Assessment of marginal leakage around Class II composite restorations in retrieved primary molars

The aim of the present investigation was to evaluate, by means of dye penetration, the microleakage around Class II composite restorations, in retrieved primary molars that functioned in the mouth for at least one year. The experimental material consisted of 13 exfoliated primary molars that had been restored with Herculite (Kerr Corporation, Romulus, Michigan 48174 USA) at least one year previously, utilizing an incremental or a bulk filling technique. The retrieved teeth were insulated with utility wax and nail polish, immersed in 2% basic fuchsin, embedded in acrylic resin, and ground off to various depths. The marginal leakage was assessed according the degree of dye penetration at the occlusal and cervical margins. No difference was observed between the two filling techniques. In most teeth, no leakage at the occlusal margins was observed; minimal leakage, limited to the enamel, was observed at the occlusal margins of two teeth, one of each filling technique. Severe penetration was evident at the cervical margin of three restorations, two of them filled incrementally and the third using the bulk technique. Mild to moderate penetration was observed at the cervical margin in the majority of the other restorations. It was concluded that an incremental filling technique could not eliminate microleakage at the cervical margins of Class II composite restorations.     

An ART field study in western Nepal

AIM: To evaluate the effectiveness of three different types of glass ionomer restorations placed in children's teeth using the ART technique two years after placement by either dentists or primary health care workers. SETTING: The rural district of Palpa in western Nepal. METHOD: An opportunistic non-randomised field study, commenced in April 1997. Three different glass ionomer restorative cements were used: Fuji IX (GC), Dentsply Baseline (DENTSPLY/DeTrey), and S.S. WhiteR (S.S. White). The restorations were assessed two years later by an independent evaluator, who was blind to the type of restorations used and also blind to the operators. RESULTS: Four primary health care workers and two dentists restored 163 primary and permanent teeth using hand instruments. One and two surface restorations were placed in 105 students ranging from 3 to 19 years of age from seven schools. After two years, 79 (75%) of the restorations survived and 27 (25%) failed, while 100% of 21 evaluated single surface restorations placed on permanent molars with Fuji IX survived. There was no statistically significant difference in the survival of the restorations placed by dentists and placed by primary health care workers, which corroborates that both groups are both capable of performing the technique satisfactorily. CONCLUSIONS: ART is very effective for one surface permanent molars using improved glass ionomer cements designed for the ART technique.     

Effect of different application and polymerization techniques on the microleakage of proximal resin composite restorations in vitro

This in vitro study investigated cervical microleakage of proximal resin composite restorations placed with three application and polymerization techniques. Uniform mesio-occlusal-distal (MOD) preparations featuring cervical margins above (mesial) and below (distal) the CEJ suitable for restoration with resin composite were copy milled into 33 recently extracted permanent molars. The teeth were divided randomly into three groups of 11 teeth and restored using a conventional incremental technique (Group A) and two novel curing devices (Groups B and C). After 24 hours, a dye penetration test was used to assess microleakage. Conventional placement in preparations with cervical margins in enamel had significantly lower interfacial leakage scores than those recorded for placement in preparations with margins in cementum regardless of the technique used to place the restorative material. Use of the two novel curing devices conferred no advantage in reducing microleakage irrespective of where preparation margins were placed.     

Four-year clinical evaluation of posterior resin-based composite restorations placed using the total-etch technique

