Minimal invasive treatment for defective restorations: five-year results using sealants.

Replacement of dental restorations has been the traditional treatment for restorations that are defective. In this five-year randomized clinical trial, restorations with localized marginal defects were treated with sealants. Thirty-two patients (mean age, 26.8 years) with 126 Class I and Class II restorations with defective margins (amalgam n=69 and resin-based composite n=57) were recruited. Treatment was seal with pit and fissure sealant on localized marginal defects (group A: n=43) and was compared with total restoration replacement (group B: n=40) and untreated restorations (group C: n=43) as negative and positive controls. Restorations were assessed by two examiners using the modified US Public Health Service criteria, observing five clinical parameters: marginal adaptation, roughness, marginal stain, teeth sensitivity, and secondary caries at baseline and at five years after treatment. At the five-year recall examination, 23 patients with 90 restorations (71.4% recall rate) were examined. A significant improvement was observed in the marginal adaptation of the restorations in group A compared with group B. None of the treated group showed trends to downgrade in any parameter. Tooth sensitivity and secondary caries showed a low frequency in all groups. No significant difference in marginal adaptation of the restorations was found between amalgam and resin-based composite restorations (p=0.191). This study demonstrated that marginal sealing of restorations is a minimally invasive treatment that may be used instead of the replacement of restorations with localized marginal defects.

12 Years of Repair of Amalgam and Composite Resins: A Clinical Study.

OBJECTIVE: The objective of this study was to clinically evaluate repaired posterior amalgam and composite restorations over a 12 year period, investigate the influence of repair in the survival of restorations, and compare their behavior with respect to controls. METHODS: Thirty-four patients, 18 to 80 years of age with 167 restorations, 67 composite resin (RC), and 100 amalgam (AM) restorations, participated. Restorations with localized, marginal, anatomical deficiencies and/or secondary caries, and "clinically judged" suitable for repair or replacement according to US Public Health Service (USPHS) criteria, were randomly assigned to four groups: repair (n=35, 20 AM, 15 RC), replacement (n=43, 21 AM, 22 RC), positive control (n=71, 49 AM, 22 RC), or negative control (n=18, 10 AM, 8 RC). The quality of the restorations was blind scored according to the modified USPHS criteria. Two examiners scored them at initial status (κ=0.74) and after one to five, 10, and 12 years (κ=0.88). Wilcoxon and Mann-Whitney tests provided for comparisons within the same group and between years, respectively. RESULTS: After 12 years, all groups behaved similarly in marginal adaptation, marginal stain, teeth sensitivity, anatomic form, and luster ( p≥0.05). Better behavior in roughness was observed in replaced RC ( p=0.049). CONCLUSIONS: Given that most clinical parameters investigated were similar between all groups during the follow-up, the repair of RC and AM restorations is a good clinical option because it is minimally invasive and can consistently increase the longevity of restorations.

Effect of Refurbishing Amalgam and Resin Composite Restorations After 12 Years: Controlled Clinical Trial.

OBJECTIVES: The aim of this study was to clinically evaluate posterior amalgam and resin composite restorations refurbished over a period of 12 years by investigating the influence of refurbishing on the survival of restorations and comparing their behaviors with respect to controls. METHODS AND MATERIALS: Thirty-four patients were enrolled, ages 18 to 80 years, with 174 restorations, 48 restorations of resin composite (RC), and 126 restorations of amalgam (AM). Restorations with localized defects in anatomy, roughness, luster, or marginal staining that were clinically judged as suitable for refurbishing according to US Public Health Service (USPHS) Ryge criteria were assigned to group A-refurbishing (n=85; 67 AM, 18 RC)-or group B-control (n=89; 59 AM, 30 RC); the quality of the restorations was evaluated blindly according to the modified USPHS criteria. Two observers conducted evaluations at the initial state (k=0.74) and after one to five, 10, and 12 years (k=0.88). Wilcoxon, Friedman, and Mantel-Cox tests were performed to compare the groups, respectively. RESULTS: After 12 years, both groups experienced a similar decline, except for an evidently better performance in marginal adaptation in RC control (p=0.043) and in anatomy in AM refurbished (p=0.032). CONCLUSIONS: After 12 years, no difference was found in the clinical condition and longevity of the refurbished restorations compared to the control group.

