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

The preventive effect of glass ionomer cement restorations on secondary caries formation: A systematic review and meta-analysis

OBJECTIVE

The objective is to compare the preventive effect on secondary caries of glass ionomer cement (GIC) restorations with amalgam or resin-composite restorations.

METHODS

Two independent researchers conducted a systematic search of English publications in PubMed, Web of Science, Cochrane and Scopus. They selected randomized clinical trials comparing secondary caries incidences around GIC restorations (conventional GIC or resin-modified GIC) with amalgam or resin-composite restorations. Meta-analysis of the secondary-caries incidences with risk ratio (RR) and 95% confidence interval (95% CI) as the effect measure was performed.

RESULTS

This review included 64 studies. These studies included 8310 GIC restorations and 5857 amalgam or resin-composite restorations with a follow-up period from 1 to 10 years. Twenty-one studies with 4807 restorations on primary teeth and thirty-eight studies with 4885 restorations on permanent teeth were eligible for meta-analysis. The GIC restorations had a lower secondary caries incidence compared with amalgam restorations in both primary dentition [RR= 0.55, 95% CI:0.41-0.72] and permanent dentition [RR= 0.20, 95% CI:0.11-0.38]. GIC restorations showed similar secondary caries incidence compared with resin-composite restorations in primary dentition [RR= 0.92, 95% CI:0.77-1.10] and permanent dentition [RR= 0.77, 95% CI:0.39-1.51]. Conventional GIC restorations showed similar secondary caries incidence compared with resin-modified GIC-restored teeth in both primary dentition [RR= 1.12, 95% CI:0.67-1.87] and permanent dentition [RR= 1.63, 95% CI:0.34-7.84].

CONCLUSIONS

GIC restorations showed a superior preventive effect against secondary caries compared to amalgam restorations, and a similar preventive effect against secondary caries compared to resin-composite restorations in both primary and permanent teeth. [PROSPERO Registration ID: CRD42022380959].

Clinical efficacy of bioactive restorative materials in controlling secondary caries: a systematic review and network meta-analysis

BACKGROUND

This systematic review and network meta-analysis aimed to compare the clinical efficacy of bioactive and conventional restorative materials in controlling secondary caries (SC) and to provide a classification of these materials according to their effectiveness.

METHODS

A search was performed in Pubmed, Web of Science, Embase, BBO, Lilacs, Cochrane Library, Scopus, IBECS and gray literature. Clinical trials were included, with no language or publication date limitations. Paired and network meta-analyses were performed with random-effects models, comparing treatments of interest and classifying them according to effectiveness in the permanent and deciduous dentition and at 1-year or 2/more years of follow-up. The risk of bias and certainty of evidence were evaluated.

RESULTS

Sixty-two studies were included in the qualitative syntheses and 39 in the quantitative ones. In permanent teeth, resin composite (RC) (RR = 2.00; 95%CI = 1.10, 3.64) and amalgam (AAG) (RR = 1.79; 95%CI = 1.04, 3.09) showed a higher risk of SC than Glass Ionomer Cement (GIC). In the deciduous teeth, however, a higher risk of SC was observed with RC than with AAG (RR = 2.46; 95%CI = 1.42, 4.27) and in GIC when compared to Resin-Modified Glass Ionomer Cement (RMGIC = 1.79; 95%CI = 1.04, 3.09). Most randomized clinical trials studies showed low or moderate risk of bias.

CONCLUSION

There is a difference between bioactive restorative materials for SC control, with GIC being more effective in the permanent teeth and the RMGIC in the deciduous teeth. Bioactive restorative materials can be adjuvants in the control of SC in patients at high risk for caries.

Comparative evaluation of shear bond strength of calcium silicate-based liners to resin-modified glass ionomer cement in resin composite restorations - a systematic review and meta-analysis

Purpose The aim of this systematic review was to evaluate the difference in shear bond strength between calcium silicate-based liners to resin-modified glass ionomer cement (RMGIC) in resin composite restorations.Materials and methods The protocol was registered in PROSPERO following which primary research was carried out on Medline, Scopus and Cochrane library. To assess the risk of bias, a customised tool was used. Among the 194 records retrieved from the databases, only ten articles qualified for qualitative and quantitative synthesis after meeting all the requirements of the eligibility criteria. Covidence software was used to record the decisions. Studies published until 31 March 2021 were taken up for the review. The articles showed a low-to-moderate risk of bias. I2 test was used to check the percentage variation due to heterogeneity.Results RMGIC showed a higher shear bond strength value compared to the three calcium silicate liners MTA, Biodentine and TheraCal LC. However, TheraCal LC and MTA showed better bond strength than Biodentine. Cohesive failure was seen predominantly in liners followed by adhesive failure. RMGIC shows mixed mode of failure in some studies.Conclusions RMGIC is preferred over calcium silicate-based materials as the liner to be used under resin composite restorations. Among calcium silicate-based materials, TheraCal LC showed a better bond strength value. The mode of failure was predominantly cohesive in all the liner groups in majority.

Evaluation of the Mechanical Properties of Three Resin-Modified Glass-Ionomer Materials

This study is aimed at evaluating the flexural strength (FS), fracture toughness (FT), and diametral tensile strength (DTS) of three resin-modified glass-ionomer cements (RMGICs): Ketac Nano, Riva Light Cure, and Fuji II LC. One hundred twenty specimens were prepared from the RMGIC materials ( $n=10$ ). The cements were mixed and inserted into different mould sizes according to the test performed: FS: rectangular Teflon mould ( $32\text{mm}\times 3.15\text{mm}\times 2\text{mm}$ ); FT: notchless triangular prism (NTP) Teflon mould ( $6\text{mm}\times 6\text{mm}\times 6\text{mm}\times 12\text{mm}$ ); and DTS: ring road stainless steel mould ( $6\text{mm}\times 3\text{mm}$ ). Specimens were light cured for 20 seconds on each surface and stored in distilled water at ${37}^{°}\text{C}\pm 2^{°}\text{C}$ for seven days prior to tests. To evaluate the influence of storage in the mechanical properties of the RMGIs, specimens tested for DTS were stored in distilled water at ${37}^{°}\text{C}\pm 2^{°}\text{C}$ for 32 days prior to test. Data were analyzed by ANOVA and Tukey’s test ( $\alpha =0.05$ ). Fuji II LC presented significantly higher values for all tests employed when compared to Ketac Nano and Riva LC RMGIs. There was no significant difference on DTS before and after the 32-day storage for each material. Fuji II LC presented superior mechanical properties when compared to Ketac Nano, and Riva LC storage showed no influence on the mechanical properties of the RMGI materials tested.

Demineralization Inhibition by Two Calcium-releasing Restorative Materials

OBJECTIVE

To compare the ability of two calcium-releasing restorative materials to inhibit root dentin demineralization in an artificial caries model.

