Ex-vivo and in-vivo validation of a novel measuring protocol for guided endodontics.

OBJECTIVES: To (1) validate the use of a post-operative intraoral scan (IOS) versus Cone Beam Computed Tomography (CBCT), gold standard, on its ability to measure the accuracy of guided endodontics, and (2) present clinical data on the accuracy of guided endodontics. METHODS: Four models, including 10 extracted teeth each, were created. Forty guided access cavities were planned on dentin to simulate pulp canal obliteration (PCO). Two operators performed guided access cavities. A post-operative CBCT and IOS were acquired. The coronal, apical, and angular deviations were measured with CBCT and IOS. Clinical accuracy was measured using an IOS acquired immediately after drilling the access cavity with the aid of a guide. Data analysis was performed using multiway Anova and corrected for simultaneous hypothesis testing according to Tukey. P ≤ 0.05 was considered statistically significant. Descriptive statistics on the clinical accuracy of guided endodontics were performed. RESULTS: Thirty-eight cavities were assessed with a mean length of 13.8 mm. No statistical difference between operators and methods was found for all parameters (P > 0.05). Thirty-three patients were treated with guided endodontics and measured using an IOS. Results show an average coronal, apical, and angular deviation of 0.2 mm, 0.45 mm, and 1.91° respectively. The average length of the access cavities was 12.5 mm. CONCLUSIONS: An IOS can be used to measure the accuracy of guided endodontics. Clinical data showed high accuracy of guided endodontics with a mean apical deviation smaller than 0.5 mm and a mean angular deviation of less than 2°. CLINICAL SIGNIFICANCE: The use of an IOS does not involve additional radiation exposure. A safety margin of at least 1 mm around the planned trajectory should be respected when planning the case to minimize the possibility of root perforation.

In vitro study on the accuracy of sleeveless guided endodontics and treatment of a complex upper lateral incisor.

PURPOSE: The present study aims to assess the accuracy of sleeveless guided endodontics for root canal treatment of severe pulp canal obliteration (PCO) in 3D printed jaws. Additionally, the treatment of a complex lateral incisor is presented to illustrate the use of sleeveless guides in a clinical situation. METHODS: Two cone-beam computed tomography (CBCT) volumes of an upper and lower jaw were selected to design 3D printed models with PCO. Virtual planning of the access cavities was performed from right to left second premolar. Then, the models were mounted into a phantom head to simulate an actual patient. Two operators with different levels of experience in endodontics performed guided access cavities. The handpiece was guided by guiding rails placed against each other on the sides of the tooth. A post-operative CBCT scan was taken for analysis. RESULTS: Eighty-eight guided access cavities (44 per operator) were drilled on eight 3D printed models. The mean length of the access cavities was 15.3 mm, with a mean coronal and apical deviation of 0.5 mm and 0.7 mm respectively. The mean angular deviation was 1.5°. No statistically significant difference was found between operators for the three measured parameters. CONCLUSIONS: This study demonstrates, within its limitations, that sleveless guides represent an accurate method for guided endodontic treatment. No statistically significant difference between operators was found when using the guide. CLINICAL SIGNIFICANCE: This method offers a valuable alternative to conventional endodontic guides with similar accuracy results.

Clinical applications, accuracy and limitations of guided endodontics: a systematic review.

BACKGROUND: The novel concept of guided endodontics has been reported as an effective method to obtain safe and reliable results in root canal treatment. AIM: To evaluate by means of a systematic review the clinical applications, accuracy and limitations of guided endodontic treatment. DATA SOURCES: A search of the literature was performed on PubMed, Embase, Web of Science and Cochrane Library databases, until 25 April 2019. No language or year restrictions were applied. STUDY ELIGIBILITY CRITERIA: Articles that answered the research question, including case reports, in vitro and ex vivo studies were included. Data extraction was performed independently by two reviewers. STUDY APPRAISAL: Quality assessment was done using STROBE, CARE and Modified CONSORT guidelines for observational, case reports and pre-clinical studies, respectively. RESULTS: A total of 22 articles, including fifteen case reports, six pre-clinical studies (in vitro and ex vivo studies) and one observational study, were included. LIMITATIONS AND CONCLUSIONS: Even though the level of evidence is low, and the methodology described among studies heterogeneous, all articles describe guided access cavity preparation and guided surgery as being highly accurate and successful techniques when comparing the drilled path to the planned treatment. More studies with a larger number of patients are necessary to obtain significant conclusions.

