Does the liner material influence pulpal vitality in deep carious cavities submitted to selective caries removal? A network meta-analysis review

OBJECTIVES

To evaluate whether the restorative material in direct contact with the dentin influences pulp vitality in primary and permanent teeth with deep carious lesions restored after selective caries removal (SCR).

MATERIAL AND METHODS

Systematic searches of databases MEDLINE via PubMed, Scopus and ISI Web of Science were performed for primary and permanent teeth. Inclusion criteria were applied for title and abstract reading of databases search results. After full texts review of included studies, those that did not meet exclusion criteria were excluded from meta-analysis.

RESULTS

For meta-analysis, 2 studies were included for permanent teeth and 6 for primary teeth. The failure events reported were meta-analyzed using two statistical methods: standard pairwise meta-analysis (SPMA) and network meta-analysis (NMA). The SPMA identified similar failure occurrence of restorations performed with calcium hydroxide (CH) and other liner materials (RR 0.84, 95% CI 0.41, 1.74; p = 0.64), no significant difference between the use of alternative liners or CH regardless deciduous or permanent teeth (RR 0.79, 95% CI 0.36, 1.71; p = 0.55) and similar risk of failing at different follow-ups for all liner materials tested (RR 0.77, 95% CI 0.35, 1.70; p = 0.52). Probabilistic analysis indicated GIC as liner material with the highest probability of clinical success (SUCRA = 72.76%), and CH ranked as the worst liner material (SUCRA = 21.81%).

CONCLUSION

Pulpal vitality was not affected by material used as liner after selective caries removal in deep carious cavities.

CLINICAL RELEVANCE

Current clinical evidence supports the weak recommendation to not use calcium hydroxide as liner after SCR.

A Quality Improvement Project to Optimize Fluoride Varnish Use in a Pediatric Outpatient Clinic with Multiple Resident Providers

The pediatric clinic at Kapi'olani Medical Center provides dental varnish to prevent decay. A chart review (conducted August 1-31, 2017) revealed that only 49.6% of eligible children received varnish. Among those who did not receive varnish, no explanation was provided in 83.9% of the charts. This quality improvement project was designed to increase delivery and documentation of dental varnish. The participants were 14-15 pediatric and psychiatry residents (11 present for all cycles). Cycle 1 interventions were a 5-minute resident educational session on the importance and process of fluoride varnish, and visual reminders on all order entry computers in the clinic. Cycle 2 intervention consisted of a prompt added to the clinic's default well child visit templates requiring notation of whether varnish was given and a reason if not. Data for cycle 2 was collected over 6 weeks as some residents chose to use their own templates, serving as an unplanned comparison group. Application of varnish increased to 77.7% (P < .001) after cycle 1, and was statistically unchanged for cycle 2 (74% (P = .24)). Documentation of reason for lack of varnish was missing in 80% (P = .59) after cycle 1 and 17 % (P < .001) after cycle 2 (with prompt). In the cycle 2 comparison group using their own templates, the varnish application rate was 71% (P < .001) with no explanation for lack of varnish 84% of the time (P = .95). Brief educational interventions may result in increased use of fluoride varnish in resident-based clinics. Task based prompts or stop measures in electronic medical record templates can improve documentation, which can inform efforts to improve varnish application.

In vitro evaluation of apical microleakage in retrofillings with different resection angles

The aim of this study was to evaluate the effect of flowable composite or glass ionomer liners on the shrinkage stress of a restorative composite resin. Fifteen previously sandblasted metal boxes were attached to a universal mechanical testing machine (INSTRON 1011, Instron Corporation). Five of these boxes were filled with Filtek Z350 XT (FXT) Universal Restorative A2 (3M ESPE) (Group 1 or Control). Two further groups of 5 boxes were prepared by interposing a layer of Vitrebond Light Cure Glass Ionomer 3M ESPE (VGI) (Group 2 or G.I.) or Filtek Z350 XT Flowable Restorative A2 3M ESPE (FFR) (Group 3 or Flowable) between the box and the composite resin, completing with the same volume of composite as in Group 1. Upon activating lightcuring, the filled boxes mounted on the testing machine were videoed for 60 seconds (40 s photoactivation and 20 s postcuring), timed with a digital chronometer. Force values were recorded in newtons and converted into stress according to contact surface. Stress values were recorded every 10 s. Results were analyzed using repeated measures ANOVA. Mean and standard deviation in kPa (stress) recorded for each group were: Control group: 126.2 (30.8); G.I.: 48.4 (18); Flowable: 27.9 (19.5). Statistical analysis showed significant differences between the control group and the rest (p<0.01), with no significant difference between groups with glass ionomer liners and flowable resin liners (G.I. and Flowable). Under the experimental conditions of this study, it can be concluded that polymerization shrinkage stress can be reduced by the presence of a liner between the preparation and the restorative material.

Effect of Different Cavity Lining Techniques on Marginal Sealing of Class II Resin Composite Restorations In Vitro

This study investigated the effect of different cavity lining techniques on the marginal sealing of Class II composite restorations. A total of 36 human molar teeth, free of caries and fillings, were each prepared with two proximal Class II boxes mesially and distally. In mesial boxes, cavity liners were applied as follows: in group 1, separately cured flowable composite; in group 2, co-cured flowable composite; and in group 3, resin-modified glass ionomer (RMGI). The remaining cavities were filled incrementally with a universal restorative composite. The distal boxes were filled with no liner as controls. After thermocycling, the specimens were immersed in a silver nitrate solution and the microleakage was evaluated. Analysis of variance showed that the degree of microleakage for group 3 was significantly lower than that of the other groups. Based on the results, it was concluded that the use of RMGI as a cavity liner under composite restorations showed the least microleakage. Flowable composites, whether co-cured or separately cured, had no influence on the marginal sealing.

Comparison Of Frequency Of Post Operative Sensitivity In Amalgam Restorations Using Copal Varnish And Dentin Adhesive Liner

BACKGROUND

Micro leakage around the margins of a restoration is believed to be one of the main causes of postoperative sensitivity. Dental amalgam is a non-insulating material and has the potential to transfer heat and cold causing irritation of the pulp. Different dentin tubule sealers are used under amalgam restoration to compensate for this post-operative sensitivity. This study was conducted to compare the frequency of sensitivity in amalgam restorations using copal varnish and dentin adhesive liner (dentin bonding agent).

METHODS

A total of 60 patients of either gender, aged 18-40 years having class 1 carries in posterior teeth were included. Teeth with restorations, dentinal sensitivity and patients taking analgesic drugs for chronic pain conditions were excluded. The selected patients were placed randomly into Group A (copal varnish) & Group B (dentin adhesive liner), by using computer generated table of random numbers. Restored teeth were evaluated 1-month post operatively for sensitivity.

RESULTS

Mean age was 25.63±5.42 years. Out of 60 patients, 68.0% were females and 32.0% were males with a female to male ratio of 2:1. The mean post-operative pain score was 2.83±2.79 in Group A and in Group B, it was 1.43±2.14 with a p-value of 0.03. There was no pain on application of a cold stimulus in 14 (46.7%) patients in Group A (copal varnish) while in Group B (Dentin adhesive), no pain was seen in 23 (76.7%) patients with p-value of 0.02.