Purpose : To report the 4-year clinical performance of posterior resin-based composite restorations placed using the total-etch technique.
Materials and Methods : Over a period of 1 year, 726 restorations (248 molars, 478 premolars; 260 Class I, 466 Class II; 540 replacements, 186 primary decay) were placed on conservative preparations, using the incremental placement technique in a clinical environment. Baseline data were collected, and the restorations were evaluated after 4 years. Z100 and Scotchbond Multipurpose (SBMP) (3M Dental Products, St. Paul, Minnesota) were used as the restorative system. The criteria evaluated were color match, marginal adaptation, anatomic form, cavosurface marginal discoloration, axial contour, interproximal contact, secondary caries, postoperative sensitivity, and tooth vitality.
Results : At baseline, 24% of the teeth restored presented postoperative sensitivity; 86% of the sensitive teeth were from the replacement group. At 4 years, all teeth were vital to cold test. Eighteen restorations (2.5%) presented clinically detectable marginal fracture. The shade was acceptable in all restorations. Cavosurface marginal discoloration was observed in 47 restorations (6.5% bravo scores). Axial contour, interproximal contact, and marginal adaptation received 100% alfa scores. No secondary caries was diagnosed in any of the teeth examined. None of the examined restorations required replacement.
CLINICAL SIGNIFICANCE
Under controlled clinical conditions, posterior resin-based composite restorations placed with the total-etch technique and restorative Z1OO/SBMP have the potential to present a high success rate at 4 years. None of the examined restorations required replacement, and there was no clinically detectable wear in any of the restorations. Simultaneous etching of enamel and dentin followed by the application of a resin adhesive can be considered an adequate modality of pulp protection in nonexposed tooth preparations.     

Amalgam alternatives – micro‐leakage evaluation of clinical procedures. Part I: direct composite/composite inlay/ceramic inlay

This study investigated the degree of dye penetration with three different types of tooth‐coloured restorations. Twenty‐four intact extracted molars were collected. The teeth were immediately stored in water at room temperature. Class II cavity preparations were prepared and restored with three different types of tooth‐coloured restorations: A, composite resin in the incremental technique; B, composite inlay technique; and C, ceramic inlay. Specimens were subjected to 700 cycles of thermal stress. They were than immersed in 2% basic fuchsin dye. The teeth were sectioned in three planes before being ranked as to the amount of dye penetration. The highest score obtained on three plano‐parallel sections was adopted as the representative value. The three groups were compared using the Kruskal Wallis non‐parametric test. Dye penetration was significantly lower at the enamel margins when using the composite inlay system and the incremental technique compared to the ceramic inlay technique. The restorations placed using the composite inlay technique showed less dye penetration than the incremental technique at the dentine margins ( P < 0·017).     

Wear of composite resin restorations in primary versus permanent molar teeth

The purpose of this investigation was to compare the wear rates of posterior composite resin restorations in primary versus permanent teeth. Based on theories of composite wear in primary molars, as well as on empirical observations, we hypothesized that wear would be greater in permanent tooth restorations. In Part I of the study, quantitative wear data from four different clinical trials (three permanent tooth studies and one primary tooth study) were compared. The same posterior composite restorative material was investigated in each of the four studies. In Part II of the study, quantitative wear data were drawn from a single clinical trial wherein the same experimental posterior composite material was placed in primary and permanent molars in the same children. In Part II, the baseline sample size included posterior composite restorations placed in 92 primary and 95 permanent molars in all children (ages 7-10). Quantitative wear data were obtained by the cast assessment method at baseline, six, 12, and 24 months. The 24-month sample size was based on 48 available primary molar restorations and 89 permanent molar restorations. The loss of primary restorations was due almost exclusively to natural exfoliations. Findings in Part I revealed no significant difference in the wear of primary versus permanent molar restorations. In Part II, wear findings for primary molar versus permanent teeth, respectively, were as follows (in micrometers): 47 versus 49 at six months; 86 versus 80 at 12 months; and 133 versus 131 at 24 months. With a Wilcoxon two-sample test and an alpha level of 0.05, there were no significant differences at any recall for the wear rate of primary versus permanent restorations. These results differ sharply from findings reported by others.     

