Visible Occlusal Plaque Index Predicting Caries Lesion Activity.

This study was undertaken to appraise the predictive validity of the Visible Occlusal Plaque Index (VOPI) in assessing occlusal caries lesion activity in adolescents. A total of 618 adolescents aged 10 to 15 y were examined at the beginning of the trial and 511 (82.7%) at the 2-y follow-up. Adolescents and parents answered questionnaires about demographics, oral health behavior, and family sociodemographic variables. The VOPI has a 4-point ordinal scale ranging from no plaque to heavy plaque. Molar teeth were assigned to group VOPI 0-1 (no/thin plaque; n = 2,539) and group VOPI 2-3 (thick/heavy plaque; n = 843). At baseline examination, occlusal surfaces at risk of transition (n = 3,382) were either sound (55%), inactive noncavitated lesions (21%), inactive cavitated lesions (1%), active noncavitated lesions (15%), or active cavitated lesions (7%). The relative risk (RR) for caries lesion transition was estimated. Sound occlusal surfaces with no or thin plaque were significantly more likely to remain sound (RR = 1.3; 95% confidence interval [CI]: 1.1-1.4) than those harboring thick or heavy plaque. Inactive noncavitated occlusal lesions presenting no or thin plaque were significantly less likely to progress to active noncavitated lesions (RR = 0.1; CI: 0.0-0.8) than their counterparts with thick or heavy plaque. Active noncavitated lesions harboring thick and heavy plaque had a significantly lowest chance of becoming sound (RR = 0.7; CI: 0.5-0.9) and a highest risk of remaining active (RR = 1.5; CI: 1.1-1.9). Stepwise logistic regression analyses were run according to surface status at baseline and showed that none of the nonclinical predictors were significant for the outcome. The presence of thick and heavy plaque on occlusal surfaces was a predictor for caries lesion development, progression and activity (P < 0.0001). In conclusion, besides being an additional clinical tool for oral hygiene assessment, the VOPI is a predictor for development, progression, and activity of occlusal caries lesion. This is of particular interest for assessment of occlusal lesions undergoing health-promoting transitions.

Approximal morphology as predictor of approximal caries in primary molar teeth.

OBJECTIVE: To evaluate the predictive power of the morphology of the distal surface on 1st and mesial surface on 2nd primary molar teeth on caries development in young children. SAMPLE AND METHODS: Out of 101 3-to 4-year-old children from an on-going study, 62 children, for whom parents' informed consent was given, participated. Upper and lower molar teeth of one randomly selected side received a 2-day temporarily separation. Bitewing radiographs and silicone impressions of interproximal area (IPA) were obtained. One-year procedures were repeated in 52 children (84%). The morphology of the distal surfaces of the first molar teeth and the mesial surfaces on the second molar teeth (n=208) was scored from the occlusal aspect on images from the baseline resin models resulting in four IPA variants: concave-concave; concave-convex; convex-concave, and convex-convex. Approximal caries on the surface in question was radiographically assessed as absent/present. RESULTS: Of the 52 children examined at follow-up, 31 children (60%) had 1-4 concave surfaces. In total 53 (25%) of the 208 surfaces were concave. A total of 22 children (43%) had 1-4 approximal lesions adding up to 59 lesions. Multiple logistic regression analyses disclosed that gender, surface morphology on one of the approximal surfaces (focus-surface), and adjacent-surface morphology were significantly related to caries development (p values ≤ 0.03). The odds ratio for developing caries in the focus-surface/adjacent-surface in the four IPA variants were convex-convex, 1.0; convex-concave, 5.5 (CI 2.0-14.7); concave-convex, 12.9 (CI 4.1-40.3); and concave-concave, 15.7 (CI 5.1-48.3). CONCLUSION: Morphology of approximal surfaces in primary molar teeth, in particular both surfaces being concave, significantly influences the risk of developing caries. CLINICAL RELEVANCE: The concave morphology of approximal surfaces can predict future caries lesions supporting specific home-care and in-office preventive strategies.

Validation of the Visible Occlusal Plaque Index (VOPI) in estimating caries lesion activity.

