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PubMed1991

A study of endodontically apexified teeth.

This study was undertaken to determine the clinical and radiographic success of calcium hydroxide apexification in a group of 48 patients requiring endodontic therapy because of pulpal necrosis prior to root-end closure. The study examined tooth number, etiology of pulpal necrosis, age, sex, size of root-end opening, size of radiolucency, crown discoloration, interappointment symptoms, and total treatment time from initial instrumentation to completion of apexification. Apexification required an average of 1 year +/- 7 months. A statistically significant relationship was found between: the presence of a radiolucency and development of interappointment symptoms (p less than 0.04); and the size of apex opening and development of interappointment symptoms (p less than 0.02). If symptoms did develop, apexification was delayed an additional 5 months when compared to patients who did not have symptoms. Calcium hydroxide apexification was found to be statistically highly successful regardless of the clinical variables encountered.

Age Factors↗
PubMed2006

Tubular sclerosis rather than the smear layer impedes dye penetration into the dentine of endodontically instrumented root canals.

AIM: To evaluate the effect of different root canal irrigating regimes on dentine penetration of Patent Blue dye. METHODOLOGY: Eighty extracted single-rooted human mandibular premolar teeth with narrow root canals were prepared using ProFile instruments. After each instrument, canals were irrigated with 1% sodium hypochlorite. Subsequently, teeth were randomly assigned to receive a 10 mL rinse of aqueous 17% (w/v) ethylenediaminetetraacetic acid or tap water for 2 or 10 min, followed by a final rinse with a 2% Patent Blue dye solution for 2 or 10 min (eight groups, n = 10 teeth per group). Teeth were then horizontally sectioned 3, 6 and 9 mm from the apex. Sections were digitally photographed and dye penetration was calculated as percentage of total dentine area using NIH Image J. Values were compared using one-way anova and Bonferroni correction with the alpha-type error set at <0.05. Representative tooth sections from all groups were further analysed using scanning electron microscopy. RESULTS: No significant impact of irrigating protocols on dye penetration was found. Dye penetration was significantly (P < 0.001) greater in the coronal than middle, and in middle than in apical root thirds. When observed microscopically, irrigant penetration was independent of the presence of a smear layer, but was rather a function of tubular sclerosis. CONCLUSIONS: Tubular sclerosis, a physiological phenomenon that starts in the third decade of life in the apical root region and advances coronally with age, was the main factor influencing penetrability of root dentine.

Analysis of Variance↗
PubMed1992

Plasmacytoma of anterior maxilla mimicking periapical cyst.

An unusual case of plasmacytoma mimicking a large periapical cyst in the anterior maxilla is described. Of the involved teeth, 22 was discoloured and had an open, immature apex, a feature strongly suggestive of the lesion being of pulpal origin. The case was treated by a conservative endodontic approach, but failed to show any improvement. Apical surgery comprising complete enucleation of the cystic lesion and extraction of the involved tooth was carried out. The unexpected histopathological finding was a plasmacytoma.

Adult↗
PubMed1997

Pain control in recovering alcoholics: effects of local anesthesia.

OBJECTIVE: The medical literature suggests that alcoholics may present greater challenges to achieving clinical pain control than nonalcoholics. This study was undertaken to test the hypotheses that: (1) significant differences exist between alcoholics and nonalcoholics on detection and pain thresholds during electric tooth stimulation; (2) group differences exist in the depth and time course of pulpal anesthesia; and (3) responses to tooth stimulation are associated with severity of alcoholism and/or other psychological factors. METHOD: Male alcoholics (n = 22) in aftercare treatment (mean length of sobriety = 113 days) and age-matched nonalcoholics (n = 22) received 1.0 ml of 3% mepivicaine at the apex of a maxillary lateral incisor and saline placebo at the apex of the contralateral incisor. RESULTS: At baseline no group differences were found on sensory thresholds. During drug intervention significant drug and time effects for both detection threshold (p < .0001) and pain threshold (p < .0001) were found, but group differences and interactive effects were not significant. By exploratory regression analysis of alcoholic subjects, history of depression/unhappiness was significantly associated with shallower pulpal anesthesia, whereas high need for control/low actual control and frequency of treatment for detoxification were associated with deeper anesthesia. CONCLUSIONS: Our findings suggest alcoholics in recovery are not at increased risk for inadequate pain control with local anesthesia.