CONCLUSIONS

This study concluded that dentin adhesive liner (dentin bonding agent) is better than copal varnish in reducing postoperative sensitivity in amalgam restorations.

Microleakage of Class II composite resin restorations with self-adhesive composite resin liners

This study investigated the microleakage of Class II composite restorations with composite resin liners. Standardized box cavities were prepared on the mesial and distal surfaces of 84 extracted intact human molars. Proximal margins were located in enamel (occlusal) and 1.0 mm apical to the cementoenamel junction (gingival). The teeth were randomly divided into 6 groups (n = 28 cavities) and restored with Filtek Z350 nanohybrid composite resin (FZ). The test groups were lined with a conventional flowable composite resin, Premise Flowable (PF), or 1 of 2 self-adhesive composites (SACs): Vertise Flow (VF) or Clearfil SA luting cement (CSA) with or without their respective self-etching adhesives: Optibond All-in-One (OB) or Clearfil SE Bond (CSE). The adhesive/lining procedure was performed as follows: OB/FZ (control), OB/PF/FZ, VF/FZ, OB/VF/FZ, CSA/FZ, or CSE/CSA/FZ. Microleakage was evaluated at the occlusal and gingival margins using a dye penetration technique and quantitative assessment. Kruskal-Wallis and Mann-Whitney U tests were used to analyze the data at the significance level of α = 0.05. None of the restorative techniques was capable of preventing microleakage completely. The greatest amount of microleakage was detected in the VF/FZ and CSA/FZ groups at both margins (P < 0.02). Among the groups placed with a bonding agent, OB/VF/FZ showed significantly greater values of microleakage at the occlusal margins than did OB/FZ, OB/PF/FZ, and CSE/CSA/FZ (P < 0.05). At the gingival margins, the OB/PF/FZ group exhibited the least leakage compared with the OB/VF/FZ and CSE/CSA/FZ groups (P < 0.001). The results indicated that the additional application of bonding agents improved the marginal sealing of SACs in Class II composite restorations.

Evaluation of the efficacy of flowable composite as lining material on microleakage of composite resin restorations: A systematic review and meta-analysis

OBJECTIVE

The efficacy of flowable composite in improving marginal adaptation or reducing microleakage is not fully understood. The purpose of this study was to systematically evaluate existing evidence to verify whether an application of flowable composite as a liner provided less microleakage in Class 2 composite restorations.

METHOD AND MATERIALS

PubMed, ISI (Web of Science), and Scopus databases were searched according to the selected keywords, up to 15 Feb 2015, without any restriction on date or language. Full texts of published articles that seemed to meet primary criteria for inclusion in this research were obtained. Data of studies were extracted if they were assessed as high or moderate level of evidence. Due to the variation of methods used in different studies, they were divided into five groups: groups 1 and 2, studies that evaluated the effect of flowable composite as a liner on dentinal or enamel margins and applied flowable composite on all of the cavity wall margins; groups 3 and 4, studies that evaluated the effect of flowable composite as a liner on dentinal and enamel margins and applied flowable composite only on gingival margin; and group 5, clinical studies.

RESULTS

The initial search yielded 1,370 publications. After hand searching, six extra studies were included in the review. The abstracts of all were read independently by AB and SG. After methodologic assessment and evaluation of the level of evidence, 18 studies were selected for this study. The results of this study indicate that flowable composite liners have no significant effect on microleakage of composite restorations in all of five groups.

CONCLUSION

Application of flowable composite as a liner in composite restorations cannot reduce microleakage or improve clinical performance.

Effect of Lining Materials on Shear Bond Strength for Composite Restorations In Vitro

This study evaluated the influence of liner agents placed under resin composite restorations on shear bond strength (SBS) to dentin. A total of 40 extracted bovine incisors were used. Enamel surfaces were ground to expose a flat dentin area of 7 mm in diameter. Teeth were divided into four groups according to tested liners: Group 1 (control) used no liner; Group 2 used a resin-modified glass-ionomer cement liner (Vitrebond Plus, 3M ESPE); Group 3 used a light-activated calcium hydroxide resin liner (Ultra-Blend Plus, Ultradent); and Group 4 used a polyacrylic acid surface treatment + conventional glass-ionomer cement liner (Vidrion F, SSWhite). All groups were subjected to bonding procedures with Single Bond (3M ESPE) and 4-mm-thick buildups of resin composite were fabricated. Artificial aging was performed, and the specimens were submitted to mechanical shear testing. One-way analysis of variance (ANOVA) revealed significant differences among liners (P = .00). Group 4 showed the highest SBS. Group 1 showed significantly higher mean SBS compared with Group 3. Results showed that SBS is improved when using polyacrylic acid surface treatment + conventional glass-ionomer cement and decreased when using light-activated calcium hydroxide when compared with no liner. Polyacrylic acid surface treatment + conventional glass-ionomer cement as a liner placed under adhesion surface can improve the shear bond strength between dentin and resin, while light-activated calcium hydroxide resin should be used restrictedly in very deep cavities, because they may reduce the bond strength of the restoration submitted to masticatory forces and temperature changes in the oral environment.

Polymerization shrinkage of different types of composite resins and microleakage with and without liner in class II cavities

AIM

To determine the volumetric polymerization shrinkage of four different types of composite resin and to evaluate microleakage of these materials in class II (MOD) cavities with and without a resin-modified glass ionomer cement (RMGIC) liner, in vitro.

MATERIALS AND METHODS

One hundred twenty-eight extracted human upper premolar teeth were used. After the teeth were divided into eight groups (n=16), standardized MOD cavities were prepared. Then the teeth were restored with different resin composites (Filtek Supreme XT, Filtek P 60, Filtek Silorane, Filtek Z 250) with and without a RMGIC liner (Vitrebond). The restorations were finished and polished after 24 hours. Following thermocycling, the teeth were immersed in 0.5% basic fuchsin for 24 hours, then midsagitally sectioned in a mesiodistal plane and examined for microleakage using a stereomicroscope. The volumetric polymerization shrinkage of materials was measured using a video imaging device (Acuvol, Bisco, Inc). Data were statistically analyzed with Kruskal-Wallis and Mann-Whitney U-tests.

RESULTS

All teeth showed microleakage, but placement of RMGIC liner reduced microleakage. No statistically significant differences were found in microleakage between the teeth restored without RMGIC liner (p>0.05). Filtek Silorane showed significantly less volumetric polymerization shrinkage than the methacrylate-based composite resins (p<0.05).

CONCLUSION

The use of RMGIC liner with both silorane- and methacrylate-based composite resin restorations resulted in reduced microleakage. The volumetric polymerization shrinkage was least with the silorane-based composite.

Efficacy of four lining materials in sandwich technique to reduce microleakage in class II composite resin restorations

OBJECTIVES

The aim of the present study was to evaluate the effect of four different sandwich techniques on gingival microleakage of Class II direct composite resin restorations.

