Restoration of the endodontically treated posterior tooth

ObjectivesTo analyse the key factors of the restoration in the posterior endodontically treated teeth, through a literature review and clinical cases presentation. To focus on the clinical advantages of the adhesive indirect restorations, describing the basic principles for long-term success.Materials and methodsThe biomechanical changes due to the root canal therapy and the degree of healthy dental tissue lost because of pathology and iatrogenic factors are the critical points leading the clinician to the restorative treatment planning. The full crown is considered by the literature as the gold standard and is indicated in case of teeth heavily weakened by dental caries, fractures or previous conservative-prosthetic preparations. The improvement of the adhesion and the composite materials, with mechanical properties close to those of dental tissues, offers to the clinician the option of a conservative restoration, able to seal, reinforce and protect the tooth and to delay the execution of a full crown, with the subsequent sacrifice of dental tissue. Although in the presence of small-sized cavity, direct bonded restoration is considered an effective short and medium-term restoration, cuspal coverage with indirect restoration is the treatment of choice in case of mesio-occlusal-distal cavities. Adhesive overlays preserve coronal structure, avoid contamination of the root canal system, reinforce residual dental tissues, guarantee optimal form, function, aesthetics and offer ergonomic and economic undoubted clinical advantages.Results and conclusionsDirect adhesive restorations, indirect bonded restorations and traditional full crown are three therapeutic options for the single posterior endodontically treated teeth. The amount of remaining sound tooth structure is the most significant factor influencing the therapeutic approach. The clinician's operative skill is a determining aspect for long-term success of adhesive inlays.     

Immediate fixed temporization with a natural tooth crown pontic following failure of replantation

Extracted teeth can be bonded directly to adjacent teeth utilizing a prefabricated composite resin framework reinforced with polyethylene fiber as a noninvasive long-term provisional tooth replacement. This immediate provisional restoration allow for exact repositioning of the coronal part of the extracted tooth in its original intraoral three-dimensional position and thus relieves the apprehension of the patient caused by the sudden loss of an anterior tooth.     

The restoration of a maxillary central incisor fracture with the original crown fragment using a glass fiber‐reinforced post: a clinical report

Abstract – This report describes an esthetic, conservative, and economical alternative restoration technique for a fractured central incisor using the patient’s own tooth crown piece and a bondable reinforcement glass fiber. Although the long‐term durability of this adhesive post core restoration remains unknown, it remains successful after 1 year.     

Use of glass fiber post and composite resin in restoration of a vertical fractured tooth

Abstract –  Combined coronal and vertical root fractures are difficult to treat and extraction of the affected tooth is quite often indicated. In anterior teeth, esthetics and function must be reestablished immediately. This case describes the restoration of a fractured upper right central incisor using a glass fiber post and adhesive composite. At the follow-up appointment, 13 months later, clinical and radiographical examinations revealed the glass fiber post and restoration in place, suggesting the efficacy of the treatment in maintaining fractured tooth.     

Prevention of postoperative tooth sensitivity: a preliminary clinical trial

The purpose of this study was to evaluate clinically the effects of pre-treatments with a 35% hydroxyethyl metacrylate/5% glutaraldehyde dentine desensitizer (Gluma Desensitizer) and a 2% chlorexidine-based cavity disinfectant (Cav-Clean) on postoperative sensitivity. Three premolar teeth with no pain symptoms were selected from each one of 17 patients, totalling 51 teeth, for which Class II restoration using a composite was indicated. Each one of the three premolar teeth of the same patient was submitted to a different treatment. After acid etching, only a dental adhesive was applied to the first tooth, which served as the control. Gluma Desensitizer dentinal desensitizer was applied to the second premolar tooth prior to applying the dental adhesive. Cav-Clean cavity disinfectant was used on the third premolar tooth before applying the dental adhesive. Only one tooth was restored per session, and all premolar teeth were restored with a condensable composite, according to current restoration technique guidelines. Sensitivity to different stimuli (cold, heat, sweet and dental floss) was assessed on Day 1, Day 4 and Day 7 by questionnaire following restorative procedures. The results of this clinical research showed that, as far as the investigated stimuli and postoperative course are concerned, there was no statistically significant difference in the three different treatments (P>0.05). Postoperative sensitivity resulting from Class II restorations using composite resin cannot be completely eliminated with the prior use of a dentinal desensitizer or a cavity disinfectant. In day-to-day clinical treatment, postoperative sensitivity may possibly be related to the technique employed.     