Adult↗
PubMed1982

A study of freeze-dried (lyophilized) dentin used as an apical barrier in adult monkey teeth.

Thirty-two fully formed vital teeth of four adult cynomolgus monkeys were endodontically prepared to simulate conditions of an open apex. The apical 2 to 5 mm. of 24 teeth were filled with freeze-dried dentin. The eight remaining teeth received no implant material and served as controls. All the teeth were obturated with gutta-percha. The monkeys were sacrificed at 6, 13, 23, and 27 week periods, and the specimens were prepared for histologic examination. The early specimens showed acute inflammation apically; later specimens showed osseous healing. Some experimental teeth had partial cementum bridging against the implant material. Freeze-dried dentin was found to be a biocompatible material which can be used effectively as a substitute barrier against which gutta-percha can be condensed in mechanically prepared open-apexed monkey teeth.

Animals↗
PubMed1992

Root end isolation for retrograde fillings.

Isolation and moisture control of the root end of a tooth with a large periapical lesion is normally accomplished with the aid of bone wax, cotton pellets, or sterile gauze saturated with a suitable hemostatic agent. An alternative procedure, a simple and effective rubber dam technique, is presented demonstrating isolation of an apex before reverse filling.

Adult↗
PubMedDate not supplied

Partial pulpotomy in a traumatized primary incisor with pulp exposure: case report.

Crown fracture with pulp exposure in primary incisors is a rare condition. Despite the fact that the vitality of the pulp can be preserved, such teeth are usually extracted due to lack of patient cooperation. This article reports a successful conservative treatment of a fractured primary incisors with pulp exposure and undeveloped root. The child was sedated with midazolam and nitrous oxide, and partial pulpotomy was performed using calcium hydroxide. Follow-up radiographs 21 weeks later revealed closure of the apex and apposition of a dentin bridge close to the amputation site.

Calcium Hydroxide↗
PubMed1993

Calcospherites in rabbit incisor predentin.

Calcospherites from the lower incisor dentin of rabbits were investigated by scanning and transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and electron diffraction analyses. In the labial predentin, globular calcospherites of 8-31 microns were present at the root apex, decreasing in size toward the incisal region. The calcospherites at the intermediate region were of mulberry- as well as of spindle-shape of 1.5-4 microns diameter. The incisal pulp horn contained micro-calcospherites of 0.3-0.6 micron in diameter. In the lingual predentin, small granular calcospherites of 1.8-3 microns were present at the root apex, increasing in size toward the intermediate region. Ultrathin sections of globular calcospherites showed bundles of collagen fibrils at the root apex of the labial predentin. The diameters of individual bundles ranged from 1.2-3.4 microns. The width of the fibrils in the bundles was approximately 120-170 nm. Bundles of collagen fibrils were not found in the lingual predentin. Crystals of calcospherites were identified as apatite by electron diffraction. Those at the intermediate region showed preferred orientation of the c-axis. TEM-EDS analyses indicated that Ca and P were the major elements, with small amounts of Mg. The Mg/Ca molar ratios decreased from the root apex to the incisal pulp horn. Ca peak intensities increased from the root apex to the incisal region.

Animals↗
PubMedDate not supplied

A retrospective assessment of zinc oxide-eugenol pulpectomies in vital maxillary primary incisors successfully restored with composite resin crowns.

PURPOSE: The purpose of this retrospective study was to evaluate, via clinical and radiographic assessments, the treatment outcome of zinc oxide-eugenol (ZOE) pulpectomies performed in vital maxillary primary incisors successfully restored with composite resin crowns. METHODS: Pulpectomized vital primary incisors were treated by a uniformed technique, filled with ZOE paste, and successfully restored with composite resin crowns. Those that remained intact and noncarious for the assessment interval were evaluated for the outcome (success or failure) based on clinical and radiographic findings and compared to: (1) the reason for treatment; (2) the canal filling extent; (3) the type of composite resin crown restoration performed; and (4) the eruption status of its succedaneous tooth. RESULTS: For 104 maxillary primary incisors meeting the inclusion criteria, failure, as judged by presence of pathologic root resorption and/or apical lucency, was determined to be 24% (25/104), for a mean duration of 18 months observation. Failures were statistically associated with the reason for treatment (higher for trauma), the extent of ZOE paste filler in the pulp canal (higher for gross overfill), and the eruption status of the associated succedaneous permanent incisor (higher for delayed eruption). CONCLUSIONS: This study determined a failure rate (24%) for pulpectomies-using ZOE paste and performed on vital primary incisors-comparable to that reported for nonvital pulpectomies. A statistically significant increase in failure rates was found for: (1) incisors treated for trauma (42%) vs those treated for dental caries (19%); and (2) grossly overfilled canals (80%) vs canals filled to the apex (0%).

