In vitro longevity of bonding properties of universal adhesives to dentin

PURPOSE

To evaluate the immediate and 6-month resin-dentin bond strength (μTBS) and nanoleakage (NL) of universal adhesives that contain or do not contain methacryloyloxydecyl dihydrogen phosphate (MDP) and are used in the etch-and-rinse and self-etch strategies.

METHODS AND MATERIALS

Forty caries-free extracted third molars were divided into eight groups for μTBS (n=5). The groups were bonded with the Clearfil SE Bond (CSE) and Adper Single Bond 2 (SB) as controls; Peak Universal, self-etch (PkSe) and etch-and rinse (PkEr); Scotchbond Universal Adhesive, self-etch (ScSe) and etch-and-rinse (ScEr); and All Bond Universal, self-etch (AlSe) and etch-and-rinse (AlEr). After composite restorations, specimens were longitudinally sectioned to obtain resin-dentin bonded sticks (0.8 mm(2)). The μTBS of the specimens was tested immediately (IM) or after 6 months of water storage (6M) at 0.5 mm/min. Some sticks at each storage period were immersed in silver nitrate and photo developed, and the NL was evaluated with scanning electron microscopy. Data were analyzed with two-way repeated-measures analysis of variance and Tukey test (α=0.05).

RESULTS

At the IM period, PkSe and PkEr showed μTBS similar to the control adhesives (p>0.05) but increased NL pattern and lower μTBS after 6M (p<0.05). ScSe and ScEr showed intermediary μTBS values at the IM period but remained stable after 6 months (p>0.05). AlSe showed the lowest μTBS (p<0.05), but μTBS and NL remained stable after 6M (p>0.05). AlEr showed higher IM μTBS but showed higher degradation after 6M (p<0.05).

CONCLUSIONS

Universal adhesives that contain MDP showed higher and more stable μTBS with reduced NL at the interfaces after 6 months of water storage.

Immediate Dentin Sealing: A Fundamental Procedure for Indirect Bonded Restorations

The purpose of this article is to review evidence-based principles that could help optimize dentin bonding for indirect composite and porcelain restorations. More than 30 articles were reviewed, most of them addressing the specific situation of dentin bonding for indirect restorations. It appears that the combined results of this data plus clinical experience suggest the need for a revision in the dentin bonding procedure. Immediate application and polymerization of the dentin bonding agent to the freshly cut dentin, prior to impression taking, is recommended. This new application procedure, the so-called immediate dentin sealing (IDS), appears to achieve improved bond strength, fewer gap formations, decreased bacterial leakage, and reduced dentin sensitivity. The use of filled adhesive resins (low elastic modulus liner) facilitates the clinical and technical aspects of IDS. This rational approach to adhesion also has a positive influence on tooth structure preservation, patient comfort, and long-term survival of indirect bonded restorations.

CLINICAL SIGNIFICANCE

Tooth preparation for indirect bonded restorations (eg, composite/ceramic inlays, onlays, and veneers) can generate significant dentin exposures. It is recommended to seal these freshly cut dentin surfaces with a dentin bonding agent (DBA) immediately following tooth preparation, before taking impression. A three-step total-etch DBA with a filled adhesive resin is recommended for this specific purpose. The major advantages, as well as the technical challenges of this procedure, are presented in detail.

Caries-preventive effect of fissure sealants: a systematic review

The objectives of this study were to evaluate systematically the evidence of the caries-preventive effect of fissure sealing of occlusal tooth surfaces and to examine factors potentially modifying the effect. The search strategies included electronic databases, reference lists of articles, and selected textbooks. Inclusion criteria were randomized or quasi-randomized clinical trials or controlled clinical trials comparing fissure sealing with no treatment or another preventive treatment in children up to 14 years of age at the start; the outcome measure was caries increment; the diagnostic criteria had been described; and the follow-up time was at least 2 years. Inclusion decisions were taken and grading of the studies was done independently by two of the authors. The main measure of effect was relative risk reduction. Thirteen studies using resin-based or glass ionomer sealant materials were included in the final analysis. The results showed that most studies were performed during the 1970s and a single application had been utilized. The relative caries risk reduction pooled estimate of resin-based sealants on permanent 1st molars was 33% (relative risk = 0.67; CI = 0.55-0.83). The effect depended on retention of the sealant. In conclusion, the review suggests limited evidence that fissure sealing of 1st permanent molars with resin-based materials has a caries-preventive effect. The evidence is incomplete for permanent 2nd molars, premolars and primary molars and for glass ionomer cements. Overall, there remains a need for further trials of high quality, particularly in child populations with a low and a high caries risk, respectively.

