Effect of surface treatments on repair with composite resin of a partially monoclinic phase transformed yttrium-stabilized tetragonal zirconia.

STATEMENT OF PROBLEM: Studies of composite resin repairs of yttrium-tetragonal zirconia polycrystal (Y-TZP) are usually performed in its tetragonal phase, but it may be partially transformed into a monoclinic phase in a clinical fracture. PURPOSE: The purpose of this in vitro study was to evaluate the effect of airborne-particle abrasion (APA) and a bonding agent on the shear bond strength (SBS) between a composite resin and hydrothermally aged Y-TZP. MATERIAL AND METHODS: Specimens (7.0×7.0×1.7 mm, N=112) of Y-TZP Lava were obtained, and 50% were aged in an autoclave at 134°C at 300 kPa for 8 hours. The surfaces were treated with APA 50-µm Al2O3 particles (ALU) or Rocatec Soft (30 µm) (ROC) followed by Clearfil SE Bond Primer (10-methacryloyloxydecyl dihydrogen phosphate [10-MDP]) plus Clearfil porcelain bond activator (3-methacryloxypropyl-trimethoxy silane [3-MPS]) (CLE) or RelyX Ceramic Primer plus a layer of RelyX U100 adhesive-resin cement (REL). Composite resin cylinders were built on the Y-TZP treated surfaces. After thermocycling (6000 cycles, 5°C and 55°C, 30-second dwell time), an SBS test was carried out (n=14). Data were analyzed by 3-way ANOVA and the Tukey honest significant differences test (α=.05). The failure mode was analyzed. RESULTS: The 3-way ANOVA was not significant for aging (P>.05), but the APA (P<.001), bonding agent (P<.001), and their interaction (P<.001) were significant. APA with ALU or ROC did not influence the SBS of the groups bonded with CLE, but the REL APA with ROC provided higher SBS. The failure mode was adhesive for all specimens. CONCLUSIONS: Adhesion was not different on monoclinic partially transformed Y-TZP. The APA with ROC followed by REL was the most effective treatment for repairing Y-TZP.

Management of a Damaged Implant for Retention of an Overdenture Prosthesis and Fixed Single Crown: Clinical Reports.

This article demonstrates a method to salvage an implant that has been damaged or is no longer usable because of a fractured screw that cannot be removed. In the first situation the patient had a Locator abutment that fractured during torqueing of the abutment. Despite the attempt to remove the fractured screw, it was not retrievable, and the internal threads of the implant were damaged in the attempt to remove the screw. Rather than removing the implant or covering it and sleeping the implant, a custom cast post was used to restore the implant to function. A second example describes a patient with a fixed implant crown. The implant was damaged during attempts to remove the fractured screw. A custom post was fabricated and cemented, and a new crown was fabricated.

In Vitro Comparison of the Bond Strength between Ceramic Repair Systems and Ceramic Materials and Evaluation of the Wettability.

PURPOSE: When fracture of an all-ceramic restoration occurs, it can be necessary to repair without removing the restoration. Although there are many studies about the repair of metal-ceramic restorations, there are few about all-ceramic restorations. The aim of this study was to evaluate the shear bond strength between ceramic repair systems and esthetic core materials and to evaluate the wettability of all-ceramic core materials. MATERIALS AND METHODS: Disk-like specimens (N = 90) made of three dental ceramic infrastructure materials (zirconia ceramic, alumina ceramic, glass ceramic) were polished with silicon carbide paper, prepared for bonding (abrasion with 30 µm diamond rotary cutting instrument). Thirty specimens of each infrastructure were obtained. Each infrastructure group was divided into three subgroups; they were bonded using 3 repair systems: Bisco Intraoral Repair Kit, Cimara & Cimara Zircon Repair System, and Clearfil Repair System. After 1200 thermocycles, shear bond strength was measured in a universal testing machine at a 0.5 mm/min crosshead speed. In addition, the contact angle values of the infrastructures after surface treatments were examined for wettability. Data were analyzed by using ANOVA and Tukey post hoc tests. RESULTS: Although there were no significant differences among the repair systems (p > 0.05) in the glass ceramic and zirconia groups, a significant difference was found among the repair systems in alumina infrastructure (p < 0.001). There were no statistically significant differences among the infrastructures (p > 0.05); however, a statistically significant difference was found among the repair systems (p < 0.05). No difference was found among the infrastructures and repair systems in terms of contact angle values. CONCLUSIONS: Cimara & Cimara Zircon Repair System had higher bond strength values than the other repair systems. Although no difference was found among the infrastructures and repair systems, contact wettability angle was decreased by surface treatments compared with polished surfaces.

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.

Effectiveness of silica-lasing method on the bond strength of composite resin repair to Ni-Cr alloy.