A confocal optical microscope study of the morphology of the tooth/restoration interface using Scotchbond 2 dentin adhesive

It is difficult to avoid specimen damage when one is preparing an adhesive/adherend interface for examination using conventional optical or scanning electron microscopy. Fluorescence imaging with a confocal optical microscope has facilitated evaluation of the distribution of Scotchbond 2 dentin adhesive, in an in vitro study with P50 composite resin used as the restorative material. The adaptation of the adhesive and restoration to the tooth was excellent. Gap formation between the restoration and the tooth was observed only when the adhesive system was used incorrectly. Contributions of the primer film former (Scotchprep) and hardening film former (Scotchbond 2) to the adhesive interface with the tooth and overlying composite restoration could be identified. The dentin smear layer was incorporated by the Scotchprep and subsequently impregnated by the Scotchbond 2. Control of the film thickness was difficult. Cracking and cohesive failure within the adhesive were observed when the film thickness exceeded 70 microns, with such thicknesses easily achieved in internal line angles. The extent of the slippery air-inhibited layer was considerable, but could be reduced if the adhesive was wiped with a cotton wool pledget. The distribution of the Scotchbond 2 within the tooth was localized to the smear layer and dentin up to 50 microns deep to it. This study has shown the penetration of Scotchbond 2 dentin adhesive within the tooth and its distribution within the restoration.     

Fracture strength of Class I versus Class II restored premolars tested at the marginal ridge. 2. Cavosurface bonding and cavosurface plus internal enamel bonding

The purpose of this study was to test the difference between the strength of the marginal ridge of extracted teeth with a Class I composite resin restoration and the strength of the marginal ridge of teeth with a Class II amalgam restoration with retention grooves. A statistically significant difference in fracture strengths was found among groups. No statistically significant difference was found among restored preparations, beveling technique, and restorative material. Statistically significant differences in fracture strength were found between the whole tooth group and treatment groups; between the whole tooth group and Class II amalgam restoration group; and between the unrestored tooth preparation group and all other tooth groups.     

In vitro evaluation of push-out bond strength of direct ceramic inlays to tooth surface with fiber-reinforced composite at the interface

STATEMENT OF PROBLEM: Failure of a restoration, where a part of a ceramic inlay and/or a cusp is fractured, is a common clinical problem. The application of fiber-reinforced composites at the tooth-inlay interface may prevent undesirable fractures in dental restorations. There is little information regarding the effect of a fiber- reinforced composite layer on the push-out bond strength of ceramic inlays to tooth structure. PURPOSE: The purpose of this study was to compare push-out bond strengths of ceramic inlays to tooth structure using a layer of fiber weave-reinforced composite at the tooth interface with different adhesive systems. MATERIAL AND METHODS: Forty standardized occlusal, conically-shaped cavities, 5 mm in occlusal diameter, 3.5 mm in cervical diameter and 3.5 mm deep, were prepared in extracted human molars using a truncated cone-shaped diamond rotary cutting instrument, the dimensions of which corresponded with those of prefabricated ceramic inlays. The teeth were divided into 2 groups according to the adhesive system used. Solobond Plus was used as a total-etching system and Futurabond NR as a self-etching system. Preetched and silanized ceramic inlays were bonded to tooth structure with or without a layer of bidirectional fiber weave (StickTech). The groups without fiber-reinforced composite layer served as controls. The inlays were cemented with dual-polymerizing luting composite (Bifix QM) and light polymerized for 40 seconds from the buccal, lingual, and occlusal surfaces. Specimens were thermal cycled (6000 x 5 degrees -55 degrees C) and 3.5-mm-thick discs were prepared for the push-out test. The discs (n=10) were tested in a universal testing machine and pushed out with a cross-head speed of 1.0 mm/min. The data were analyzed with analysis of variance (ANOVA) (alpha=.05). Failure modes were analyzed using a stereomicroscope and SEM. RESULTS: Push-out mean bond strength (SD) values in MPa of direct ceramic inlays were: Solobond Plus (control): 9.7 (3.9), Solobond Plus with fiber-reinforced composite: 10.5 (5.0), Futurabond NR (control): 8.4 (2.5), Futurabond NR with fiber-reinforced composite: 8.6 (2.2). The differences between groups were not significant for either adhesive system or with the use of fiber-reinforced composite layer at the interface. Mixed failures were observed in the control groups, whereas in the fiber-reinforced composite layer groups, failures were mostly cohesive within the fiber layer. No cohesive fracture of the tooth was observed when a layer of fiber weave was placed at the interface. CONCLUSION: Within the limitations of this in vitro study, a fiber-reinforced composite layer at the bonding interface of ceramic inlay did not influence the push-out bond strength. Futurabond NR self-etching system and Solobond Plus total-etching system demonstrated similar push-out bond strengths.     