Influence of Class II amalgam fillings on attachment loss

176 extracted teeth restored with Class II amalgam fillings, having identical distribution regarding tooth type, jaw and proximal surface localization, were investigated. The loss of attachment was measured on stained teeth under a stereomicroscope fitted with an ocular micrometer. The cervical margins of restorations were examined with a probe. Defective cervical margins were found in 85.8% of the 176 restorations. The mean loss of attachment on the restored surfaces (1.4 mm) was significantly higher (P less than 0.001) than on the sound unrestored surfaces of the same teeth (0.9 mm). Little difference was found between mesial and distal surfaces. The restored surfaces of the lower molars showed less loss of attachment, when compared to similar surfaces of upper molars and lower premolars (P less than 0.05).     

Adhesion of resin-modified glass-ionomer cements may affect the integrity of tooth structure in the open sandwich technique

ObjectiveTo study the interfaces between model cavities prepared in teeth and four glass ionomer cements (two conventional and two resin-modified).MethodsTen non-cavitated molars and premolars were used and, in each, two 3 mm deep slot preparations were created on opposing sides of the tooth. The teeth were conditioned as appropriate, then restored using the open sandwich technique, using a conventional glass ionomer (Fuji IX, Ketac Molar) or resin modified glass ionomer (Fuji II LC or N100), followed by completion with composite resin. The teeth were then embedded in a transparent acrylic resin and cut parallel to the long axis through both restorations, using a low speed diamond wheel saw. Samples were evaluated using a metallographic light microscope (100×). Three areas were assessed: the axial wall, the axial gingival line angle and the cavo-surface line angle. Bonding was categorized as inadequate or adequate based on the appearance and inadequate bonding was further studied and classified. Data were analysed statistically using the McNamara analysis.ResultsThe majority of materials failed to make adequate contact with the axial wall, and there were also flaws at the axial/gingival line angle in several samples. By contrast, the cavo-surface line angle was generally soundly filled and the materials showed intimate contact with the tooth surface in this region. The most serious inadequacy, though, was not lack of intimate contact and/or adhesive bond, but the presence of perpendicular cracks in 30% of the Fuji II LC samples which extended into the underlying dentin.SignificanceThe problems of placement and dentin cracking experienced with these materials demonstrate that adhesive bond strength alone cannot be used as the criterion of success for restorative materials. In fact good adhesion can, in certain cases, promote cracking of the dentin due to stresses within the material, an outcome which is undesirable.     

Evaluation of fracture resistance of pulpotomized second primary molars restored with fiber-reinforced composite

ObjectivesFiber reinforcement of composite restorations can help decrease the fracture risk in restored pulpotomized teeth with severe coronal lesions.This study aimed to evaluate the fracture resistance of pulpotomized second primary molars restored with fiber-reinforced composite (FRC).MethodsThis experimental study was done on 40 extracted primary second molars in four groups (n = 10). The negative controls were intact untreated teeth; while, other samples were pulpotomized with the mesio-occlusal-distal (MOD) access cavities prepared on their buccal and lingual surfaces. Positive control group was left unrestored. Composite group received glass ionomer on Zonalin and was restored with flowable composite and then composite. The FRC group received glass ionomer as the preceding group; the glass fiber was embedded within flowable composite, and the cavity was restored with composite. The compressive forces leading to fracture were recorded in Newton. Comparisons were made through one-way ANOVA and Tukey's post-hoc test (α = 0.05).ResultsThe highest mean fracture resistance belonged to the intact teeth (604.45 ± 59.02 N), then the FRC group (584.31 ± 57.18 N). Unrestored teeth had the lowest fracture resistance (235.60 ± 45.60 N); however, they were not significantly different from composite group in this regard (P = 0.47). Although FRC group had significantly higher fracture resistance than the unrestored and composite group, it was not significantly different from intact teeth.ConclusionsFiber reinforcement improved the fracture resistance of pulpotomized primary molar with large MOD cavities.     