Fracture resistance and microleakage of endocrowns utilizing three CAD-CAM blocks

This study assessed marginal leakage and fracture resistance of computer-aided design/computer-aided manufacturing (CAD/CAM) fabricated ceramic crowns with intracoronal extensions into the pulp chambers of endodontically treated teeth (endocrowns) using either feldspathic porcelain (CEREC Blocks [CB], Sirona Dental Systems GmbH, Bensheim, Germany), lithium disilicate (e.max [EX], Ivoclar Vivadent, Schaan, Liechtenstein), or resin nanoceramic (Lava Ultimate [LU], 3M ESPE, St Paul, MN, USA).). Thirty extracted human permanent maxillary molars were endodontically treated. Standardized preparations were done with 2-mm intracoronal extensions of the endocrowns into the pulp chamber. Teeth were divided into three groups (n=10); each group was restored with standardized CAD/CAM fabricated endocrowns using one of the three tested materials. After cementation with resin cement, specimens were stored in distilled water at 37°C for one week, subjected to thermocycling, and immersed in a 5% methylene-blue dye solution for 24 hours. A compressive load was applied at 35 degrees to long axis of the teeth using a universal testing machine until failure. Failure load was recorded, and specimens were examined under a stereomicroscope for modes of failure and microleakage. Results were analyzed using one-way analysis of variance and Bonferroni post hoc multiple comparison tests (α=0.05). LU showed significantly (p<0.05) higher fracture resistance and more favorable fracture mode (ie, fracture of the endocrown without fracture of tooth) as well as higher dye penetration than CB and EX. In conclusion, although using resin nanoceramic blocks for fabrication of endocrowns may result in better fracture resistance and a more favorable fracture mode than other investigated ceramic blocks, more microleakage may be expected with this material.

Prevention of enamel demineralization: An in-vitro study using light-cured filled sealant

INTRODUCTION

Enamel demineralization is an undesirable side effect of orthodontic treatment with fixed appliances. The purpose of this in-vitro study was to evaluate the efficacy of applying a light-cured filled sealant onto the buccal tooth surfaces to prevent demineralization.

METHODS

Fifty extracted human third molars were allocated to 1 of 5 groups: (1) enamel surface untreated (control); (2) surface etched; (3) fluoride varnish applied; (4) enamel etched and coated with a light-cured, unfilled sealant (control sealant); and (5) enamel etched and coated with a light-cured, filled sealant (Pro Seal, Reliance Orthodontic Products, Itasca, Ill). The enamel surface of each specimen was brushed for 15,000 strokes with nonfluoride toothpaste slurry with a piston-action brushing machine under a standardized load. All samples were then cycled for 14 days through a daily procedure of demineralization for 6 hours and remineralization for 17 hours. Then the teeth were sectioned and evaluated quantitatively by cross-sectional microhardness testing.

RESULTS

Demineralization in the Pro Seal group was significantly less (P < .05) than in the other groups. Teeth treated with fluoride varnish exhibited 30% less demineralization than the control teeth, the enamel-etched teeth, and the teeth treated with a light-cured, unfilled sealant (P < .05).

CONCLUSIONS

Pro Seal can be considered for use as a preventive method to reduce enamel demineralization adjacent to orthodontic attachments, particularly in patients who exhibit poor compliance with oral hygiene and home fluoride use.

Three-year clinical effectiveness of a two-step self-etch adhesive in cervical lesions