METHODS AND MATERIALS

Preparations were made at the cementum-enamel junction of extracted human molars (40, n=10/material) and restored with two calcium-releasing materials (Experimental composite, Pulpdent Corporation and Cention N, Ivoclar Vivadent), a resin composite (Filtek Supreme Ultra, 3M Oral Care), and a resin-modified glass ionomer (RMGI) (Fuji II LC, GC). All materials (other than the RMGI) were used with an adhesive (Scotchbond Universal Adhesive, 3M Oral Care) in the self-etch mode, which was light cured for 10 seconds. All restorative materials were light cured in 2-mm increments for 20 seconds and then finished with a polishing disc. Teeth were incubated (37°C) for 24 hours in water. An acid-resistant varnish was painted onto the teeth around the restoration, leaving a 2-mm border of uncovered tooth. A demineralization solution composed of 0.1 M lactic acid, 3 mM Ca3(PO4)2, 0.1% thymol, and NaOH (to adjust pH=4.5), and a remineralization solution composed of 1.5 mM Ca, 0.9 mM P, and 20 mM Tris(hydroxymethyl)-aminomethane (pH=7.0) were prepared. Specimens were placed in the demineralization solution for 4 hours, followed by the remineralization solution for 20 hours and cycled daily for 30 days. The specimens were embedded, sectioned into 100-μm sections, and the interface between the restorative material and root dentin was viewed with polarized light microscopy. A line was drawn parallel with the zone of demineralization for each tooth. The area of "inhibition" (defined as the area external to the line) or "wall lesion" (defined as the area internal to the line) was measured with image evaluation software. Areas of inhibition were measured as positive values, and areas of wall lesions were measured as negative areas.

RESULTS

A one-way analysis of variance (ANOVA) found significant differences between materials for "inhibition/wall lesion" areas in root dentin (p<0.001). Tukey post hoc analysis ranked materials (μm2, mean ±SD): Fuji II LC (5412±2754) > Cention N (2768±1576) and experimental composite (1484±1585) > Filtek Supreme Ultra (-1119±1029).

CONCLUSION

The experimental composite and Cention N materials (used with an adhesive) showed net areas of inhibition greater than a reference resin composite, albeit at a lower level than a reference RMGI material (used with no adhesive).

Three-year performance of a nano-filled resin-modified glass ionomer cement in class II primary molar restorations

PURPOSE

To compare the clinical failure rate of two resin-modified glass ionomer cements (RMGICs) used for Class II primary molar restorations over a 3-year period.

METHODS

Healthy, cooperative children aged 4-8 years with carious, asymptomatic primary molars requiring class II restorations received either nano-filled (Ketac Nano, 3 M ESPE) or regular (Vitremer, 3 M ESPE) RMGIC restorations. These were blindly assessed semiannually for 3 years using the modified USPHS criteria with all-cause failure as primary outcome and failure for each criterion as secondary outcome. Data was analysed with Fisher's exact tests and survival analysis with robust standard errors at 5%.

RESULTS

Outcome assessment included 159 teeth at 12 months, 141 teeth at 24 months, and 98 teeth at 36 months. No difference in all-cause failure was found between regular and nano-filled RMGIC at 12 (8.6% versus 14.1%), 24 (9.0% versus 14.9%) or 36 months (7.4% versus 20.5%) (P > 0.05). The nano-filled RMGIC retained better its anatomical form and the regular RMGIC likewise its marginal integrity (P < 0.05), but only in the acceptable range (Alpha-Bravo). Overall, survival analysis found no significant difference for all-cause failure [hazard ratio (HR) 0.58; 95% confidence interval (CI) 0.25-1.31; P = 0.19] or any secondary outcomes other than contact point integrity. Finally, subgroup analysis by jaw indicated that the regular RMGIC performed better than the nano-filled RMGIC for mandibular molars (HR 0.36; 95% CI 0.13-0.96; P = 0.04), but further data are needed.

CONCLUSION

Nano-filled RMGIC showed less occlusal wear but more mild marginal defects than regular RMGIC, but these findings were of limited clinical significance and both materials performed favourably for 3 years.

Restorative treatment of primary teeth: an evidence-based narrative review

Various methods, with a variety of materials, exist for restoring carious primary teeth. Successful restoration of primary teeth is dependent on accurate diagnosis, knowledge of the caries process, knowledge of dental materials, and treatment choice. The purpose of this evidence-based review is to present evidence that will help clinicians to make an appropriate diagnosis, from which the optimum treatment plan can be made; to explore the literature regarding restoration of carious primary teeth; and to try and draw conclusions as to which materials and methods can be recommended. This review will primarily deal with the restoration of carious cavities in primary molars. A short discussion on restoration of primary incisors is included, with presentation of what limited evidence there is relating to this.

In vitro evaluation of microleakage in primary teeth restored with three adhesive materials: ACTIVA™, composite resin, and resin-modified glass ionomer

PURPOSE

Microleakage is one of the most important problems that can adversely affect the longevity of dental restorations. The aim of this in vitro study is to assess microleakage of a new BioActive-Restorative composite (ACTIVA™, Pulpdent, USA), in comparison to standard adhesive materials used in restoring class II cavities in primary teeth.

DESIGN

One hundred and four extracted human primary molars were randomly allocated into three groups. In each group, class II cavities were prepared and restored with one of the three restorative materials: ACTIVA, Filtek Z250, or Vitremer. Microleakage was assessed using dye penetration method under a stereomicroscope. Chi-square test was used followed by pairwise comparisons to assess the association between microleakage and the materials used. A significance level of 0.05 was assumed throughout the study.

RESULTS

According to leakage analysis per tooth, there were no statistically significant differences in microleakage percentages between ACTIVA and both Filtek Z250 and Vitremer. Leakage analysis per surfaces showed significantly higher leakage percentages in ACTIVA compared to Filtek Z250 at both occlusal and cervical margins and lower than Vitremer at occlusal margin.

CONCLUSION

ACTIVA can be a potential restorative material in class II cavities in primary molars; clinical studies are recommended.

An In Vivo Comparative Evaluation of Dental Anxiety Level and Clinical Success Rate of Composite and Multicolored Compomers in 6 to 12 years of Children

BACKGROUND

Pediatric dentistry is not just about treating the tooth, but it also involves giving an overall comprehensive treatment to the child. Children like different colors and when the child is allowed to select the color of the restoration, it will positively motivate the child to accept dental treatment.

AIM

The aim of our study was to evaluate and compare the clinical success rate of composite and multicolored compomer restorations and dental anxiety level in children.

MATERIALS AND METHODS

A total of 60 samples equally divided into two study groups by of split-mouth design. In the control group, subjects received composites and in experimental group, they received colored compomers. The dental behavior was assessed using the Frankl behavior rating scale for both the groups. Dental anxiety was checked in the patients using visual analogue scale (VAS) before and after the treatment for both the groups. Children were recalled for follow up at 1, 3 and 6 months to evaluate clinical success rate amongst control and experimental group and results were subjected to statistical analysis.

RESULTS

Colored compomer proved to reduce the anxiety in the child and had a better behavioral response and positive attitude. Both restorative materials had comparable clinical success rates.

CONCLUSION

At 6 months follow-up evaluation colored compomer restorative material showing promising with similar properties like that of composites with the added advantage of multicolors and can be considered as the new restorative material in the child dentistry.

CLINICAL SIGNIFICANCE

Colored compomers are known to be excellent alternative restorative materials for restoration of teeth in children as they aid in behavior modification and good compliance from the patient.