Interfacial adaptation of in vivo aged polyacid-modified resin composite (compomer) restorations in primary molars

Polyacid-modified resin composite (PMC) restorations are being increasingly used in class II cavities in primary teeth. The aim of this study was to evaluate the interfacial adaptation of 1-month- and 30-month-old in vivo restorations by quantitative scanning electron microscopy (SEM) evaluation. Twelve PMC restorations were performed under clinically controlled conditions in primary molars planned for extraction 1 month later for orthodontic reasons. Eleven other PMC restorations, aged 30 months (range 1.5–3 years) and part of a multicenter study, were collected after exfoliation. To observe the interfacial adaptation of each restoration at several levels a thin layer of the proximal surface was ground off 2–3 times. Replica impressions of each level were prepared for SEM. The interfaces of the replicas were evaluated at ×200 and ×1000. In the 1-month-old restorations gap-free adaptation to enamel was found in 87% and to dentin in 84% of the total interfacial length investigated. For the 30-month-old restorations gap-free adaptation was registered in 59 and 63%, respectively. The interfacial quality was significantly better in the 1-month-old restorations than in those 30 months of age. Adaptation to enamel was significantly better in the cervical part of the 1-month-old restorations than in the axial walls, whereas there was no significant difference in dentin. No significant difference was found between the cervical and axial cavity walls of the 30-month-old restorations. Enamel fractures were registered in 31 and 24%, respectively of the interfacial length of the 1-month- and 30-month-old restorations. The corresponding findings in dentin were 0 and 0.9%. It can be concluded that restorations aged for a short time showed a high percentage of sealing, which decreased significantly for the 30-month-old ones. Received: 24 June 1998 / Accepted: 7 October 1998     

Clinical performance and caries inhibition of resin-modified glass ionomer cement and amalgam restorations

BACKGROUND: The authors clinically examined two restorative materials to evaluate their effectiveness in Class II restorations in primary molars and their ability to inhibit recurrent caries. METHODS: Forty subjects, each in need of two Class II restorations in primary molars, took part in this study. Each patient received one Class II restoration of resin-modified glass ionomer cement and one of amalgam. The authors evaluated the restorations at six-month, one-year, two-year and three-year recall appointments. On exfoliation, teeth with experimental restorations were retrieved and microscopically examined for inhibition of demineralization at restoration margins. RESULTS: The results of the clinical evaluation demonstrated no significant differences between the resin-modified glass ionomer cement restorations and the amalgam restorations (P < .05). Polarized light microscopic examination of the returned teeth that were restored as a part of this study indicated that the resin-modified glass ionomer cement had significantly less enamel demineralization at restoration margins than did amalgam (P < .0001). CONCLUSIONS: The resin-modified glass ionomer cement functioned clinically as well as amalgam for Class II restorations in primary molars. However, the resin-modified glass ionomer exhibited significantly less enamel demineralization at restoration margins than did amalgam. CLINICAL IMPLICATIONS: Resin-modified glass ionomer cement restorative material functions well for Class II restorations in primary molars and exhibits less recurrent caries at restoration margins than does amalgam.     

Evaluation of the microleakage at the proximal walls of Class II cavities restored using resin composite and precured composite inserts.

OBJECTIVE: This in vitro study compared the microleakage of resin composite restorations placed in Class II cavity preparations using an incremental placement technique with and without the addition of precured resin composite inserts. METHOD AND MATERIALS: Sixty standardized mesio-occlusal and disto-occlusal cavities were prepared in 30 recently extracted molar teeth. Twenty cavities were restored by employing the incremental placement technique (group I), and 40 cavities were restored using the incremental placement in the presence of precured composite inserts of two sizes: 1 x 3 mm (group II) and 1.25 x 3 mm (group III). The restored teeth were thermocycled for 250 cycles in water baths set at temperatures of 5 degrees C and 50 degrees C using a 30-second dwell time, stained, and sectioned horizontally at the middle of the restoration. Following sectioning, each specimen was microscopically examined at x 4 magnification. The extent of dye penetration at the tooth/restoration interface was scored for each test group, and the scores obtained were subjected to one-way analysis of variance (ANOVA) and Tukey's pairwise comparison at a 95% significance level. RESULTS: The current investigation showed statistically significant differences in dye penetration between the three test groups. CONCLUSION: The use of precured resin composite inserts with the incremental placement technique in the restoration of Class II cavity preparations seems to improve the marginal seal of the proximal walls of finished restorations.     

