A minimally invasive approach for a compromised treatment plan

A primary goal in dentistry is the execution of appropriate treatment plans that are minimally invasive and maintainable. However, it is sometimes necessary to repair existing dental restorations or revise treatment plans to accommodate changes in a patient's condition. In the present case, a patient who was satisfied with a removable partial overdenture lost a critical abutment tooth. A creative, minimally invasive approach enabled the patient to keep his existing partial prosthesis and avoid the need for a full reconstruction or complete denture.

Management of a complication with a fractured zirconia implant abutment in the esthetic zone

Technical complications in implant prosthetic cases represent a major challenge in dentistry. This case report describes minimally invasive management to recover an implant with a fractured remnant of a zirconia abutment, including provisional rehabilitation during a sequential treatment protocol in the esthetic zone. A patient was treated with a screw-retained one-piece implant-supported reconstruction made of a customized zirconia abutment with direct ceramic veneering in the maxillary right central incisor position. During the prosthetic try-in, a fracture in the apical portion of the abutment was evident. The first rescue attempt led to fracture of the retrieval instrument. Immediately, an individualized wired construction was applied to bond the existing fractured reconstruction to the neighboring teeth to maintain the peri-implant mucosal architecture. Because the implant screw canal was blocked, a customized round bur had to be manufactured and was placed in the implant axis with a specific bracket tool from the service set to protect the interior implant threads. Then, the drills of the service set were guided by the newly created access to remove the fractured remnants. The implant screw was retapped and the area rinsed with chlorhexidine solution. All remnants were removed without the need for surgical intervention. Neither the implant connection nor the bone-to-implant interface was damaged. The stepwise treatment approach with the customized round bur combined with the system-specific drills of the service set saved the blocked implant so that the patient could be successfully rehabilitated with a new implant reconstruction.

Clinical evaluation of fractured metal-ceramic fixed dental prostheses repaired with indirect technique

OBJECTIVES

Metal ceramic restorations continue to be widely used in dental practice, as they combine esthetics with superior mechanical properties. However, ceramic materials have the potential to fracture due to their brittle nature. The purpose of this study was to evaluate the clinical survival of fractured metal-ceramic restorations repaired with an indirect technique which uses a new "overlay" metal-ceramic crown that is luted to the existing restoration.

METHOD AND MATERIALS

The study population consisted of 92 patients. Only patients with one or more fractured retainers of multipleunit metal-ceramic fixed partial dentures were involved in this study. In all cases there were a bulk fracture of the overlaying ceramic material and exposure of the underlying metal substructure. The remaining retainers of the fixed partial dentures were intact. The total number of fractured retainers was 106. All clinical procedures of the indirect repairs were carried out by a single investigator, according the previously published technique. The patients were examined clinically at 1, 2, 4, 6, and 8 years after placement of the new restorations. The repaired restorations were examined for debonding, fracture rate, and esthetics. Patient acceptance was also recorded.

RESULTS

Of the 92 patients re-examined, all were satisfied with the function and the esthetic appearance of their restorations. None of the repaired restorations fractured after 8 years of service, and there were no gingival margin problems of significance. Four restorations debonded during the evaluation period. The overall survival rate was 96.2% after 8 years.

CONCLUSION

Repair methodology and materials employed in this study resulted in satisfactory longevity for metal-ceramic dental prostheses. The success rate was 96.2% after 8 years. The retention rate was very good, patient satisfaction was very encouraging, and maintenance of the esthetics was good.

Replacement versus repair of defective restorations in adults: resin composite

BACKGROUND

Composite filling materials have been increasingly used for the restoration of posterior teeth in recent years as a tooth-coloured alternative to amalgam. As with any filling material composites have a finite life-span. Traditionally, replacement was the ideal approach to treat defective composite restorations, however, repairing composites offers an alternative more conservative approach to the tooth structure where restorations are partly still serviceable. Repairing the restoration has the potential of taking less time and may sometimes be performed without the use of local anaesthesia hence it may be less distressing for a patient when compared with replacement.

OBJECTIVES

To evaluate the effects of replacing (with resin composite) versus repair (with resin composite) in the management of defective resin composite dental restorations in permanent molar and premolar teeth.

SEARCH METHODS

For the identification of studies relevant to this review we searched the Cochrane Oral Health Group's Trials Register (to 24 July 2013); the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 6); MEDLINE via OVID (1946 to 24 July 2013); EMBASE via OVID (1980 to 24 July 2013); BIOSIS via Web of Knowledge (1969 to 24 July 2013); Web of Science (1945 to 24 July 2013); and OpenGrey (to 24 July 2013). Researchers, experts and organisations known to be involved in this field were contacted in order to trace unpublished or ongoing studies. No restrictions were placed on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

Trials were selected if they met the following criteria: randomised controlled trial (including split-mouth studies), involving replacement and repair of resin composite restorations in adults with a defective molar restoration in a permanent molar or premolar teeth.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed titles and abstracts for each article identified by the searches in order to decide whether the article was likely to be relevant. Full papers were obtained for relevant articles and both review authors studied these. The Cochrane Collaboration statistical guidelines were to be followed for data synthesis.

MAIN RESULTS

The search strategy retrieved 298 potentially eligible studies, after de-duplication. After examination of the titles and abstracts, full texts of potentially relevant studies were retrieved but none of the retrieved studies met the inclusion criteria of the review.