Child, Preschool↗
PubMed2002

Determination of the elasticity parameters of the human periodontal ligament and the location of the center of resistance of single-rooted teeth a study of autopsy specimens and their conversion into finite element models.

MATERIAL AND METHODS: The aim of this study was to determine the elasticity parameters of the human periodontal ligament by measuring three-dimensionally the initial buccolingual tooth displacements of eight single-rooted teeth in human jaw specimens, using a noninvasive method. Subsequently the specimens were used to develop finite element models presenting the same individual geometry as the respective autopsy material. These models formed the basis for computerized movement simulations, whose characteristic was brought into line with the experimentally registered movements by adapting the elasticity parameters of the periodontal ligament. Using the individual elasticity parameters determined in this way, with which the displacement of the computer models could be realistically calculated, the centers of resistance of the examined teeth were determined by simulating the effects of different force systems. RESULTS: The nonlinear character of the initial tooth movement could be effectively simulated by using a bilinear parameter set for the elasticity of the periodontal ligament and by determining a critical expansion value for the transition from the validity range of the first Young's modulus to the second. The mean Young's modulus of the first phase of movement was 0.05 MPa, that of the second phase 0.28 MPa, and the critical expansion 7.5% (Poisson's ratio mu = 0.3). The centers of resistance of single-rooted teeth were found to be at approximately 42% of the alveolar height from the alveolar crest to the apex, irrespective of root length and direction of loading. CONCLUSION: The elasticity parameters were found to be on a similar scale to those determined in previous studies on multi-rooted pig teeth.

Biomechanical Phenomena↗
PubMed2000

A comparison of two nickel-titanium instrumentation techniques in teeth using microcomputed tomography.

AIM: The aim of the study was to compare the shaping of root canals by two nickel-titanium instrumentation techniques using microcomputed tomography (MCT). METHODOLOGY: Ten mandibular first molar teeth (30 canals) that had intact crowns and fully formed roots were scanned using MCT. Fifteen canals were instrumented using NiTiFlex hand files (Maillefer) using balanced force. The remainder were instrumented using prototype ProFile 0.04 Taper instruments (Dentsply) in a crown-down manner to an apical size ISO 25. The teeth were scanned again following instrumentation. The two instrumentation techniques were compared in a total of 27 canals. The area of dentine removed at predetermined levels (2.0, 3.0, 4.5, 6.0, 7.5 mm) from the apex was measured. Transportation and centring were recorded. Images constructed at these levels were compared with video images of equivalent physical sections created after the second scan. The volume of dentine removed in the apical 7.5 mm of the root canals of each tooth was calculated and the different techniques compared. Rendered three-dimensional images were used to assess the preparations qualitatively. The time taken for preparation was recorded. RESULTS: There was no significant difference between hand instrumentation with NitiFlex files and machine instrumentation with prototype ProFile 0.04 Taper instruments for any of the variables tested. CONCLUSIONS: Both techniques produced well centred and tapered preparations.

Dental High-Speed Technique↗
PubMed2005

Technical quality of root canal treatment and detection of iatrogenic errors in an undergraduate dental clinic.