An in vitro comparison of marginal microleakage of alternative restorative treatment and conventional glass ionomer restorations in extracted permanent molars

PURPOSE: The objective of this study was to compare the marginal leakage of cervical restorations made using alternative restorative treatment (ART) and conventional glass ionomer restorations. METHODS: Sixteen permanent maxillary and mandibular first and second molars extracted for periodontal reasons with Class V carious dentin on the buccal surfaces were prepared using ART while a second set of 29 noncarious molars had Class V preparations made with a high-speed handpiece. The occlusal margin was located in the enamel, and the gingival margin was located in the dentin/cementum. All teeth were restored with glass ionomer cement (GIC). The teeth were thermally stressed for 300 cycles and stained with methylene blue. Samples were sectioned and evaluated for microleakage. RESULTS: One-way analysis of variance on ranks revealed no significant difference in leakage at both the dentin and enamel margins between the conventional and ART groups. The microleakage at the dentin margin, however, was significantly greater (P < .001) than at the enamel margins in the conventional group. CONCLUSION: Alternative restorative treatment with GIC provides enamel and dentin margins that show comparable marginal leakage to conventionally restored permanent teeth. For the conventional restorations, leakage at the dentin margins occurs to a significantly higher extent than at the enamel margins.     

Microleakage of restorative techniques for pulpotomized primary molars

PURPOSE: This study's purpose was to assess in vitro microleakage of different restorative materials after pulpotomies in primary molars. METHODS: Proximo-occlusal cavity preparations were prepared in 60 extracted primary molars. The selected teeth had at least 3 sound walls and one half to two thirds of root length remaining. Carious tissue was removed, pulpotomy was performed, and IRM filled the pulp chamber. The teeth were then randomly divided equally into 5 groups and restored as follows: (1) group 1 with a compomer; (2) group 2 with a reinforced glass ionomer material; (3) group 3 with amalgam; (4) group 4 with a stainless steel crown (SSC); and (5) group 5 with IRM only (control). After thermocycling for 500 cycles, teeth were immersed in dye for 24 hours and progressively ground prior to microleakage evaluation. The worst result for each section was logged and results were statistically analyzed (Kruskal-Wallis and Mann-Whitney). RESULTS: Group 1 showed the highest percentage of no leakage of all groups. Leakage from occlusal and cervical margins was markedly shown for all specimens of groups 2, 3, and 5. CONCLUSIONS: (1) Bonding agents and resin based restorations were able to provide the best total margin protection. (2) SSCs cemented with glass ionomer cement were unable to hermetically seal teeth; and (3) Tytin, Ketac Molar, and IRM restorations did not appear to be leakage-resistant materials for pulpotomies of primary molars.     

A novel filling technique for packable composite resin in Class II restorations

ABSTRACT: The use of composite resin restorations in posterior teeth has increased considerably in the past few years. Specific composite resins for posterior teeth, as well as new operative techniques, have been developed to overcome some clinical difficulties. The present article describes a new technique to reconstitute the interproximal contour and contact of Class II restorations using a pack-able composite resin. Two lower first molars from the same patient are reported in detail, illustrating the technique step by step. The technique indicates the use of a metallic matrix band and wood wedges to provide an interproximal contour and contact with the adjacent tooth as well as to provide an adequate cervical adaptation. The first increment of the packable composite resin is applied on the gingival wall of the proximal box, packed cervically near the axial wall and, automatically, the resin climbs up in contact with the inner surface of the matrix band. This increment is sculpted and light-cured and the metallic matrix band is removed. Thus, the Class II cavities are transformed into Class I, with free access for light-curing. Small incremental layers of composite fill the remaining cavities. This technique is faster than conventional techniques and permits appropriate embrasure, better contour, and contact points.     