AUTHORS' CONCLUSIONS

There are no published randomised controlled trials relevant to this review question. There is therefore a need for methodologically sound randomised controlled trials that are reported according to the Consolidated Standards of Reporting Trials (CONSORT) statement (www.consort-statement.org/). Further research also needs to explore qualitatively the views of patients on repairing versus replacement and investigate themes around pain, anxiety and distress, time and costs.

Two case reports involving implants and fractured healing caps

The widespread use of endosseous osseointegrated implants to replace missing natural teeth increases the chances of implant complications and failures, despite the high initial success rate reported in the literature. Implant and healing cap fracture are possible rare complications that can cause significant problems for both clinicians and patients. This article reports on 2 unique cases of implant and healing cap fracture, their possible causes, and how the cases were managed.

Retrieval technique for the Branemark Novum protocol: replacement of a lost implant

In the past, the Branemark Novum protocol for the immediate functional loading of a mandibular fixed implant supported prosthesis provided an effective alternative for select patients. However, the manufacturer has discontinued this design, and only a few selected prosthetic-related replacement components are currently available. This clinical report presents the loss of an implant associated with a discontinued system. To take advantage of all of the preexisting components, it proposes a rescue procedure that allows continuous use of the original fixed restoration during the restoration of the tripod support at the implant level.

[Esthetic evaluation of Cerec 3D anterior crowns]

OBJECTIVE

To observe the short-term effect of clinical application of Cerec 3D anterior crowns.

METHODS

A total of 16 patients were restored with 31 Cerec 3D anterior crowns. All restorations were stained before cementation. The evaluation started 1 week after luting. The restorations were examined in accordance with the modified US Public Health Service (USPHS) criteria at baseline and every 6 - 12 months.

RESULTS

The observation period of 31 Cerec 3D anterior crowns varied from 8 to 33 months. The mean observation period was 22 months. All restorations scored A or B by modified USPHS standard. And 22 out of 31 restorations scored A for all criteria while 8 restorations scored B in color matching. Slight differences of translucency and chroma could be observed. Between baseline and follow-up examinations, insignificant shift from A-to B-rating occurred.

CONCLUSION

Cerec 3D anterior crowns may achieve favorable short-term esthetic effects.

Wear and repair of stainless steel crowns

AIM

The purpose of this study was to determine the wear of stainless steel crowns (SSCs) in children, and compare the extent of microleakage in SSCs that had been repaired using either a cermet glass-ionomer cement (GIC) or a packable composite resin (CR).

MATERIALS AND METHODS

For the first aim, the occlusal surface thickness of 31 harvested SSCs (21 primary first and 10 second molars) and 18 unused SSCs was measured, and then examined under scanning electron microscopy. For the second aim, standardised holes were prepared on the occlusal surfaces of 20 SSCs, and then repaired using either a cermet GIC or packable CR. After their repair, the extent of microleakage was determined using 0.5% basic fuchsin and stereomicroscopy.

RESULTS

The thickness of all the harvested SCCs was 5.3 μm less than that of the unused SCCs (p<0.02), and there were no significant differences between the thickness and occlusal wear rates of harvested SSCs from the first and second primary molars. Although neither of the two repair materials completely prevented microleakage, the number of specimens in which microleakage occurred after repair with a cermet GIC was significantly lower than the number of specimens in which a packable CR was used (p<0.05).

CONCLUSION

We concluded that the occlusal surfaces of SSCs for first and second primary molars display wear. Although perforated SSCs can be repaired using either a cermet GIC or a packable CR, less microleakage occurs in SSCs that were repaired with a cermet GIC than those with a packable CR.

Evaluation of shear bond strength of porcelain bonded to laser welded titanium surface and determination of mode of bond failure

The aim of this study was to evaluate the shear bond strength of porcelain to laser welded titanium surface and to determine the mode of bond failure through scanning electron microscopy (SEM) and energy dispersive spectrophotometry (EDS). Forty five cast rectangular titanium specimens with the dimension of 10 mm x 8 mm x 1 mm were tested. Thirty specimens had a perforation of 2 mm diameter in the centre. These were randomly divided into Group A and B. The perforations in the Group B specimens were repaired by laser welding using Cp Grade II titanium wire. The remaining 15 specimens were taken as control group. All the test specimens were layered with low fusing porcelain and tested for shear bond strength. The debonded specimens were subjected to SEM and EDS. Data were analysed with 1-way analysis of variance and Student's t-test for comparison among the different groups. One-way analysis of variance (ANOVA) showed no statistically significant difference in shear bond strength values at a 5% level of confidence. The mean shear bond strength values for control group, Group A and B was 8.4 +/- 0.5 Mpa, 8.1 +/- 0.4 Mpa and 8.3 +/- 0.3 Mpa respectively. SEM/EDS analysis of the specimens showed mixed and cohesive type of bond failure. Within the limitations of the study laser welding did not have any effect on the shear bond strength of porcelain bonded to titanium.

[Coping mechanisms of mentally disabled patients in need of dental treatment]

The concept of the study appeared as a necessity of a better understanding the patients with mental disabilities, exposed to the need of professional dental treatment.

AIM

The study's purpose consists in the investigation of mechanisms by which the patients with mental disabilities react while exposed to the action of a stress agent, represented in the study by the necessity of following a dental treatment.