HOW TO CITE THIS ARTICLE

Hugar SM, Kohli D, Badakar CM, Gokhale NS, Thakkar PJ, Mundada MV. An In Vivo Comparative Evaluation of Dental Anxiety Level and Clinical Success Rate of Composite and Multicolored Compomers in 6 to 12 years of Children. International Journal of Clinical Pediatric Dentistry, 2018;11(6):483-489.

Comparative Assessment of Conventional Composites and Coloured Compomers in Permanent Molars of Children with Mixed Dentition: A Pilot Study

INTRODUCTION

Early treatment of carious lesions in children is important for the maintenance of oral health. Multicoloured restorations could be the impetus for an extremely nervous or defiant child to take dental treatment.

AIM

The aim of this study was to assess and compare the clinical success of conventional composites and coloured compomer material in first permanent molars of children with mixed dentition.

MATERIALS AND METHODS

A total of sixty sites, divided into two groups, with thirty subjects in each group using split mouth design were chosen amongst patients reporting to Department of Pedodontics and Preventive Dentistry. In control group conventional composites were placed, similarly coloured compomers were placed in experimental group under standard operating protocol. Patients were recalled for assessment of clinical success amongst control as well as experimental group at regular intervals of one; three and six months follow up based on Modified Ryge's Criteria. Statistical analysis was done using Chi-square test using SPSS version 20.0 (Chicago, USA).

RESULTS

Both conventional composites and coloured compomers had comparable retention rates in terms of anatomical form, marginal integrity, secondary caries and marginal discolouration.

CONCLUSION

The coloured compomer material showed promising results in this six month follow up study in permanent molars and had properties comparable to that of conventional composites.

WITHDRAWN: Dental fillings for the treatment of caries in the primary dentition

BACKGROUND

Childhood caries (tooth decay) consists of a form of tooth decay that affects the milk teeth (also known as baby or primary teeth) of children. This may range from tooth decay in a single tooth to rampant caries affecting all the teeth in the mouth. Primary teeth in young children are vital to their development and every effort should be made to retain these teeth for as long as is possible. Dental fillings or restorations have been used as an intervention to repair these damaged teeth. Oral health professionals need to make astute decisions about the type of restorative (filling) material they choose to best manage their patients with childhood caries. This decision is by no means an easy one as remarkable advances in dental restorative materials over the last 10 years has seen the introduction of a multitude of different filling materials claiming to provide the best performance in terms of durability, aesthetics, symptom relief, etc when placed in the mouth. This review sought to compare the different types of dental materials against each other for the same outcomes.

OBJECTIVES

The objective of this review was to compare the outcomes (including pain relief, survival and aesthetics) for restorative materials used to treat caries in the primary dentition in children.  Additionally, the restoration of teeth was compared with extraction and no treatment.

SEARCH METHODS

Electronic searches of the following databases were undertaken: the Cochrane Oral Health Group's Trials Register (up to January 2009); CENTRAL (The Cochrane Library 2009, Issue1); MEDLINE (1966 to January 2009); EMBASE (1996 to January 2009); SIGLE (1976 to 2004); and conference proceedings on early childhood caries, restorative materials for paediatric dentistry, and material sciences conferences for dental materials used for children's dentistry (1990 to 2008). The searches attempted to identify all relevant studies irrespective of language.Additionally, the reference lists from articles of eligible papers were searched, handsearching of key journals was undertaken, and personal communication with authors and manufacturers of dental materials was initiated to increase the pool of suitable trials (both published and unpublished) for inclusion into this review.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-randomised controlled trials with a minimum period of 6 months follow up were included. Both parallel group and split-mouth study designs were considered. The unit of randomisation could be the individual, group (school, school class, etc), tooth or tooth pair. Included studies had a drop-out rate of less than 30%. The eligible trials consisted of young children (children less than 12 years) with tooth decay involving at least one tooth in the primary dentition which was symptomatic or symptom free at the start of the study.

DATA COLLECTION AND ANALYSIS

Data were independently extracted, in duplicate, by two review authors. Disagreements were resolved by consultation with a third review author. Authors were contacted for missing or unclear information regarding randomisation, allocation sequence, presentation of data, etc. A quality assessment of included trials was undertaken. The Cochrane Collaboration statistical guidelines were followed for data analysis.

MAIN RESULTS

Only three studies were included in this review. The Fuks 1999 study assessed the clinical performance of aesthetic crowns versus conventional stainless steel crowns in 11 children who had at least two mandibular primary molars that required a crown restoration. The outcomes assessed at 6 months included gingival health (odds ratio (OR) 0.3; 95% confidence interval (CI) 0.01 to 8.32), restoration failure (OR 3.29; 95% CI 0.12 to 89.81), occlusion, proximal contact and marginal integrity. The odds ratios for occlusion, proximal contact and marginal integrity could not be estimated as no events were recorded at the 6-month evaluation. The Donly 1999 split-mouth study compared a resin-modified glass ionomer (Vitremer) with amalgam over a 36-month period. Forty pairs of Class II restorations were placed in 40 patients (21 males; 19 females; mean age 8 years +/- 1.17; age range 6 to 9 years). Although the study period was 3 years (36 months), only the 6- and 12-month results are reported due to the loss to follow up of patients being greater than 30% for the 24- and 36-month data. Marks 1999a recruited 30 patients (age range 4 to 9 years; mean age 6.7 years, standard deviation 2.3) with one pair of primary molars that required a Class II restoration. The materials tested were Dyract (compomer) and Tytin (amalgam). Loss to follow up at 24 and 36 months was 20% and 43% respectively. This meant that only the 24-month data were useable. For all of the outcomes compared in all three studies, there were no significant differences in clinical performance between the materials tested.No studies were found that compared restorations versus extractions or no treatment as an intervention in children with childhood caries.

AUTHORS' CONCLUSIONS

It was disappointing that only three trials that compared three different types of materials were suitable for inclusion into this review. There were no significant differences found in all three trials for all of the outcomes assessed. Well designed, randomised controlled trials comparing the different types of filling materials for similar outcomes are urgently needed in dentistry. There was insufficient evidence from the three included trials to make any recommendations about which filling material to use.

Materials for Paediatric Dentistry. Part 2: The Evidence

Which materials should be used to restore primary teeth? The second part in this series summarizes the current evidence base relating to this question, and describes the biological approach to caries management. CPD/Clinical Relevance: Our decisions regarding material choices should be based, where possible, on up-to-date evidence. This will help to ensure that the appropriate material is placed in the appropriate clinical scenario.

Comparative Evaluation of Microleakage in Conventional and RMGIC Restorations following Conventional and Chemomechanical Caries Removal: An in vitro Study

Background: Conventional caries removal involves use of high-speed handpiece. Current concepts of caries excavation in cavitated lesions consist of manual excavators. Principles of minimal invasive approach indicate the need to excavate only carious tissue.

Aim: The aim of this study was to compare the microleakage in conventional and resin modified glass ionomer cement restorations following conventional and chemomechanical caries removal.