Morphological characterization of the tooth/adhesive interface

The purpose of this study was to assess the morphological characteristics of the tooth/adhesive interface using different adhesive systems in MOD restorations under scanning electron microscopy (SEM). The tested hypothesis was that the morphology of the bonding interface would vary in different areas of MOD restorations for the three adhesive systems. MOD cavities were prepared in 12 sound extracted human third molars and restored with Filtek Z250 composite resin and one of the following adhesive systems: Experimental ABF (n=4), Clearfil SE Bond (n=4) self-etching primers and Single Bond etch-and-rinse adhesive system (n=4). After 24-h storage in distilled water at 37 degrees C, teeth were sectioned and prepared for SEM. The interfacial morphology varied depending on the adhesive system and also on the evaluated area. The null hypothesis was accepted because the morphology of the tooth/adhesive interface reflected the characteristics of both the dental substrate and the adhesive systems.     

Alternative treatment procedure in the case of fractured abutment of adhesive bridge: a clinical report

In this case report, an alternative approach was presented for treatment of coronal fracture including pulp of maxillary central incisor, one of the abutments of an adhesive bridge, by using fiber post and tooth's own fractured component. The patient was referred to our clinic with the complaint of pain from the upper right central incisor and mobility of the adhesive bridge in maxillary anterior segment. It was realized that, the upper right central incisor, one of the abutments of the adhesive bridge, had been fractured at middle thirds of the crown including the pulp chamber. After dismounting the adhesive bridge and completion of the root canal treatment, a fiber post was placed into the fractured tooth. The fractured component, adherent to adhesive bridge retainer, was concorded to the fiber post. The whole structure was cemented with adhesive resin. A 1-mm-wide groove was made along the fracture line and restored with composite resin. The patient was evaluated clinically and radiographically at 12 and 30 months after the treatment. CLINICAL SIGNIFICANCE: Adhesive cementation of fractured component by supporting the remaining tooth structure with a fiber post is an inexpensive and conservative treatment alternative when the fractured component is compatible with the remaining tooth structure in cases of tooth fractures including the pulp chamber at anterior segment.     

Endoscopic visualization of the submarginal gingiva dental sulcus and tooth root surfaces

BACKGROUND: Direct, real-time visualization of the hard and soft tissues within the gingival sulcus may aid the clinician in diagnosis and therapy of periodontal disease. This report describes an endoscope specifically designed for this purpose and the interpretation of dental endoscopic images. METHODS: Medical endoscope technology was modified for application in the dental environment. A fixed, fused fiber optic bundle, less than 1 millimeter in diameter, was coupled to an active matrix LCD-TFT flat panel video monitor for viewing by the clinician. A bilumen sheath was designed to provide irrigation of the sulcus and a sterile barrier between the patient and the fiber bundle. Standard dental curets and ultrasonic scalers were adapted for instrumentation aided by the endoscope. RESULTS: Endoscope technology has been successfully adapted for use in periodontal diagnosis and therapy. Techniques for identification and interpretation of the hard and soft tissue images, as well as the location of root deposits and caries, have been developed. CONCLUSIONS: The dental endoscope gives the clinician direct, real-time visualization and magnification of the subgingival tooth root surface, aiding in the location of deposits on the tooth root. The subgingival soft tissue, including the gingival attachment, sulcus wall, and sulcus contents, can be assessed. Identification and location of subgingival caries, root fractures, tooth root deposits, post perforations, and open restoration margins may aid the clinician in diagnosis and therapy.     