MATERIALS

The lot consisted in 52 patients with mental disabilities from the University Hospital of Psychiatry "Socola"-Iasi, who needed prosthetic restaurative treatment which implies the use of syringe with needle, extraction and endodonthic tools, dental turbine.

METHOD

The evaluation was made on the basis of: the coping COPE questionnaire. The procedure consists in registering 14 scales for the measurement of so many forms of coping which can have a preponderantly active state or a passive one.

RESULTS

From the statistical point of view, the only significant differences were found depending on the sex of patients in the case of coping C14 study method (using alcohol or medicines). The highest score was obtained for coping C7 (positive reinterpretation).

CONCLUSIONS

Due to the analysis of parameters' values of coping in the studied lot, we can conclude that the patients with mental disabilities, in the need of dental treatment, preponderantly react by active mechanisms of coping, focused on the issue, in disfavour of passive ones.

Tensile bond strength of immediately repaired anterior microfine hybrid restorative composite using nontrimmed hourglass specimens

PURPOSE

To investigate the effect of different surface treatments on the tensile bond strength (TBS) of immediately repaired anterior microfine hybrid restorative composite using nontrimmed hourglass-shaped specimens.

MATERIALS AND METHODS

Fifty-six nontrimmed hourglass composite specimens were prepared in this study. Eight specimens were used for the evaluation of the cohesive tensile strength as the control group. The remaining 48 were divided into 6 equal groups according to the method of proposed treatment. Groups IM1 and IM2: The specimens were repaired without intermediate treatment. Group IM3: A thin layer of Excite self-priming adhesive was applied to the proposed repaired area of each half-specimen. Group IM4: The repaired area was ground using an abrasive stone, each half-specimen was rinsed and dried, and the adhesive applied. Group IM5: Treatment consisted of 37% phosphoric acid etching of the proposed repair area. The adhesive was then applied. Group IM6: The repaired area was ground and acid etched before applying the adhesive. In all repaired groups except for IM2, repaired specimens were prepared and cured against a single layer of transparent polyester strip (matrix) to prevent the formation of an oxygen inhibition layer. In group IM2, specimens were cured in air without the polyester strip. Specimens were then tested for the repair tensile bond strength (TBS) in a universal testing machine at a crosshead speed of 0.5 mm/min until failure. Twelve more samples were used for SEM characterization of nontreated, ground, acid-etched, and ground/acid-etched samples. The failure mode was evaluated using a stereomicroscope at 30X magnification. All TBS data were expressed as mean and standard deviation, and were analyzed using StatsDirect 2.5.7. One-way ANOVA followed by Tukey-Kramer multiple-comparison post-hoc tests were used to compare the TBS between all tested groups. Differences were considered significant at p < 0.05.

RESULTS

Groups that were cured against a matrix and received no treatment or were repaired with adhesive only had significantly lower TBS than the control group. Groups which were cured without the matrix and received no treatment or grinding/adhesive, acid etching/adhesive, and grinding/acid etching/adhesive showed no significant difference in TBS compared to the control group. SEM evaluation showed that acid etching did not change the morphology of the composite surface. The ground specimens showed a grooved pattern with smeared grinding products. Ground/acid-etched specimens showed removal of the smeared products with a less distinct grinding-groove pattern. Stereomicroscopic evaluation of the debonded surfaces for all repaired groups showed that the failure mode was predominantly adhesive for all evaluated debonded surfaces in each repair group.

CONCLUSION

In the absence of an oxygen inhibition layer, the immediate repair bond strength was decreased. In contrast, in the presence of an oxygen inhibition layer, the immediate repair bond strength of composite was improved. The application of a thin adhesive layer did not improve the immediate repair bond strength as the other surface treatments did. When the composite was cured against a matrix, chemical and/or mechanical treatments of composite surface prior to application of the adhesive proved to be an effective method to improve the immediate repair bond strength.

[Esthetic repair of crown margins with composite. A case report]

Gingival recessions can cause severe aesthetical problems, especially when associated with the exposure of the margin of crown or bridge restorations. When complete root coverage can not be achieved by periodontal surgery techniques, prosthetic restorations are usually replaced to improve the aesthetic situation. This clinical report describes the application of a composite repair filling as an alternative technique to correct the restoration margin and cover the exposed root surface. From the published literature it is known that metallic and ceramic surfaces can be repaired adhesively using composite materials. This procedure is less costly and invasive, but provides satisfactorily aesthetic results.

Effect of size of defect on the repair strength of amalgam

OBJECTIVES

This study tested the hypothesis that the size of repair sites on amalgam restorations with mechanical undercuts on the repair surface would affect interfacial strength using a 3-point bending test.

METHOD AND MATERIALS

Six groups of 12 rectangular bars each were fabricated from an admix alloy and a spherical alloy. Each specimen was cut into 2 equal-sized end sections, and 1 smaller midsection, which was discarded. A medium-coarse diamond disk was used to roughen and flatten the surface for repair. The 2 end sections were fit back into the original mold. The empty space in the middle was approximately 1, 1.5, and 2 mm, mimicking the size of repair sites to be filled with amalgam. There were 2 groups for each repair size; 1 group had rounded undercuts prepared on the surface for repair with a 1 /2 round bur, and the other group received no additional treatment. Condensation was carried out with condensers having a dimension slightly less than the width of the repair defect. After 7-day storage, a 3-point bending test was used to determine the repair strengths of the specimens.

