Dental materials for posterior restorations

Abstract Assessment of the quality of dental restorations by the Ryge system is described. Generally, the quality of dental restorations is shown to be dependent on the technique sensitivity of the restorative material as well as the skill and experience of the dentist. Concerning biocompatibility, adverse reactions related to amalgam restorations are unlikely or scarce, due to small amounts of released mercury. Resin based restorative materials contain a large number of organic compounds and, as such, the toxic and allergenic potentials are unknown. Gold and ceramics turn out to be the most biotolerable dental materials. Based on studies on longevity, data indicate that the median age of amalgam restorations is 10-12 years, of gold castings 13-14 years and more, and of composite restorations 4 years. Data on longevity of ceramic restorations are sparse. Secondary caries appears to be the most frequent cause for replacement of the different restorations, followed by marginal degradation. Secondary caries account for more failures among the resin based restorations than among amalgam. Reviewing the literature, it appears that amalgam is the best and most economic dental material for routine posterior restorations with reasonable durability. Gold is recommended for complex restorations. Resin based composites may be limited to small restorations where cosmetics is the main aspect, as wear and recurrent caries are main problems. Ceramic restorations comprise aesthetic restorations with excellent bio-compatibility, however, data on longevity and marginal adaptation are not encouraging.     

Dental materials for posterior restorations.

Assessment of the quality of dental restorations by the Ryge system is described. Generally, the quality of dental restorations is shown to be dependent on the technique sensitivity of the restorative material as well as the skill and experience of the dentist. Concerning biocompatibility, adverse reactions related to amalgam restorations are unlikely or scarce, due to small amounts of released mercury. Resin based restorative materials contain a large number of organic compounds and, as such, the toxic and allergenic potentials are unknown. Gold and ceramics turn out to be the most biotolerable dental materials. Based on studies on longevity, data indicate that the median age of amalgam restorations is 10-12 years, of gold castings 13-14 years and more, and of composite restorations 4 years. Data on longevity of ceramic restorations are sparse. Secondary caries appears to be the most frequent cause for replacement of the different restorations, followed by marginal degradation. Secondary caries account for more failures among the resin based restorations than among amalgam. Reviewing the literature, it appears that amalgam is the best and most economic dental material for routine posterior restorations with reasonable durability. Gold is recommended for complex restorations. Resin based composites may be limited to small restorations where cosmetics is the main aspect, as wear and recurrent caries are main problems. Ceramic restorations comprise aesthetic restorations with excellent biocompatibility, however, data on longevity and marginal adaptation are not encouraging.     

Long-term results of front teeth restoration using light-curing composite materials

200 patients (500 restorations of front teeth) were examined. All the restorations were made of light-curing composite materials (microfills, hybrids, compomers, and combination of microfills and hybrids) from 5 do 9 years ago. Clinical and esthetical parameters were evaluated. We had to replace 96 restorations of 500 (19.2%), only 50 (10%) restorations were marked as "excellent". Direct veneers made of microfilled composite materials showed the best results (30%--"excellent" restorations). The restorations of devital teeth and V-class restorations of compomer material show the worse result (20% restorations replaced).     

Influence of patient factors on age of restorations at failure and reasons for their placement and replacement

OBJECTIVE: This study examined the reasons given by a selected group of dental practitioners for placement and replacement of restorations and correlated the data provided with patient factors, such as patients' age and gender, caries risk, occlusal function and oral hygiene, with restoration longevity. METHOD: A group of general dental practitioners (GDPs) were recruited to take part in the study. Each participant was asked to record the reason for placement or replacement of restorations from a list of potential reasons. The age and Class of the restoration being replaced was also recorded, as also was the material being used and the material being replaced. RESULTS: Details of reason for placement/replacement was received on 3196 restorations from 32 GDPs. Of the restorations placed, 54% were amalgam, 32% composite, 8% compomer and 7% glass ionomer. The reasons for placement/replacement of the restorations were principally primary caries (28%), secondary caries (29%), margin fracture (10%), tooth fracture (7%), and non-carious defects (6%). Overall, the mean age of restorations at failure was 7.1 years. Of the patients who received glass ionomer restorations, 29% were rated as having poor oral hygiene, compared with 18% of the patients who received amalgam restorations, 18% of the patients who received composite restorations and 23% of the patients who received compomer restorations. Of the patients who received glass ionomer restorations, 35% were rated as having high caries susceptibility, compared with 27% of those receiving amalgam restorations, 21% of those receiving composite restorations and 30% of those receiving compomer restorations. CONCLUSION: Primary caries was the principal reason for initial restorations. Secondary caries was the most prevalent reason for replacement of restorations. The results also indicate a selective application of different materials for different patients.     