Treatment of oblique crown fractures in maxillary premolars using adhesive tooth fragment reattachment: 19 years of follow up

Abstract – This report presents an oblique crown fracture in the maxillary right premolars of an adolescent because of fall, which was treated using adhesive tooth fragment reattachment. The impact of the mandible base to the floor caused minor fractures in multiple teeth, severe fracture of teeth 14 and 15, and condylar fractures. The fragments of teeth 43, 45, 46, and 16 were lost at the site of accident. The condylar fractures were managed with a non‐surgical conservative approach combining mandibular immobilization and stabilization of temporomandibular joints with maxillomandibular fixation using acrylic splints. After 3 months, the interocclusal splints were removed, and the patient was referred for dental care. Teeth 14 and 15 presented complicated oblique crown fractures causing separation of the buccal and palatal fragments, which were in place, attached to the gingival tissue. Tooth 15 presented chronic hyperplastic pulpits. The fragments were banded for stabilization during the endodontic treatment, and the bands served as matrix for adhesive tooth fragment reattachment. The other fractured teeth received direct composite resin restorations. After 8 years, tooth 16 developed pulp necrosis and was treated endodontically and restored with composite resin. Clinical and radiographic examination 19 years after trauma showed a good adaptation of the tooth fragment/composite resin restoration, good periodontal health, no signs of root resorption, and intact lamina dura.     

EFFECT OF ADDITIONAL ENAMEL ETCHING AND A FLOWABLE COMPOSITE TO THE INTERFACIAL INTEGRITY OF CLASS II ADHESIVE COMPOSITE RESTORATIONS

Objective : The purpose of this study was to evaluate microleakage of Class II composite restorations using a self‐etching adhesive system with additional enamel etching and/or a flowable resin composite material. Materials and Methods : Fifty standardized Class II cavities were prepared in the mesial and distal surfaces of extracted human third molars. All teeth were bonded with a self‐etching primer adhesive system (Clearfil® Liner Bond 2, Kuraray Co. Ltd., Osaka, Japan) according to the manufacturer's instructions and were restored with a resin composite (Clearfil® AP‐X, Kuraray Co. Ltd.). In the control group, only a self‐etching adhesive system was used. In the various experimental groups, the preparation surfaces were coated with a layer of flowable resin composite (Protect® Liner F, Kuraray Co. Ltd.) before the placement of resin composite, etched with 37% phosphoric acid (K‐Etchant®, Kkraray Co. Ltd.) before the application of the adhesive system, or treated with both of these options. In four groups of specimens, the preparation had a gingival margin in enamel. In a fifth group, the gingival margin was in dentin. All teeth were subjected to thermocycling, 300 cycles between 4°C and 60°C, and were sectioned in half through the restorations. Gaps or cracks at the resin‐tooth interfaces were observed directly using a laser scanning microscope and were recorded as percentages of the entire interface length. Results : Separate enamel etching with phosphoric acid did not improve the resin‐enamel seal produced by the self‐etching primer alone. Flowable resin composite produced gap‐free resin‐dentin interfaces but could not prevent cracks and gap formation at the resin‐enamel interface. Conclusions : Neither flowable resin composite nor enamel etching could prevent gap formation at enamel‐resin interfaces and crack formation in enamel walls when used with a self‐etching primer adhesive system. However, the flowable composite provided gap‐free resin‐dentin interfaces.     