RESULTS

The strength values ranged from 33.9 to 75.6 MPa, which is comparable to published data. ANOVA showed that the mean strength values were higher with spherical amalgam (P <.0001), were lower with undercut (P = .0148), and increased as the width of repair site decreased (P <.0001).

CONCLUSION

Reducing the dimension of the repair site improved repair strength, but rounded undercuts reduced the repair strength values slightly.

Effect of physicochemical aging conditions on the composite-composite repair bond strength

PURPOSE

This study evaluated the effect of different physicochemical aging methods and surface conditioning techniques on the repair bond strength of composite. It was hypothesized that the aging conditions would decrease the repair bond strength and surface conditioning methods would perform similarly for the repair of resin composites.

MATERIALS AND METHODS

Disk-shaped resin composite specimens (Clearfil Photo Bright, Kuraray) were randomly assigned to one of the three aging conditions (N=120, n = 12/per group): (1) immersion in deionized water (37 degrees C, 1 week), (2) immersion in citric acid (pH: 3.0, 1 week), (3) boiling in water (8 h), (4) thermocycling (5000 times, 5 degrees C to 55 degreesC), (5) immersion in water (37 degrees C, 2 months). After aging procedures, the specimens were subjected to one of the following surface conditioning methods: (1) chairside silica coating (30-microm SiOx) (CoJet, 3M ESPE) + silane (ESPE-Sil) (SC method), (2) silane (Clearfil SE Bond Primer and Clearfil Porcelain Bond Activator) + bonding agent (Clearfil SE Bond) (SB method). The fresh and aged composite surfaces were also examined using SEM (n=6, 1/group). Resin composite (Quadrant Anterior Shine) was bonded to the conditioned substrates using polyethylene molds and then light polymerized. Shear force was applied to the adhesive interface in a universal testing machine (1 mm/min). The failure types were categorized as: (A) cohesive in the substrate, (B) adhesive at the interface, or C) cohesive in the adherend. Bond strength values were statistically analyzed using two-way ANOVA and Tukey's test (alpha < 0.05).

RESULTS

A significant influence of the conditioning method (p < 0.0001) and aging method was observed (p < 0.01) (two-way ANOVA, Tukey-Kramer). The SC method showed significantly higher bond values (7.8 +/- 1.2 to 11.6 +/- 5 MPa) than those of SB method (4.6 +/- 2.3 to 7.6 +/- 3.9 MPa) in all groups (p < 0.0001). While the SC method showed 96% cohesive (A type), the SB method demonstrated 92% adhesive failures (B type). SEM images showed distinct pattern of microcracks in the boiled specimens and filler dissolution with disorganized matrix resin in the other aged specimens. Aging the composite substrates through water storage for 2 months produced significantly lower bond strengths than those of water or acid storage for 1 week (p = 0.011).

CONCLUSION

Chairside silica coating and silanization provided the highest bond strength values with almost exclusively cohesive failures on aged composites. Aging methods showed significant differences on the composite-composite repair strength.

Effect of air-drying temperature on the effectiveness of silane primers and coupling blends in the repair of a microhybrid resin composite

PURPOSE

To evaluate the effect of different silane agents and air-drying temperatures on the repair strength of a microfilled hybrid composite.

MATERIALS AND METHODS

Composite cylinders (8 x 4 mm) of Gradia Direct Anterior (GC, N=36), stored in a saline solution at 37 degrees C for 1 month, were sandblasted (50-microm aluminium oxide), cleaned (35% phosphoric acid) and randomly divided into six groups (n=6). Two prehydrolyzed silane primers (Monobond-S, Ivoclar-Vivadent, Porcelain Primer, Bisco), a non prehydrolyzed silane primer (Porcelain Liner M, Sun Medical) and three silane/adhesive coupling agents (Porcelain Bond Activator-PBA/Clearfil New Bond, PBA/Clearfil SE Bond, PBA/Clearfil Tri-S Bond, Kuraray) were investigated. Silane-coated surfaces were air dried at two different temperatures (23 degrees C and 38 degrees C) and repairs (8 x 8 mm) were fabricated (Gradia Direct Anterior). Unrepaired composite cylinders (8 x 8 mm, n=6) were used as control to evaluate the cohesive strength of the material. Microtensile bond strength measurements (microTBS) were performed.

RESULTS

The silane agent applied (p < 0.001), the airdrying temperature (p < 0.001) and their interaction (p < 0.001) were significant factors (two-way ANOVA, Tukey test; p < 0.05). Silane primers achieved inferior microTBS when air dried at 23 degrees C as compared to silane/adhesive blends. Warm air-drying was significantly beneficial to composite repairs mediated by silane primers. Comparable results were achieved by silane/adhesive couplings at 23 degrees C and 38 degrees C. At 38 degrees C all the intermediate agents resulted in repair microTBS that were comparable to the 24-h cohesive strength of the composite (one-way ANOVA, Dunnett t-tests; p < 0.05).

CONCLUSION

The chemical interactions between silane primers and compozite substrate may be optimized through warm airdrying. Silane/adhesive couplings were not influenced by the air drying temperature.

