alloy. These materials do not provide strength to the tooth structure. CASE DESCRIPTION: A 29-year-old woman was referred to a dental clinic for treatment of a large internal resorptive defect in the coronal and middle one-third of the maxillary left central incisor root with no apparent periapical pathosis, as well as a large periapical radiolucency at the apex of the maxillary left lateral incisor that was associated with a necrotic pulp. The authors used a dual-cure syringable composite resin in conjunction with a bonding agent within the defect to treat it. CLINICAL IMPLICATIONS: This technique seals the dentinal tubules and strengthens the remaining tooth structure. It also improves the outcome of resorptive defects and reduces operators' chair time.

Adult↗
PubMed1987

Hemorrhagic cyst of the mandible associated with a retained root apex of the lower third molar.

An unusual case of hemorrhagic cyst of the mandible, associated with a retained root of the lower right third molar, is reported. The cyst was revealed by routine radiologic examination as part of treatment of the lower right second molar. Radiologically, a faintly outlined cavity with radiopaque mass was found in the third molar region. A final diagnosis of this condition was made after surgical intervention and histologic examination. A nonepithelial lining cavity was found, and the radiopaque mass was identified as a root apex.

Adult↗
PubMed1987

Three-dimensional finite element analysis for stress in the periodontal tissue by orthodontic forces.

This study was designed to investigate the stress levels induced in the periodontal tissue by orthodontic forces using the three-dimensional finite element method. The three-dimensional finite element model of the lower first premolar was constructed on the basis of average anatomic morphology and consisted of 240 isoparametric elements. Principal stresses were determined at the root, alveolar bone, and periodontal ligament (PDL). In all loading cases for the buccolingually directed forces, three principal stresses in the PDL were very similar. At the surface of the root and the alveolar bone, large bending stresses acting almost in parallel to the root were generally observed. During tipping movement, stresses nonuniformly varied with a large difference from the cervix to the apex of the root. On the other hand, in case of movement approaching translation, the stresses induced were either tensile or compressive at all occlusogingival levels with some difference of the stress from the cervix to the apex. The pattern and magnitude of stresses in the periodontium from a given magnitude of force were markedly different, depending on the center of rotation of the tooth.

Alveolar Process↗
PubMed1999

A case of an odontogenic cutaneous sinus tract.

CASE REPORT: A 22-year-old female presented with a draining sinus tract on her left cheek. The tooth responsible was examined clinicopathologically. On clinical examination, the mandibular left first molar tooth was restored with an amalgam filling. Radiographic examination revealed base or pulp capping material below the restoration and a radiolucent periapical lesion surrounding the distal root apex. Conservative non-surgical root canal treatment was performed; 10 months later, the sinus had healed completely and the periapical lesion had resolved. Histopathological examination of pulp tissue recovered during treatment revealed foreign bodies, made up of capping material and amalgam, associated with chronic inflammation. These findings suggested that chronic inflammation in the pulp tissue had resulted in a draining sinus tract.

Adult↗
PubMed2001

Complete 3-D reconstruction of dental cast shape using perceptual grouping.

To achieve the complete three-dimensional (3-D) data retrieval of the shape of dentition, dental casts were measured from four directions; occlusal, right, left, and labial sides using a line laser scanner. Reconstruction of the entire shape, including undercuts and tooth crowding area, was attempted by applying a perceptual grouping algorithm, which is one of pattern-recognition theories. In the data measured from occlusal, right and left sides, the rows of measurements were parallel to the frontal plane, and three-directionally combined data (3-DC data) was accomplished by affine transformation. While, in the labial side, transformation to the frontal plane was done since rows of the measured data were parallel to the sagittal plane. To combine the labial data with the 3-DC data and reconstruct the complete image, rearrangement of the order of the data in the file was attempted by applying the perceptual grouping. That is, the minimum total length of data combining was examined by considering the factor of proximity and continuity between the data. The most appropriate order of data combining and recognition of islands were accomplished. Using a computer graphic (CG) with a wire-frame model, complicated regions such as anterior segments showing tooth crowding and undercut area were found to be successfully reconstructed without any data defects. The accuracy of reconstruction was ascertained by comparing the characteristic distances between apexes of molars in the reconstructed model with the real cast. The difference was within 0.3 mm, and present method for dental cast reconstruction is considered to be satisfactory for the present purpose such as orthodontics.

Dental Casting Technique↗
PubMed2006

[Dental trauma protocol--treatment of avulsion and luxation injury].