OBJECTIVE: The present study appraises the construct validity of the Visible Occlusal Plaque Index (VOPI) along with its sub-types, convergent and discriminant validity. METHODS: 618 10-15year old Brazilian adolescents were included. The VOPI has a four-point ordinal scale ranging from no plaque to heavy plaque. VOPI scores and caries status on permanent molars were mapped and recorded at individual anatomical sites of the groove-fossa-system and at surface level. Outcomes were presence of sound site/surface and site/surface with active or inactive caries lesions (non-cavitated or cavitated). RESULTS: Construct validity was assumed based on qualitative assessment as no plaque (score 0) and thin plaque (score 1) reflected the theoretical knowledge that a regular disorganization of the dental biofilm either maintains the caries process at sub-clinical levels or inactivate it clinically. The VOPI also showed convergent validity since the likelihood that anatomical sites with no or thin plaque had inactive lesions simultaneously with sites with thick plaque (score 2) or heavy plaque (score 3) having active lesions were overall significant (RR=1.0-7.8). At surface level, discriminant validity of the VOPI was evidenced with multivariable analysis (GEE), by its ability to discriminate between the groups of adolescents with different oral hygiene status; negative association between adolescents with thick and heavy plaque and those with sound occlusal surfaces was found (OR=0.3, p<0.001). CONCLUSION: The VOPI has construct as well as convergent and discriminant validity and is therefore recommended as an additional clinical tool to estimate caries lesions activity and support treatment decisions. CLINICAL SIGNIFICANCE: The Visible Occlusal Plaque Index is an additional clinical tool to the assessment of oral hygiene and caries lesion activity. The VOPI is recommended to standardize and categorize information on the occlusal biofilm, thus being suitable for direct application in research and clinical settings.

Sealing Occlusal Dentin Caries in Permanent Molars: 7-Year Results of a Randomized Controlled Trial.

The purpose of this study was to investigate the possibility of postponing restorative intervention of manifest occlusal caries in young, permanent dentition by non-invasive sealing. This RCT-designed study included 521 occlusal lesions in 521 patients aged 6 to 17 y. Based on clinical and radiographic assessments, all lesions required restorative treatment. After randomization (ratio 2:1), 368 resin sealings and 153 composite-resin restorations were performed by 68 dentists in 9 municipalities. The primary aims were to 1) analyze survival of sealings until replacement by restoration, 2) compare longevity of sealings and restorations until retreatments, and 3) compare effectiveness of sealings and restorations to halt caries progression in sealed lesions and beneath restorations. Furthermore, we aimed to identify factors influencing longevity and the effectiveness of sealings and restorations. Treatments were annually controlled, clinically and radiographically. After 7 y, the drop out rate was 8%, and 54% of the treatments were completed due to age. Of the sealings, 48% were retreated, including 31% replaced by restorations; 12% were still functioning. Of the restorations, 7% were repaired/renewed and 20% were still functioning. No endodontics was performed. Kaplan-Meier and Cox regression survival analyses were performed on 341 sealings and 152 restorations in first and second molar teeth. The 7-y survival was 37% (CI, 29% to 45%) for sealings and 91% (CI, 85% to 96%) for restorations (P < 0.001). The median survival time for sealings not replaced by restorations was 7.3 y (CI, 6.4 y to NA). Survival of sealings was increased in patients with low caries risk and/or excellent oral hygiene, second molars compared with first molars, and lesions not extending the middle one-third of the dentin. Survival of sealings was not influenced by municipality, sex, eruption stage or clinical surface cavitation. The results underline that it is possible to postpone or avoid restorative intervention of occlusal dentin caries lesions in young permanent teeth by non-invasive sealing. Knowledge Transfer Statement: The first restoration can ultimately be fatal for a young permanent tooth. A restoration may not be the final treatment but the start of an ongoing treatment with still more loss of tooth substance. The present study shows the possibility of treating occlusal dentin caries lesions with non-invasive resin sealings instead of conventional resin composite restorations in children and adolescents. Improved oral health can be expected.

Characteristics, detection methods and treatment of questionable occlusal carious lesions: findings from the national dental practice-based research network.