Longitudinal results of a 10-year clinical trial of repair of amalgam restorations.

The aim of this prospective, blind, and randomized clinical trial was to assess the effectiveness of repair of localized clinical defects in amalgam restorations that were initially scheduled for replacement. A cohort of 20 patients with 40 (Class I and Class II) amalgam restorations that presented one or more clinical features that deviated from the ideal (Bravo or Charlie) according to US Public Health Service criteria, were randomly assigned to either the repair or the replacement group-A: repair, n = 19; and B: replacement, n = 21. Two examiners who had calibration expertise evaluated the restorations at baseline and 10 years after according to seven parameters: marginal occlusal adaptation, anatomic form, surface roughness, marginal staining, contact, secondary caries, and luster. After 10 years, 30 restorations (75%) were evaluated (Group A: n = 17; Group B: n = 13). Repaired and replaced amalgam restorations showed similar survival outcomes regarding marginal defects and secondary caries in patients with low and medium caries risk, and most of the restorations were considered clinically acceptable after 10 years. Repair treatment increased the potential for tooth longevity, using a minimally interventional procedure. All restorations trend to downgrade over time.

Seal, replacement or monitoring amalgam restorations with occlusal marginal defects? Results of a 10-year clinical trial.

The aim of this prospective and blind clinical trial was to assess the effectiveness of sealing localized marginal defects of amalgam restoration that were initially scheduled to be replaced. A cohort of twenty six patients with 60 amalgam restorations (n=44Class I and n=16Class II), that presented marginal defects deviating from ideal (Bravo) according to USPHS criteria, were assigned to either sealing or replacement groups: A: sealing n=20, Replacement n=20, and no treatment (n=20). Two blind examiners evaluated the restorations at baseline (K=0.74) and after ten years (K=0.84) according with USPHS criteria, in four parameters: marginal adaptation (MA), secondary caries (SC), marginal staining (MS) and teeth sensitivity (TS). Multiple comparison of restorations degradation/upgrade was analyzed by Friedman test and the comparisons within groups were performed by Wilcoxon test. After 10 years, 44 restorations were assessed (73.3%), Group A: n=14 and Group B: n=16; and Group C: n=14 sealing and replacement amalgam restorations presented similar level of quality in MA (p=0.76), SC (p=0.25) and TS (p=0.52), while in MS (p=0.007) presented better performance in replacement group after 10-years. Most of the occlusal amalgam restorations with marginal gaps showed similar long term outcomes than the restorations were sealed, replaced, or not treated over a 10-year period. Most of the restorations of the three groups were clinically acceptable, under the studied parameters. All restorations had the tendency to present downgrade/deterioration over time.

Dentin-predentin complex and its permeability: pathology and treatment overview.

This review paper focuses attention on tissue changes which may take place in dentin and on localized alterations in tissue formation in the predentin area. A number of reaction patterns has been described in dentin affecting both the inorganic and organic components. Dentinal tubules may become partly or completely obturated by growth of the peritubular dentin. Precipitation of mineral salts within the tubules, which may be a reprecipitation of minerals from adjacent demineralized dentin, represents a fundamentally different mode of obturation of dentinal tubules. Initially, demineralization selectively affects the peritubular dentin. If dentin is exposed to the oral environment, the surface layer may become hypermineralized. The surface layer of dentin, exposed by grinding, becomes covered by a smear layer. Displacement of the contents of the tubules or of the odontoblasts is a characteristic change in the organic components. Odontoblast destruction or degeneration will lead to a lack of, or reduced, predentin formation. Changes in the protein components which lead to alterations in dentin permeability have also been reported. The structure of the interface between dentin and localized formations of irregular secondary dentin varies considerably. If there is no tubular communication between primary and secondary dentin, the interface will act as an impermeable barrier. Changes in dentin, including irregular secondary dentin formation, affect the permeability of the tissue. Such changes are clinically important for the outcome of all types of restorative work performed on vital teeth.