Randomized controlled trial on the performance of direct and indirect composite restorations in patients with severe tooth wear

ObjectiveThe study aimed to evaluate survival and failure behavior of Direct Composite Restorations (DRC) and Indirect Composite Restorations (ICR) on molars and anterior teeth, in a Randomized Controlled Trial (RCT).MethodsPatients with generalized severe tooth wear were included, and randomly assigned to one of 2 protocols: (1) DCR: All teeth were restored with directly applied micro-hybrid composite restorations (Clearfil AP-X, Kuraray) for load bearing areas and nano-hybrid composite restorations (IPS Empress Direct, Ivoclar Vivadent) for buccal veneers; (2) ICR: First molars were restored with indirect composite ‘tabletop’ restorations and maxillary anterior teeth were restored with indirect palatal veneer restorations (Clearfil Estenia C&B, cemented with Panavia F, Kuraray). Remaining teeth were restored directly. Restorations were evaluated after 3 years, focusing on clinical acceptability. Statistical analysis was performed using Kaplan Meier curves, Annual Failure Rates (AFRs), and univariate Cox regression analyses (p < 0.05).Results41 patients (age: 36.6 ± 6.6y) were evaluated after 3 years (40.0 ± 2.2 m). 408 restorations on first molars and palatal veneers on maxillary anterior teeth were part of this RCT, with 220 DCRs and 188 ICRs. No differences in survival between treatment modality for palatal veneers for any failure criteria were found. Tabletop restorations on first molars showed a considerable higher failure rate for ICR compared to DCR (p = 0.026, HR: 3.37, 95%CI = 1.16–9.81).SignificanceIn this RCT, directly applied composite restorations showed superior behavior compared to the indirect composite restorations, when used in the molar region.     

A one-year clinical evaluation of a high-viscosity glass ionomer cement in primary molars

In this study one-year clinical results of high-viscosity glass ionomer cement (GIC) (Fuji IX, A3, GC, Japan) were determined in class I and class II restorations in 68 primary molars with occlusal or approximal caries. Following caries removal and cavity preparation, the teeth were restored with Fuji IX. The restorations were evaluated according to the U.S. Public Health Service's (USPHS) criteria at the end of one year. Statistical analyses of the data obtained were analyzed using the X2 test. The evaluations showed no statistically significant difference between class I and class II restorations in terms of the color mismatch, anatomic form, marginal adaptation, and secondary caries (P>0.05), but they were statistically significant with regard to cavosurface marginal discoloration (P<0.05). At the end of one year, the success rate of the class I and class II restorations of the primary molars restored with Fuji IX was 94%.     

SEM study of a self-etching primer adhesive system used for dentin bonding in primary and permanent teeth

PURPOSE: The purpose of this study was to evaluate the interfacial micromorphology of direct esthetic restorations bonded to primary or permanent tooth dentin with a self-etching primer adhesive system. METHODS: Superficial dentin at the occlusal surface of 15 primary and 15 permanent molars was exposed with a carbide bur. Prompt-L-Pop was applied in one half of each surface. A control bonding system, Single Bond or Vitremer Primer, was used in the other half Teeth were restored either with a composite resin (Filtek Z250), a compomer (Hytac), or a resin-modified glass ionomer (Vitremer). Twenty-five scanning electron microscope fields from 5 teeth were evaluated blindly by two investigators for each condition. RESULTS: In this study, a significant difference in quality of the interfacial seal was not observed when restorations performed in primary teeth were compared to restorations in permanent teeth. Interfacial gaps were observed in most restorations bonded with Prompt-L-Pop and restored with Filtek Z250 (9/10), Hytac (9/10), or Vitremer (5/10). No interfacial gaps were observed in teeth bonded with Single Bond and restored with Filtek Z250 (0/10) or Hytac (0/10), while all teeth bonded with Vitremer Primer and restored with Vitremer presented gaps (10/10). To understand the reason for the interfacial gaps observed with Prompt-L-Pop, we examined if this system generated a hybrid layer at the dentin/restorative material interface. All surfaces bonded with Single Bond and restored with Filtek Z250 or Hytac presented a visible hybrid layer. In contrast, 0/10 (Z250) and only 3/10 (Hytac) restorations bonded with Prompt-L-Pop showed signs of a hybrid layer. CONCLUSION: The self-etching primer adhesive system Prompt-L-Pop failed to generate sealed interfaces consistently between the dentin of primary and permanent teeth and the composite resin or the compomer evaluated in this study.     