Fracture resistance of composite resin restorations and porcelain veneers in relation to residual tooth structure in fractured incisors

Abstract – The aim of the present study was to investigate whether there is a direct correlation between the amount of residual tooth structure in a fractured maxillary incisor and the fracture resistance of composite resin restorations or porcelain veneers after cyclic loading. Sixty human‐extracted maxillary central and lateral incisors were mounted in an acrylic block with the coronal aspect of the tooth protruding from the block surface. The teeth were assigned to two groups: 2‐mm incisal fracture and 4‐mm incisal fracture. Then, the teeth were further divided into two different restoration subgroups, porcelain laminate veneer and composite resin restoration, therefore obtaining four groups for the study (n = 15). The specimens were subjected to 1000 cycles of thermocycling and were mechanically tested with a custom‐designed cyclic loading apparatus for 2 × 106 cycles or until they failed. The specimens that survived the cyclic loading were loaded on the incisal edge along the long axis of the tooth with a flat stainless steel applicator until they fractured using a universal testing machine to measure the failure load. Two‐way anova was used to assess the significance of restoration, amount of fracture, and interaction effect (α = 0.05). During the cyclic loading, for the composite resin group, two specimens with 2‐mm fracture and three specimens with 4‐mm fracture failed. For the porcelain veneer group, two specimens with 2‐mm fracture and one specimen with 4‐mm fracture failed. The 2‐way anova did not show statistical significance for restoration (P = 0.584), amount of fracture (P = 0.357), or interaction effect (P = 0.212). A composite resin restoration and a porcelain veneer could perform similarly for replacing a fractured incisor edge up to 4 mm. Other factors such as esthetic and/or cost would be considerations to indicate one treatment over the other.     

Failure of resin ionomers in the retention of multi-rooted teeth with Class III furcation involvement: a rebuttal case report

BACKGROUND: Severe periodontal furcation invasion has long been a treatment dilemma for the clinician. Many techniques have been advocated in the treatment of multi-rooted posterior teeth ranging from conventional scaling and root planing (SRP), apically positioned flaps, root amputations, root resections, tunnel procedures, guided tissue regeneration, and restorations. The keys to success depend on the clinician's ability to access the furcation to remove local factors and create an environment that enhances the patient's own hygiene efforts. Long-term success in treating teeth with furcation invasion depends upon tooth retention and arresting the destructive processes within the furcation area. METHODS: A Class III furcation invasion in a mandibular molar was treated by surgical access for SRP along with obliterating the furcation utilizing a resin ionomer restoration. RESULTS: Initially, the patient was asymptomatic. Within 3 months of treatment, the patient presented with suppuration that was refractory to local efforts. Radiographs taken only 5 months postsurgery demonstrated advanced bone loss apical to the restoration. The tooth ultimately was extracted because mobility increased and the tooth became symptomatic. CONCLUSIONS: The clinician must consider the multi-factorial etiology of periodontal breakdown within a furcation. For this patient, the technique of sealing off the exposed furcation with restorative material appeared to have resulted in progressive bone loss and accelerate tooth loss. This single case report is presented as a rebuttal to recently published articles, which have demonstrated excellent results when treating furcations with ionomer restorations.     

Short fiber‐reinforced composite restorations: A review of the current literature

A newly‐recommended method for restoring large cavities is the biomimetic approach of using short fiber‐reinforced composite (SFRC) as dentine‐replacing material. The aim of the current review was to present an overview of SFRC and to give the clinician a detailed understanding of this new material and treatment strategy based on available‐literature review. A thorough literature search was done up to December 2017. The range of relevant publications was surveyed using PubMed and Google Scholar. From the search results, articles related to our search terms were only considered. The search terms used were “short fiber‐reinforced composite”, “everX posterior”, and “fiber‐reinforced composite restorations”. Of the assessed articles selected (N = 70), most were laboratory‐based research with various test specimen designs prepared according to the ISO standard or with extracted teeth; only four articles were clinical reports. A common finding was that by combining the SFRC as a bulk base with conventional composite, the load‐bearing capacity and failure mode of the material combination were improved, as compared to plain conventional composite restoration. In the reviewed studies, the biomimetic restoration technique of using SFRC showed promising characteristics, and therefore, might be recommended as an alternative treatment option for large cavities.     

In vitro tooth reattachment techniques: A systematic review

Background/Aims

Fragment reattachment is a procedure that offers advantages, such as preservation of tooth structure and maintenance of color, shape, and translucency of the original tooth. The aim of this study was to analyze the reattachment techniques used to restore anterior teeth fractured by trauma.