A 3-yr randomized, controlled prospective study evaluated the clinical effectiveness of a mild two-step self-etch adhesive, Clearfil SE, in Class-V non-carious lesions. The hypothesis tested was that prior selective etching of enamel with phosphoric acid does not affect the 3-yr clinical performance of this adhesive. A total of 100 lesions in 29 patients were randomly restored in one or two pairs, according to two experimental protocols: (i) application of Clearfil SE according to the instructions of the manufacturer (C-SE non-etch); and (ii) similar application of Clearfil SE with prior etching of enamel cavity margins with phosphoric acid (C-SE etch). Clearfil AP-X was used as a restorative material. At 3 yr, 90% of the restorations were examined for retention, marginal integrity, marginal discoloration, caries recurrence, postoperative sensitivity, and preservation of tooth vitality. An excellent retention rate (100%) was noted after 3 yr of clinical functioning. Only one restoration of the C-SE etch group was clinically unacceptable owing to the presence of a severe cervical marginal defect. A pairwise comparison between both groups showed a significant difference only in the number of small marginal defects at the enamel side, which was higher in the C-SE non-etch group. These incisal defects were small and clinically irrelevant. Superficial marginal discoloration increased slightly in the C-SE non-etch group and was related to the higher frequency of small incisal marginal defects. In this latter group, localized marginal discoloration was observed significantly more in smokers. In conclusion, the clinical performance of the mild two-step self-etch adhesive, Clearfil SE, remained excellent after 3 yr of clinical functioning. Additional etching of the enamel cavity margins was not critical for its clinical performance.

The effect of sandblasting and different primers on shear bond strength between yttria-tetragonal zirconia polycrystal ceramic and a self-adhesive resin cement

PURPOSE

To evaluate the effect of zirconia primers, air-abrasion, and tribochemical surface treatment methods on the shear bond strength between yttria-tetragonal zirconia polycrystal (Y-TZP) ceramic and self-adhesive resin cement.

METHODS AND MATERIALS

Y-TZP ceramic surfaces were ground flat with 600-grit silicon carbide paper and then divided into seven groups of 10 and treated as follows: untreated (control), Monobond Plus, Z-PRIME Plus, ESPE Sil with CoJet, air-abrasion, Monobond Plus with air-abrasion, and Z-PRIME Plus with air-abrasion. Self-adhesive resin cement was placed onto the treated Y-TZP specimens for each group. All specimens were thermocycled and subjected to a shear bond strength test. Scanning electron microscope images of the fractured areas and x-ray diffraction (XRD) analysis of the surface-treated Y-TZP specimens were performed. Data were statistically analyzed using one-way analysis of variance and the Student-Newman-Keuls multiple comparison test (p<0.05).

RESULTS

The Z-PRIME Plus treatment in combination with air-abrasion produced the highest bond strength (16.50±2.26 MPa), followed by air-abrasion (10.56±3.32 MPa), and then Monobond Plus combined with air-abrasion (8.93±3.13 MPa), ESPE Sil after CoJet application (8.54±3.98 MPa), and the Z-PRIME Plus group (8.27±2.79 MPa). The control (3.91±0.72 MPa) and Monobond Plus (4.86±1.77 MPa) groups indicated the lowest results (p<0.05). The XRD results showed the peaks of the monoclinic phase for the air-abrasion and CoJet treatment groups compared with the Y-TZP control.

CONCLUSION

Z-PRIME Plus primer application after air-abrasion presented the best results for improving the bond strength between Y-TZP ceramic and self-adhesive resin cement.

The evaluation of direct composite restorations for the worn mandibular anterior dentition ? clinical performance and patient satisfaction

This prospective split-mouth clinical trial evaluated the performance and patient satisfaction of 168 Herculite XRV direct composite restorations bonded to the worn anterior dentition of 18 patients with localized anterior tooth surface loss. One hundred and six of these restorations were placed on the mandibular anterior teeth. The restorations increased the anterior occlusal vertical dimension between 0.5 and 5 mm and the posterior occlusal contacts were restored after a mean duration of 6.2 months (range: 3-13 months) in 14 out of the 15 'Dahl' sub-group patients. The restorations were evaluated after 2.5 years of service by five examiners. Four patients and 23 mandibular restorations were lost to follow-up. Multiple clinical and restorative variables were assessed to determine their influence on restoration performance. Complete failure occurred in 6% of the restorations. Circumferential preparation and height of the restorative addition did not influence the performance of the restorations. A Visual Analogue Scale (VAS) was used to assess the patient's opinion regarding sensitivity, aesthetics, longevity and function of the worn mandibular anterior teeth. A statistically significant difference (95% CI) was found between the pre-operative and 1-month review VAS responses for aesthetics and longevity and this was maintained at the 2.5-year review. Direct composite restorations placed at an increased occlusal vertical dimension are a simple and time-efficient method of managing the worn mandibular anterior dentition. Patient's acceptance and adaptation to the technique is good and the results are accompanied with a high level of patient satisfaction that is maintained for the medium-term.

