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At least 145 records · Page 8Linked to original sources
PubMed2006

Lack of correlation between ex vivo apical dye penetration and presence of apical radiolucencies.

OBJECTIVE: The aim of this study was to determine if there is a significant correlation between the in vivo presence of periapical radiolucency and ex vivo apical dye penetration on the same human teeth. STUDY DESIGN: Eighty-four endodontically filled teeth that were scheduled for extraction were classified into 2 groups according to the presence or absence of a periapical radiolucency and further divided into 2 subgroups according to the quality of the root canal filling. After extraction, the apical filling was evaluated by a dye penetration method. RESULTS: The dye extraction evaluation showed no correlation between apical dye penetration and the presence of a periapical radiolucency (not significant), but a statistically significant correlation with the quality of the root canal filling (P = .03). CONCLUSION: The results of the dye penetration study were correlated to the quality of the root canal filling but had no predictive value for the development of periapical radiolucency.

Coloring Agents↗
PubMed2006

Effect of a calcium hydroxide-based root canal dressing on periapical repair in dogs: a histological study.

OBJECTIVE: To compare the periapical repair of teeth with periapical lesion following root canal treatment by using a calcium hydroxide-based intracanal dressing for several time periods or filling in a single visit. STUDY DESIGN: After induction of periapical lesions in 4 dogs, the root canals were prepared using 5.25% sodium hypochlorite for irrigation, and animals were separated into 4 experimental groups; in group I, root canals were filled in a single session; in groups II, III, and IV, a calcium hydroxide-based dressing was kept in place for 15, 30, or 180 days, respectively. Root canals from groups I, II, and III were filled with gutta-percha cones and AH Plus sealer. After 180 days, animals were killed and histological sections were stained with hematoxylin-eosin to evaluate periapical repair. RESULTS: Periapical repair was better in groups II, III, and IV (intracanal dressing) compared with group I (single session; P < .05). CONCLUSION: The use of a calcium hydroxide-based intracanal dressing was important for periapical repair in teeth with periapical lesion. Dressing with calcium hydroxide paste results in better periapical repair than when the root canal is filled in a single-session treatment.

Animals↗
PubMed2002

Restoration of the endodontically treated tooth.

It has been the purpose of this article to provide a rationale for the restoration of endodontically treated teeth. Treatment recommendations have been made in the areas of post design, placement technique, cements, core materials, and definitive restorations, based on a review of the clinical and laboratory data.

Dental Prosthesis Retention↗
PubMed2003

Assessment of the resistance to fracture of endodontically treated molars restored with amalgam.

STATEMENT OF PROBLEM: Controversy exists concerning the preferred type of final restoration of endodontically treated molars regarding their resistance to fracture under occlusal load. PURPOSE: The aim of this study was to assess the resistance to fracture of endodontically treated molars with various degrees of tooth structure loss restored with amalgam under simulated occlusal load. MATERIAL AND METHODS: . The study teeth consisted of 90 noncarious, nonrestored molars stored in physiological saline solution. The teeth were endodontically treated and randomly divided into 9 experimental groups of 10 specimens each with various degrees of tooth loss, ranging from a conservative endodontic access to removal of all cusps. All teeth were restored with a standardized technique to their original contour with amalgam. Each specimen was mounted onto a specialized jig for loading at the central fossa at a 30-degree angle to the long tooth axis. The resistance to fracture, under continuous compressive force at a cross-head speed of 2 mm/minute, was applied by a universal testing machine and was recorded. One-way analysis of variance with Scheffé contrast was used to statistically compare the differences between the groups at significance level P<.05. RESULTS: One-way analysis of variance showed that the group with a conservative endodontic access (1137.6 +/- 311.6 N) and the group with removal of all cusps (1261.4 +/- 195.1 N) presented a significantly higher resistance to fracture when compared with the other groups (P<.05). There was no significant difference in resistance to fracture under the simulated load between the other 7 groups, which ranged from 655.8 +/- 229.4 to 906.3 +/- 168.1 N (P>.05). CONCLUSION: Within the limitations of this study, the endodontically treated molars with a conservative endodontic access or after removal of all cusps that were restored to their original contour with amalgam presented the highest resistance to fracture under a simulated occlusal load.