Design: Hundred class I carious human mandibular first molar s were collected and divided into two groups: I and II (50 each). Each group was further divided into subgroups, i.e. (IA, IB and IIA, IIB). Caries was completely removed using conventional method in group one and chemomechanically in group two. The teeth in group IA, IIA are restored with conventional glass ionomer comment (GIC) and in group IB, IIB restored with resign-modified glass ionomer comments (RMGIC), followed by fnishing and polishing. Subsequently, the specimens were thermocycled and then placed in dye solution. The teeth were sectioned through the restorations and evaluated for microleakage scores using a stereomicroscope. The data were analyzed using Mann-Whitney U-test.

Results: Statistical analysis showed no significant difference in microleakage between the conventional GIC and RMGIC following conventional and chemomechanical caries removal method.

Conclusion: Carisolv is minimally invasive and an effective alternative treatment for the removal of occlusal caries.

How to cite this article: Pavuluri C, Nuvvula S, Kamatham RL, Nirmala SVSG. Comparative Evaluation of Microleakage in Conventional and RMGIC Restorations following Conventional and Chemomechanical Caries Removal: An in vitro Study. Int J Clin Pediatr Dent 2014;7(3):172-175.

Restorative dentistry for children

This article discusses contemporary pediatric restorative dentistry. Indications and contraindications for the choice of different restorative materials in different clinical situations, including the risk assessment of the patient, are presented. The specific use of glass ionomer cement or resin-modified glass ionomer cement, resin-based composite, and stainless steel crowns is discussed so that preparation design and restoration placement is understood.

Restorative materials in the primary dentition of poli-caries patients

BACKGROUND

Despite an overall caries decline in children, still 50-60% of carious primary teeth of 6-year-olds remain untreated, in 3-year-olds 13%. There are an increasing number of poli-caries patients with insufficiently treated primary teeth. Therefore, early treatment is fundamental.

REVIEW

The assessment and indication for the use of restorative materials can be summarized as follows: Glass ionomer cements (GIC) are associated with easy handling and high fluoride release. This makes them attractive especially for Class I cavities in uncooperative children. However, low flexural strength causes high fracture rates in Class II cavities. Further developments (viscous and resin-modified GIC) have improved handling characteristics, but conventional non-resin-modified GIC are still prone to fracture. Compomers exhibit a clear potential as an alternative to amalgam. Long-term results are good even in stress-bearing areas. The compliance of the child should at least last long enough for adhesive application. Resin composites are still the most time-consuming alternative. Under a correct application protocol, resin composites behave in a similar manner to compomers. Therefore, the effort has to be judged individually. Finally, especially in severely decayed teeth and after endodontic treatment, preformed metal crowns should be taken into account as a last and appropriate alternative to direct restorations.

CONCLUSION

Based on the high clinical success rates, compomers with self-etch adhesives can be recommended for restorative therapy in anterior and posterior primary teeth.

Durability of amalgam in the restoration of class II cavities in primary molars: a systematic review of the literature

AIM

To review the available literature on the durability of amalgam when used to restore interproximal (class II) cavities in primary molars.

METHODS

The literature was searched using OVID Medline and EMBASE from 1966 to 2006. The search plan of the electronic databases included: "dental amalgam or amalgam or alloy" and "deciduous or primary or milk or first or baby or natal" or "tooth or teeth or dentition" and "permanent restorations or permanent fillings". Relevant prospective clinical studies were reviewed by 2 reviewers against a set of defined criteria. Papers were graded according to the number of criteria met as A = >90%, B1 = 75%, B2 = 50% and C = <50%.

RESULTS

No study achieved a Grade A; four studies rated Grade B1 and thirteen B2. Seven studies were rated Grade C. A wide range of failure rates for amalgam were reported from 0 - 58%. However, in the context of a controlled clinical environment in a developed country the failure rate varied between 0 and 22%.

CONCLUSION

Amalgam remains an appropriate choice of material for the restoration of the primary dentition. However, factors other than durability are increasingly influencing its use in clinical practice.

Restoration of class II cavities in primary molar teeth with conventional and resin modified glass ionomer cements: a systematic review of the literature

AIM

To review the literature concerning the restoration of primary teeth with glass ionomer (GIC) or resin modified glass ionomer cement (RMGI) used in conventional class II cavities.

METHODS

A search of the literature identified through Medline between 1966 and 2006 using the key words: glass ionomer, resin modified, glass polyalkenoate, deciduous/primary teeth. Studies that used ART or tunnel preparations were excluded. Papers of relevant clinical studies (prospective and retrospective) were assessed and graded using predetermined criteria. Papers were graded according to the number of criteria met as (A >90%, B1 = 75%, B2 = 50%, C <50%).

RESULTS

The search identified 411 papers, from which an application of the inclusion criteria yielded 20 studies. Of these, 2 were rated B1 and 18 B2. Failure rates varied from 6.6% to 60% for GIC, and from 2% to 24% for RMGI.

CONCLUSION

GIC cannot be recommended for class II cavities in primary molars. There is evidence that RMGIC can perform successfully in small to moderate sized class II restorations.

Durability of bonds and clinical success of adhesive restorations

Resin-dentin bond strength durability testing has been extensively used to evaluate the effectiveness of adhesive systems and the applicability of new strategies to improve that property. Clinical effectiveness is determined by the survival rates of restorations placed in non-carious cervical lesions (NCCL). While there is evidence that the bond strength data generated in laboratory studies somehow correlates with the clinical outcome of NCCL restorations, it is questionable whether the knowledge of bonding mechanisms obtained from laboratory testing can be used to justify clinical performance of resin-dentin bonds. There are significant morphological and structural differences between the bonding substrate used in in vitro testing versus the substrate encountered in NCCL. These differences qualify NCCL as a hostile substrate for bonding, yielding bond strengths that are usually lower than those obtained in normal dentin. However, clinical survival time of NCCL restorations often surpass the durability of normal dentin tested in the laboratory. Likewise, clinical reports on the long-term survival rates of posterior composite restorations defy the relatively rapid rate of degradation of adhesive interfaces reported in laboratory studies. This article critically analyzes how the effectiveness of adhesive systems is currently measured, to identify gaps in knowledge where new research could be encouraged. The morphological and chemical analysis of bonded interfaces of resin composite restorations in teeth that had been in clinical service for many years, but were extracted for periodontal reasons, could be a useful tool to observe the ultrastructural characteristics of restorations that are regarded as clinically acceptable. This could help determine how much degradation is acceptable for clinical success.

Effect of a new desensitizing material on human dentin permeability

OBJECTIVES

Resin-modified glass ionomers (RMGI) have demonstrated clinical success providing immediate and long-term relief from root sensitivity. RMGIs have been recently introduced as paste-liquid systems for convenience of clinical usage. The objective of this study was to measure the ability of a new paste-liquid RMGI to reduce fluid flow through human dentin, compared to an established single-bottle nanofilled total etch resin adhesive indicated for root desensitization.

METHODS

Dentin permeability was measured on human crown sections on etched dentin, presenting a model for the exposed tubules typical of root sensitivity, and permitting measurement of the maximum permeability. In the first two groups, the etched dentin was coated with either the RMGI or adhesive, and permeability measured on the coated dentin. In a third group, a smear layer was created on the dentin with sandpaper, then the specimens were coated with the RMGI; permeability was measured on the smeared and coated dentin. Specimens from each group were sectioned and examined via scanning electron microscopy (SEM).