Assessment of variables in clinical studies of amalgam restorations.

Marginal degradation of two amalgams with different creep properties was studied as a function of clinical variables. The amalgam with the highest creep values showed the most marked marginal degradation, irrespective of operator, doubling of the trituration time, and the use of contralateral, opposing, or unrelated teeth for comparison.

Mutans streptococci in plaque from margins of amalgam, composite, and glass-ionomer restorations.

Levels of mutans streptococci in plaque samples from margins of Class II amalgam (Dispersalloy), composite (P-10), and glass-ionomer (Ketac Silver) restorations were compared. Fifty-one children, each having one of the restorations in a permanent first molar, were part of an inter-individual comparison, giving 17 restorations of each material. The age of the children, the age of the restorations, and the salivary levels of mutans streptococci were comparable in the three groups. Another seven children--each having both a composite and a glass-ionomer restoration of the same age placed on contralateral premolar or molar teeth--were part of an intra-individual comparison. The percentage mutans streptococci of total CFU count in plaque was higher on composite (mean 13.7) and amalgam (mean 4.3) than on glass-ionomer (mean 1.1) restorations in the inter-individual comparison, and higher on composite (mean 4.2) than on glass-ionomer (mean 0.4) restorations in the intra-individual comparison. In both comparisons, the differences in values between samples from glass-ionomer restorations and samples from composite or amalgam restorations were statistically significant (p less than 0.05).

Biological assessments of experimental cavity cleansers: correlation between in vitro and in vivo studies.

Adhesive bonding of resins to dentin surfaces requires the removal of the layer of debris caused by the cutting. Certain isotonic acidic solutions can do this rapidly. Five solutions were evaluated using cell cultures and pulp studies in monkeys. At concentrations above 10%, each solution caused the cultured human epithelial cells to respond unfavorably, probably due to the low pH of the culture medium. None of these experimental cleanser solutions caused significant pulpal irritation.

The density and branching of dentinal tubules in human teeth.

Detailed knowledge of dentine structure, and especially that of the dentinal tubules, is essential in order to understand dentine permeability and to interpret data from investigations on dentine adhesive materials. The aim here was to examine the density and branching of dentinal tubules in human teeth by light and scanning electron microscopy. Stained and unstained demineralized sections and undemineralized fractured specimens were studied. Statistically significant differences in the density of tubules were found depending on location. Differences in density of tubules between the peripheral and inner aspects were more marked in the crown than in root. The mean number of dentinal tubules in the middle part of the root was significantly lower than in the middle part of the crown. The density of the tubules in the outer dentine at the cusp location was also significantly different from that subjacent to the occlusal fissure. The number of branches of dentinal tubules was particularly abundant in locations where the density of tubules was low. The branching patterns revealed an intricate and profuse canalicular, anastomosing system, criss-crossing the intertubular dentine. Three types of branches, major, fine and microbranches, were identified on the basis of size, direction and location. Major branches, 0.5-1.0 micron dia., were the typical delta branchings found peripherally. Fine branches, 300-700 nm dia., forked off at 45 degrees and were abundant in areas such as in the root where the density of the tubules was relatively low. Microbranches, 25-200 nm dia., extended at right angles from the tubules in all parts of the dentine. The findings emphasize the need for detailed characterization of dentine substrates for adhesive testing and of samples used in permeability studies.

Bonding of all-porcelain crowns: structural characteristics of the substrate.