PURPOSE: The aim of this study was to evaluate the effectiveness of silica-lasing method for improving the composite resin repair of metal ceramic restorations. MATERIALS AND METHODS: Sixty Ni-Cr cylindrical specimens were fabricated. The bonding surface of all specimens was airborne-particle abraded using 50 µm aluminum oxide particles. Specimens were divided into six groups that received the following surface treatments: group 1-airborne-particle abrasion alone (AA); group 2-Nd:YAG laser irradiation (LA); group 3-silica coating (Si-CO); group 4-silica-lasing (metal surface was coated with slurry of opaque porcelain and irradiated by Nd:YAG laser) (Si-LA); group 5-silica-lasing plus etching with HF acid (Si-LA-HF); group 6-CoJet sand lased (CJ-LA). Composite resin was applied on metal surfaces. Specimens were thermocycled and tested in shear mode in a universal testing machine. The shear bond strength values were analyzed using ANOVA and Tukey's tests (α = 0.05). The mode of failure was determined, and two specimens in each group were examined by scanning electron microscopy and wavelength dispersive X-ray spectroscopy. RESULTS: Si-CO showed significantly higher shear bond strength in comparison to other groups (p < 0.001). The shear bond strength values of the LA group were significantly higher than those of the AA group (p < 0.05). No significant difference was found among lased groups (LA, Si-LA, Si-LA-HF, CJ-LA; p > 0.05). The failure mode was 100% adhesive for AA, Si-LA, Si-LA-HF, and CJ-LA. LA and Si-CO groups showed 37.5% and 87.5% cohesive failure, respectively. CONCLUSION: Silica coating of Ni-Cr alloy resulted in higher shear bond strength than those of other surface treatments.

Minimally Invasive Long-Term Management of Direct Restorations: the '5 Rs'.

The assessment and operative long-term management of direct restorations is a complex and controversial subject in conservative dentistry. Employing a minimally invasive (MI) approach helps preserve natural tooth structure and maintain endodontic health for as long as possible during the restorative cycle. This paper discusses how minimally invasive techniques may be applied practically to reviewing, resealing, refurbishing, repairing or replacing deteriorating/failed direct coronal restorations (the'5 Rs') and provides an update of contemporary MI clinical procedures. CPD/CLINICAL RELEVANCE: The assessment and long-term clinical management of deteriorating/failing direct restorations is a major component of the general dental practice workload and NHS UK budget expenditure for operative dentistry.

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.

Defective composite restorations--repair or replace?

DATA SOURCES: The Cochrane Oral Health Group's Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), Medline, Embase, BIOSIS via Web of Knowledge, Web of Science and Opengrey databases were searched. In addition researchers and experts in the field were contacted to trace unpublished or ongoing studies. No restrictions were placed on the language or date of publication. STUDY SELECTION: Randomised controlled trials (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 were to be considered. DATA EXTRACTION AND SYNTHESIS: 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 followed for data synthesis. 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. CONCLUSIONS: There are no published randomised controlled trials relevant to this review question. Therefore there is 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.

A technique to salvage a single implant-supported fixed dental prosthesis having a nonretrievable implant screw fragment.

An implant screw fracture is one of the common problems associated with the implant components. In some situations, it may not be possible to retrieve the fractured implant screws. As a result, clinicians either remove the implant or the implant may need to be covered over with soft tissue. The salvage of an implant with a nonretrievable screw fragment may be highly beneficial to the patients. This report describes a technique to salvage an implant-supported single restoration that has a nonretrievable implant screw fragment.

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.

Teaching of the repair of defective composite restorations in Scandinavian dental schools.

Given increased tooth retention into later years of life, dentists face increasing challenges in maintaining teeth with extensive composite restorations. Accompanying the increase in placement of composite restorations in general practice, there has also been increased evidence that repair, rather than replacement, of composite restorations is being increasingly considered as a treatment option. Previous work has demonstrated that such techniques are often underutilised in practice. The aim of this study was to examine contemporary teaching of composite repair techniques in Scandinavian dental schools. A questionnaire was distributed by email to each of the 12 Scandinavian dental schools in late 2010/early 2011. This questionnaire sought information on the undergraduate teaching of composite repair techniques as well as indications and materials utilised for this technique. A 100% response rate was achieved (12 schools). Eleven of the 12 respondent schools indicated that they included the teaching of composite repair techniques within their dental school programme. The most commonly reported indications for the teaching of the repair of direct composite restorations were tooth substance preservation (11 schools) and reduced risk of harmful effects on the pulp (10 schools). The most commonly taught surface treatment was mechanical roughening of the existing composite restoration, including the removal of the surface layer of material, prior to application of fresh composite (11 schools). Overall, the results of this study showed that the teaching of composite repair techniques is established within Scandinavian dental schools. This may influence the practising habits of dentists graduating from these schools when considering treatment options for defective composite restorations.

[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.

Three-dimensional location of the retaining screw axis for a cemented single tooth implant restoration.