Materials and Methods

The PubMed, LILACS, Web of Science, Cochrane, and Scopus databases were searched in October 2016, and the search was updated in February 2017. A search of the gray literature was performed in Google Scholar and OpenGrey. Reference lists of eligible studies were evaluated to identify additional studies. Two authors assessed studies for inclusion and extracted the data. In vitro studies that evaluated permanent human teeth fractured by trauma were included.

Results

Twenty‐one studies remained after screening. The bond strength between the fragment and the crown was evaluated in 119 experimental groups. Ten different techniques were evaluated as follows: no preparation, chamfer, bevel, anchors, overcontour, internal groove, no preparation associated with chamfer after reattachment, fragment dentin removal associated with chamfer after reattachment, bevel associated with overcontour, and groove associated with shoulder. Five different materials were used to reattach the fragment: bonding system, luting composite resin, flowable composite, microhybrid composite, and nanocomposite.

Conclusion

Fragment reattachment using a technique with no preparation and an adhesive system associated with an intermediate composite with good mechanical properties can restore part of the resistance of the fractured tooth.     

Evaluation of plasma treatment effects on improving adhesive–dentin bonding by using the same tooth controls and varying cross‐sectional surface areas

The objective of this study was to evaluate and verify the effectiveness of plasma treatment for improving adhesive–dentin interfacial bonding by performing microtensile bond‐strength (μTBS) testing using the same‐tooth controls and varying cross‐sectional surface areas. Extracted unerupted human third molars were used after removal of the crowns to expose the dentin surface. One half of each dentin surface was treated with a non‐thermal argon plasma brush, whilst the other was shielded with glass slide and used as an untreated control. Adper Single Bond Plus adhesive and Filtek Z250 dental composite were then applied as directed. The teeth thus prepared were further cut into micro‐bar specimens, with cross‐sectional sizes of 1 × 1 mm², 1 × 2 mm², and 1 × 3 mm², for μTBS testing. The test results showed that plasma‐treated specimens gave substantially stronger adhesive–dentin bonding than their corresponding same‐tooth controls. Compared with their untreated controls, plasma treatment gave statistically significant higher bonding strength for specimens with a cross‐sectional area of 1 × 1 mm² and 1 × 2 mm², with mean increases of 30.8% and 45.1%, respectively. Interface examination using optical and electron microscopy verified that plasma treatment improved the quality of the adhesive–dentin interface by reducing defects/voids and increasing the resin tag length in dentin tubules.     

Effectiveness of adhesive containing MDPB: A practice-based clinical trial

ObjectivesThis prospective practice-based trial assessed the longevity of composite restorations made with an adhesive containing an antibacterial monomer compared to a conventional adhesive.Methods9 general practices in the Netherlands were provided with two composite resin adhesives, each for a period of 9 months. Adhesive P contained the quaternary ammonium salt MDPB, and Adhesive S was a control. Patient’s age and caries risk, as well as tooth type/number, reason for restoration placement, used restorative material and adhesive, and restored surfaces were recorded. All interventions carried out on these teeth in the 6 years after restoration were extracted from the electronic patient records, along with their date, type, reason, and surfaces. Two dependent variables were defined: general failure, and failure due to secondary caries. All data handling and multiple Cox regression analysis were carried out in R 4.0.5.Results11 dentists from 7 practices made 10,151 restorations over a period of two years in 5102 patients. 4591 restorations were made with adhesive P, whereas 5560 were made with adhesive S. The observation period was up to 6.29 years, median observation time was 3.74 years. Cox regression showed no significant difference between the two adhesive materials when corrected for age, tooth type and caries risk, for general failure nor failure due to caries.SignificanceNo difference in restoration survival could be shown between composite restorations made using an adhesive containing MDPB and control. Restorations made with the adhesive containing MDPB also did not fail more or less frequently due to secondary caries.This trial is registered on clinicaltrials.gov with identifier NCT05118100     

Replacement of a tooth with a fiber-reinforced direct bonded restoration

Today's methods and materials for tooth replacement are multiple and varied. Modern materials now allow for highly conservative abutment preparations that can retain bonded single tooth replacement fixed prostheses. A case report is presented in which fiber reinforced with composite resin was used for placement of a three-unit fixed long-term provisional restoration, providing fracture resistance while achieving an esthetically pleasing, durable restoration.