Microguided Endodontics: a case report of a maxillary lateral incisor with pulp canal obliteration and apical periodontitis.

AIM: To describe a minimally invasive method to create a 3D-printed guide to gain access to obliterated root canals on the basis of CBCT data. SUMMARY: A 85-year-old female ASA III was referred for root canal treatment of tooth 22. Clinically, there were no complaints, no percussion pain or sinus tract. Radiologically, the tooth had an obliterated canal with an apical radiolucency. The tooth was diagnosed with asymptomatic apical periodontitis. Microguided Endodontic treatment was performed with the help of a 3D-printed guide. The root canal was localized initially with the aid of the 3D-printed guide using a round carbide bur with a head diameter of 0.8 mm. Then, the canal was shaped and cleaned using mechanical rotary files under copious irrigation with 5% NaOCl, 17% EDTA and passive ultrasonic activation. A completely healed apical area of tooth 22 was visible after 6 months on periapical radiographs and small field of view CBCT. KEY LEARNING POINTS: Using the Microguided Endodontics concept, a minimally invasive access was achieved up to the middle of the root, in a maxillary lateral incisor with pulp canal obliteration (PCO) and apical periodontitis. This technique is a valuable tool for the negotiation of PCO, reducing chair time and risk of iatrogenic damage to the root.

European Society of Endodontology position statement: External Cervical Resorption.

This Position Statement represents the consensus of an expert committee convened by the European Society of Endodontology (ESE) on External Cervical Resorption (ECR). The statement is based on current clinical and scientific evidence as well as the expertise of the committee. The primary aim is to provide a current authoritative position on the aetiology, histopathology, clinical presentation and management of ECR, and also to highlight areas where there is minimal evidence. Previously published review articles provide more detailed background information and the basis for this position statement (International Endodontic Journal 51, 1205, 2018, International Endodontic Journal 51, 1224, 2018). It is intended that this position statement will be updated at appropriate intervals, as further evidence emerges.

External cervical resorption-part 1: histopathology, distribution and presentation.

External cervical resorption (ECR) is the loss of dental hard tissue as a result of odontoclastic action. It is a dynamic process that involves periodontal, dental and in later stages pulpal tissues. Over the last two decades, ECR has attracted increased interest; this is in part due to novel micro-CT and histopathological techniques for its assessment and also improved radiographic detection using CBCT. This literature review will cover the aetiology, potential predisposing factors, histopathology and diagnosis of ECR. Part 2 will cover the management of ECR.

Multimodular assessment of a calcified extraradicular deposit on the root surfaces of a mandibular molar.

AIM: To achieve a better understanding of a calcified extraradicular deposit on the apical root surfaces of a mandibular first molar associated with a radicular cyst and a sinus tract. A multimodular approach was applied using a combination of multiple investigation methods. SUMMARY: This case report presents a mandibular first molar with a calcified extraradicular deposit on the apical root surfaces of both roots. An apical periodontitis lesion was present and a sinus tract served as the only communication with the oral cavity. Diagnosis and treatment planning were based on clinical, radiographic (two- and three-dimensional) and ultrasound examination. The tooth was further analysed after extraction using microscopic imaging, nano-computed tomography (nano-CT), hard- and soft tissue histology and electron probe microanalysis. This multimodular approach revealed the calculus-like appearance and mineral composition of the extraradicular deposit. Multiple hypotheses about its aetiology are discussed. KEY LEARNING POINTS: Calcified extraradicular deposits can develop on the apical root surfaces of teeth with apical periodontitis in association with a radicular cyst and sinus tract. A sinus tract can serve as the only communication between the apical lesion and the oral cavity whilst no periodontal defects are present. The interplay of intra-oral radiography, high resolution CBCT, nano-CT, hard tissue histology and EPMA can reveal the calculus-like appearance and composition of the extraradicular deposit. Calcified extraradicular deposits appear hyperechoic on ultrasound imaging and can lead to the occurrence of twinkling artefacts due to their rough mineralized surface.

Understanding external cervical resorption patterns in endodontically treated teeth.