The goal of this protocol is to provide clear instructions which simplify the process of decision making and treatment of Luxation and Avulsion. In teeth with a closed apex, one should perform root canal therapy at the second appointment in teeth with injuries of luxation and avulsion (except for injuries of subluxation and concussion). The tooth should be reimplanted at site of accident if it possible. For avulsed teeth, the preferred storage medium is milk. One should condition the roots of teeth which have been avulsed. In teeth which have not finished development, the preferred treatment is to allow the continued development of the root.

Animals↗
PubMed1991

[Use of the stereo-microscope in endodontic surgery].

The authors present several significant photographs of the apical anatomy of a tooth made using a stereo-microscope in the course of surgery. The authors generally use the stereo-microscope from the time of preparation of the apex to the retrograde filling. One of the changes which the authors have brought to traditional surgical procedures, the use of endodontic cement to improve the amalgam seal is illustrated. It consists of a modification which they introduced into their practice more than six years ago and even though it may be a simple clinical technique to use, it assured a significant long-term improvement in the cases treated.

Apicoectomy↗
PubMed1989

[Stress distribution in the periodontal ligament induced by orthodontic forces. Use of finite-element method].

This study was designed to investigate the stress levels induced in the periodontal tissue by orthodontic forces using the three-dimensional finite element method. The three-dimensional finite element model of the lower first premolar was constructed on the basis of average anatomic morphology and consisted of 240 isoparametric elements. Principal stresses were determined at the root, alveolar bone, and periodontal ligament (PDL). In all loading cases for the buccolingually directed forces, three principal stresses in the PDL were very similar. At the surface of the root and the alveolar bone, large bending stresses acting almost parallel to the root were generally observed. During tipping movement, stresses nonuniformly varied with a large difference from the cervix to the apex of the root. On the other hand, in case of movement approaching translation, the stresses induced were either tensile or compressive at all occlusogingival levels with some difference of the stress from the cervix to the apex. The pattern and magnitude of stresses in the periodontium from a given magnitude of force were markedly different, depending on the center of rotation of the tooth.

Dental Stress Analysis↗
PubMed1988

Effects of prostaglandin E2 on alveolar bone resorption during orthodontic tooth movement.

Twenty Sprague-Dawley rats weighing 280-300 g were divided into two groups of ten animals each. They were treated by daily submucosal injections of 50 micrograms prostaglandin E2 (PGE2) per kilogram body weight into the region below the apex of the left first maxillary molar (experimental), or vehicle into the region below the apex of the right first molar (control), for a period of 5 days. The animals of the first group were sacrificed immediately following the treatment period, while those of the second group were sacrificed 5 days after the treatment period. Twenty-two hours prior to sacrifice, a piece of latex orthodontic elastic was secured to the adjacent area between the first and second maxillary molars of both sides of each rat by using two mosquito hemostats. The periodontal ligament (PDL) mesial to the mesiobuccal root of the first maxillary molar was assayed for changes in PDL cell factors. The results showed that immediately following the 5-day treatment period the left PDL had a significant decrease in the total number of fibroblasts and a significant increase in the total number of both osteoclasts and nuclei per osteoclast, while no significant changes in the osteoblasts when compared with those of the right control PDL. The left PDL of animals which were sacrificed 5 days after the treatment period revealed a significant decrease in the number of total fibroblasts and only a slight decrease in both numbers of total osteoclasts and total nuclei per osteoclast, but again no significant changes in osteoblasts when compared with those of the right control PDL.(ABSTRACT TRUNCATED AT 250 WORDS)

Alveolar Process↗
PubMedDate not supplied

Timing of Demirjian's tooth formation stages.

BACKGROUND: Global differences in Demirjian et al.'s method of assessing dental maturity are thought to be due to population differences. AIM: The aim of this study was to investigate the timing of individual tooth formation stages in children from eight countries. RESEARCH DESIGN: This was a meta-analysis of previously published data from retrospective cross-sectional studies of dental maturity. METHOD: Data of mandibular permanent developing teeth from panoramic radiographs (Demirjian's stages) were combined from Australia, Belgium, Canada, England, Finland, France, South Korea and Sweden (n = 9002, ages 2-16.99 years). Age-of-attainment was calculated using logistic regression for each group by sex and meta-analysis of the total. Overlapping 95% confidence intervals of the means was interpreted as no significant difference. RESULTS: Mean ages for each group and total were significantly different in 65 out of 509 comparisons (p < 0.05). Some of these were of small sample size but there was no consistent pattern. Apex closure of the first molar was significantly later in children from Quebec and this might explain differences found in the dental maturity score. CONCLUSIONS: These results suggest no major differences in the timing of tooth formation stages between these children. This fails to explain previous findings of differences using Demirjian's dental maturity method.

Adolescent↗