The long-term effectiveness of five current desensitizing products on cervical dentine sensitivity

The aim of this study was to compare the long-term effectiveness of five desensitizing products on 25 male and 27 female patients (total 52) aged 21-67 years (mean 36 +/- 7 years) suffering from cervical dentine sensitivity. All subjects were seen by the same examiner (ID) who was blinded to the applied treatment for 3-month clinical study. Patients were asked to record their overall sensitivity by marking a point on a 10 cm Visual Analogue Scale (VAS). Two hundred and seventy-seven sensitive teeth were treated by one of the five desensitizing products, all of which were placed following manufacturers' instructions by the other investigator (AS). A paired (split mouth) study design was used and selection of quadrants was randomized. At the post-treatment and at 10 days and 3 months periods, sensitivity measurements were recorded by the same investigator (ID). Statistical analysis showed that all of the VAS scores at post-treatment evaluation points were significantly decreased compared with baseline data (P < 0.05). There was a significant reduction in mean sensitivity scores in the Protect Liner F and the Health-Dent Desensitizer groups when compared with Fluoline varnish at the 10-day time point (P < 0.05). At 3 months, the Protect Liner F group continued to show a significantly reduced sensitivity level when compared with Health-Dent Desensitizer, Single Bond, Fluoline and Gluma Desensitizer (P < 0.05). The present study demonstrated that although at the end of 3-month evaluation period all desensitizers showed lower VAS sensitivity values compared with baseline, there were differences in the level of reduction of cervical dentine sensitivity.

Caries-preventive effect of a one-time application of composite resin and glass ionomer sealants after 5 years

The aim of the present trial was to (1) compare the caries-preventive effect of glass ionomer sealants, placed according to the atraumatic restorative treatment (ART) procedure, with composite resin sealants over time and (2) investigate the caries-preventive effect after complete disappearance of sealant material. Forty-six boys and 57 girls, mean age 7.8 years, were randomly divided into two treatment groups in a parallel-group study design. A light-polymerized composite resin sealant material and a high-viscosity glass ionomer were each placed in 180 fully erupted first molars in their respective treatment groups. Evaluation took place annually for 5 years by calibrated examiners. After 5 years, 86% composite resin and 88% glass ionomer sealants did not survive. Three categories of re-exposure periods for caries development in pits and fissures after complete loss of sealants were distinguished: 0-1, 1-2 and 2-3 years. In the 2- to 3-year group, 13 and 3% of pits and fissures previously sealed with composite resin and glass ionomer, respectively, were diagnosed as having developed a dentine lesion. The relative risks (95% CI) of dentine lesion development in surfaces sealed with glass ionomer compared to those sealed with composite resin after 3, 4 and 5 years were 0.22 (0.06-0.82), 0.32 (0.14-0.73) and 0.28 (0.13-0.61), respectively. The relative risks of dentine lesion development in pits and fissures previously sealed with glass ionomer compared with composite resin over re-exposure periods of 1-2 and 2-3 years were 0.26 (0.14-0.48) and 0.25 (0.09-0.68), respectively. We conclude that the caries-preventive effect of high-viscosity glass ionomer sealants, placed using the ART procedure, was between 3.1 and 4.5 times higher than that of composite resin sealants after 3-5 years. Furthermore, high-viscosity (ART) glass ionomer sealants appear to have a four times higher chance of preventing caries development in re-exposed pits and fissures of occlusal surfaces in first molars than light-cured composite resin sealant material over a 1- to 3-year period. A well-designed clinical trial using different types of oral health personnel should be implemented to confirm these initial results.

Conventional versus resin-modified glass-ionomer cement for Class II restorations in primary molars. A 3-year clinical study

OBJECTIVE

To compare the clinical performance of two glass-ionomer cements (GICs)for Class II restorations in primary molars: a conventional cement (Fuji II) and a resin-modified cement (Vitremer).

DESIGN

Split mouth and random assignment to the two materials were used for the majority of the molars.

SAMPLE AND METHODS

Forty consecutive 4-7-year-old children were included. One operator made 115 restorations: 53 with Vitremer and 62 with Fuji II. The restorations were evaluated clinically, radiographically and from colour photographs.