RESULTS

Both the resin adhesive and the new paste-liquid RMGI protective material significantly reduced fluid flow through dentin, and exhibited excellent seal on dentin with either open tubules or smear-layer occluded tubules. The RMGI infiltrated the smear layer with resin during placement, penetrated dentin tubules, and formed resin tags.

SIGNIFICANCE

The RMGI was equivalent to the adhesive in its ability to reduce fluid flow and seal dentin. It is therefore concluded that the new RMGI and the adhesive show the potential to offer excellent sensitivity relief on exposed root dentin.

Effect of a new liner/base on human dentin permeability

OBJECTIVES

Resin-modified glass ionomers (RMGI) have demonstrated clinical success in their ability to minimize post-operative sensitivity of restorations. RMGIs have been recently introduced as paste-liquid systems for convenience of clinical usage. The objective of this study was to measure the ability of a new paste-liquid RMGI liner/base to reduce fluid flow through human dentin.

METHODS

Dentin permeability was measured on human crown sections on etched dentin, using etched dentin as a model for the exposed tubules typical of root sensitivity, and permitting measurement of the maximum permeability. In the one group, the etched dentin was coated with the RMGI, and pre- and post-treatment permeability was measured on the coated dentin. In the second group, a smear layer was created on the dentin with sandpaper, then the samples were coated with the RMGI; permeability was measured on the smeared and coated dentin. Samples from each group were sectioned and examined via scanning electron microscopy (SEM).

RESULTS

The new paste-liquid RMGI liner/base significantly reduced fluid flow through dentin, and exhibited excellent seal on dentin with either a smear layer or open tubules. SEM images show evidence that the RMGI infiltrated the smear layer with resin during placement, penetrated dentin tubules, and formed resin tags in acid-etched dentin.

CONCLUSIONS

Based on these results, combined with previous research on adhesion and microleakage, it is concluded that the new RMGI liner/base should minimize post-operative sensitivity in restorations.

A field-trial of two restorative materials used with atraumatic restorative treatment in rural Turkey: 24-month results

Objective:

The purpose of this study was to investigate the clinical performance of high-strength glass ionomer cement (HSGIC) and resin-modified glass ionomer (RMGIC) in single and multiple surface carious cavities in the field conditions.

Material and Methods:

A split-mouth design, including ninety-one fillings placed on contra lateral molar pairs of 37 children, was used in permanent dentition. As filling materials, a HSGIC (Ketac Molar/3M ESPE) and a RMGIC (Vitremer/ 3M ESPE) were used with the Atraumatic Restorative Treatment (ART). Baseline and 6, 12 and 24-month evaluations of the fillings were made with standard-ART and USPHS criteria by two examiners with kappa values of 0.92 and 0.87 for both criteria.

Results:

According to the USPHS criteria, the retention rates of RMGIC and HSGIC restorations were 100% and 80.9% for single surface, and 100% and 41.2% for multiple surface restorations after 24 months, respectively. Irrespective of surface number, RMGIC was significantly superior to HSGIC (p= 0.004), according to both standard-ART and USPHS criteria.

Conclusion:

The results indicate that RMGIC may be an alternative restorative technique in comparison to high-strength GIC applications in ART-field-trials. However, further clinical and field trials are needed to support this conclusion.

Dental fillings for the treatment of caries in the primary dentition

BACKGROUND

Childhood caries (tooth decay) consists of a form of tooth decay that affects the milk teeth (also known as baby or primary teeth) of children. This may range from tooth decay in a single tooth to rampant caries affecting all the teeth in the mouth. Primary teeth in young children are vital to their development and every effort should be made to retain these teeth for as long as is possible. Dental fillings or restorations have been used as an intervention to repair these damaged teeth. Oral health professionals need to make astute decisions about the type of restorative (filling) material they choose to best manage their patients with childhood caries. This decision is by no means an easy one as remarkable advances in dental restorative materials over the last 10 years has seen the introduction of a multitude of different filling materials claiming to provide the best performance in terms of durability, aesthetics, symptom relief, etc when placed in the mouth. This review sought to compare the different types of dental materials against each other for the same outcomes.

OBJECTIVES

The objective of this review was to compare the outcomes (including pain relief, survival and aesthetics) for restorative materials used to treat caries in the primary dentition in children. Additionally, the restoration of teeth was compared with extraction and no treatment.

SEARCH STRATEGY

Electronic searches of the following databases were undertaken: the Cochrane Oral Health Group's Trials Register (up to January 2009); CENTRAL (The Cochrane Library 2009, Issue1); MEDLINE (1966 to January 2009); EMBASE (1996 to January 2009); SIGLE (1976 to 2004); and conference proceedings on early childhood caries, restorative materials for paediatric dentistry, and material sciences conferences for dental materials used for children's dentistry (1990 to 2008). The searches attempted to identify all relevant studies irrespective of language.Additionally, the reference lists from articles of eligible papers were searched, handsearching of key journals was undertaken, and personal communication with authors and manufacturers of dental materials was initiated to increase the pool of suitable trials (both published and unpublished) for inclusion into this review.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-randomised controlled trials with a minimum period of 6 months follow up were included. Both parallel group and split-mouth study designs were considered. The unit of randomisation could be the individual, group (school, school class, etc), tooth or tooth pair. Included studies had a drop-out rate of less than 30%. The eligible trials consisted of young children (children less than 12 years) with tooth decay involving at least one tooth in the primary dentition which was symptomatic or symptom free at the start of the study.

DATA COLLECTION AND ANALYSIS

Data were independently extracted, in duplicate, by two review authors. Disagreements were resolved by consultation with a third review author. Authors were contacted for missing or unclear information regarding randomisation, allocation sequence, presentation of data, etc. A quality assessment of included trials was undertaken. The Cochrane Collaboration statistical guidelines were followed for data analysis.

MAIN RESULTS

Only three studies were included in this review. The Fuks 1999 study assessed the clinical performance of aesthetic crowns versus conventional stainless steel crowns in 11 children who had at least two mandibular primary molars that required a crown restoration. The outcomes assessed at 6 months included gingival health (odds ratio (OR) 0.3; 95% confidence interval (CI) 0.01 to 8.32), restoration failure (OR 3.29; 95% CI 0.12 to 89.81), occlusion, proximal contact and marginal integrity. The odds ratios for occlusion, proximal contact and marginal integrity could not be estimated as no events were recorded at the 6-month evaluation. The Donly 1999 split-mouth study compared a resin-modified glass ionomer (Vitremer) with amalgam over a 36-month period. Forty pairs of Class II restorations were placed in 40 patients (21 males; 19 females; mean age 8 years +/- 1.17; age range 6 to 9 years). Although the study period was 3 years (36 months), only the 6- and 12-month results are reported due to the loss to follow up of patients being greater than 30% for the 24- and 36-month data. Marks 1999a recruited 30 patients (age range 4 to 9 years; mean age 6.7 years, standard deviation 2.3) with one pair of primary molars that required a Class II restoration. The materials tested were Dyract (compomer) and Tytin (amalgam). Loss to follow up at 24 and 36 months was 20% and 43% respectively. This meant that only the 24-month data were useable. For all of the outcomes compared in all three studies, there were no significant differences in clinical performance between the materials tested.No studies were found that compared restorations versus extractions or no treatment as an intervention in children with childhood caries.