Factors Affecting the Strength of Denture Repairs

Fracture of dentures is a common clinical finding in daily prosthodontic practice, resulting in great inconvenience to both patient and dentist. A satisfactory repair should be cost-effective, simple to perform, and quick; it should also match the original color and not cause distortion to the existing denture. Different repair materials, surface designs, and mechanical and chemical surface treatments have been recommended in order to obtain stronger repairs. This article reviews some of the available literature with regard to the most important factors that may influence the strength of denture repairs.

[Acrylic resin reinforcement with metallic and nonmetallic inserts]

In the current use of acrylic resin for removable dentures and orthodontic treatments we are frequently facing the fact of base fracture. The repairing of this, determine most of the time, discomfort of the patient, by excluding the prosthetic device, affecting the treatment, loosing patient's time, doctor's time, implying the dental laboratory and extra expenses. The causes of fractures are many, from clinical cases with some specific anatomic and functional particularities, or parafunctional, to the incorrect designing, manufacturing or wearing of the prosthetic part, being connected with the materials characteristics. The consequences and costs of these fractures are leading to unsatisfying results in some of the clinical cases, in presence of parafunctions like bruxism or clenching and specifically for the new types of prosthetic rehabilitation, on natural teeth or implants.

A comparison of two different methods and materials used to repair polycarbonate crowns

AIM

The aim of this study was to evaluate the bond strength and crown-repair material interface of polycarbonate crown repaired using flowable resin composite and hybrid resin composite following two different surface preparations.

METHODS AND MATERIALS

The facial surfaces of fifty-two polycarbonate crowns were flattened and roughened. Specimens were then divided into four test groups. A bonding agent alone (Groups 1 and 2) or a combination of methylmethacrylate (MMA) + bonding agent (Groups 3 and 4) was applied to the prepared surfaces. Then either a flowable (Groups 1 and 3) or a microfilled hybrid (Groups 2 and 4) resin composite was placed on the surfaces. Forty-eight of the original fifty-two specimens were used for shear bond strength testing. Failure types (adhesive, cohesive, and mixed) were evaluated. The remaining four specimens, one from each group, were used for crown-resin composite interface analysis using a scanning electron microscope (SEM).

RESULTS

There were significant differences in both mean shear bond strength values and failure types (P<0.05). The SEM evaluation revealed a close interface relationship in Groups 3 and 4.

CONCLUSION

MMA monomer application on a polycarbonate crown prior to application of an adhesive agent improved the shear bond strength of the repair material.

Comparison of Repair Methods for Ceramic-Fused-to-Metal Crowns

PURPOSE

The objective of this study was to evaluate the effect of four repair methods on the fracture load of repaired ceramic-fused-to-metal crowns.

MATERIALS AND METHODS

Metal-ceramic crowns were fractured, and the failure load was measured. The fractured metal-ceramic crowns (n = 9) were assigned randomly to the following treatment groups: (1) hydrofluoric acid (9.5%) etching, (2) air-particle abrasion (50 microm Al(2)O(3)), (3) silica coating (30 microm SiO(x)), and (4) the application of a layer of glass fiber-reinforced composite (FRC) (thickness: 0.12 mm) on the repair surface. The crowns were repaired with a highly filled resin composite and subjected to 3 repair cycles (n = 27). All specimens were stored in water at 37 degrees C for 24 hours and then thermocycled (6000 cycles, 5 degrees C to 55 degrees C). The fracture load values for final failure of intact and repaired crowns were measured with a universal testing machine, and failure types were recorded.

RESULTS

No significant differences (p > 0.05) were found between the final failure values for the groups treated with 9.5% hydrofluoric acid (376 N) and airborne particle abrasion with either Al(2)O(3) (432 N) or SiO(x) (582 N) followed by silanization, respectively. Significantly, higher (p < 0.0001) final failure values (885 N) were obtained with the use of the FRC layer when compared with the other repaired groups. There was no significant difference (p > 0.05) between the final fracture load of intact crowns (872 N) and those repaired with FRC (885 N) (One-way ANOVA with repeated measures, Bonferroni test). No significant difference in fracture loads was found between the 1st, 2nd, and 3rd repair cycles (558 N, 433 N, 485 N, respectively). Failure sites were predominantly at the alloy/veneering resin interface in Group 1; Groups 2 and 3 both showed more cohesive failures than Group 1. In the case of FRC, the failure pattern was exclusively cohesive between the two laminates of FRC layer.

CONCLUSIONS

The conditioning methods (Groups 1 to 3) of the repair surfaces did not show differences between each other; each resulted in mean fracture loads at lower levels than that of the intact crowns. Addition of an FRC layer increased the fracture load to the level of intact crowns. This suggests that the use of FRC in repairs of metal-ceramic crowns might be a viable option.

Core buildup repair using a clear matrix: a case report and clinical technique

The fracture of core buildup material is common in dental practice. This article describes a core buildup repair technique utilizing a custom matrix. This technique enables the dentist to reestablish the original contour and alignment of the broken core buildup and assures excellent crown fit in a short amount of time with a predictably successful outcome.

[A three-year clinical evaluation of galvano-ceramic bridges made by Ni-Cr pontic bonding galvano caps]

OBJECTIVE

To evaluate the clinical effect of galvano-ceramic bridges made by Ni-Cr pontic fired bonding galvano caps with highly temperature-resistant adhesive based on three-year clinical trials.