Analysis of Variance↗
PubMed1997

Effect of different surface textures on retentive strength of tapered posts.

STATEMENT OF PROBLEM: Tapered posts allow for the preservation of tooth substance in the fragile apical area and are advantageous in clinical situations where they conform to the root and canal configuration of endodontically treated teeth. However, their lower retention compared with passive parallel-sided or active threaded posts is a disadvantage. PURPOSE: This study determined the retentive strength of tapered titanium posts with different surface textures and examined the effect of roughening dentinal walls of the prepared post space. MATERIAL AND METHODS: Posts with four surface configurations (smooth, with and without grooves, and sandblasted, with and without grooves) were examined when cemented in extracted anterior teeth. RESULTS: The smooth post showed the lowest retentive strength. Sandblasting the smooth post more than doubled its retentive strength. The retentive strength of both smooth and sandblasted posts could be further increased by the addition of circumferential grooves. Roughening the dentinal walls of the prepared post space increased the retentive strength of sandblasted posts with and without grooves even more. CONCLUSIONS: These findings indicated that, when a tapered post is used, roughening the dentin canal wall, as well as sandblasting and grooving the post, can provide statistically significant additional resistance to dislodgment.

Analysis of Variance↗
PubMed1997

Influence of dentinal adhesives and a prefabricated post on fracture resistance of silver amalgam cores.

PURPOSE: Failures of silver amalgam cores for endodontically treated teeth have been attributed to the use of posts. The use of adhesive agents has been reported to improve the strength of silver amalgam restorations. The purpose of this study was to test the effects of two adhesive agents on the fracture resistance of silver amalgam cores with and without a post. MATERIAL AND METHODS: Sixty mandibular molars were restored with the use of silver amalgam, with or without one of the adhesive agents and/or a tapered prefabricated post. A universal testing machine, with a constant load rate of 0.5 mm/minute, was used to determine the force in kilograms at failure. RESULTS: The use of either adhesive agent with silver amalgam significantly increased the force at failure, and neither adhesive agent was significantly better than the other. Silver amalgam with a post and without an adhesive agent had the least resistance to fracture. CONCLUSIONS: The results indicated that endodontically treated mandibular molars restored with silver amalgam are more resistant to fracture when an adhesive agent is used.

Analysis of Variance↗
PubMed1998

Comparison of the fracture resistances of pulpless teeth restored with a cast post and core or carbon-fiber post with a composite core.

STATEMENT OF PROBLEM: The survival of pulpless teeth restored with a post and core system is a controversial issue. PURPOSE: This study compared the fracture resistance of 2 types of restorations: teeth restored with prefabricated carbon-fiber posts and composite cores to cast dowel-core restored teeth. MATERIAL AND METHODS: A total of 44 recently extracted sound premolars were randomly distributed into 2 equal groups: group I, restored with prefabricated carbon-fiber post and a composite core; and group II, with custom-cast type III gold alloy post and cores. The size and shape of the posts were identical in the 2 groups. All teeth were fully covered with a nonprecious cast crown. Fracture resistance was measured by applying a point force at 45 degrees to the long angle of the tooth. RESULTS: Mean fracture threshold was 103.7 +/- 53.1 kg for group I versus 202.7 +/- 125.0 kg for group II (differences significant with P = .003). In group II, however, fracture nearly always affected the tooth itself, whereas in group I, the post-core nearly always failed first. CONCLUSIONS: Significantly higher fracture thresholds were recorded for the cast post and core group. Teeth restored with cast posts typically showed fracture of the tooth, although at loads rarely occurring clinically.

Adolescent↗
PubMed1998

Esthetic considerations in restoring endodontically treated teeth with posts and cores.

Posts and cores are often required for the restoration of endodontically treated teeth. Many methods for making post-and-core reconstructions have been described. With the increased use of all-ceramic systems for esthetic tooth restorations, there is a need for esthetic core reconstructions. This article describes several methods for fabricating esthetic posts and cores.

Dental Porcelain↗
PubMed1998

Microleakage along apical root fillings and cemented posts.