MATERIALS AND METHODS

Fifty sound human premolars were selected and randomly divided into five groups (n=10). Class II box only cavities were prepared in one of the proximal surfaces of each tooth with a gingival margin located approximately 0.5 mm below the cemento-enamel junction. Group A (control) was restored incrementally with composite resin (Tetric Ceram). Groups B, C, D, and E were restored with the sandwich technique using a compomer (Compoglass F), flowable composite resin (Tetric Flow), self-cure composite resin (Degufill SC), or resin modified glass ionomer (Fuji II LC), respectively. After thermal-load cycling, the specimens were immersed in 0.5% basic fuschin for 24 hours. Dye penetration (10(-1) mm) was detected using a sectioning technique. Data were analyzed with repeated measurements and Duncan test at α=0.05.

RESULTS

The least amount of microleakage was detected in the incremental group (1.28 ± 0.98). The sandwich technique using resin modified glass ionomer (7.99 ± 9.57) or compomer (4.36 ± 1.78) resulted in significantly more leakage than did the sandwich technique using flowable (1.50 ± 1.97) or self-cure composite (2.26 ± 1.52).

CONCLUSION

According to the results of this study, none of the four sandwich technique composite resin restorations used in this study could reduce gingival microleakage to a greater degree than the incremental technique.

Marginal adaptation of direct class II composite restorations with different cavity liners

The aim of this study was to evaluate how cavity linings with different elastic modulus can influence the marginal adaptation (MA) of Class II composite restorations before and after thermo-mechanical loading.

MATERIALS AND METHODS

Forty Class II cavities with margins extending 1 mm below the cement-enamel junction were prepared in extracted human third molars. In each group except the control group, a lining material of 1-mm thickness was applied to the bottom of the cavity and polymerized before placing the resin composite Herculite XRV Ultra (group A: control; group B: Premise Flowable lining; group C: Herculite XRV Ultra lining; and group D: Optibond FL lining). MA was evaluated (with a scanning electron microscope) before and after loading (200,000 loading cycles). Statistical analysis was done using the Shapiro-Wilks test, the analysis of variance test, and Duncan post hoc test at p<0.05.

RESULTS

Before loading, the percentages of continuous margins in dentin were superior (p<0.05) for groups C and D (71.1% and 87.2%, respectively) compared to groups A and B (55.7% and 48.3%, respectively). After loading, group D (79.8%) was statistically superior in dentin compared to all of the other groups (43.6%, 35.9%, and 54.4%, respectively). In occlusal enamel, no significant difference was found between groups. The percentage of enamel fractures and the percentage of noncontinuous margins in proximal enamel were high, with no significant difference between liners. It can be concluded that for the materials used in this study, a 1-mm-thick lining with an extremely low elastic modulus (2-3 GPa) could redistribute shrinkage stress. The use of a flowable composite did not significantly improve MA.

Observational: prospective study of indirect pulp treatment in primary molars using resin-modified glass ionomer and 2% chlorhexidine gluconate: a 12-month Follow-up

PURPOSE

This study's purpose was to determine the efficacy of indirect pulp treatment (IPT) in primary molars when using 2% chlorhexidine gluconate disinfecting solution and resin-modified glass ionomer (RMGI) liner after 12 months.

METHODS

Three- to 10-year-old subjects with deep carious lesions who met selection criteria participated. Infected dentin was removed using a caries detector, and residual affected dentin was left on the pulpal floor to prevent pulp exposure. A 2% chlorhexidine gluconate solution and a RMGI liner were placed. Teeth were restored with composite or full-coverage (stainless steel crown [SSC]) restorations. Follow-up evaluations at 3, 6, and 12 months included clinical, radiographic, and photographic assessments.

RESULTS

A total of 60 teeth were treated. Treatment was successful in 50/50 (100%), 41/42 (∼98%), and 31/32 (∼97%) teeth at the 3-, 6-, and 12-month follow-up visits, respectively. Failures included one at 6 months in a primary second molar with a composite restoration and another at 12 months in a primary first molar with a SSC.

CONCLUSIONS

Indirect pulp treatment is effective in primary teeth, although appropriate case selection and an adequate marginal seal are essential for a successful outcome. Further prospective studies are needed to expand the body of evidence that clinicians use to justify decisions on clinical care.

Clinical wear rate of direct and indirect posterior composite resin restorations

The purpose of this randomized clinical trial was to determine the clinical wear behavior of three nanofilled composites (Filtek Supreme XT [FS], Tetric EvoCeram [TEC], and Aelite Aesthetic [AA]) with two indirect composites (Estenia [E] and Tescera ATL [TATL]) on permanent molar teeth. Fifty-four patients whose treatment plans included moderate Class I and/or II restorations on molar teeth were selected for inclusion in this study. Wear was measured by use of gypsum replicas at baseline and 6 and 12 months using three-dimensional scanning and rapid-form software to elucidate the wear mechanisms. For statistical analyses, one-way analysis of variance and the Scheffe test were used. Statistical results revealed that wear behavior of TATL was significantly different from that of AA (P < .05). No significant differences were detected between AA and E (P > .05) or between TEC, FS, and TATL composite resins (P > .05). The results showed similar clinical performance between the five composite resins evaluated. Therefore, composite resins may be indicated for the restoration of posterior teeth. However, the composition of the composite resin did affect the wear behavior of the composite material.

Energy dispersive x-ray analysis of corrosion products in nondiscolored dentin and a dye-extraction study of Class 2 composite restorations following amalgam removal

OBJECTIVE

To evaluate the effect of corrosion products on the microleakage of composite placed adjacent to nondiscolored dentin after amalgam removal.

METHOD AND MATERIALS

Sixty Class 2 cavities were prepared on extracted premolars, which were divided into four equal groups according to the manner in which they were restored: group 1, light-cured packable composite (Elite LS) to establish a microleakage baseline; group 2, a high-copper amalgam (World Work) previously stored in 37°C normal saline for 6 months to create amalgam corrosion products; group 3, identical to group 2, but the amalgam was later replaced with composite, leaving the cavity walls intact; and group 4, identical to group 3 except the cavity walls were extended 0.5 mm after amalgam removal prior to insertion of the composite. Groups 1, 3, and 4 were kept in a 37°C normal saline for 1 week. Ten specimens from each of these three groups were randomly selected for dye-extraction testing, while dentin elemental microanalysis of five specimens from all four experimental groups was also conducted. Data were analyzed using ANOVA and the Tukey tests (α = .05).

RESULTS

Corrosion products were not detected in group 4, and no statistically significant difference (P > .05) in microleakage was found between this group and group 1. The highest dye absorbance was associated with group 3 (P < .05).

CONCLUSION

After amalgam removal, a 0.5-mm extension of the cavity walls could improve the dentinal marginal seal to replicate that of an initial composite restoration.

Clinical evaluation of bonded amalgam restorations in endodontically treated premolar teeth: a one-year evaluation

AIM

The aim of this clinical study was to compare the fracture resistance, marginal adaptation, and rate of recurrent caries of bonded and nonbonded amalgam restorations in endodontically treated premolar teeth.

METHODS AND MATERIALS

A total of 36 patients with endodontically treated maxillary first or second premolars were selected and divided into three groups. The treatments in all groups consisted of lingual cusp coverage and cementation of a prefabricated intracanal post (No. 2 long, Dentatus USA, New York, NY, USA). One type of cavity liner was used for each group as follows: copal varnish (Group A), Amalgambond Plus (Group B), and Scotchbond Multi-Purpose (Group C). The teeth were then restored with Cinalux high-copper spherical amalgam (Cinalux, Sh. Dr Faghihi Dental Co., Tehran, Iran). After one year, fracture resistance, marginal adaptation, and secondary caries were evaluated. Fischer's exact test was used for statistical analysis using a 0.05 percent significance level.