METHODS

A total of 29 galvano-ceramic bridges made by Ni-Cr pontic fired bonding on the galvano caps were used for 26 patients. Abutment teeth plaque indices (PI) were compared according to Silness and Löe standards and their papillary bleeding indices (PBI) according to Mazza standards before restoration and after 36 months' restoration. At the same time, the integrity and marginal fitness of galvano-ceramic bridges were observed.

RESULTS

The PBI at abutment teeth were higher than those before restoration, Wilcoxon test revealed significant difference. Their PI were lower than those before restoration, Wilcoxon test revealed significant difference. All the galvano-ceramic bridges were perfect in marginal fitness and color. The rate of integrity was 89.7% in the period of observation.

CONCLUSION

Galvano-ceramic bridges made by Ni-Cr pontic fired bonding galvano caps with highly temperature-resistant adhesive hold out good prospects for clinical use in fixed restoration.

A technique for locating implant abutment screws of posterior cement-retained metal-ceramic restorations with ceramic occlusal surfaces

With the increased use of cement-retained implant-supported restorations for the replacement of missing teeth, clinicians may choose to use a definitive cement to lute the definitive restoration. A complication that may occur, especially for a single-tooth replacement, is loosening of the abutment screw. In those situations, it may be difficult to locate the abutment-screw access to remove the restoration. The purpose of this article is to describe a technique that may facilitate the clinician's ability to locate the abutment-screw access in the event of abutment-screw loosening, thus reducing the need for refabricating the restoration.

Accuracy of Temporary Laser Welding of FPDs by Nd:YAG Laser in the Oral Cavity

The purpose of this study was to investigate the accuracy of temporary fixation with laser welding for fixed partial dentures (FPDs). Five kinds of experimental FPD with different welding/soldering gaps were fabricated (0, 20, 50 microm for welding; 300 microm for soldering). Then, FPDs were temporary-fixed by laser welding or with a self-curing resin. Fixation accuracy was evaluated by the change in distance and the angular deformation between two retainers. The change in distance and the angular deformation between two retainers of the FPD without welding/soldering gap were significantly larger than the other FPDs (p<0.05). With due consideration to the displacement of teeth or implants especially in the mesiodistal direction, and by taking into account the inevitable errors of the indirect method, it seemed reasonable to provide a welding space of approximately 20 microm.

Urgent denture repair in a medically compromised patient

Dental practices will see an increasing number of older patients as our population ages over the next decade. The following article describes a denture repair in a patient with Parkinson's disease. The patient and his caregiver were unable to make multiple trips to the clinic for treatment. The type of repair described in this article minimized the amount of expense and time required to repair the denture.

Evaluation of shear bond strength of composite to porcelain according to surface treatment

This study evaluated the shear bond strength of porcelain/composite using 40 metal + porcelain + composite cylindrical specimens divided into 4 groups, according to porcelain surface treatment: 1) no treatment, 2) mechanical retentions performed with diamond burs, 3) etching with phosphoric acid+silane, and 4) etching with hydrofluoric acid+silane. After being stored in distilled water at room temperature for one week, the specimens were submitted to a shear force (load) and the data were analyzed statistically (ANOVA). The means (in Mpa) of the groups were: 4.71 (group 1); 4.81 (group 2); 11.76 (group 3); 11.07 (group 4). There were no statistically significant differences between groups 1 and 2 and between groups 3 and 4.

Influence of different repair procedures on bond strength of adhesive filling materials to etched enamel in vitro

Contamination of etched enamel with repair bond agents during repair of dental restorations may interfere with the bonding of composite to enamel. This study examined the bond strength of adhesive filling materials to etched bovine enamel after pre-treatment with the repair systems Monobond S, Silibond and Co-Jet. The materials Tetric Ceram, Dyract and Definite and their corresponding bonding agents (Syntac Single Comp, Prime & Bond NT, Etch and Prime) were tested in combination with the repair systems. One hundred and thirty-five enamel specimens were etched (37% phosphoric acid, 60 seconds) and equally distributed among three groups (A-C). In Group A, the repair materials were applied on etched enamel followed by applying the composite materials without using their respective bonding material. In Group B, the composite materials were placed on etched enamel after applying the repair materials and bonding agents. In control Group C, the composite materials and bonding agents were applied on etched enamel without using the repair systems. In each sub-group, every composite material was applied on 15 specimens. Samples were stored in artificial saliva for 14 days and thermocycled 1,000 times (5 degrees C/55 degrees C). The shear bond strength of the samples were then determined in a universal testing machine (ISO 10477). Applying Monobond or Silibond followed by the use of its respective bonding agents resulted in a bond strength that was not statistically different from the controls for all filling materials (Group C). The three composites that used Monobond and Silibond without applying the corresponding bonding agent resulted in bond strengths that were significantly lower than the controls. Utilizing the Co-Jet-System drastically reduced the bond strength of composites on etched enamel. Contamination of etched enamel with the repairing bonding agents Monobond and Silibond does not interfere with bond strength if the application of Monobond and Silibond is followed by using its corresponding bonding system of the composites tested.