Longevity of posterior composite and compomer restorations in children placed under different types of anesthesia: a retrospective 5-year study

Objectives

The aims of this study were (i) to assess cumulative survival rates of class II resin-based composite and compomer restorations in primary molars with a 5-year observation period and (ii) to analyze the influence of different types of anesthesia and different localizations of the restorations in the teeth.

Methods

Patient charts of a private practice for pediatric dentistry were screened for class II resin-based composite (Spectrum TPH3) and compomer (Dyract Posterior; both Dentsply DeTrey) restorations in primary molars with a 5-year observation period used with Adper Prompt L-Pop (3M-ESPE). One restoration per patient (age ≤ 6 years at placement) was randomly selected.

Results

Two hundred sixty restorations were included (43% resin-based composites, 57% compomers). After 5 years, cumulative survival rates were 43% for resin-based composite and 49% for compomer restorations with no statistically significant differences. There was a tendency for higher survival rates for restorations placed under N₂O inhalation sedation or general anesthesia. Distal-occlusal compomer restorations showed significantly lower survival rates (p = 0.003) as compared to mesial-occlusal compomer restorations.

Conclusion

Within the limitations of the study, we conclude that type of restorative material as well as the type of anesthesia do not influence restoration survival rates, although restorations placed in patients receiving N₂O inhalation sedation or general anesthesia tend to perform better as compared with patients receiving no anesthesia or only local infiltration.

Clinical relevance

Resin-based composite and compomer restorations show similar survival rates of more than 43% (annual failure rates less than 11.5%) after 5 years for restoration of primary molars.

     

NANOLEAKAGE PHENOMENON ON DEPROTEINIZED HUMAN DENTIN

Objective:

The purpose of this study was to evaluate the influence of dentin deproteinization on the nanoleakage phenomenon.

Material and Methods:

Class V cavities were prepared in 12 human molars with cervical margins located in dentin. The cavities were assigned to 2 groups (n=6) according to dentin treatment: Group I - dentin treated in accordance with the manufacturer’s instructions and Group II - dentin treated following the manufacturer’s instructions + 10% NaOCl. Each group was sub-divided into three groups, according to the DBS (dentin bonding system) used: Scotchbond Multi Purpose (SBMP), Prime & Bond NT (PB) and Clearfil SE Bond (SE), which were applied according to manufacturer’s instructions. The cavities were restored with composite resin, and the specimens were immersed in a tracer agent (AgNO₃ 50%) for 24 h. The teeth were sectioned buccolingually through the center of the restorations, and nanoleakage pattern was evaluated by scanning electron microscopy (SEM) using the backscattered electron image mode.

Results:

SEM analysis showed different nanoleakage patterns for each DBS. Irrespective of dentin treatments, all SBMP specimens showed nanoleakage. SE did not show any nanoleakage with both dentin treatments used. PB showed nanoleakage within the hybrid layer only in Group I.

Conclusions:

The influence of dentin deproteinization on the nanoleakage phenomenon was dependent on dentin bonding system formulation and bonding strategies.