AUTHORS' CONCLUSIONS

It was disappointing that only three trials that compared three different types of materials were suitable for inclusion into this review. There were no significant differences found in all three trials for all of the outcomes assessed. Well designed, randomised controlled trials comparing the different types of filling materials for similar outcomes are urgently needed in dentistry. There was insufficient evidence from the three included trials to make any recommendations about which filling material to use.

Stainless steel crown versus modified open-sandwich restorations for primary molars: a 2-year randomized clinical trial

OBJECTIVE

The aim of this study was to investigate the clinical performance and survival of stainless steel crown (SSC) restoration and modified open-sandwich technique using resin-modified glass ionomer cement.

DESIGN

Randomized clinical trial.

SETTING

General dental practice.

MATERIALS AND METHODS

A total of 87 children aged 4-7 years at baseline with one or more primary molars that have undergone pulp therapy were randomly assigned to receive either SSC or modified open-sandwich restoration. One hundred and sixty restorations were placed and evaluated after 6, 12, 18, and 24 months using the Ryge criteria.

RESULTS

Comparable survival rates were observed for both SSC and modified open-sandwich restoration. With only four SSCs and six modified open-sandwich restorations failing over 24 months, the survival rates were high for both materials (2-year survival rate: 95.0% for SSCs and 92.5% for modified open-sandwich restorations). Significantly better gingival health (P < 0.05) was observed for the modified open-sandwich restorations compared with SSCs, as only one modified open-sandwich restoration was rated Charlie compared to 13 SSCs. No significant differences were observed between the two materials for marginal integrity, proximal contact, occlusion, or recurrent caries.

CONCLUSION

The 2-year results indicated that the modified open-sandwich restoration is an appropriate alternative to SSC in extensive restorations, particularly where aesthetic considerations are important.

Different dental care setting: does income matter?

In this paper we consider the use of mobile dental clinics as a means of improving access to dental care among primary school children in Southern Thailand by reducing the opportunity cost of service use to parents. Parents' willingness to pay (WTP) is measured for three different services provided in a community hospital dental clinic and a school-based mobile clinic. Although the service setting does not affect significantly the WTP for treatment directly, the estimated positive association between WTP and income is modified by setting. The results indicate that the potential for mobile clinics to increase utilization of services among primary school children is associated with parents' income, with the difference in valuation of dental services between the two settings being less among lower income parents than higher income parents. However, even among lower income parents our results indicate that the potential for increasing service utilization among children depends on the improvements in access associated with the mobile clinic not being achieved at the opportunity cost of lower levels of effectiveness.

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.

A novel technique using preformed metal crowns for managing carious primary molars in general practice - a retrospective analysis

BACKGROUND

There is a high level of untreated dental decay in primary teeth in Scotland. Despite evidence for the efficacy of preformed metal crowns (PMCs) for the restoration of primary molars, few are placed in general practice, possibly due to the interventive nature of the clinical procedure. There is, however, a novel way of placing PMCs involving no local anaesthesia, no caries removal and no preparation of the tooth: the Hall technique.

AIM

To investigate the survival of carious primary teeth treated with PMCs placed using a novel, simplified method - the Hall technique.

SETTING

General dental practice, in Scotland.

METHOD

A retrospective analysis of practice records from one general practitioner, from 1988 to 2001. The majority of the 978 PMCs fitted on 259 children, using the Hall technique, were placed when there was clinical evidence of approximal caries into dentine. The Kaplan-Meier approach was used to analyse survival times and the Mantel-Haenszel Log rank test for comparison between tooth types.

RESULTS

For all tooth types, the probability of surviving three years without being extracted or the PMC being lost, was 73.4% (95% confidence interval 70.1% to 76.4%), and for five years was 67.6% (95% confidence interval 63.3% to 71.5%). The probability of surviving without extraction alone for three years was 86.0% (95% confidence interval 83.2% to 88.4%), and for five years was 80.5% (95% confidence interval 76.5% to 83.9%).

CONCLUSIONS

Hall technique restorations placed on primary molars with decay clinically into dentine, by a single operator in general dental practice, have a similar success rate to some other, more conventional, restorative techniques. The technique requires further evaluation through a prospective randomised control clinical trial before its use could be generally recommended.

The outlook for implants and endodontics: a review of the tissue engineering strategies to create replacement teeth for patients

Ideally, root canal therapy involves the removal of diseased pulp tissues and permanent replacement with healthy pulp to revitalize teeth. Rather than placing implants, the ideal solution is to grow new replacement teeth. Success rates of implants and endodontic treatments can exceed 90%, which presents a formidable challenge to tissue engineering researchers to ensure that future dental treatments are even more successful. The purpose of this article is to explain how tissue engineering can be used to create replacement teeth. The science of tissue engineering has evolved from growing simple tissues in cell culture incubators to a multistep process. Although the problems of introducing tissue engineering therapies as part of routine dental treatments are substantial, the potential benefits are equally ground breaking.

Review on fluoride-releasing restorative materials--fluoride release and uptake characteristics, antibacterial activity and influence on caries formation

OBJECTIVES

The purpose of this article was to review the fluoride release and recharge capabilities, and antibacterial properties, of fluoride-releasing dental restoratives, and discuss the current status concerning the prevention or inhibition of caries development and progression.

METHODS

Information from original scientific full papers or reviews listed in PubMed (search term: fluoride release AND (restorative OR glass-ionomer OR compomer OR polyacid-modified composite resin OR composite OR amalgam)), published from 1980 to 2004, was included in the review. Papers dealing with endodontic or orthodontic topics were not taken into consideration. Clinical studies concerning secondary caries development were only included when performed in split-mouth design with an observation period of at least three years.

RESULTS

Fluoride-containing dental materials show clear differences in the fluoride release and uptake characteristics. Short- and long-term fluoride releases from restoratives are related to their matrices, setting mechanisms and fluoride content and depend on several environmental conditions. Fluoride-releasing materials may act as a fluoride reservoir and may increase the fluoride level in saliva, plaque and dental hard tissues. However, clinical studies exhibited conflicting data as to whether or not these materials significantly prevent or inhibit secondary caries and affect the growth of caries-associated bacteria compared to non-fluoridated restoratives.

SIGNIFICANCE

Fluoride release and uptake characteristics depend on the matrices, fillers and fluoride content as well as on the setting mechanisms and environmental conditions of the restoratives. Fluoride-releasing materials, predominantly glass-ionomers and compomers, did show cariostatic properties and may affect bacterial metabolism under simulated cariogenic conditions in vitro. However, it is not proven by prospective clinical studies whether the incidence of secondary caries can be significantly reduced by the fluoride release of restorative materials.