RESULTS

There was no significant difference among groups with respect to fracture resistance (p=0.49). However, significant differences in marginal adaptation existed among the three groups (p=0.02) and no recurrent caries were found in any of the restored teeth.

CONCLUSION

Bonding amalgam restorations using Amalgambond Plus and Scotchbond Multi-Purpose Plus did not improve the fracture resistance or affect the resistance to secondary caries in endodontically treated premolar teeth. However, the teeth in both these bonded groups showed significant improvement in marginal adaptation compared with restorations placed with copal varnish (p=0.02).

CLINICAL SIGNIFICANCE

Amalgambond Plus or Scotchbond Multi-Purpose adhesive resins significantly improved marginal adaptation of amalgam compared with copal varnish, but did not enhance fracture resistance or affect the prevention of secondary caries.

[SEM comparative analysis of the composite diacrylic resin-enamel interface in laser and bur prepared cavities]

The aim of this study was to demonstrate that the size of the hybrid layer (HL) in the prepared enamel mechanic (M) and kinetic (K) with laser (WaterlaseMDBiolase), evaluated by scanning electron microscopy (SEM) restored with two types of resin composite is different.

MATERIAL AND METHOD

The study was realized in vitro on a sample of 40 extracted human premolar and molars teeth for orthodontic or periodontal reasons. The teeth were divided at random into equal four groups (Gr). There has been Class I cavities with a depth of 2 mm (M) at high and low speed with cylindrical diamond No.1 and globular carbide and (K) peaks MZ6-5, 5W+20 Hz 30% water 60% air. The teeth were restored using 3M Schotchbond Etch, 3M Single Bond Dental Adhesive System: Gr. 1: (K)(n = 10)-3M Filtekflow; Gr.2 : (K)(n = 10)3M FiltekZ250; Gr.3: (M)(n = 10)3M Filtekflow; Gr.4: (M)(n = 10)3M FiltekZ250. The materials were placed in a single layer and photoactivate source LED SmartLite (Dentsply), termocycling 500 cycles (5 degrees-55 degrees), stored (48h), cut lengthwise (diamond), polished, conditioned (H3PO4-37% -5s) analyzed by SEM (JEOLJSM 6390), SPSS 13.00 statistically analyzed (ANOVA, p = 0.05).

RESULTS

Analysis of the (HL) has highlighted differences between groups p = 0.05 average size (HL) being Gr.1;20.80 (+/- 0.72)microm, Gr.2;4.034 (+/- 0.0076)microm, Gr.3, 14.13 (+/- 0.63)microm, Gr.4, 1,43 (+/- 0.16)microm. Value size (HL) was influenced by the cavity preparation method for samples prepared by laser p = 0,005 in terms of size and in advantage of mechanical preparations in terms of quality (HL). Also the value of (HL) size was influenced by the type of material used in advance Gr.2 p = 0.0017.

CONCLUSIONS

The sealing of cavity depends more on the creep of materials and less on the type of preparation. Permission was obtained from a institutional ethical committee of "Gr.T. Popa" University of Medicine and Pharmacy Iaşi and that subjects gave written, informed consent).

Flowable glass ionomer cement as a liner: improving marginal adaptation of atraumatic restorative treatment restorations

PURPOSE

The present study aims to evaluate the in vitro microleakage of two layers GIC proximal restorations in primary molars.

METHODS

Forty primary molars received proximal cavity preparations and were randomly divided in two groups. G1 was restored with a regular powder/liquid ratio GIC. G2 firstly received a flowable layer of GIC and secondly a regular GIC layer. After 24h water storage (37 degrees C), the teeth were made impermeable with the exception of the restoration area and 1 mm of their surrounding, immersed in 0.5% methylene blue solution (4h), rinsed and sectioned mesio-distally. One side was polished and analyzed under light microscope. Replicates from the other side were observed under SEM. Microleakage evaluation was carried out by 3 evaluators.

RESULTS

The data analysis (Mann-Whitney) showed a significant (P<0.01) better result for G2. Regarding the SEM evaluation, irregularities were observed in the G1 at the tooth/GIC interface. For G2, it was not possible to observe any displacement of the GIC in relation to the tooth structure, which confirmed better adaptation as seen in the microleakage test.

CONCLUSION

the insertion of a flowable GIC layer in proximal cavities before the insertion of a regular GIC layer improves the material adaptation to the tooth.

Trends in dental education in the Persian Gulf--an example from Iran: contemporary placement of posterior composites

In recent years, there has been expansion of dental education programmes from established European and North American schools into regions in the Middle East, the Persian Gulf States, and Asia. Accompanying this, there has been migration of dentists from these regions of the world to Europe and North America in the hope of finding employment or to pursue postgraduate education. Little awareness exists, however in western countries on the amount and level of clinical training provided in dental schools in which these dentists have trained. The aim of this paper is to investigate the teaching to undergraduate students in Iran of an important aspect of clinical dentistry which is showing continual development in western schools, namely the use of resin-based composites in the restoration of posterior teeth. In 2008, a questionnaire seeking information on the teaching of posterior resin-based composites was distributed by email to the person responsible for delivering teaching of operative dentistry in each of the 18 dental schools with undergraduate dental degree programmes in Iran. All 18 schools teach the placement of occlusal and occlusoproximal resin-based composite restorations in premolar and permanent molar teeth. Resin-based composites currently account for 42% of posterior direct restorations placed by undergraduates in Iran. Despite variations between dental schools being noted in the teaching of certain techniques for posterior resin-based composites, the overall extent and content of teaching of posterior resin-based composites in Iran could be described as comparable to that observed in western countries.

The effect of thermocycling on the determination of microleakage in Permite amalgam restorations

INTRODUCTION

Microleakage is an important clinical performance parameter of restorative materials. A literature review of the effect of thermocycling on microleakage revealed an incongruity of results.

AIMS AND OBJECTIVES

The aim of this study was to describe the effect of thermocycling on microleakage in Class V Permite amalgam restorations.

METHODS

Class V cavities were prepared at the mesial and distal cemento-enamel junctions of 20 extracted, sound, human molar teeth. Cavities were treated with Polyvar cavity varnish and restored with Permite amalgam as per manufacturer's directions. Teeth were randomly divided into two groups of 10 teeth each. After one day only one group was thermocycled for 500 hundred cycles (5 - 55 degrees C; dwell time of 30 seconds: transfer time of 10 seconds). Teeth were subsequently submersed in 0.5% Basic Fuchsin solution (24 hours: room temperature), then cleaned and embedded in polyester potting resin. Teeth were sectioned longitudinally along the long axis of the tooth into three slices using the Isomet low speed saw. Microleakage was scored under a light microscope at 10 times magnification.

RESULTS

While microleakage at cementum margins was significantly and negatively influenced by thermocycling, enamel margins appeared to be significantly unaffected.

CONCLUSION

The effect of thermocycling on the determination of microleakage was only significant at the cementum margins of Permite restorations.