Evaluation of alternative intra-oral repair techniques for fractured ceramic-fused-to-metal restorations

Ceramic fractures are serious and costly problems in dentistry. Moreover, they pose an aesthetic and functional dilemma both for the patient and the dentist. This problem has created demand for the development of practical repair options which do not necessitate the removal and remake of the entire restoration. Published literature on repair techniques for fractured fixed partial dentures, concentrating on the data obtained both from in vitro and in vivo studies, reveals that the repair techniques based on sandblasting and silanization are the most durable in terms of adhesive and cohesive failures compared with those using different etching agents.

Defective direct composite restorations--replace or repair? A survey of teaching in Scandinavian dental schools

A questionnaire based survey was undertaken in Scandinavian dental schools to investigate aspects of the teaching of the repair of failing direct composite restorations, as a conservative alternative to total restoration replacement. The findings indicate that all undergraduate students in Scandinavian schools are taught and gain clinical experience in the repair of direct composite restorations. Although the findings reveal general agreement in relation to the teaching of reasons and operative procedures for the repair of direct composite restorations, variations were found in relation to the teaching of indications for, and the expected longevities of such repairs.

Repair of metal-ceramic restorations using an abrasive silica-impregnating technique: two case reports

The loss or fracture of porcelain from a crown or bridge may be viewed by patients as a dental problem in need of urgent repair. Resin-based and silica coating materials are available that demonstrate good bond strengths to metal and porcelain in the laboratory. This paper describes two cases in which a recently introduced silica coating system was used for repairing fractured metal-ceramic restorations. However, no long-term studies on the success of these materials in repairing fractured porcelain are available.

Bonding procedures for intraoral repair of exposed metal with resin composite

PURPOSE

To determine if tin plating can be recommended for intraoral repair of ceramic veneered cast restorations where metal of unknown composition is exposed by loss of ceramic. This study investigated the effectiveness of surface treatments incorporating tin plating and unfilled resin to enhance the tensile bond strength of a resin composite restorative to three different metal ceramic casting alloys.

MATERIALS AND METHODS

Gold-platinum, palladium-tin and nickel-chromium alloys were used to fabricate 120 rods of each alloy, 4 x 15 mm. The end of each rod was ground perpendicular on 600-grit SiC paper and grit blasted with 50-micron alumina. Rods from each alloy were divided into four groups of 30 to receive one of the following treatments before bonding pairs end to end with a visible light-polymerized resin composite (Herculite XRV): 1) direct bonding with the resin composite; 2) tin plating (Micro-Tin) and bonding; 3) application of unfilled resin (Chameleon) and bonding; 4) tin plated, application of unfilled resin and bonding. The bonded samples were stored in distilled water, incubated at 37 degrees C for 24 hours and tested for tensile bond strength at a crosshead speed of 1 mm/min in a Lloyd 1000R machine. The mode of failure was examined using a stereo zoom microscope.

RESULTS

A statistically significant increase in tensile bond strength was demonstrated between the control (group 1) and both the gold and palladium alloy treated with tin plating and unfilled resin (group 4). Tin plating, or tin plating with the application of unfilled resin had no statistically significant effect on the tensile bond strength of resin composite to the nickel-chromium alloy.

CONCLUSION

The results demonstrate that tin plating, in conjunction with the application of a low-viscosity unfilled resin, optimizes the tensile bond of a resin composite to the three alloys used in the study. This procedure can be recommended for intraoral repair of exposed metal when the type of alloy belongs to one of the investigated alloy groups.

[Repair and revision 7. Endodontic treatment of crowned teeth: restoration replacement, removal or trephining]

Endodontic complications with crowned teeth are not uncommon in the daily practice. When a tooth, restored with a crown or a fixed bridge, requires endodontic (re)treatment the dentist has a choice to either discard the restoration, remove it and recement it after endodontics, or to trephine the restorations. Discarding is indicated when clear shortcomings of the crown or bridge are encountered. Removal facilitates endodontic treatment. If removal is not feasible, an endodontic access cavity is prepared in the restoration. Based on case reports practical advice is presented in this article.

[Filling repair and repair fillings]

The possibility of repair of restorations have been regarded for long time as "patchwork dentistry" in standard textbook literature and university education. The current knowledge of the biohazards of dental restorations do not allow an unreflected attitude towards repair techniques. Since there is a lack of investigations on the indication and longevity of repair restorations this technique remains empiric in character. The survey discusses the indication of repair and re-restoration.

The use of resin cements in restorative dentistry to overcome retention problems

The use of resin cements in combination with dentin bonding agents can result in superior attachment of prostheses to tooth structure. This paper describes four clinical cases in which dentin-bonded resin cements were used to overcome retention problems. In the first case, a detached fixed partial denture, which was in good condition when separated, was recemented to abutment teeth prepared with less-than-ideal angle of convergence. In the second case, a detached all-porcelain crown was recemented with a dentin-bonded resin cement after appropriate surface treatment. In the third case, a porcelain-fused-to-metal crown made for a molar tooth was cemented to a short clinical crown, avoiding crown-lengthening surgery. In the fourth case, a 3-unit fixed partial denture was recemented to abutments with less-than-ideal supporting features. Dentin-bonded resin cements can help to extend the life of detached prostheses until the patient is financially prepared for replacement or it can help to avoid crown-lengthening surgery.

Effect of soldering on metal-porcelain bond strength in repaired porcelain-fused-to-metal castings

STATEMENT OF PROBLEM

Chemical bonding plays a major role in the adherence between metal and porcelain. The formation of an oxide layer on solder material has not been described in the literature. It is unknown whether the application of solder negatively affects the bond strength between porcelain and metal.