AIM: To understand the patterns of external cervical resorption (ECR) in endodontically treated teeth. To compare characteristics and mechanisms of ECR in root filled teeth with those established in teeth with vital pulps. METHODOLOGY: Seven cases of endodontically treated permanent teeth displaying ECR were investigated. ECR diagnosis was based on clinical findings and radiographic examination with cone-beam computed tomography. The extracted teeth were further analysed by a nano-focus computed tomographic (nano-CT) system, hard-tissue histology and scanning electron microscopy (SEM). To make a comparison with teeth with vital pulps, representative cases with ECR were also included. RESULTS: All endodontically treated teeth had a similar ECR pattern. This pattern reflected many similarities to that seen in teeth with vital pulps; that is, three stages were observed namely initiation, resorption and repair. In particular, during the initiation stage (1st stage), the resorption started below the gingival epithelial attachment, at the level of cementum. In the resorption stage (2nd stage), ECR spreads towards the treated pulp space and in a coronal-apical direction, creating multiple resorption channels. The pulp and the pericanalar resorption resistant sheet (PRRS) had been removed during root canal treatment and thus offered no retarding or defence mechanism towards ECR. In the reparative stage (3rd stage), reparative hard-tissue formation occurred at a localized scale. CONCLUSIONS: Similar ECR patterns were observed in all examined teeth. These patterns consisted of an initiation, a resorption and a reparative stage. Some differences were noticed between endodontically treated and teeth with vital pulps, mainly in the resorption and reparative stages. The resorption stage in root filled teeth was more intense than the repair stage, as many clastic cells and abundant granulation tissue were observed in all samples. This is possibly due to the absence of the pulp and protective PRRS layer and/or to the altered chemical composition of the root dentine after root canal treatment. Furthermore, at the repair stage, formation of reparative bonelike tissue took place to a lesser extent in root filled teeth.

Prevalence of apical periodontitis and root filled teeth in a Belgian subpopulation found on CBCT images.

AIM: To investigate the prevalence of apical periodontitis (AP) and root filled teeth found on cone-beam computed tomography (CBCT) scans in a Belgian subpopulation in a retrospective cross-sectional study. METHODOLOGY: At the university hospital of Leuven, 804 patients received a CBCT scan between 01/01/2013 and 01/01/2014. The investigated sample included 631 scans with a permanent dentition and a total of 11 117 teeth. Prevalences and their confidence intervals are reported and the association between treatment, position of a tooth, gender and age with AP was determined using logistic regressions. RESULTS: A total of 656 teeth (5.9%) had signs of AP and 1357 teeth (12.2%) had been root filled. AP was present in 212 of the 9760 nonroot filled teeth (2.2%) and in 444 of the 1357 root filled teeth (32.7%). Adequate root fillings were detected in approximately half (49.3%) of the root filled teeth. The prevalence of AP was 22.8% when the root filling was adequate, when scored inadequate the prevalence increased to 41%. Univariate and multivariable logistic regression analyses revealed a significant relation of tooth position and treatment with AP. No difference in the prevalence of AP between male and female patients was detected. CONCLUSION: The prevalence of AP was comparable with findings in other epidemiological studies. Root filled teeth had significantly more AP than nonroot filled teeth. The technical quality of the root fillings had a significant impact on the presence of AP. Therefore, emphasis on the quality of work and continuing education in the field of Endodontology must be provided in Belgium.

European Society of Endodontology position statement: Revitalization procedures.

This position statement represents a consensus of an expert committee convened by the European Society of Endodontology (ESE) on revitalization procedures. The statement is based on current clinical and scientific evidence as well as the expertise of the committee. The goal is to provide suitably trained dentists with a protocol including procedural details for the treatment of immature teeth with pulp necrosis as well as a patient consent form. Revitalization is a biologically based treatment as an alternative to apexification in properly selected cases. Previously published review articles provide more detailed background information and the basis for this position statement (Journal of Endodontics, 39, 2013, S30; Journal of Endodontics, 39, 2013, 319; Journal of Endodontics, 40, 2014, 1045; Dental Traumatology, 31, 2015, 267; International Endodontic Journal, 2015, doi: 10.1111/iej.12606). As controlled clinical trials are lacking and new evidence is still emerging, this position statement will be updated at appropriate intervals. This might lead to changes to the protocol provided here.

A novel multimodular methodology to investigate external cervical tooth resorption.