OBJECTIVES: The aim of this in vitro study was to evaluate the morphology of dentin in teeth prepared for single-unit all-porcelain crowns (SUAPC) in terms of tubule orientation, density and increase in surface area after etching. METHODS: Twenty anterior and 20 posterior teeth from adults were prepared 1mm below the cemento-enamel junction (CEJ) for SUAPC. The samples were divided into groups based on type of tooth (anterior or posterior) and bonding system employed. The teeth were processed for evaluation of morphology of the substrate, hybrid layer thickness and resin tag formation. The observations were subdivided according to location in the preparation and tubule density was calculated. RESULTS: The observations revealed the variability in tubule density and orientation in different areas within any one preparation. The morphology of the cervical margin was less predictable with the presence of cementum and an ill-defined cemento-dentinal junction. Statistically significant differences in the density of tubules were found depending on location. Groups 2, 3, 5 and 6 samples showed that the hybrid layer thickness and resin tag morphology depended on the density and direction of tubules. In those sectors with parallel and oblique tubule orientation and with a low density of tubules, the hybrid layer was significantly thinner than in areas with cross-sectioned tubules. SIGNIFICANCE: The cementum and the peripheral intertubular dentin surface area are likely to be responsible for the bond strength after acid etching of crown preparations, but not all areas exhibited equal responses to etching. In particular, the bonding substrate at the gingival margins may contribute little in terms of micromechanical retention.

Occlusal restorative decisions based on visual inspection--calibration and comparison of different methods.

The purpose of this in vitro study was to calibrate occlusal restorative decision-making based on visual inspection (VI), and to compare it with visual inspection with magnifying (x1.25) lenses (VIM), and fibre-optic transillumination (VIF). Sixty extracted human third molars mounted in plaster were examined using VI by ten dentists three times during the calibration process. After wash-out periods, the teeth were re-examined by the same dentists using VI, VIM and VIF. The inter-examiner reproducibility for VI, expressed as Kappa (kappa) statistics (kappa +/- SD), was 0.46 +/- 0.10 before and 0.59 +/- 0.11 after the calibration process and remained at the same level after the wash-out period. Intra-examiner reproducibility was substantially higher for VI (kappa -0.68 +/- 0.15) before and after the wash-out period. There were no significant changes in restorative treatment decisions based on VIM and VIF when compared to VI. The reproducibility between the methods was good for VI vs. VIM (kappa = 0.64) and moderate for VI vs. VIF (kappa = 0.56). In contrast, the inter-examiner reproducibilities expressed as Kappa were considerably lower for VIM (kappa = 0.46 +/- 0.17) and VIF (K = 0.42 +/- 0.19). It was concluded that the inter-examiner reproducibility can be improved with a calibration process based on a simple feedback method and that inter-examiner variation, especially without calibration, may be as important a factor for restorative treatment decisions as the diagnostic method itself.

Biological assessment of dental materials in Europe 1993--recommendations and regulations.

The requirements for biological testing in Europe have evolved over the last 30 years. A milestone was passed when the EEC Directive concerning Medical Devices was published on 1 February, 1993. It included the essential requirements for medical devices used in dentistry. Many administrative problems have to be resolved in the following two years until the requirements outlined become mandatory. The certification of medical devices used in dentistry will be based on European standards which are identical or similar to international (ISO) standards.

Five-year study of Class II restorations in permanent teeth using amalgam, glass polyalkenoate (ionomer) cerment and resin-based composite materials.

The aim of this study was to compare the clinical performance of an amalgam, a glass polyalkenoate (ionomer) cerment material and a resin-based composite material used in small Class II cavities in permanent teeth. All restorations were inserted under rubber dam. They were examined yearly for 3 years. One clinician continued the study up to 5 years. The clinical examination focused on two criteria: clinically acceptable and failure. In addition, impressions were taken of the prepared cavities immediately before restoration and at each clinical examination using an elastomeric material. The study comprised 274 Class II restorations (88 amalgams, 95 cerments and 91 resin composites) placed in 142 adolescent patients. One hundred and sixty-seven restorations were in molar and 107 in premolar teeth. Patient dropout after 5 years resulted in the loss of 161 restorations, evenly distributed for restorative material and type of tooth involved. Four amalgam restorations, 22 glass ionomer cerment and nine resin composite restorations failed. The glass ionomer cerment and amalgam restorations failed primarily due to bulk fractures, while the resin composite restorations failed due to secondary caries and bulk fractures.

Ten years' clinical evaluation of three luting cements.