Five year evaluation of class III composite resin restorations in cavities pre-treated with an oxalic- or a phosphoric acid conditioner

An oxalic acid solution has been proposed as a conditioning agent for resin composite restorations in two commercial adhesive systems. The durability of 163 class III restorations, including 12 class IV restorations, in cavities pre-treated with an oxalic acid total etch technique or an enamel etch with phosphoric acid was studied. Each of 52 patients received at least one of each of three experimental restorations. The restorations were evaluated yearly with slightly modified United States Public Health Service (USPHS) criteria. After 5 years 95% of the restorations were evaluated as acceptable. Reasons for failure were the fracture of four fillings, including three class IV, secondary caries contiguous to two fillings and a non-acceptable colour match for one restoration. For eight class III restorations a fracture of the incisal tooth structure was registered. No differences were seen between the three experimental restorations.     

Adapting fixed prosthodontics principles to screw-retained restorations

Implant restorations may be visualized clinically using a provisional fixed partial denture and in the laboratory with a fully contoured waxing on the master cast. The benefits of eggshell restorations for provisional restorations are as valid in implant prostheses as in conventional restorations. A technique is presented using the plastic laboratory sleeves to provide reliable anchorage as well as protection and preservation of the abutments. A fully contoured waxing on the master cast predictably determines the most appropriate design for screw-retained restorations. When unfavorable implant placement would create compromised morphology, a retrievable auxiliary substructure is indicated.     

Monomer release from direct and indirect adhesive restorations: A comparative in vitro study

ObjectivesIndirect dental restorations produced by computer-aided design and computer-aided manufacturing (CAD/CAM) are relatively new in daily dental practice. The aim of the present study was to compare the monomer release between direct composite restorations and indirect CAD/CAM produced restorations (composite, ceramic and hybrid).MethodsIdentical crown restorations were prepared from three indirect materials (Cerasmart, Vitablocs Mark II and Vita Enamic) and one composite material (Clearfil AP-X). For each restoration, eight crown restorations were luted onto tooth samples and immersed into 2.5 mL of an aqueous extraction solvent. Additionally, three nonluted crowns of each restoration type were also immersed in the extraction solvent, and served as controls. Every week, the extraction solvent was collected and refreshed, during a period of 8 weeks. The released monomers were quantified using ultra-performance liquid chromatography-tandem mass spectrometry.ResultsIndirect restorations release significantly lower quantities of residual monomers than direct restorations, and the monomers released by the luted indirect restorations are mainly derived from the composite material used for cementation. The quantity of monomers released by direct restorations greatly depended on the time of light polymerization.SignificanceIn terms of monomer release, indirect restorations are a good alternative to direct restorations to limit patient exposure to residual monomers. It is important to ideally design the fit of indirect restoration so that the cement layer is as thin as possible and the monomer release from this cement layer remains as low as possible.     

A cross-sectional longitudinal survey into the durability of amalgam restorations.

The durability of amalgam restorations was assessed from a cross-sectional survey based upon 6000 defective restorations and a longitudinal survey based on the amalgam restorations of 400 males and females spanning a 20-year period. The data showed that amalgam restorations are not as durable as traditionally assumed, with failure on the part of the dental surgeon being the pre-dominant defect.     

Long-term evaluation of extensive restorations in permanent teeth

OBJECTIVES: The present prospective, longitudinal study assessed the outcome of posterior extensive restorations and identified risk factors for failure of the restorations. MATERIALS AND METHODS: The sample consisted of 722 amalgam restorations, 115 composite resin restorations and 89 crowns placed in 428 adults by one dentist from 1982 to 1999 in Belgium. Well-defined criteria were used for cavity preparation design, type of retention and selection of restorative material. RESULTS: At the closure of the study 48% of the restorations were well functioning, 24% were lost to lack of follow-up, and 28% had failed. The most frequent reasons for failure were fracture of restoration (8%), secondary caries (6%) and fracture of cusp (5%). Failures were more often found in premolar teeth (34%) than in molars (27%) (P=0.05) and occurred in 28% of the amalgam restorations, 30% of the resin restorations and 24% of the crowns (P=0.55). Molar restorations were more frequently repaired than replaced in contrast to premolar restorations. The highest percentage of extractions was related to complete amalgam restorations in premolars. The Kaplan-Meier median survival times were 12.8 years for amalgam restorations, 7.8 years for resin restorations, and more than 14.6 years for crowns, considering all retreatment as failures (P=0.002). The survival was influenced by extension of restoration, age of patient, pulpal vitality, 3-year period of treatment, use of base material and dentinal retentive pins. CONCLUSION: Within the limits of the study the data support the view that extensive amalgam restorations but not composite resin restorations can be used as an appropriate alternative to crowns, with due consideration to the longevity of the restorations.     