Fluoride-containing restorative materials

Dental practitioners are exposed to an increasing number of dental materials, which claim the benefits of fluoride release. The purpose of this paper is to critically review the literature of these materials. Glass ionomers, resin modified glass ionomers, compomers, resin composites, fissure sealants and amalgam are discussed. It is clear that a long-term measurable release of fluoride can be observed from certain restorative materials, in vitro, particularly glass ionomer cement, resin modified glass ionomer cement, fluoridated cements, fluoridated dental amalgam and certain fissure sealants. In general, the rate of fluoride release is not constant but exhibits a relatively rapid initial rate, which decreases with time. However, the fluoride release profiles may be dependent on specific formulation and on experimental design and sampling methods. These materials may feature greater longevity, a reduced incidence of marginal failure, an elevated concentration of fluoride in contingent plaque, together with an antibacterial action when compared with non-fluoride releasing materials. In addition, fluoride-releasing materials may perform better in caries inhibition in artificial caries model studies than non-fluoridated materials. While any, or all, of these anti-cariogenic effects may be associated with fluoride release, a direct relationship between fluoride release profiles and such effects has not been determined in vivo.

Prevention of Artificial Caries: Effect of Bonding Agent, Resin Composite and Topical Fluoride Application

This study investigated the effect of fluoride containing resin composites and bonding agents, as well as the topical fluoride (F) application on the inhibition of artificial caries progression by using a pH-cycling model with alternating demineralizing (pH:4.5) and remineralizing (pH:7.0) solutions. Two bonding systems (F-containing bonding system [Reactmer Bond: RB] and non-F containing bonding system [Clearfil SE Bond: SE]), two resin composites, (F-containing [Reactmer Paste: RP] and non-F containing [Clearfil AP-X: AP]) were used. A combination of each bonding agent and a resin composite, RB+RP, RB+AP, SE+RP and SE+AP, was placed in 2 x 3 x 1.5-mm cavities on root dentin of extracted molars (n=96). Specimens were subjected to pH-cycling for 6 or 12 weeks. Half of all specimens were immersed in 0.05% NaF solution for 1 minute once a day as a topical F application. After the pH cycling period, a microradiograph of each specimen was taken, and the outer lesion depth of the artificial caries was measured by means of image analyzing software. The depths of the outer lesions at different periods were analyzed by one-way ANOVA and Sheffe's test at p=0.05. The combination that received F treatment showed reduced lesion depth compared to the same combination without F application. Except for the F application group of 12 weeks, there was no significant difference in lesion depth among each bonding and composite combination (p>0.05). At week 12 with the F application, RB+RP showed the shallowest lesion compared to the other combinations (p<0.05). The results indicated that the F application reduced the progression of artificial caries. Moreover, the combination of fluoride containing bonding agent and restorative material was the most effective for the inhibition of artificial caries progression based on the 12-week experimental period with topical F application.

The survival of resin modified glass ionomer and stainless steel crown restorations in primary molars, placed in a specialist paediatric dental practice

AIMS

To prospectively report on the survival of resin-modified glass ionomer cement (RMGIC), photac-fil and pre-formed stainless steel crown (SSC) restorations in primary molar teeth placed over a seven-year period in a specialist paediatric dental practice under private contract of remuneration.

METHOD

All primary molar restorations placed by a specialist paediatric dentist over a seven-year period were reviewed and the outcome results recorded. Data were recorded at review visits until June 30, 2003. Data recorded included Class I restorations, Class II restorations and SSC. The Class II cavities were either mesial or distal, with or without buccal/palatal extensions. If both proximal surfaces were decayed or if after cavity preparation the resultant outline form was significantly larger than the minimal classical form, RMGIC was not used; an SSC was placed instead. Stainless steel crown preparation followed conventional guidelines. The crowns were cemented with reinforced zinc oxide and eugenol (Kalzinol). The status was recorded as satisfactory restoration, tooth exfoliated, tooth extracted for orthodontic reasons with the date of extraction, or needing replacement. If replaced then the reason for replacement was also recorded.

RESULTS

A total of 544 Class I RMGICs, 962 Class II RMGICs, and 1,010 SSCs were placed. At the last review of each restoration, 98.3% of Class I, 97.3% of Class II RMGICs and 97.0% of SSCs were either satisfactory or withdrawn intact.

CONCLUSION

Under the conditions of private specialist practice-based study SSCs continued to prove very successful for the restoration of larger cavities and for pulp-treated primary molar teeth. For the smaller cavities RMGIC were also very successful.

Obtaining an evidence-base for clinical dentistry through clinical trials

Ideally, all clinical practice should be based on the best available evidence; however, in general dental practice even a very routine issue, such as the appropriate management of the carious primary dentition, is hampered by the lack of a sound evidence-base from high quality clinical trials run in general dental practices. Furthermore, the use of the evidence that is available may be confounded by inadequate reporting. This paper reviews the difficulties reported in successfully completing such clinical trials, and reports on the authors' own experiences. Suggestions are made for overcoming the challenge of patient recruitment in randomised controlled clinical trials in primary dental care. These include: regular contact with a principal investigator, who is viewed as a peer; ensuring the relevance of the research topic to the dentists' daily practice; appropriate remuneration; acknowledgement of the contribution made and recognition of the contribution of research activity to continuing professional development. Use of the CONSORT statement to improve planning and reporting of clinical trials is recommended.

Restoration materials for primary molars—results from a European survey

OBJECTIVE

The aim of this study was to obtain an overview of the materials and restorative techniques taught for Class I and Class II restorations in primary molars of different European departments for paediatric dentistry and to compare the results to those for North America.

METHODS

The forms were sent to the chairmen of the departments of paediatric dentistry or-when included into the department for operative dentistry-to the director of 200 universities in 32 European Countries. The questions concerned the preferred materials and techniques, as well as the indications or contraindications for the use of the different tooth coloured materials.

RESULTS

Forty-three percent of the universities from western European countries (excluding Germany) responded to the survey. A 97% answer rate was obtained from German Schools. Of the other European regions, the response rate varied remarkably (24-54%). Also, opinions on materials used and methods applied were different from country to country. Only in a few regions (Eastern Europe), amalgam remains the filling material of first choice for Class I and II cavities in primary molars, whereas in others, the use has been restricted and tooth coloured materials, especially compomers or resin-modified glass ionomer cements, are being preferred.

CONCLUSIONS

Great diversity in teaching was observed not only among the European countries, but also within the countries themselves which makes it difficult to compare the results of our study to the ones obtained from the US.

Research in general dental practice

Spurred by an initiative by the National Institute of Dental and Craniofacial Research in the USA, this article presents the need for a change in clinical dental research towards practice-based research. It outlines the shortcomings of past and present-day research in dentistry, with emphasis on the lack of clinical relevance of much of the research performed. The slow transfer of sound research findings to clinical practice is also a major problem. The article reviews some problems related to restorative dentistry and how they have adversely affected general dental practice. Practice-based research places emphasis on the problems experienced by clinicians in the routine care of patients. Clinicians should be linked together in research networks. The problems they face in dental practice and the clinical experience they have will form the basis for studies by the network. Experienced clinical researchers will provide guidance and statistical support for the studies initiated by the clinicians.