The Effect of Flowable Materials on the Microleakage of Class II Composite Restorations That Extend Apical to the Cemento-enamel Junction

The use of a flowable resin composite or compomer may reduce microleakage at the gingival floor of a deep Class II composite restoration that extends apical to the cemento-enamel junction.

Effect of Fiber Nets, Application Techniques and Flowable Composites on Microleakage and the Effect of Fiber Nets on Polymerization Shrinkage in Class II MOD Cavities

Fiber nets applied to Class II composite restorations resulted in a significant reduction in microleakage. Fiber nets also decreased polymerization shrinkage. Therefore, these materials may be acceptable for clinical applications. Incremental placement remains the preferred restorative technique for posterior composite restorations.

A technique for restoring Class V caries in primary canines

This article describes a technique for restoring Class V carious lesions in the primary dentition. The discussion will include the treatment of aprismatic enamel in primary teeth, bonding to dentin, and the restorative techniques that are available for composite bonding. A case report is presented that utilizes several modern techniques for restoring Class V lesions.

Effect of different adhesive protocols vs calcium hydroxide on primary tooth pulp with different remaining dentin thicknesses:24-month results

The aim of this randomized, controlled, single-blind and prospective study was to evaluate the clinical and radiographic success rates of three different bonding protocols vs calcium hydroxide liner for protection of the dentin-pulp complex of primary molars with different remaining dentin thicknesses. Two hundred forty primary molar teeth with moderate to deep occlusal caries were restored in 97 children who met inclusion criteria. After cavity preparation, the teeth were randomly assigned into four groups (n = 60/group) with respect to the material used for protection of the dentin-pulp complex: (1) total-etching with 36% phosphoric acid followed by an acetone-based adhesive (Prime&Bond NT), (2) a self-etch adhesive system (Xeno III), (3) an acetone-based adhesive (Prime&Bond NT) without prior acid conditioning, and (4) control: calcium hydroxide cement (Dycal). Teeth in groups 1-3 were restored with a polyacid-modified resin-based composite (Dyract AP) and those in group 4 with amalgam. The remaining dentin thickness was calculated using image analysis software (ImageJ). The teeth were evaluated clinically and radiographically for 24 months. The distribution of restored teeth with minimal remaining dentin thickness (< or =0.5 mm) was 3.3, 8.3, 8.3, and 10% for groups 1, 2, 3, and 4, respectively. Despite the absence of pulpal protection in groups 1-3, none of those teeth exhibited any significant clinical or radiographic symptom during the study period. After 2 years, the clinical and radiographic success rate of restorative treatments was 100%. Protection of the dentin-pulp complex with the tested bonding protocols resulted in similar outcomes in mainly shallow and medium deep cavities as compared to calcium hydroxide amalgam in more deep cavities, when indirect pulp treatment was performed in class I compomer restorations.

Gingival microleakage of Class II resin composite restorations with fiber inserts

PURPOSE

This investigation evaluated the effect of glass and polyethylene fiber inserts on the microleakage of Class II composite restorations with gingival margins on root surfaces.

METHODS

Fifty-four intact molars were sterilized with Gamma irradiation and mounted in acrylic bases. Class II slot cavities were made on both proximal sides of each tooth (3 mm wide, 1.5 mm deep) with the gingival margin on the root surface. The teeth were divided into nine groups, according to the technique of restoration and type of bonding agent. Filtek P-60 (3M/ESPE) was used to restore all cavities. Two types of fiber inserts were used: glass fiber (Ever Stick, StickTech) and polyethylene (Ribbond-THM), with three bonding agents being employed: Scotch Bond Multipurpose (3M/ESPE), Clearfil SE Bond (Kuraray) and Xeno IV (Dentsply). In the experimental groups, 3 mm long fiber inserts were inserted into restorations at the gingival seat. The control groups had no fiber inserts. The restorations were made incrementally and cured with LED light (UltraLume5, Ultradent). The restored teeth were stored in water for two weeks, then thermocycled for 3000 cycles (5 degrees C and 55 degrees C). The tooth surfaces were sealed with nail polish, except at the restoration margins. The teeth were immersed in 2% procion red dye solution, sectioned and dye penetration was assessed to determine the extent of microleakage according to a six-point scale.

RESULTS

The fiber groups generally showed reduced microleakage scores compared to the control groups. The Clearfil SE Bond (Kuraray)/Filtek P-60 (3M/ESPE) combination produced the lowest degree of microleakage, irrespective of fiber type. However, the glass fiber groups were more consistent in reducing microleakage than the polyethylene groups.

CONCLUSIONS

The use of fiber inserts significantly reduced gingival microleakage in Class II composite restorations with gingival margins in dentin, irrespective of the adhesive used. Clearfil SE Bond (Kuraray)/Filtek P60 (3M/ESPE) produced the lowest microleakage scores.

The effect of two root canal sealers on the retentive strength of glass fibre endodontic posts

This study was undertaken to examine the effect of eugenol-containing and non-eugenol-containing root canal sealers on the retention strength of glass fibre endodontic posts (ParaPost Fibre White) luted with a resin cement (ParaPost cement). We also examined the mode of failure that occurred visually by using scanning electron microscopy. Seventy-two single rooted, recently extracted, premolar teeth were root canal treated and randomly divided into two groups. Group 1 was obturated with gutta percha and a calcium hydroxide-based sealer (Sealapex, Kerr). Group 2 was obturated with gutta percha and a eugenol-based sealer (Tubli-Seal Kerr). The teeth were stored for 1 week in distilled water at 37 degrees C and then prepared for 9 mm posts with a 1.40-mm drill. The matching glass fibre post was luted with a resin cement following the manufacturer's instructions. The samples were stored for 1 week and thermocycled. The posts were removed from the root canals using a calibrated testing machine in tensile mode. The mean dislodging force for group 1 was 190.46 N and for group 2 was 183.8 N, with standard deviations of 54.9 and 56.0 N respectively. The t-test indicated no significant difference between the two groups. Failure of the posts occurred mainly within the resin layer. This study showed that under experimental conditions there was no statistically significant difference between Sealapex sealer and Tubli-Seal sealer on the retention of glass fibre posts using a resin cement.

Indirect pulp capping in the primary dentition: a 4 year follow-up study

PURPOSE

Evaluate clinical and radiographic changes in primary teeth submitted to indirect pulp capping (IPC) over a 48-month-period.

METHODS

Twenty seven primary molars with deep caries, but without preoperative signs of irreversible pulpits, were treated with IPC. The teeth were randomly divided into two groups, according to the material used for protection of the dentin-pulp complex. (1) a calcium hydroxide liner (Dycal) and (2) glass ionomer cement (Vitremer).

RESULTS

After 48 months, Group-1 showed a success rate of 88.8% and Group-2 of 93%. No statistical significant difference between the groups was observed (P = 0.62).

CLINICAL SIGNIFICANCE

The results of this study suggested that indirect pulp capping in primary teeth arrests the progression of the underlying caries, regardless of the material used as a liner.

Effect of a Novel Er:YAG Laser in Caries Removal and Cavity Preparation: A Clinical Observation

OBJECTIVE

We evaluated the applicability of a novel Er:YAG laser under clinical conditions.