AIM: To introduce a multimodular combination of techniques as a novel minimal invasive approach to investigate efficiently and accurately external cervical resorption (ECR). METHODOLOGY: One case of a central incisor with extensive external cervical resorption was selected to demonstrate the potential of a comparative novel study methodology. ECR diagnosis was based on clinical inspection, digital radiography and cone-beam computed tomography (CBCT). After extraction, the tooth was investigated using microfocus computed tomography (micro-CT), nano-CT and hard tissue histology. These techniques were compared for their accuracy and applicability to highlight their advantages and disadvantages. RESULTS: Nano-CT was more effective than micro-CT and CBCT for detailed ex vivo exploration of ECR. The reparative tissue, pericanalar resorption resistant sheet (PRRS), pulp tissue reactions, resorption channels and their interconnection with the periodontal ligament space were accurately visualized by detailed processing and analysis of the nano-CT data set with Dataviewer and CTAn software. Nano-CT analysis provided better insight in the true extent of the resorption, based on quantitative measurements and 3D visualization of the tooth structure. Nano-CT imaging results were similar to hard tissue histology at the mineralized tissue level. To clarify the dynamic phenomenon of reparative tissue formation and substitution of the resorbed tissues, nano-CT needed to be associated with hard tissue histology. CONCLUSION: Nano-CT is a fast and minimal invasive technique for the ex vivo analysis and understanding of ECR and is complementary with hard tissue histology. A combined approach of clinical and CBCT examination, with nano-CT and histological mapping measurements, can provide an ideal platform for future ECR imaging and exploration studies.

European Society of Endodontology position statement: the use of CBCT in endodontics.

This Position Statement represents a consensus of an expert committee convened by the European Society of Endodontology (ESE) on the use of Cone Beam Computed Tomography (CBCT). The statement is based on the current scientific evidence, and provides the clinician with evidence-based criteria on when to use CBCT in Endodontics. Given the dynamic and changing nature of research, development of new devices and clinical practice relating to CBCT, this Position Statement will be updated within 3 years, or before that time should new evidence become available.

External cervical resorption: an analysis using cone beam and microfocus computed tomography and scanning electron microscopy.

AIM: To provide a three-dimensional representation of external cervical resorption (ECR) with microscopy, stereo microscopy, cone beam computed tomography (CT), microfocus CT and scanning electron microscopy (SEM). SUMMARY: External cervical resorption is an aggressive form of root resorption, leading to a loss of dental hard tissues. This is due to clastic action, activated by a damage of the covering cementum and stimulated probably by infection. Clinically, it is a challenging situation as it is characterized by a late symptomatology. This is due to the pericanalar protection from a resorption-resistant sheet, composed of pre-dentine and surrounding dentine. The clastic activity is often associated with an attempt to repair, seen by the formation of osteoid tissue. KEY LEARNING POINTS: Cone beam CT is extremely useful in the diagnoses and treatment planning of ECR. SEM analyses provide a better insight into the activity of osteoclasts. The root canal is surrounded by a layer of dentine that is resistant to resorption.

Playing wind instruments as a potential aetiologic cofactor in external cervical resorption: two case reports.

AIM: To present two cases of external cervical resorption (ECR) on maxillary incisors, in which the primary aetiologic factor is suggested to be pressure trauma by frequently playing wind instruments. SUMMARY: The exact aetiological spectrum of ECR is still poorly understood. For resorption to occur, a defect in the cementum layer (trigger) is a likely prerequisite. Whilst the mechanism for continuation (stimulus) is still unclear, knowledge of potential predisposing factors is important in assessing patients at risk. Pressure generated by playing wind instruments could present an aetiological factor in ECR because it affects the cervical region of the root surface. The cases that are presented may confirm this hypothesis and the extent of resorption defects is shown by cone-beam computer tomography (CT) and micro-focus CT imaging techniques.

Eight-year clinical evaluation of a 2-step self-etch adhesive with and without selective enamel etching.