Stem Cell Responses in Tooth Regeneration

Scientific advances in the creation of restorative biomaterials, in vitro cell culture technology, tissue grafting, tissue engineering, molecular biology, and the human genome project provide the basis for the introduction of new technologies into dentistry. This review is intended to facilitate the development of stem cell therapy for use with established therapeutic modalities to restore and regenerate oral tissues. Teeth have been shown to mineralize in response to injury for many decades, but only in recent years has the position of the stem cells been localized around blood vessels. The cells have been identified as myofibroblastoid pericytes. The ability to control the differentiation and proliferation of these cells is being examined to create stem cell therapies that can solve dental problems more effectively than current treatment regimes. Although the problems of introducing these technologies are substantial, the potential benefits to patients and the profession are equally promising - a cure for caries and diseases, a cure for oral cancer, correction of congenital defects, and the regeneration of teeth and tissues to restore oral functions. The purpose of this review is to describe how these new technologies can most usefully be employed in dentistry to enable clinicians to satisfy patient demand for a nondefective dentition.

Resin-modified and conventional glass ionomer restorations in primary teeth: 8-year results

OBJECTIVES

To compare the longevity and cariostatic effects of resin-modified (RMGIC) and conventional glass ionomer (GIC) restorations in primary teeth in the Danish Public Dental Health Service.

METHODS

The sample consisted of 543 RMGIC and 451 GIC restorations in all cavity types in the primary teeth of 640 children, aged 3.0-17.5 years. The restorations were in contact with 480 unrestored surfaces. The restorations and the adjacent surfaces were followed until exfoliation/extraction of the teeth, repair/replacement of restorations or operative treatment of adjacent surfaces. Survival analyses supplied with multivariate analyses were performed to assess the influence of different factors on the longevity of restorations, occurrence of prevalent failures, and caries treatment of adjacent surfaces.

RESULTS

After 8 years, 2% of the restorations were still in function and 37% of the RMGIC and 44% of the GIC restorations had been repaired or replaced. Fracture and loss of retention predominated as the reasons for failure of restorations in both materials. The 50% survival time for restorations was 55 months for RMGIC and 48 months for GIC (p = 0.01). Progression of caries lesions required operative treatment on 20% of the surfaces in contact with RMGIC and on 14% of surfaces adjacent to GIC restorations. The 75% survival time was 35 months for surfaces in contact with both materials (p = 0.37).

CONCLUSIONS

RMGIC and GIC showed similar cariostatic effects on restored teeth and adjacent tooth surfaces, but RMGIC should be preferred for class II restorations in the primary dentition, and class III/V restorations should be made in GIC due to enhanced longevity.

Class II restorations in primary teeth: 7-year study on three resin-modified glass ionomer cements and a compomer

The aim of this randomized study was to compare the longevity and cariostatic effects of 1565 class II restorations in primary teeth placed by 15 clinicians in the Danish Public Dental Health Service in 971 children, aged 3.6-14.9 yr. The restorations were performed using three resin-modified glass ionomer cements and one compomer (polyacid-modified composite resin) with and without their respective cavity conditioners. The restorations were in contact with 1023 unrestored proximal surfaces in 853 primary and 170 permanent teeth. The study was terminated after 7 yr with 1% of the restorations in function, 7% patient dropouts, 18% failed restorations, and operative treatment on 24% of the adjacent surfaces. Multivariate survival analyses showed that the restorative material and cavity conditioning influenced the survival of restorations but not the progression of caries on adjacent surfaces. The 50% survival times were estimated to exceed 5 yr for the restorations and 4.5 yr for the adjacent unfilled surfaces in all treatment groups. It was concluded that resin-modified glass ionomer cement and compomer are both appropriate materials for class II restorations in primary teeth. The differences in longevity and cariostatic effects among the four materials used with and without conditioner were less than the intra-individual differences between clinicians.

Bacterial microleakage and pulp inflammation associated with various restorative materials

OBJECTIVES

Many restorative materials are claimed to be successful in preventing bacterial microleakage and minimizing pulp inflammation. However, information regarding the in vivo performance of materials in comparison with each other is limited. The aim of this study was to evaluate and compare the pulp response of nine restorative materials when placed in non-exposed monkey cavities.

METHODS

279 standardized non-exposed Class V cavities, were prepared into buccal dentin. Cavities were restored with a number of materials in the following categories: Zinc oxide eugenol (ZnOE), Calcium hydroxide [Ca(OH)(2)], zinc phosphate (ZP), Resin-modified glass ionomer (RMGI), Composite resin (CR), Bonded amalgam (BA), Gutta-percha (GP), Compomer and Silicate. Pulp tissues were collected and evaluated at short, intermediate and long-term intervals according to ISO guidelines; employing histomorphometric analysis, Spearman's rho and ANOVA statistics. Pulp responses were categorized according to FDI, ISO and ADA standards. Bacteria were detected using McKay stains.

RESULTS

Pulp inflammation was found to be correlated to bacterial microleakage around the restoration (p < or =0.0001). The frequency of bacterial microleakage was found to vary between restorative materials (p < or =0.0001). In rank order of preventing bacterial microleakage from best to the worst; RMGI (100%), BA (88%), ZnOE (86%), CR (80%), GP (64%), Ca(OH)(2) (58%), compomer (42%), silicate (36%) and ZP (0%).

SIGNIFICANCE

The most effective restorative materials to prevent bacterial microleakage and pulp injury from inflammatory activity were RMGI, BA, ZnOE and CR restorations.

Fluoride-releasing restorative materials and secondary caries

Secondary caries are responsible for 60% of all replacement restorations in the typical dental practice. Risk factors for secondary caries are similar to those for primary caries development. Unfortunately, it is not possible to predict accurately which patients are at risk for restoration failure. Fluoride-releasing dental materials provide for improved resistance against primary and secondary caries in coronal and root surfaces and have become a part of the dentist's armamentarium. This article discusses the improvement in the properties of dental materials with the ability to release fluoride. It is anticipated that in the near future, the vast majority of restorative procedures will employ fluoride-releasing dental materials as bonding agents, cavity liners, luting agents, adhesives for orthodontic brackets, and as definitive restoratives.

Conference report. Direct adhesive materials: current perceptions and evidence--future solutions

This paper reports the proceedings, including the consensus views of an Australasian expert group convened to consider current perceptions, evidence and future solutions in the field of direct adhesive materials. This group, in anticipating a trend to preservative dentistry, formed the view that caries risk assessment should increasingly influence the selection of restorative materials. In low caries risk patients, aesthetic demands typically favour the use of resin-based composites. Interactive (biomimetic) materials based on glass-ionomer chemistry have particular application in high caries risk patients. Teaching in dental schools, continuing education programmes and research, both in the laboratory and in the clinical environment should be more attuned to the ever-increasing use of tooth-coloured restorative materials in everyday clinical practice. Linked to this trend are changes in patient--dentist relationships, whereby patients should be encouraged to become more involved in treatment decision-making. Expert group meetings are suggested to be of value in addressing some of the shortfall between the need for good evidence and the relentless challenge of the introduction of new products and concepts in the field of direct adhesive materials.