PURPOSE

This in vitro study assessed the effect of solder on the bond strength between metal and porcelain.

MATERIAL AND METHODS

Forty 20 x 6 x 0.5 mm patterns were divided into test (20) and control (20) groups. Test samples were perforated and repaired with solder, and 2 layers of opaque and dentin porcelain subsequently were applied on all samples. The samples were subjected to a 3-point flexural test on a screw-driven mechanical testing machine at a crosshead speed of 0.5 mm/min. Failure type (adhesive vs cohesive) was quantified by digitizing photographs of test and control samples. Three samples in each group also were examined with an SEM coupled with an x-ray energy-dispersive spectroscopy apparatus (SEM/EDS). Means and standard deviations of loads at failure, sample thickness, and surface area covered with porcelain were calculated, and data were analyzed with Student t test (P < or = 0.05).

RESULTS

The mean fracture load for test samples was significantly greater than for control samples (P = 0.0038). Test samples also were significantly thicker (mean thickness difference 0.14 mm) (P = 0.0001). When the data were controlled for thickness by using a multiple linear regression analysis, no significant difference was found (P = 0.68). Test samples had a greater surface area covered with opaque porcelain (P = 0.0006) as determined by visual inspection.

CONCLUSION

In this study, soldered and nonsoldered samples did not show any significant difference in porcelain-to-metal bond strength. Visual analysis revealed a significant difference in the amount of porcelain remaining on the fracture surface of the test and control samples; a complete quantitative elemental analysis with SEM/EDS is in progress.

A technique for compensating for the loose CeraOne screw

Clinical experience indicates that implant-supported crowns for the replacement of individual molars using the original, regular platform CeraOne protocol (Nobel Biocare) infrequently result in gold screws loosening. This article offers a technique that may prevent the CeraOne gold screw from working loose. It is intended to be a correction for a problem, not a first-time treatment. Also, this is a treatment that should be offered only after the prescribed Brånemark protocol for screw tightening and elimination of excursive contacts has proven ineffective.

Intraoral repair of cosmetic restorations

The longevity of porcelain and composite resin restorations can often be prolonged by using sound principles, up-to-date materials, and judicious attention to repair when fracture problems arise. Careful case selection and correct usage of surface treatment agents, followed by the use of a quality bonding system and restorative materials, can result in a repair that exhibits excellent retention and natural color blending. This article outlines procedures and materials to repair both resin composite and porcelain intraorally.

Extending the use of a 4-META material: repair of fractured metal/ceramic crowns and bridges

The dentist who undertakes to carry out fixed bridgework or crowns will be faced with the fracture of a number of these restorations. Repair of such fractures may provide a faster, less traumatic and less expensive form of treatment than replacement of the restoration. Alternative methods of repair of metal/ceramic crowns and bridges are suggested, but further work is required to evaluate the long-term success of these repairs and, if required, to develop reliable methods of repair of metal/ceramic restorations.

Effects of surface treatments on amalgam repair

Dentists are faced with clinical situations that require the decision to replace or repair an amalgam restoration. The purpose of this study was to compare five amalgam repair techniques. Six groups of 15 amalgam beams each were fabricated by mechanical condensation of Tytin into an anodized aluminum split mold. Specimens were aged for 7 days prior to repair. Repaired specimens were stored for 7 days and thermocycled 500 times. Repair strength was measured by transverse strength testing in an Instron testing machine. Data were analyzed by a one-way ANOVA and a Student-Newman-Keuls test at the P < or = 0.05 level. The surface treatments were: Group A) intact beams, B) roughened with a #557 bur, C) air abraded with 50 microns aluminum oxide, D) retentive undercuts with a #33 1/2 bur, E) Amalgambond Plus, and F) no treatment. The repair strength of the various experimental groups ranged from 7-18% of the intact specimens. The #557 bur-roughened group yielded statistically higher repair strengths than all other surface treatments, which were statistically equivalent to each other.

Surface treatment techniques for resin composite repair

PURPOSE

To compare bond strengths of fresh resin composites to previously polymerized ("aged") composites following various surface treatments.

MATERIALS AND METHODS

Eighty Pertac Hybrid (PH) and an equal number of Silux Plux (SLX) specimens were fabricated and stored for 1 week prior to surface treatment. The specimens were then polished and stored for an additional 24 hours prior to final surface treatment. The surface treatments included use of one of the following: (1) diamond bur (DB), (2) microetcher with 50 microns Al2O3@80 psi pressure (ME), (3) high-pressure air abrasion with 27 microns Al2O3@psi, (KCP), or (4) low-pressure silicate ceramic deposition using 30 microns particles@34 psi (CJ-S) with a microetcher. Half of the samples were treated with a silanating agent. Fresh resin composite (same type as used for the aged specimen) was bonded to the treated surfaces, and specimens were then stored 24 h and thermocycled 300 x at 5 degrees and 55 degrees C prior to testing for shear bond strength. Two-way ANOVA was used to determine significant differences between mean shear bond strengths for both composite materials.

RESULTS

Significant differences were found between the groups for both surface treatment and silane use (P < 0.05). The interaction between the two main effects was also significant (P < 0.05). Overall, the highest bond strengths were found when the low-pressure silicate ceramic deposition system (CJ-S) was used, with or without silane.