OBJECTIVE: The aim of the present clinical longitudinal study was to observe, over 10 years, the prognosis of abutment teeth restored with fixed prostheses retained by glass ionomer luting cements and one conventional zinc phosphate cement. METHODS: Three dentists prepared 135 abutment teeth in 61 patients to retain 81 fixed prostheses. The prostheses were retained by two glass ionomer luting cements (Ketac-Cem, Fuji Ionomer), or a conventional zinc phosphate cement (De Trey Zinc Zement Improved). The patients were examined yearly for 10 years. RESULTS: Post-operative hypersensitivity occurred in five teeth restored with glass ionomer luting cement. The prevailing reason for abutment tooth failure was secondary caries (n = 21) and pulp necrosis (n = 5). Non-parametric survival estimates indicated that 80-85% of the abutment teeth remained intact after 5 years and 71-81% after 10 years. CONCLUSIONS: The 10-year results indicate that the prognosis of abutment teeth restored with fixed prostheses is good, regardless of whether a glass ionomer or a zinc phosphate luting cement is used.

The teaching of Class I and Class II direct composite restorations in European dental schools.

OBJECTIVES: The purpose of this descriptive study was to provide updated data on the teaching of Class I and Class II direct composite restorations in Europe as part of a survey of this aspect of the primary dental curriculum in Europe and North America. METHODS: Data on the teaching of posterior composite restorations and related matters were collected by means of a postal questionnaire sent to 185 dental schools known to exist in Europe. Non-respondents were sent a second questionnaire after two months. Further information pertaining to student requirements was sought after six months from all respondents. RESULTS: The response ranged from 92% for dental schools in Scandinavia to 40% from dental schools in Southern Europe with an overall response of 56%. All but four of the 104 participating schools were found to teach the use of composites in Class I and Class II, two-surface situations in at least premolar teeth. Contraindications and techniques taught for posterior composites varied within and between the country groupings of Northern and Central Europe. Scandinavia, Southern Europe and Eastern Europe. However, certain consensus views were identified. The experience of adverse biological reactions to the use of resin-based restoratives in European dental schools was found to be limited. CONCLUSIONS: Notwithstanding the variation in the response from the four geographic regions investigated and the relatively low overall response to the questionnaire, it is concluded that the data reported indicates that most dental schools in Europe teach the use of composites in selected Class I and Class II situations. However, considerable variation exists both within and between the regions investigated in relation to this teaching. Further research and consensus conferences should be planned to reduce variability across Europe in relation to the contraindications and techniques taught for posterior composites.

Marginal failures of amalgam and composite restorations.

OBJECTIVES: The aim of the study was to clinically assess marginal failures of amalgam and composite restorations. METHOD: Marginal defects with and without clinical evidence of secondary caries were evaluated by practitioners pre-operatively and after the restoration had been carefully removed. RESULTS: Analyses of 235 amalgam and 193 composite restorations with marginal failures showed that secondary caries was the most frequent diagnosis resulting in replacement. The secondary caries was predominately found along the gingival section of the restoration. A comparison of pre-operative diagnoses of marginal discrepancies, and the condition of the cavities at the site of the defects after the restorations had been carefully removed, showed fairly good consistency, but both false negative and false positive diagnoses were made. CONCLUSION: The observations indicated that diagnosis of the outer lesion of secondary caries provides a good basis for treatment planning.

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.

Teaching Class I and Class II direct composite restorations: results of a survey of dental schools.

The authors surveyed 54 North American dental schools about their teaching programs for posterior composite restorations. Marked variations were noted in the time spent teaching the use of these restorations, their indications and contraindications, and the techniques used for preparing and inserting the restorations. Although the time devoted to teaching placement of posterior composite restorations has increased during the last 10 to 12 years, most recent dental school graduates have minimal clinical experience with Class I and Class II composite restoration.

Placement and replacement of amalgam restorations in Italy.

The reasons for placement and replacement and the longevity of amalgam restorations were recorded by 62 Italian private practitioners. The survey compiled 1935 amalgam restorations inserted due to primary caries (59%) and failed restorations (41%). The clinical diagnosis of secondary caries constituted 59% of failures of amalgam restorations. The age of 46% of the restorations needing replacement was noted. The median longevity was 4.7 years.