RESULTS

The cumulative success rate of the Vitremer restorations was 94% and that of the Fuji II restorations 81%. The difference is statistically significant. The risk of a failed restoration was more than five times higher with Fuji II than with Vitremer as the restorative material. Of the 13 unsuccessful restorations, seven had lost their retention, four had secondary caries, and two were fractured.

CONCLUSIONS

The resin-modified GIC offered advantages over the conventional GIC for restoring approximal caries in primary molars.

Fracture Resistance of Simulated Immature Teeth Filled with Resilon, Gutta-Percha, or Composite

The purpose of this study was to evaluate the fracture resistance gained by filling root canals of simulated immature teeth with either Resilon, gutta-percha, a self-curing flowable composite resin (BisFil 2B), or a self-curing hybrid composite resin (BisFil II). Seventy-two sheep incisors were divided into six groups of 12 teeth each. Negative controls received no treatment. Teeth in all other groups were prepared until a size 120 LightSpeed LSX instrument could be passed out the apex. After apical placement of a mineral trioxide aggregate (MTA) barrier, the canals were filled with their respective test material to the facial CEJ. The positive control canals were left unfilled. The access openings (including positive controls) were restored with BisFil II. Each root was horizontally fractured through the test material using an Instron. The mean peak loads to fracture were recorded. The hybrid composite resin (BisFil II) was the only material significantly more fracture resistant than positive controls (p < 0.017).

Progression of Sealed Initial Bovine Enamel Lesions under Demineralizing Conditions in vitro

The use of sealants for the infiltration of proximal enamel lesions could be a promising alternative to the common strategies of remineralization and operative treatment. The aim of the present study was to compare the progression of sealed initial enamel lesions after exposure to a demineralizing solution in vitro. In each of 54 bovine enamel specimens three subsurface lesions were created. Two of the lesions were etched with phosphoric acid and sealed with either a fissure sealant or with various adhesives (1-5) for 15 s or 30 s, respectively, whereas one lesion remained as the untreated control. Subsequently, half of each specimen was covered with nail varnish (baseline) and the other half was reexposed to a demineralizing solution for 14 days (experimental). The specimens were cut perpendicularly to the surface, infiltrated with a low-viscosity fluorescent resin and observed with a confocal laser scanning microscope (CLSM). For lesions sealed with the fissure sealant and adhesives 1-3, the progression of lesion depth (0-31 microm) was significantly decreased (p<0.01; paired t test) compared with the untreated control (57 microm). For the fissure sealant and adhesives 1 and 3 extended penetration times (30 s) resulted in significantly reduced lesion progression compared to 15 s. It can be concluded that filling of the pores in initial enamel lesions with the fissure sealant and adhesives 1-3 can inhibit further demineralization in vitro.

The measurement and prevention of erosion and abrasion

OBJECTIVES

To develop a reproducible method to measure tooth wear and assess the protection given by dentine bonding agents in an erosive/abrasive wear regime.

METHODS

Seal and Protect (Dentsply, UK) and Optibond Solo (Kerr, UK) were each applied to 20 extracted teeth and subjected to 3000 cycles in a reciprocating erosion/abrasion wear machine. A further 20 teeth, without protection, were subjected to the same wear regime and were either brushed in water or immersed in acid. Impressions were taken by a standardised technique and were scanned with a non-contacting laser profilometer. The amount of erosion was measured at the same co-ordinates before and after erosion using 2mm diameter metal discs as reference points.

RESULTS

The amount of wear on Seal and Protect had a mean 24.8 microm (SD 57.4 microm) and for Solo it was 1.4 microm (24.5 microm), and this difference was statistically significant (p=0.02). There was no statistically significant difference in the wear measured on the teeth brushed in water or immersed in acid. The wear measured on the unprotected teeth was 243 microm (SD 120 microm) and was statistically significantly different to the protected surfaces (p=0.001).

CONCLUSION

Both Seal and Protect and Solo protected the teeth in this wear regime and the technique could be used clinically for patients with uncontrolled dental erosion.

The surface effects of erosion and abrasion on dentine with and without a protective layer

OBJECTIVE

The aim of this in situ study was to investigate with four imaging modalities whether covering dentine with adhesive resins could protect against erosion from acids. The objectives were to observe and quantify the effects of acids and the soft tissues, especially the tongue, on dentine and the bonding agents using four assessment techniques: qualitative assessment with SEM, surface roughness and thickness of resin with the TSM and volume loss with the laser profilometer.