A preliminary study on a resin-modified glass-ionomer cement for transitional restorations and subsequent core buildups

PURPOSE: The purpose of this study was to evaluate the serviceability of a resin-modified glass-ionomer cement for transitional restorations and subsequent core buildups in endodontically treated maxillary premolars. MATERIALS AND METHODS: Fifty Vitremer restorations were made in 42 patients by one operator during a period of 5 months. After 1 year of follow up, the quality of the restorations was assessed for the variables occlusal contacts, proximal contacts, marginal adaptation, and surface roughness. Survival was estimated at 2 years of service either as a transitional restoration or as a core buildup. RESULTS: The percentage survival of the transitional restorations was 85% +/- 6%. When the crowned Vitremer restorations were added to the transitional restorations, the 2-year survival was 98% +/- 2%. With respect to the quality assessment, the majority of the restorations showed either no or light occlusal contacts and no or light contacts on at least one of their proximal surfaces. Marginal integrity and surface roughness were considered to be suboptimal on average. CONCLUSION: The described restorations seem to perform adequately for a transitional period of 1 to 2 years. Their viability as substructures for permanent cast restorations remains to be tested in long-term clinical studies.     

Clinical performance of posterior composite resin restorations.

Two formulations of posterior composite resin (P-30 and Bisfil-P) were evaluated and compared to a high-copper, dispersed-phase amalgam (Dispersalloy). One hundred twenty-eight restorations were placed in 27 patients so that each patient received at least one of each material. After 3 years of clinical service, all three restorative materials produced clinically acceptable restorations, according to US Public Health Service and Leinfelder criteria. The amalgam restorations, however, underwent less wear (44 microns) than did the posterior composite resin restorations (60 to 74 microns). Stratification of data by type of tooth, class of restoration, and size of restoration produced the same ranking of wear from lowest to highest: Dispersalloy, Bisfil-P, and P-30. Resin restorations showed 45% more wear in molars than in premolars, and more wear was associated with moderately sized restorations than with conservative restorations. The surface texture of restorations of composite resin with porous strontium glass filler was nearly as smooth as that of enamel and was significantly smoother than that of the restorations of composite resin with zinc glass filler or of unpolished amalgam.     

Quality assessment of amalgam and inlay restorations on posterior teeth: a retrospective study

This study was designed to assess and compare the quality of posterior proximo-occlusal amalgam and inlay restorations relative to type of restoration (material, surfaces involved, and cusp protection) and length of service of the restorations. A clinical evaluation system based on operationally defined and clinically important criteria was used. Clinically and statistically significant differences were found between overall ratings for amalgam and inlay restorations and between small (two-surface) amalgam and inlay restorations, as well as between larger (three-surface) amalgam and inlay restorations. In all cases, inlay restorations were of higher quality. A not acceptable rating for marginal integrity was the most frequent reason for not acceptable overall ratings. There was no difference in satisfactory/not acceptable ratings for inlay restorations with or without protected cusps (p = .95).     

Despite all--do we have an appropriate substitute for amalgam?

The ultimate success or failure of a restored tooth is largely dependent on clinical management. Clinicians may choose from a number of restorative materials, different clinical techniques and cavity preparation procedures. Composite resin has been used for nearly 50 years as a restorative material in dentistry. The use of this material has recently increased as a result of patients' demands for esthetic restorations. Failure of dental restorations is a major concern in dental practice. Replacement of failed restorations constitutes the majority of operative work. Clinicians should be aware of the longevity of, and likely reasons for the failure of, direct posterior restorations. Higher failure rates were observed in resin-based composite restorations as compares amalgam restorations. Secondary caries was the main reason for failure. Posterior interproximal resin-based composite restorations should be considered with caution, and their limited long-term performance should be kept in mind. Patients should be informed about the potential longevity of restorative treatment for posterior teeth as they make decisions about treatment for their oral restorative needs.     

Probability of failure of highly filled indirect resin-veneered implant-supported restorations: an in vitro study

PURPOSE: The study compared the probability of failure of three highly filled resin-veneered restorations to that of conventional metal-ceramic restorations when used as implant-supported prostheses. The effect of the location of load application on the fracture resistance of the restorations was also studied. MATERIALS AND METHODS: Twenty samples each of the three resins, Artglass, Targis, and Estenia, were applied on type IV gold frameworks. Twenty metal-ceramic restorations of equal dimensions (VMK 95 and Degudent Universal) were used as controls. Compressive load was applied vertically at 1 mm (n = 10) and 2 mm (n = 10) from the periphery of the occlusal table until the restorations failed. Weibull analysis was applied to the data. RESULTS: There was no significant difference in the probability of failure among the metal-ceramic restorations and three resin-veneered restoration systems. Loading the resin-veneered restorations at the 1-mm location significantly increased their probability of failure when compared to the 2-mm loading location. The loading location did not significantly change the probability of failure of the metal-ceramic restorations. CONCLUSION: The probability of failure of resin-veneered restorations tested was not significantly different from that of the metal-ceramic restoration under two compressive loading conditions. Eccentric loading of resin-veneered restorations should be minimized in light of the higher probability of failure associated with such a loading condition.     