BACKGROUND DATA

The Er:YAG laser has been demonstrated to be a safe and effective alternative to the conventional turbine bur, but the relatively low cutting speed prevented the wide application of Er:YAG laser in clinical cavity preparation.

METHODS

A Smart 2940 D laser developed by Deka Corporation was used for cavity preparation in 95 teeth of 45 patients. Parameters were as follows: wavelength 2.94 microm, pulse energy 700 mJ, repetition rate 8 Hz. Pain, discomfort, assessment during cavity preparation, prognosis factor, and overall clinical evaluation were assessed during or after treatment.

RESULTS

No adverse reaction was observed in any tooth. No intraoperative pain or only slight intraoperative pain was described in 85 teeth (89.5%). Cavity preparation was completed with the laser system alone in 90 teeth (94.7%). Overall clinical evaluation showed no safety problems, with a very good or good rating in 86 teeth (90.5%). The overall operation time was 49 sec on average.

CONCLUSION

The Smart 2940 D is an efficient, effective, safe, and suitable instrument for caries removal and for cavity preparation. It greatly shortens operation time.

Microtensile Bond Strengths to Cavity Floor Dentin in Indirect Composite Restorations using Resin Coating

PURPOSE

The aims of this study were (1) to evaluate the effect of a resin coating on the microtensile bond strengths (mu-TBSs) of indirect composite restorations bonded to dentin with resin cement and (2) to compare the mu-TBSs with that of a directly placed composite.

MATERIALS AND METHODS

Class I cavities were prepared in extracted human molars. The specimens were divided into five groups: For the indirect restorations, the cavity surfaces of the control group were left uncoated (group 1), while the surfaces of the experimental groups were resin coated with a dentin bonding system, Clearfil Protect Bond (PB; groups 2 and 3), or with a combination of PB and a flowable resin composite, Protect Liner F (PLF; group 4). The cavities were temporized for 1 day. Indirect composite restorations (Estenia) were cemented with a resin cement (Panavia F). Pretreatment with ED Primer II was performed in the groups 1, 3, and 4. For the direct restorations, the cavities were restored with PB and a direct composite (Clearfil AP-X; group 5). After 24 hours of water storage, mu-TBSs were measured at a crosshead speed of 1 mm/min. The data were analyzed with one-way analysis of variance and Sheffe's test (p < 0.05). In addition, fracture modes were determined visually and by scanning electron microscopy.

RESULTS

A combination of PB and PLF showed significantly higher bond strengths compared with the original bond strength of Panavia F and the single use of PB (p < 0.05). However, the highest bond strengths were obtained when PB was used for direct composite restorations (p < 0.05).

CONCLUSION

The application of a resin coating consisting of a self-etching primer dentin bonding system and a flowable resin composite significantly improved the mu-TBS of indirect restorations bonded to dentin using resin cement.

CLINICAL SIGNIFICANCE

A resin coating should be required to improve dentin bonding performance of Panavia F in indirect restorations. However, direct composite restorations still provide higher bond strength compared to indirect restorations.

Biocompatibility of resin-based dental materials applied as liners in deep cavities prepared in human teeth

BACKGROUND

Since only a few data have been published concerning the effects of resinous dental materials on the pulp-dentin complex, the aim of this study was to evaluate the biocompatibility of resin-based materials applied as liners in deep cavities prepared in human teeth.

METHODS

After preparing class V cavities, the following dental materials were applied on the axial walls: group 1, Vitrebond (VIT; 3M ESPE); group 2, Ultra-Blend Plus (UBP; Untradent); and group 3, Clearfil SE Bond (CSEB; Kuraray). In group 4 (control), the hard-setting calcium hydroxide cement Dycal (CH; Caulk/Dentsply) was used. The teeth extracted at 7 days or between 30 and 85 days after the clinical procedures were processed for histological evaluation.

RESULTS

For all the experimental and control groups, most of specimens exhibited no pulpal response or slight inflammatory reaction associated with slight tissue disorganization at 7-day period. Moderate inflammatory pulpal response occurred only in one tooth (RDT = 262 microm) of group 3 in which transdentinal diffusion of resin components was observed.

CONCLUSION

The resin-based dental cements VIT and UBP as well as the bonding agent CSEB presented acceptable biocompatibility when applied in deep cavities prepared in sound human teeth.

Microleakage after thermocycling of 4 etch and rinse and 3 self-etch adhesives with and without a flowable composite lining

This study evaluated the microleakage of composite fillings prepared with 4 etch and rinse and 3 self-etch adhesive systems after thermocycling. Also evaluated was the potential improvement of cavity sealing when utilizing a low charged resin lining for cavity preparations. Seventy recently extracted teeth were randomly allocated to 7 experimental adhesive systems: two 3-step etch and rinse adhesive systems, Scotchbond Multipurpose (SBMP) and Optibond Solo Plus (OS); two 2-step etch and rinse adhesive systems, referred to as "one-bottle," Scotchbond 1 (SB1) and Gluma Comfort Bond + Desensitizer (G); and 3 self-etch "all-in-one" adhesives, Adper Prompt-L-Pop (PLP), Xeno III (X-III) and iBond (iB). On each tooth, 2 rectangular cavities were prepared at the cemento-enamel junction: 1 cavity was prepared with adhesive and the hybrid composite and the second was filled with the same adhesive and a thin layer of flowable composite (Filtek Flow) under the resin composite (Z100). All teeth were thermocycled for 800 cycles (5 degrees C-55 degrees C, 30 seconds dwell time). Leakage was evaluated on a 6-point (0-5) severity scale for enamel and dentin on 4 interfaces for each restoration. The results are expressed as means +/- standard deviation (SD). Microleakage scores were analyzed by means of generalized linear mixed models (GLMM), assuming an ordinal logistic link function. Covariates in the model were: (1) adhesives, (2) fluid composite and (3) interface. The model also accounts for repeated measurements on the various teeth. The authors found that the mean score of microleakage per tooth was significantly higher at the enamel rather than at the dentin interfaces (1.21 +/- 0.51 and 0.87 +/- 0.48; p<0.0001). In this study, there was no significant difference among the 4 etch and rinse adhesive systems. On the other hand, these adhesives yielded smaller mean scores of microleakage than the 3 self-etch systems (respectively, 0.85 +/- 0.2 and 1.3 +/- 0.5; p<0.0001). Among the self-etch adhesives, microleakage was significantly greater for PLP (1.74 +/- 0.46) than for the other self-etch products (p<0.0001), while X-III, an intermediary strong self-etch, was found to be as good as the etch and rinse systems, with a mean score of 0.97 +/- 0.27. In addition, results have also shown that an under layer of flowable composite significantly improved the water tightness of the PLP adhesive restorations (p=0.042). This in vitro study concluded that the self-etch adhesives remain less effective than etch and rinse. Nevertheless, X-III, a self-etch adhesive, showed acceptable performance in accordance with this study's 6-point severity scale of microleakage, but this needs to be confirmed in further clinical studies. On the other hand, this study failed to reveal that the addition of a thin layer of fluid composite improved the water tightness of the restoration, except for PLP.