OBJECTIVES: The objective of this randomized controlled clinical trial was to evaluate the 8-year clinical performance of a mild 2-step self-etch adhesive in non-carious Class-V lesions with and without prior selective phosphoric acid-etching of the enamel cavity margins. METHODS: A total of 100 non-carious Class-V lesions in 29 patients were restored with Clearfil AP-X (Kuraray). The composite restorations were bonded following two different approaches: (1) application of Clearfil SE (Kuraray) following a self-etch approach (control group; C-SE non-etch), (2) selective phosphoric acid-etching of the enamel cavity margins before application of Clearfil SE (experimental group; C-SE etch). The restorations were evaluated after 6 months, 1, 2, 3, 5 and 8 years of clinical service regarding their retention, marginal integrity and discoloration, caries occurrence, preservation of tooth vitality and post-operative sensitivity. RESULTS: The recall rate at 8 years was 76%. Only two restorations, one of the C-SE non-etch group and one of the C-SE etch group, were clinically unacceptable due to loss of retention leading to a retention rate and a clinical success rate of 97% in both groups. Aging of the restorations was characterized by an increase in the percentage of restorations with a small but clinically acceptable marginal defect (C-SE non-etch: 92%; C-SE etch: 84%) and/or a superficial marginal discoloration (C-SE non-etch: 44%; C-SE etch: 28%). At the enamel side, the presence of small marginal defects (C-SE non-etch: 86%; C-SE etch: 65%) and superficial marginal discoloration (C-SE non-etch: 11%; C-SE etch%) was more frequently noticed in the control group than in the experimental group. The difference, however, was only statistically significant for the presence of superficial marginal discoloration (McNemar, p=0.01). SIGNIFICANCE: After 8 years of clinical functioning, the clinical effectiveness of Clearfil SE remained excellent, with selective acid-etching of the enamel cavity margins only having some minor positive effect on marginal integrity and absence of marginal discoloration at enamel.

Void detection in root fillings using intraoral analogue, intraoral digital and cone beam CT images.

AIM: To compare void detection in root fillings using different radiographic imaging techniques: intraoral analogue, intraoral digital and cone beam CT (CBCT) images and to assess factors influencing small void detection. METHODOLOGY: Two straight root canals in canine teeth were prepared. Calibrated steel wires of five different diameters (200, 300, 350, 500, 800 microm) were inserted respectively in the canal after the injection of a sealer. To simulate filling voids of known dimensions, the wires were removed after the sealer had set. Each sample was imaged, using a Minray X-ray tube (Soredex, Helsinki, Finland) at optimal clinical settings combined with Vistascan PSP (Dürr Dental, Bietigheim-Bissingen, Germany), Digora Optime PSP (Soredex), Sigma CCD (Instrumentarium, Tuusula, Finland) and E-speed films (Agfa-Gevaert, Mortsel, Belgium). The teeth were also imaged using CBCT (3D Accuitomo, Morita, Japan). A generalized mixed model and ANOVA analysis were used on the acquired data (Tukey-Kramer correction). RESULTS: There was no evidence that the factor 'root level' affected void detection in root fillings. 'Void size' was a main determining factor as all voids larger than 300 microm were determined with all techniques. For the smaller voids, there were significant differences between the 5 imaging techniques at different void sizes and different root levels. CONCLUSIONS: Void size and imaging technique were main determining factors. Voids larger than 300 mum were determined with all imaging techniques. For small void detection, all digital intraoral techniques performed better than intraoral analogue and CBCT images.

Bonding effectiveness and interfacial characterization of a nano-filled resin-modified glass-ionomer.

UNLABELLED: Glass-ionomers (GIs) exhibit excellent clinical bonding effectiveness, but still have shortcomings such as polishability and general aesthetics. The aims of this study were (1) to determine the micro-tensile bond strength (microTBS) to enamel and dentin of a nano-filled resin-modified GI (nano-RMGI; Ketac N100, 3M-ESPE), and (2) to characterize its interfacial interaction with enamel and dentin using transmission electron microscopy (TEM). METHODS: The nano-RMGI was used both with and without its primer, while a conventional RMGI restorative material (conv-RMGI; Fuji II LC, GC) and a packable conventional GI cement (conv-GI; Fuji IX GP, GC) were used as controls. After bonding to freshly extracted human third molars, microspecimens of the interfaces were machined into a cylindrical hourglass shape and tested to failure in tension. Non-demineralized TEM sections were prepared and examined from additional teeth. RESULTS: The microTBS to both enamel and dentin of nano-RMGI and conv-GI were not statistically different; the microTBS of non-primed nano-RMGI was significantly lower, while that of conv-RMGI was significantly higher than that of all other groups. TEM of nano-RMGI disclosed a tight interface at enamel and dentin without surface demineralization and hybrid-layer formation. A thin filler-free zone (<1 microm) was formed at dentin. A high filler loading and effective filler distribution were also evident, with localized areas exhibiting nano-filler clustering. CONCLUSIONS: The nano-RMGI bonded as effectively to enamel and dentin as conv-GI, but bonded less effectively than conv-RMGI. Its bonding mechanism should be attributed to micro-mechanical interlocking provided by the surface roughness, most likely combined with chemical interaction through its acrylic/itaconic acid copolymers.