Retrievability is a major concern with cemented versus screw-retained implant restorations. This article describes the use of cone beam radiography to help target and create a precise screw access opening for a loosened implant-supported single crown retained by cement to its abutment.

Prosthodontic rehabilitation of dental implants with exposed threads: a clinical report.

An unconventional technique was used to address the challenge of exposed dental implant threads. Titanium dental implants were prepared with rotary instruments to eliminate the exposed threads and to receive a fixed cementable prosthesis. The technique required fabrication of a gold casting of 2 copings connected by a round bar to fit the prepared implants and an implant-retained overdenture. This technique may be applied to other situations when multiple implants present with thread exposure and bone resorption. These include single crowns, partial fixed dental prostheses, and attachments for overdentures.

Augmenting retention and stability of an occlusal device for a partially dentate patient using existing extracoronal attachments: a clinical report.

Occlusal devices are a valid treatment modality in certain clinical situations. For an occlusal device to be effective, sufficient retention and stability should be derived from coverage of the occlusal and incisal surfaces of the teeth. In the absence of most or all of the posterior teeth, the effectiveness of the device could become compromised as the incisal portions of the anterior teeth are typically not conducive to adequately retaining and stabilizing the device. This clinical report describes an approach to improving the retention and stability of an occlusal device for a patient with shortened dental arches by use of the patient's existing extracoronal attachments.

A technique for repairing a loosening abutment screw for a cement-retained implant prosthesis.

Prostheses may be attached to implants or implant abutments using screw retention or cementation. 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. Loosening of an abutment screw is a challenging complication of cement-retained, implant-supported prosthetic restorations. Often, the abutment screw becomes loose from the implant body, whereas the crown remains cemented to the abutment. In such situations, separating the cemented crown from the underlying abutment or locating the abutment-screw access for removal of the restoration is a difficult task. The purpose of this report is to describe a simple technique for locating the abutment-screw access in the event of its loosening. The advantage of this technique is that it can facilitate easy location of the abutment screw, thus minimizing damage to the existing restoration and allowing it to be reused.

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.

Defective dental restorations: to repair or not to repair? Part 2: All-ceramics and porcelain fused to metal systems.

UNLABELLED: With the increasing use of ceramics in restorative dentistry, and trends to extend restoration longevity through the use of minimal interventive techniques, dental practitioners should be familiar with the factors that may influence the decision either to repair or replace fractured metal-ceramic and all-ceramic restorations and, also, the materials and techniques available to repair these restorations. This second of two papers addresses the possible modes of failure of ceramic restorations and outlines indications and techniques in this developing aspect of restoration repair in clinical practice. CLINICAL RELEVANCE: The repair of metal-ceramic and all-ceramic restorations is a reliable low-cost, low-risk technique that may be of value for the management of loss or fracture of porcelain from a crown or bridge in clinical practice.

Durability of surface treatments and intermediate agents used for repair of a polished composite.

OBJECTIVE: To evaluate the effects of surface treatment and intermediate agent hydrophilicity on durability of the composite repair by means of the microtensile bond strength test (microTBS) and silver nitrate uptake (SNU) and the effects of surface treatment on composite roughness (Ra) and micromorphological features (SEM). METHODS: Thirty resin composite blocks (4x6x6 mm) (Opallis, FGM) were polished after seven days and divided into three groups: no treatment (NT); roughening with a fine-grit diamond bur (DB); 50 microm aluminum oxide sandblasting (AO). A hydrophobic (Adhesive bottle, Scotchbond MultiPurpose [SBMP]) or hydrophilic adhesive (Adper Single Bond 2 [SB]) was then applied. The same composite was used for repair. Composite-composite bonded sticks (0.6 mm2) were tested immediately ([IM) or after six months (6 M) of water storage in tension (1.0 mm/minute). Two bonded sticks from each resin composite block were immersed in a 50% (w/v) solution of silver nitrate, photo-developed and analyzed by SEM. The composite specimens after surface treatments were analyzed with a contact profilometer (Ra) and SEM. Three-way repeated measures and one-way ANOVA were used to analyze data from the microTBS and Ra, respectively (alpha = 0.05). RESULTS: AO showed the highest composite repair strength (MPa) and Ra (microm) (52.7 +/- 6.4; 4.1 +/- 0.5), while the no treatment group (36.1 +/- 6.1; 0.57 +/- 0.5) showed the low est. DB (44.1 +/- 5.6; 1.5 +/- 0.2) had an intermediate performance. The Ra results were confirmed by SEM images. SNU was observed only in SB specimens after 6M for all groups. CONCLUSIONS: Aluminum oxide treatment provides the highest composite repair strength, regardless of the hydrophilicity of the intermediate agent and storage period. Early signs of degradation were detected for SB after six months as silver nitrate deposits within the adhesive layer.