Using cavity liners with direct posterior composite restorations

Cavity liners have traditionally been used in direct and indirect restorations for purposes such as promoting reparative dentin and neutralizing acids. Today, liners are used when resin composites are used as the restorative materials on the posterior teeth, but for a different reason. Clinically, liners are considered to decrease sensitivity and wet the cavity better than restorative composites because of their flowability, adaptation to the dentinal surface, and adhesion. As bonding systems and composite materials continue to improve and become better understood, so do the techniques for placing composites. This has led to the reassessment of the clinical relevance and function of liners. Some clinicians don't use cavity liners, assuming they are a thing of the past; some use composite liners, and others use resin-modified glass ionomer liners. Additionally, there is not a clear agreement over the function of liners, such as when and why they should be used or what type of liner material would provide the best performance for a particular clinical situation. This article attempts to clarify some of the confusion surrounding the use of liners by reviewing the available literature on the subject and attempting to give evidence-based rationale for the use and protocol for the clinician.

Microleakage in Conventional and Bonded Amalgam Restorations: Influence of Cavity Volume

The volume of cavity preparations showed no influence on amalgam restoration microleakage. In most situations, bonded amalgam performed similarly to conventional amalgam restorations. It was also found that microleakage was higher in margins located in cementum-dentin.

The effect of base/liner use on restoration leakage

Central to the success of a restoration is the quality of the restoration-dentin interfacial seal; any compromise of the seal can lead to secondary or recurrent decay. Class V restorations have a high leakage propensity and this study evaluates the effect of base/liner placement on leakage behavior. Class V intracoronal half enamel/half dentin preparations (3.0 x 2.0 x 2.0 mm) were cut in four groups (n = 10) of extracted human teeth with a new bur used for each cavity preparation. All teeth were single-rooted, single-canal anterior teeth. Base/liner usage differed between each group. The first group of teeth had no liner or base, while a liner was placed in the second group of teeth prior to conditioning and restoration. A base was placed in the third group of cavity preparations and both the base and liner were placed in the fourth group. After preparation, a small diameter bare-end PVC-insulated copper wire was inserted within the root canal of each tooth from the apex to firm contact with the pulp chamber roof. The tooth-wire interface and root surface was sealed and leakage was followed electrochemically for 35 days in 0.9% NaCl solution. All of the teeth leaked to some degree; however, teeth that were restored without liner or base demonstrated the smallest amount of leakage. The greatest leakage was noted in teeth restored with both a base and a liner; teeth restored with only a base showed greater leakage than those restored with only a liner. The findings indicate that the presence of a base and/or a liner results in greater leakage compared with intracoronal Class V preparations that were conditioned and restored only. The data suggest that placing both a base and a liner increases restoration leakage significantly.

Effect of APF gel on micromorphology of resin modified glass-ionomer cements and flowable compomers

The purpose of this study was to evaluate the surface micromorphology of resin modified glass-ionomer cements and flowable compomers. In the study two resin modified glass-ionomers and two flowable compomers were used to prepare standardized 20 cylinderic samples. Samples were divided into four groups. Surface treatments with APF gel for experimental groups (group B,C,D) or distilled water as a control (group A) were performed four times. In group B, only APF gel was applied. In group C, after the APF gel application, the samples were immersed into the demineralizing and remineralizing solutions. In group D, before the APF gel application, the buffer solution was applied. The examinations of the surface micromorphology of the materials were made by using scanning electron microscope (SEM). Results showed that in group B all of the materials except Compoglass Flow, and in group C all of the materials showed erratic behaviours. In group D, severe erratic effect (score 2) was obtained on the surfaces of Vivaglassliner and Dyract Flow, and for the others score 1 signals were found. The moderate degradation was obtained by applying of only APF gel on the surfaces of both material groups. The addition of pH circulation caused increasing of micromorphologic changes on the surfaces of all materials. The effect of application of buffer solution on the surfaces before APF gel changed according to the materials. If acidulated fluoride gel is preferred for prophylactic therapy in patients' mouth, for the success, either buffer or neutral fluoride have to be applied on the restored teeth by resin based materials before acidulated fluoride application.

Effects of cleaning agents on bond strength to dentin

The cleaning of cavity walls aims to improve adhesive restorative procedures and longevity of restorations. This study has compared the effect of three cleaning agents--sodium bicarbonate jet (Profi II, Dabi Atlante, São Paulo, Brazil); pumice paste plus a biologic detergent (Tergestesim, Probem, São Paulo, Brazil); air water spray--on the bond strength between dentin and two different adhesive systems: Clearfil SE Bond (Kuraray, Kioto, Japan) and Scotchbond Multi-Purpose Plus (3M-ESPE, São Paulo, Brazil). Six groups (n: 10) of dental fragments obtained from young adult extracted teeth were prepared, and each one received one of the listed surface cleaning techniques. After the adhesive application, a cone-shaped test body was built with AP-X (Kuraray, Kioto, Japan) or Z100 (3M-ESPE, São Paulo, Brazil) composite resins, using a Teflon matrix. The specimens were tested for tensile bond strength after one-week storage in distilled water at 37 degrees C. Two pairs of fractured specimens of each group were randomly chosen and processed for scanning electron microscopy (SEM) analysis. ANOVA test of the bond strength values showed no statistical differences among the cleaning agents and neither between their interactions with the bonding systems. Upon SEM analysis, most surfaces showed mixed fractures of adhesive and cohesive failures in bonding resin to dentin. Based on statistical and SEM analysis, it was concluded that the cleaning agents studied did not interfere with the bond strength of the adhesive systems used to dentin.

Marginal and internal adaptation of composite restorations using a resin liner on deproteinized substrate

OBJECTIVE

The purpose of this study was to evaluate the use of resin liner on deproteinized substrate on marginal and internal adaptation of composite restorations.

MATERIAL AND METHODS

Twenty-four recently extracted 3rd molars were selected. The crowns were sectioned in a mesio-distal direction, and the specimens were ground to expose a flat enamel area of at least 6 mm in diameter. Cavities were prepared on the central area of flattened surfaces. The specimens were randomly assigned into four groups (n = 12): SB - 1. Acid etch, 2. Single bond application (SB); NaOCl/SB - 1. acid etch, 2. 10% sodium hypochlorite solution application for 60 s (NaOCl), 3. SB; SB/PL - 1. acid etch, 2. SB, 3. protect liner F (PL); NaOCl/SB/PL - 1. acid etch, 2. NaOCl, 3. SB, 4. PL. All cavities were restored with Filtek Z250 and polished. The outer and internal margins were stained using Caries Detector (Kuraray), observed under the stereomicroscope, and transferred to a computer measurement program. The length of the gap was expressed as a percentage of the total length of the margins observed. Data (internal adaptation) were submitted to ANOVA and Tukey's test.

RESULTS

There were no gaps at enamel outer margins in any specimen of any group. There was no statistically significant difference in internal adaptation between SB (18%) and NaOCl/SB (18%). NaOCl/SB/PL showed the worst internal adaptation (21%), with the higher percentage of internal gaps, statistically differing from SB/PL, which showed the best internal adaptation (12%).

CONCLUSIONS

Resin liner can effectively enhance internal adaptation on demineralized dentin. However, on demineralized and deproteinized dentin it affects the internal adaptation of composite restorations negatively.