Root resorption of the maxillary lateral incisor caused by impacted canine: a literature review.

Root resorption of maxillary lateral incisors caused by erupting canines is well known and a relatively common phenomenon. However, much debate and conflicting evidence exists with regard to the actual resorption trigger and potential etiological factors involved. Consequently, there are no obvious clinical clues concerning prevention and diagnosis as well as subsequent treatment decisions. The introduction of cone beam computer tomography has recently allowed drawing a new and much more documented light on the diagnostic and therapeutic strategies. However, no investigations have determined that this new information may result in another and better diagnostic approach and an improved treatment outcome. Therefore, the present review will attempt to summarize the existing evidence on two- and three-dimensional images and try to link the radiological observations to any further preventive, diagnostic, and/or therapeutic measures. Detection thresholds, accuracy, and reliability of impacted canine localization and neighboring root resorption risks will also be considered. This review demonstrates how adding a third-dimension to the radiographic information may notably alter the prevalence of root resorptions and descriptions of this prevalence. In any case, further investigation is needed to determine resorption detection thresholds in various two-dimensional and three-dimensional imaging techniques, as well as to determine therapeutic thresholds and criteria for strategic tooth extraction based on radiographic manifest and not manageable resorption lesions.

Influence of the chemical structure of functional monomers on their adhesive performance.

Functional monomers in adhesive systems can improve bonding by enhancing wetting and demineralization, and by chemical bonding to calcium. This study tested the hypothesis that small changes in the chemical structure of functional monomers may improve their bonding effectiveness. Three experimental phosphonate monomers (HAEPA, EAEPA, and MAEPA), with slightly different chemical structures, and 10-MDP (control) were evaluated. Adhesive performance was determined in terms of microtensile bond strength of 4 cements that differed only for the functional monomer. Based on the Adhesion-Decalcification concept, the chemical bonding potential was assessed by atomic absorption spectrophotometry of the dissolution rate of the calcium salt of the functional monomers. High bond strength of the adhesive cement corresponded to low dissolution rate of the calcium salt of the respective functional monomer. The latter is according to the Adhesion-Decalcification concept, suggestive of a high chemical bonding capacity. We conclude that the adhesive performance of an adhesive material depends on the chemical structure of the functional monomer.

A randomized controlled clinical trial of a HEMA-free all-in-one adhesive in non-carious cervical lesions at 1 year.

OBJECTIVES: One-step self-etch adhesives are the most recent generation of adhesives introduced onto the market. The objective of this randomized controlled clinical trial was to test the hypothesis that a one-step self-etch adhesive performs equally well as a conventional three-step etch&rinse adhesive (gold standard). METHODS: Fifty-two patients had 267 non-carious cervical lesions restored with Gradia Direct Anterior (GC). These composite restorations were bonded either with the 'all-in-one' adhesive G-Bond (GC) or with the three-step etch&rinse adhesive Optibond FL (Kerr). The restorations were evaluated after 6 and 12 months clinical service regarding their retention, marginal integrity and discoloration, caries occurrence, preservation of tooth vitality and post-operative sensitivity. Retention loss, severe marginal defects and/or discoloration that needed intervention (repair or replacement) and the occurrence of caries were considered as clinical failures. A logistic regression analysis with generalized estimating equations was used to account for the clustered data (multiple restorations per patient). RESULTS: The recall rate at 1 year was 98%. The statistical analysis revealed a relatively low patient factor, indicating that supplementary information could be obtained from the additional restorations placed per patient. The retention rate for G-Bond was 98.5% compared to 99.3% for Optibond FL, due to the retention loss of two and one restorations, respectively. There were no significant differences between the two adhesives regarding the evaluated parameters except for the presence of small enamel marginal defects with G-Bond. CONCLUSIONS: After 12 months, the simplified one-step G-Bond and the three-step Optibond FL were clinically equally successful, even though both adhesives were characterized by progressive degradation of marginal adaptation, and G-Bond exhibited more small enamel marginal defects.