AIM: To evaluate the technical quality of root canal treatment (RCT) and detect iatrogenic errors in an undergraduate dental clinic. METHODOLOGY: Three-hundred and eighty-eight root-filled teeth from the records of the Department of Endodontology at the Aristotle University of Thessaloniki, Greece were evaluated. Evaluation of root-filled teeth was based on two variables: length and presence of voids within the root filling. The technical standard of root fillings was categorized as: < or = 2 mm from the apex with no voids (acceptable); >2 mm from the apex with no voids; overfilling with no voids; < or = 2 mm from the apex with voids; >2 mm from the apex with voids and overfilling with voids. Iatrogenic errors that were detected included ledges, root perforations, furcation perforations, strip perforations and presence of fractured instruments. Chi-squared analysis was used to determine statistically significant differences between frequencies of root fillings between each tooth type. Significant differences were also determined between frequencies of ledges and root perforations according to tooth type and separately in molars according to tooth number, canal location and root canal curvature. Results Three-hundred and forty-three out of 620 root canals (55.3%) had a root filling that was classified as 'acceptable'. The frequency of root canals with an 'acceptable' filling was significantly greater in the anterior teeth (72.1%) than in pre-molars (55.2%) (P < 005) or in molars (46.7%) (P < 0.001). One-hundred and fifty-four (24.8%) root canals had ledges and 17 (2.7%) had a root perforation. The frequency of ledged root canals was significantly greater (P < 0.001) in molars than in anterior teeth. In molars, 105 out of 270 root canals (38.9%) had been ledged. Mesiobuccal, mesiolingual and distobuccal root canals were the most frequently ledged. Canal curvature was found to be the most important factor associated with ledges and root perforations. Conclusions Technical quality was found to be acceptable more often in anterior teeth. Ledges were identified more often in curved canals in molar teeth.

Dental Instruments↗
PubMed1989

[Canal obturation technic. Stereomicroscopic and SEM study].

The authors compared four different methods for tooths filling employing cements and gutta-percha by means of stereo and scanning electron microscopy. For this they prepared and filled 32 monoradicular teeth divided in 4 groups of 8 elements and afterwards they made sections at 2, 5, 8 mm from the apex. The thermomechanic condensation techniques showed very good effects. Good performances come using the vertical and lateral condensation techniques when the single cone method produced variable results.

Dental Cements↗
PubMed2006

Extracellular matrix-mediated tissue remodeling following axial movement of teeth.

Tooth eruption is a multifactorial process involving movement of existing tissues and formation of new tissues coordinated by a complex set of genetic events. We have used the model of the unopposed rodent molar to study morphological and genetic mechanisms involved in axial movement of teeth. Following extraction of opposing upper molars, lower molars supererupted by 0.13 mm. Labeled tissue sections revealed significant amounts of new bone and cementum apposition at the root apex of the unopposed side following supereruption for 12 days. Newly apposited cementum and alveolar bone layers were approximately 3-fold thicker in the experimental vs the control group, whereas periodontal ligament width was maintained. Tartrate-resistant acid phosphatase staining indicated bone resorption at the mesial alveolar walls of unopposed molars and provided in tandem with new bone formation at the distal alveolar walls an explanation for the distal drift of molars in this model. Microarray analysis and semiquantitative RT-PCR demonstrated a significant increase in collagen I, integrin beta5, and SPARC gene expression as revealed by comparison between the unopposed molar group and the control group. Immunohistochemical verification revealed increased levels of integrin beta5 and SPARC labeling in the periodontal ligament of the unopposed molar. Together our findings suggest that posteruptive axial movement of teeth was accomplished by significant formation of new root cementum and alveolar bone at the root apex in tandem with upregulation of collagen I, integrin beta5, and SPARC gene expression.

Acid Phosphatase↗
PubMed1989

Dens invaginatus with an open apex: a case report.

A severe case of dens invaginatus is described on an upper central incisor that was associated with a discharging sinus tract. The outer pulp chamber contained vital tissue while the inner one contained necrotic material. Root canal treatment was carried out with long-term calcium hydroxide dressings to induce apical closure. The canal system was subsequently filled and the tooth followed up for 4 years.

Child↗
PubMed1996

Comparison of radiographic and electronic working lengths.

The purpose of this study was to compare the ability of radiographic and electronic methods to determine reliably the location of the apical constriction. The working length of root canals in human cadaver teeth was determined by positioning an endodontic file at the apical termination point as indicated by an apex locator. These same teeth were radiographed at various angles with the file in place. The radiographs were evaluated by five examiners to determine a radiographic termination point for each canal. Teeth were extracted and examined histologically to determine the ideal termination point. The deviations of the two experimental termination points from the ideal termination point were compared. The mean of the absolute value of the deviations from the apical constriction for the apex locator was significantly less (p < 0.05) than that for the radiographic method. Thus, the method using the apex locator was slightly more reliable.

Dental Pulp Cavity↗