Evaluation of biocompatibility of mineral trioxide aggregate with an improved rabbit ear chamber

In the present study, the biocompatibility of mineral trioxide aggregate (MTA) to the revascularization of the connective tissues was evaluated by using the improved rabbit ear chamber, in vivo. Twenty improved rabbit ear chamber was prepared from 12 male albino-rabbit by using a well through which a material could be introduced into the living vascular tissue. Ten chambers were provided for MTA, and the remaining 10 chambers were used for a calcium hydroxide-containing root canal sealer (Sealapex), as a comparator. A volume of about 1.5 mm(3) of the materials were inserted into the chamber and the interaction between the vascular tissue and materials was observed by using a biomicroscope immediately after application, at 1, 3, 5.5, 8, 24, 48, 72 h, and once a week up to 4 weeks. The results revealed that revascularization of connective tissue took place with complete recovery of microcirculation within 4 weeks in both MTA and Sealapex. However, the precipitate-barrier and brown zone around periphery of Sealapex was not observed in MTA treated samples. It can be concluded that MTA is biocompatible and does not produce any adverse site effect on microcirculation of the connective tissue.

The effect of fibre insertion on fracture resistance of root filled molar teeth with MOD preparations restored with composite

AIM

To evaluate the effect of using flowable composite with or without leno woven ultra high modulus polyethylene fibre reinforcement on fracture resistance of root filled mandibular molars with mesio-occlusodistal (MOD) preparations.

METHODOLOGY

Sixty sound extracted human mandibular molars were randomly assigned to five groups (n = 12). Group 1 did not receive any preparation. From groups 2 to 5, the teeth were root filled and MOD preparations were created. Group 2 remained unrestored. Group 3 was restored with a dentine bonding system (DBS; SE Bond, Kuraray, Japan) and composite resin (CR) (AP-X; Kuraray). In group 4, flowable composite resin (Protect Liner F; Kuraray) was used before restoring teeth with CR. In group 5, leno woven ultra high modulus polyethylene ribbon fibre (Ribbond, Seattle, WA, USA) was inserted into the cavities in a buccal to lingual direction and the teeth were then restored with DBS and CR. After finishing and polishing, the specimens were stored in 100% humidity at 37 degrees C for 1 day. Compressive loading of the teeth was performed using a universal testing machine at a crosshead speed of 0.5 mm min(-1). The mean load necessary to fracture the samples were recorded in newtons (N) and were subjected to analysis of variance (ANOVA) and Tukey post-hoc test.

RESULTS

The mean load necessary to fracture the samples in each group were (in N): group 1: 1676.75 +/-154.63(a), group 2: 376.51 +/- 37.36(b), group 3: 733.23 +/- 133.33(c), group 4: 786.48 +/- 145.34(c), group 5: 943.63 +/- 121.15(d). There were statistically significant differences between the groups annotated with different letters.

CONCLUSIONS

(i) Use of flowable composite resin under composite restorations had no effect on fracture resistance of root filled molar teeth with MOD preparations, (ii) use of polyethylene ribbon fibre under composite restorations in root filled teeth with MOD preparations significantly increased fracture strength.

Remineralization of carious dentin. II: In vivo microradiographic and chemical studies in human permanent teeth capped with calcium hydroxide

The main aim of this in vivo study was to evaluate a possible remineralization of human carious dentin by means of chemical and microradiographic studies. Eighty-six samples of carious dentin were removed from 36 permanent teeth of 24 patients. These were divided into untreated (control) and chemically pure calcium hydroxide-capped (experimental) samples and analyzed at intervals varying from 10 to 120 days. They were classified according to depth of caries and degree of dentin softening and evaluated in relation to weight, phosphorus concentration, qualitative and quantitative microradiography and absolute values of total mineral content. One of two halves of each sample was selected for chemical studies and the other for total content of mineral salts. Experimental samples were examined with a light microscope and the results obtained showed a qualitative increase in radiopacity. Quantitatively, it was observed that, in the case of samples analyzed for phosphorus concentration, the average mean of differences in percentage increase after treatment was 9.6%, while for the samples evaluated microradiographically for total mineral content, it was 22.29%. In both cases, the differences were statistically significant.

One-year clinical evaluation of a flowable resin liner associated with a microhybrid resin in noncarious cervical lesions

The aim of this study was to compare the clinical performance over 1 year of a microhybrid composite resin for class V restorations both lined and not lined with a flowable composite resin. Nineteen patients having at least two pairs of cervical noncarious lesions under occlusion were enrolled in this study. A total of 38 restorations were placed, half for each group (Single-Bond + Filtek-Flow + Filtek Z250, and Single-Bond + Filtek Z250). Two calibrated operators placed all restorations according to the manufacturers' instructions. Two other independent examiners evaluated the restorations at baseline and after a 12-month period according to the USPHS criteria and modified criteria for color match. The classic alpha score was divided into A1 for "not detectable" and A2 for "slightly discernible" filling. Statistical analysis was conducted using Fisher's exact test and McNemar's test (P=0.05). One restoration was lost after 12 months for each group (retention rate 95% for each group). After 12 months, 18 restorations showed a trend towards dark yellowing (color match A2). The use of Filtek Flow as a liner under Filtek Z250 restorations did not improve the clinical performance of class V restorations after 6 and 12 months of evaluation.

On the diagnosis and management of neurocutaneous syndrome, a toxicity disorder from dental sealants

Neurocutaneous syndrome, a newly discovered toxicity disorder, is characterized by neurological sensations, pain, depleted energy, and memory loss as well as itchy cutaneous lesions that may invite various opportunistic infections. Components in the calcium hydroxide dental sealants Dycal, Life and Sealapex have been identified as sources of the observed symptoms. Sulfonamide and neurological toxicity issues are discussed, and three case histories are presented. Additional notes on zinc oxide, Fynal, IRM, and Sultan U/P sealers are also included. Diagnostic and management protocols at the Parasitology Center, Inc., are proposed.

In vitro microleakage of adhesive-sealed dentin with lactic acid and saliva exposure: a radio-isotope analysis

OBJECTIVES

The aim of this study was to evaluate the dentin-protective potential of two dentin-bonding systems (Syntac and Clearfil SE Bond) on artificial saliva and lactic acid exposure.

METHODS

Radiochemical analysis in combination with polarization-microscopy was used in the current study. Different applications in MOD preparations in irradiated human molars were compared. Untreated cavities and cavities covered with flowable resin served as controls. Forty-eight specimens were immersed in artificial saliva (pH 7.5), 48 in lactic acid (pH 4). Activity of (32)P was measured between days 1 and 21 and loss of mineralized tissue was estimated.

RESULTS

In lactic acid, cavities sealed with single bond, double bond or bond plus cavity sealer application resulted in significantly lower mineralized tissue loss compared to negative controls (p < 0.05). Upon both saliva and lactic acid exposure, bonding plus sealer application proved to be the most protective treatment (p < 0.05).

CONCLUSIONS

Based on these in vitro findings it may be advisable to use a filled cavity sealer or a flowable resin to protect dentin from demineralization. The radiochemical analysis appeared to be valuable in evaluating the protective potential of bonding agents against dentin demineralization.