Integration of all-ceramic restorations in reconstructive prosthetic dentistry: a case report.

A male patient presented for maxillary and mandibular complete-arch prostheses. A total of eight all-ceramic restorations, eight metal-ceramic crowns, and four metal-ceramic fixed partial dentures were placed. The restorations were examined for marginal integrity, anatomic form, surface, and color for a period of 12 months. All restorations were in function at the end of the evaluation period. There was no adverse event. No substantial difference between the all-ceramic onlays and the metal-ceramic crowns was apparent. The all-ceramic restorations exhibited the least plaque growth. Bleeding on probing was minimal at both restoration types. The marginal integrity of the all-ceramic restorations was considered to be nearly as precise as that of the metal-ceramic crowns.     

Current status of zirconia-based fixed restorations

Zirconium dioxide (zirconia) ceramics are currently used for fixed restorations as a framework material due to their mechanical and optical properties. This review article describes the current status of zirconia-based fixed restorations, including results of current in vitro studies and the clinical performance of these restorations. Adaptation of zirconia-based restorations fabricated with CAD/CAM technology is within an acceptable range to meet clinical requirements. In terms of fracture resistance, zirconia-based fixed partial dentures (FPDs) have the potential to withstand physiological occlusal forces applied in the posterior region, and therefore provide interesting alternatives to metal-ceramic restorations. Clinical evaluations have indicated an excellent clinical survival of zirconia-based FPDs and crown restorations. However, some clinical studies have revealed a high incidence of chipping of veneered porcelain. Full-coverage zirconia-based restorations with adequate retention do not require resin bonding for definitive cementation. Resin bonding, however, may be advantageous in certain clinical situations and is a necessity for bonded restorations, such as resin-bonded FPDs. Combined surface treatment using airborne particle abrasion and specific adhesives with a hydrophobic phosphate monomer are currently reliable for bonding to zirconia ceramics. Further clinical and in vitro studies are needed to obtain long-term clinical information on zirconia-based restorations.     

The science of communicating the art of esthetic dentistry. Part II: Diagnostic provisional restorations

Provisional restorations fulfill many functions in restorative dentistry. Quality provisional restorations can provide the clinician, the patient, and the laboratory technician much valuable information prior to fabrication of the definitive restoration. Such diagnostic provisional restorations fabricated with acrylic resin are easily adjusted and modified until both esthetic and functional results are approved by the patient. Once this approval has been obtained, the definitive restorations can be fabricated with confidence, using the esthetic form of the provisional restorations as a blueprint.     

The Science of Communicating the Art of Esthetic Dentistry. Part II: Diagnostic Provisional Restorations

Provisional restorations fulfill many functions in restorative dentistry. Quality provisional restorations can provide the clinician, the patient, and the laboratory technician much valuable information prior to fabrication of the definitive restoration. Such diagnostic provisional restorations fabricated with acrylic resin are easily adjusted and modified until both esthetic and functional results are approved by the patient. Once this approval has been obtained, the definitive restorations can be fabricated with confidence, using the esthetic form of the provisional restorations as a blueprint.
CLINICAL SIGNIFICANCE
Routine use of provisional restorations for esthetic diagnostic purposes can prevent the destructive cycle of failure and frustration frequently experienced when performing elective esthetic restorative dentistry.     

Direct technique for the fabrication of acrylic provisional restorations

Provisional restorations are fabricated to protect the prepared tooth structure during the period between tooth preparation and insertion of the definitive restoration. These restorations are also referred to in the literature as interim, temporary, or provisional restorations (prostheses). Such restorations should be uncomplicated and inexpensive to fabricate in a short period of time. Several laboratory and clinical techniques for the fabrication of provisional restorations have been described in the literature, such as the indirect technique, direct technique, and indirect-direct techniques for both single and multiple unit restorations. This article describes a step by step clinical technique for the fabrication of a direct provisional restoration to satisfy the issues of esthetics, patient comfort, speech and function, maintenance of periodontal health, and maxillomandibular relationships while wearing the restoration.     

Esthetic transformation of a failed implant reconstruction to fixed-supported prosthesis: a case report

This article describes a clinical situation where an ill-fitting prosthesis supported by malpositioned dental implants was esthetically transformed to fixed definitive restorations. Provisional restorations were used as a blueprint for fabrication of definitive restorations.