DESIGN

An in situ investigation using extracted dentine sections embedded in splints held on the palate of 10 volunteers. The dentine sections were protected by two resins and subjected to a tooth wear regime.

RESULTS

Both Seal and Protect and Opitbond Solo protected the tooth surfaces from a tooth wear regime. There were no statistical differences between the control surfaces and those protected with dentine bonding agents for resin thickness, roughness and profilometry. The appearance of the slabs under both confocal and SEM showed that the material remained in place despite a vigorous wear regime and therefore protected the tooth surface.

CONCLUSIONS

For patients with uncontrolled erosion or tooth wear, applying a dentine bonding agent to exposed dentine is a practical option to prevent further damage.

Vertical root fracture treated by bonding fragments and rotational replantation

These case reports describe a new treatment method for complete vertical root fractures. This method is composed of two steps. First, the fractured tooth is intentionally extracted atraumatically, and then the separated fragments are bonded with an adhesive resin cement. The restored tooth is replanted by rotating approximately 180 degrees into the original socket and fixing with an orthodontic wire. For both cases reported here, bone regeneration was observed at the 3-year follow-up. Since this modality adopts the respective advantages of both intentional replantation and adhesive treatment, it might be the treatment of choice in cases of vertical root fracture.

Microleakage beneath ceramic and metal brackets bonded with a conventional and an antibacterial adhesive system

OBJECTIVE

To assess microleakage of a tooth-adhesive-bracket complex when metal or ceramic brackets were bonded with a conventional and an antibacterial self-etching adhesive.

MATERIALS AND METHODS

Forty freshly extracted human premolars were randomly assigned to four equal groups and received the following treatments: group 1 = Transbond XT + metal bracket, group 2 = Transbond XT + ceramic bracket, group 3 = Clearfil Protect Bond + ceramic bracket, and group 4 = Clearfil Protect Bond + metal bracket. After photopolymerization, the teeth were kept in distilled water for 1 month and thereafter subjected to thermal cycling (500 cycles). Specimens were further sealed with nail varnish, stained with 0.5% basic fuchsin for 24 hours, sectioned and examined under a stereomicroscope, and scored for marginal microleakage for the adhesive-tooth and bracket-adhesive interfaces from incisal and gingival margins. Statistical analysis was accomplished by Kruskal-Wallis test and Mann-Whitney U-test with Bonferroni correction.

RESULTS

All groups demonstrated microleakage between the adhesive-enamel and bracket-adhesive interfaces. A significant difference was observed among all groups (P < .05) for the microleakage between the bracket-adhesive interface. Metal brackets exhibited significantly more microleakage than did ceramic brackets between the bracket-adhesive interface with either of the adhesives. Clearfil Protect Bond exhibited results similar to Transbond XT. Clearfil Protect Bond may be a choice of adhesive in bracket bonding because of its antibacterial activity and similar microleakage results with the orthodontic adhesive.

CONCLUSIONS

Metal brackets cause more leakage between an adhesive-bracket interface, which may lead to lower clinical shear bond strength and white-spot lesions.

Drying and rewetting anterior crown fragments prior to bonding

Fractured anterior teeth can be restored by adhesive bonding of the fragment to the remaining tooth structure. This in vitro study describes the effect on fracture strength of fragments dried and rewetted for various periods of time prior to bonding. Seventy central incisors from sheep were fractured. The resulting incisal crown fragments were then stored in air at room temperature at ambient humidity (70 +/- 16%) for 5 s, 30 min, 1 h, 3 h, 6 h, 12 h, or 24 h. The apical parts of the fractured teeth were stored in water. After storage in air each fragment was then bonded to the matching apical tooth structure with a bonding agent and a low-viscosity composite resin. After water storage for 2 days, mean fracture strength was measured. Another group of teeth comprising 40 sheep central incisors was fractured and the fragments were stored in air at room temperature for 24 h as above. The fragments were then immersed in water for 10 min, 1 h, 1 day, or 7 days, prior to bonding and measurement as described above. Statistical analysis revealed that the fracture strength of the fragment-bonded teeth was unaffected by air storage of the fragment for up to 1 h prior to bonding, after which additional drying resulted in decreased fracture strength. Fragments dried for 24 h in air and rewetted by immersion in water for at least 1 day were fragment-bonded without loss of fracture strength.