STATEMENT OF PROBLEM: Coronal leakage of endodontically treated teeth has been found to result in a high failure rate. PURPOSE: This study tested leakage along apical root fillings remaining after post space preparation and cemented posts in root canals. MATERIAL AND METHODS: A total of 120 human roots were used in the study and divided into six groups, 20 roots for each group. By using a modified fluid transport model, leakage (in microL/hr) along ParaPost dowels that were cemented in the coronal 7 mm of root canals with Fuji Duet, Ketac Cem, Panavia EX, or zinc phosphate cements was compared with that along the coronal 7 mm of conventional root canal fillings. Leakage along the apical 4 mm of root filling remaining after post space preparation was compared with that along the 11 mm root filling before post space preparation. RESULTS: More leakage was recorded along the apical 4 mm of root filling than along the 11 mm of original root filling (p = 0.0325). ParaPost dowels cemented with any test cement did not produce more leakage than the 7 mm coronal root filling (p = 0.2145). CONCLUSIONS: The apical 4 mm of root canal filling remaining after post space preparation leaks statistically significantly more than the original full-length root canal filling. The leakage created by removal of the coronal part of root canal filling during post space preparation may be compensated by the cemented posts.

Analysis of Variance↗
PubMed1999

Foundation restorations in fixed prosthodontics: current knowledge and future needs.

PURPOSE: The Ad Hoc Committee on Research in Fixed Prosthodontics established by the Academy of Fixed Prosthodontics publishes a yearly comprehensive literature review on a selected topic. The subject for this year is foundation restorations. METHODS: Literature of various in vitro and in vivo investigations that included technical and clinical articles was reviewed to provide clinical guidelines for the dentist when selecting methods and materials for restoration of structurally compromised teeth. Topics discussed and critically reviewed include: (1) desirable features of foundation restorations, (2) foundations for pulpless teeth, (3) historic perspectives, (4) cast posts and cores, (5) role of the ferrule effect, (6) prefabricated posts, (7) direct cores, (8) foundation restorations for severely compromised teeth, (9) problems and limitations, (10) future needs, and (11) directions for future research. CONCLUSION: This comprehensive review brings together literature from a variety of in vitro and in vivo studies, along with technique articles and clinical reports to provide meaningful guidelines for the dentist when selecting methods and materials for the restoration of structurally compromised teeth.

Dental Casting Technique↗
PubMed1999

Survival of Dicor glass-ceramic dental restorations over 14 years. Part II: effect of thickness of Dicor material and design of tooth preparation.

STATEMENT OF PROBLEM: The influence of different restorative design features on the long-term survival of Dicor glass-ceramic restorations is not well understood. PURPOSE: This study examined the relationship of different types of restorations and methods of preparation with the survival of Dicor glass-ceramic restorations functioning in vivo. MATERIAL AND METHODS: A total of 1444 Dicor glass-ceramic restorations were placed on the teeth of 417 adults. Failure was defined as a restoration that required remake because of material fracture. Survival of restorations of different types and with different methods of preparation was described by using Kaplan Meier survivor functions. Statistical significance between restoration type and preparation method was determined with the log rank test. RESULTS: Probability of survival of a typical partial coverage restoration was 92% at 11.3 years. There was no statistically significant difference between the survival of inlay or onlay restorations. For the 91 cores used for pulpless teeth, none failed over a total cumulative monitoring period of 419 years. There was no significant difference in survival of acid-etched Dicor restorations that were placed on shoulder or chamfer preparations. Thickness measured at the midpoint of the labial, lingual, mesial, distal, and midocclusal surfaces did not relate to risk of failure. CONCLUSIONS: The majority of Dicor glass-ceramic partial coverage inlay and onlay restorations and cores survived over time. Survival of restorations with either chamfer or shoulder preparations did not differ whether the restoration was acid-etched. Thickness of the restoration measured at the midaxial point of each surface did not relate to survival.

Acid Etching, Dental↗
PubMed1999

An in vitro study of the fracture resistance and the incidence ofvertical root fracture of pulpless teeth restored with six post-and-coresystems.