Caries-preventive effect of resin-based and glass ionomer sealants over time: a systematic review

INTRODUCTION

The difference in preventing dentine lesion development between resin-based and glass ionomer sealant materials is unclear. Two recently published reviews were unable to conclude on the difference because the comparison was an exclusion criterion in one review and there were statistical shortcomings in the relevant papers in the other (Cochrane) review.

OBJECTIVES

The aim of the present investigation was to carry out a systematic review on the caries-preventive effect of these two types of sealant materials under more liberal exclusion criteria concerning the statistical presentations in the publications.

METHODS

Based on five exclusion criteria, the literature search in the electronic libraries PubMed and MEDLINE and the publications retrieved in the Cochrane review, revealed 12 eligible publications for analyses. A variety of glass ionomers and resin-based sealant materials had been applied in the included studies. Attributable risk (AR) was chosen rather than relative risk (RR), as used in the Cochrane review, because RR is very instable in a low caries population.

RESULTS

There was no consistent pattern observed with respect to the caries-preventive effect of either resin-based or glass ionomer sealants. Therefore, it was impossible to calculate an overall AR.

CONCLUSIONS

There is no evidence that either resin-based or glass ionomer sealant material is superior to the other in preventing dentine lesion development in pits and fissures over time.

Prognosis of Intentional Replantation of Vertically Fractured Roots Reconstructed with Dentin-Bonded Resin

There is no particular treatment established to preserve vertically fractured teeth. We evaluated the long-term prognosis of the intentional replantation of 26 vertically fractured roots after reconstruction with 4-META/MMA-TBB dentin-bonded resin. Replanted teeth were evaluated according to clinical criteria and radiographic examinations for periods ranging from 4 to 76 months. Eighteen cases were functional and retained, with six fully successful; the others needed further observation. Eight cases failed to respond to treatment because of refracture, recurrence of gingival inflammation, or both. Longevity was calculated as 88.5% at 12 months after replantation, 69.2% at 36 months, and 59.3% at 60 months. All failures occurred in premolar and molar teeth. Longitudinal fractures extending more than 2/3 from the cervical portion toward the apex showed significantly shorter longevity compared with fractures within the 2/3 area (log-rank test, p = 0.02). Intentional replantation of vertically fractured roots reconstructed with dentin-bonded resin may be considered for incisors as an alternative to extraction, although the long-term success is not optimal.

Pulpal responses following direct pulp capping of healthy dog teeth with dentine adhesive systems

OBJECTIVE

The aim of the present study was to evaluate the pulpal responses following direct pulp capping of mechanically exposed teeth with new dentine adhesive systems, in the preclinical model of dog teeth.

METHODS

Class V cavities (approximately 2.50 mm wide, 3.00 mm long, 1.5-2.0 mm deep) were prepared on the buccal surface of permanent maxillary and mandibulary molars, two rooted premolars, canines and third incisors. The cavities were assigned to five experimental groups, representing one control group treated with a Ca(OH)2-based material and four experimental groups where the adhesive systems Clearfil SE Bond, Prompt-L-Pop, Etch & Prime 3.0 and Single Bond were tested. The pulpal tissue responses to dentine adhesives were assessed at post-operative periods of 7, 21, 65 days.

RESULTS

Variable responses were recorded, which were characterized by moderate to severe inflammatory reactions, progressive extension of tissue necrosis with time and total absence of continuous hard tissue bridge formation after pulp capping with each of the four adhesive systems. Application of a Ca(OH)2-based material was characterized by inflammatory cell infiltration, limited tissue necrosis as well as partial to complete hard tissue bridging.

CONCLUSIONS

It seems evident that application of dentine adhesive systems in direct contact with the mechanically exposed pulp of healthy dog teeth cannot lead to acceptable repair of the dentine-pulp complex e.g. wound healing with tertiary dentine bridge formation.

The effects of oxalate-containing products on the exposed dentine surface: an SEM investigation

In-office products containing oxalates have been claimed to be clinically effective in reducing dentine sensitivity, although there has been limited supporting clinical data. The rationale for their use appears to be based on their potential to act as occluding and/or nerve desensitizing agents. Four commercially available oxalate-containing products were applied to etched dentine discs and the extent of tubule occlusion was observed by scanning electron microscopy. Tenure Quick (aluminium oxalate), Sensodyne Sealant (ferric oxalate) and MS Coat (oxalic acid) covered the dentine surface and occluded the tubules. However, Butler Protect (potassium oxalate) did not cover the surface to any great extent but provided some occlusion. The presence of oxalates after application to glass slides and dentine discs was examined using thin film X-ray diffraction. From samples on glass, only potassium oxalate could be clearly identified (JCPDS 14-0845). No oxalate was detected on dentine discs in either thin film geometry or standard theta two theta mode. We have demonstrated that professionally applied in-office products containing oxalate are capable of covering the dentine surface and/or occluding the tubules to varying degrees. However, X-ray diffraction analysis was unable to confirm the oxalate profile for all products as described in the available commercial literature.

Periodontal healing after bonding treatment of vertical root fracture

Vertical root fractures lead to advanced periodontal breakdown with deep periodontal pockets and vertical bone defects. The purpose of this study is to evaluate clinically the periodontal healing of root fracture treatment using adhesive resin cement. In 22 patients, 23 teeth with vertical root fractures were treated with 4-META/MMA-TBB resin cement. Eleven fractured roots were bonded through the root canal (group A) and 12 fractured roots were bonded extra-orally and replanted (group B). All teeth were then restored with full cast crowns (n=20) or coping (n=3). Mean probing depth was 6.6 mm at pre-treatment and 4.4 mm 6 months after the treatment in group A, and 7.4 mm and 4.6 mm, respectively, in group B. Bleeding scores were 100% at pre-treatment and 36.4% after 6 months in group A and 91.7% and 8.3%, respectively in group B. Radiographic bone level was 56.8% at pretreatment and 59.1% after 6 months in group A, and 18.8% and 29.2%, respectively, in group B. Two roots of group A and three roots of group B were extracted due to refracture, deterioration of periodontal inflammation, mobility, and luxation. The remaining roots (n=18) presented no discomfort to the patients and there was no deterioration of periodontal conditions over a mean period of 33 months (range 14-74 months) in group A and over a mean period of 22 months (range 6-48 months) in group B. There was no ankylosed teeth nor was any root resorption detected. The results suggested that the treatment of vertical root fracture using 4-META/MMA-TBB resin has good prognostic possibilities.

Short-term evaluation of intentional replantation of vertically fractured roots reconstructed with dentin-bonded resin

The purpose of this study was to evaluate intentional replantation of vertically fractured roots reconstructed with dentin-bonded resin. Twenty vertically fractured teeth were extracted intentionally and reconstructed with 4-META/MMA-TBB dentin-bonded resin. After reconstruction, the teeth were replanted into the original sockets. The replanted teeth were evaluated by clinical criteria and radiographic examination. The observation periods ranged between 4 and 45 months. Longevity was calculated by the Kaplan-Meier method, and factors that had significant influence on the longevity were analyzed with the Log rank test at a 95% level of confidence. From this short-term observation, 14 of 20 cases were functioned in the oral environment. Of these 14 cases, 6 could be considered truly successful and 8 cases needed further observation. The other six cases were total failures and were extracted. The longevity was calculated as 83.3% at 12 months and 36.3% at 24 months. Teeth with thin roots or with longitudinal fractures extending over 2/3 of the root from the cervical portion toward the apex showed significantly lower longevity. It was concluded that this method had the potential to preserve vertically fractured teeth.

Ultrathin Monolithic Zirconia Veneers: Reality or Future? Report of a Clinical Case and One-year Follow-up

Yttria-stabilized polycrystalline zirconia ceramics have greatly advanced over the past few years. High-translucent zirconia is a newly introduced ceramic that affords high strength and esthetics and that has significantly increased the clinical indications of monolithic zirconia restorations. Thus, the purpose of this case report was to evaluate the performance of ultrathin monolithic zirconia veneers adhesively luted to enamel surfaces after minimally invasive preparations; in addition, we aimed at presenting a clinical protocol for zirconia surface treatment in order to promote bonding effectiveness to resin cement. This type of restoration presented very acceptable esthetic results and decreased the risk of fracturing the veneer during try-in and clinical use. The results were still satisfactory after one-year follow-up. However, randomized, prospective, controlled clinical trials are required to determine the long-term clinical durability of this treatment.