STATEMENT OF PROBLEM: Posts and cores are often required with pulpless teeth to provide retention and resistance form for complete crowns. Nevertheless, conventional posts may increase the potential for root fracture. PURPOSE: This study compared the resistance to vertical root fracture of extracted teeth treated with post-core systems that were modified with polyethylene woven fibers (Ribbond) with those treated with conventional post-and-core systems. MATERIAL AND METHODS: Canal instrumentation was performed for 60 maxillary central incisors, and complete crown preparations were made. The coronal portion of each tooth was amputated, and 6 post-and-core systems were studied. Specimens were mounted in acrylic resin blocks with a layer of polyvinyl siloxane covering the roots. Loads were applied at an angle of 130 degrees and measured with a universal testing machine. Results were analyzed statistically with 1-way analysis of variance with Student-Newman-Keuls grouping and chi-square analysis. RESULTS. Cast posts and cores resulted in significantly higher failure thresholds than all others, except for prefabricated, comparably sized, parallel-sided posts with composite cores. All failures in the group with cast posts involved fracture of the teeth, whereas 70% of the teeth with comparably sized parallel-sided posts and composite cores failed as a result of tooth fractures and 30% experienced core fractures. The woven fiber post-core system was significantly lower in strength than all others, and exhibited significantly fewer vertical root fractures. CONCLUSIONS: Polyethylene woven fiber and composite resin without a prefabricated post resulted in significantly fewer vertical root fractures, but mean failure load was the lowest. Smaller diameter prefabricated posts combined with the polyethylene woven fiber and composite cores improved resistance to failure. Traditional cast posts and cores were the strongest of the 6 post-core systems.

Acrylates↗
PubMed1995

Application of Ca-beta-glycerophosphate for artificial apical barrier formation.

This case demonstrates an artificial apical barrier formation by using calcium-beta-glycerophosphate paste in a nonvital permanent tooth with an open apex communicating with the maxillary sinus. The long-term satisfactory outcome of this case depended on the resolution of periapical pathosis and root canal obturation without overextension.

Adult↗
PubMed1994

Local prophylactic benadryl injections in an attempt to reduce postinstrumental pain.

This study was done to determine the clinical efficacy of a 15-mg diphenhydremine hydrochloride (Benadryl) local injection as a prophylactic treatment in the prevention of pain resulting from initial instrumentation of necrotic teeth. A double-blind study comprised of 37 subjects, each with one nonvital maxillary tooth, was completed in which patients were divided into two equal groups. The experimental group received a local anesthetic of 3% Carbocaine, followed by an additional injection of the antihistamine. The control group received the local anesthetic and an equivalent quantity of sterile saline. Patients recorded their pain levels at various time intervals: preoperatively, immediately postoperatively, and at 3, 7, 12, and 24 h postoperatively. Graphic analysis using a Quatro-Pro spread sheet program showed that there were no significant differences between the groups pain scores. However, there was a correlation between pain and time elapsed after procedure. In both groups, postoperative pain appeared to increase from 3 to 7 h and decrease from 7 to 24 h.

Adult↗
PubMed1992

Strength of roots before and after endodontic treatment and restoration.

The resistance to fracture of mandibular premolar roots before and after endodontic and restorative procedures was tested. Seven treatment groups were evaluated. A Universal testing machine was used to apply vertical and lateral (45-degree) forces. Overall, the untreated roots showed the highest resistance to fracture. Factors of importance to prevent fracture were found to be (a) the amount of remaining tooth structure; (b) strength of post and core; and (c) bonding between core material and dentin. These factors suggest that a composite core following the use of EDTA to remove the smear layer may be a successful treatment when sufficient tooth structure remains.

Bicuspid↗
PubMed1992

Effect of mechanical versus thermal removal of gutta-percha on the quality of the apical seal following post space preparation.

The objective of this study was to compare the effects of a flame-heated endodontic plugger, an electrically-heated endodontic spreader, Peeso reamers, and GPX burs on the apical seal when gutta-percha was removed from the root canal for post space preparation. Eighty-nine human canines were instrumented and obturated with gutta-percha and sealer to a standardized working length of 15 mm. An 11-mm segment of gutta-percha was removed from the roots in each of the four experimental groups of 20 teeth to simulate post space preparation. The teeth were immersed in India ink for 7 days and rendered transparent. The extent of linear dye leakage was measured with a stereomicroscope. There was no statistically significant difference in linear dye leakage among any of the experimental groups when 4 mm of gutta-percha remained.

Dental Instruments↗