Questionable occlusal carious lesions (QOC) can be defined as an occlusal tooth surface with no cavitation and no radiographic radiolucencies, but caries is suspected due to roughness, surface opacities or staining. An earlier analysis of data from this study indicates 1/3 of patients have a QOC. The objective of this report has been to quantify the characteristics of these common lesions, the diagnostic aids used and the treatment of QOC. A total of 82 dentist and hygienist practitioner-investigators from the USA and Denmark in the National Dental Practice-Based Research Network participated. When consenting patients presented with a QOC, information was recorded about the patient, tooth, lesion and treatments. A total of 2,603 QOC from 1,732 patients were analyzed. The lesions were usually associated with a fissure, on molars, and varied from yellow to black in color. Half presented with a chalky luster and had a rough surface when examined with an explorer. There was an association between color and luster: 10% were chalky-light, 47% were shiny-dark and 42% were mixtures. A higher proportion of chalky than of shiny lesions were light (22 vs. 9%; p < 0.001). Lesions light in color were less common in adults than in pediatric patients (9 vs. 32%; p < 0.001). Lesions that were chalky and light were more common among pediatric than among adult patients (22 vs. 6%; p < 0.001). This is the first study to investigate characteristics of QOC in routine clinical practice. Clinicians commonly face this diagnostic uncertainty. Determining the characteristics of these lesions is relevant when making diagnostic and treatment decisions.

A randomized clinical trial of the anti-caries efficacy of 5,000 compared to 1,450 ppm fluoridated toothpaste on root caries lesions in elderly disabled nursing home residents.

Root caries is prevalent in elderly disabled nursing home residents in Denmark. This study aimed to compare the effectiveness of tooth brushing with 5,000 versus 1,450 ppm of fluoridated toothpaste (F-toothpaste) for controlling root caries in nursing home residents. The duration of the study was 8 months. Elderly disabled residents (n = 176) in 6 nursing homes in the Copenhagen area consented to take part in the study. They were randomly assigned to use one of the two toothpastes. Both groups had their teeth brushed twice a day by the nursing staff. A total of 125 residents completed the study. Baseline and follow-up clinical examinations were performed by one calibrated examiner. Texture, contour, location and colour of root caries lesions were used to evaluate lesion activity. No differences (p values >0.16) were noted in the baseline examination with regards to age, mouth dryness, wearing of partial or full dentures in one of the jaws, occurrence of plaque and active (2.61 vs. 2.67; SD, 1.7 vs.1.8) or arrested lesions (0.62 vs. 0.63; SD, 1.7 vs. 1.7) between the 5,000 and the 1,450 ppm fluoride groups, respectively. Mean numbers of active root caries lesions at the follow-up examination were 1.05 (2.76) versus 2.55 (1.91) and mean numbers of arrested caries lesions were 2.13 (1.68) versus 0.61 (1.76) in the 5,000 and the 1,450 ppm fluoride groups, respectively (p < 0.001). To conclude, 5,000 ppm F-toothpaste is significantly more effective for controlling root caries lesion progression and promoting remineralization compared to 1,450 ppm F-toothpaste.

Measurement of histological and radiographic depth and width of occlusal caries lesions: a methodological study.

AIM: To develop a measurement method to quantify the depth and width of occlusal caries lesions. MATERIAL AND METHODS: One hundred and ten extracted permanent molars with occlusal caries lesions were selected, then visually scored by ICDAS scoring system and then sectioned mesiodistally, resulting in a facial and a lingual fraction. Digital photos and radiographs were taken from each section. By randomization, one of the sections was chosen for further examinations. First digital photos were taken. Depth and width of the lesions were marked with arrows on the images both before (H(un-col)) and after coloring (H(col)) the sections. The same types of measurements were done on the radiographs (R). The relative dentinal depth and width of the lesions were measured in the same order. RESULTS: Weighted intra- and interexaminer kappa value for ICDAS scorings varied between 0.85 and 0.90. Intraexaminer kappa for dentinal depth in 36 randomized selected teeth was calculated to 0.75 (H(un-col)), 0.91 (H(col)), 0.79 (R) and for dentinal width to 0.84 (H(un-col)), 0.96 (H(col)), 0.84 (R). Significant correlations were found between ICDAS scorings and the measurements of depth and width of lesions in H(un-col), H(col), and R (p < 0.000). The lowest difference was measured between H(un-col) and H(col) in both relative depth and width of the lesion with maximum differences up to 45% (H(un-col)-H(col)) and 73% (H(col)-R). CONCLUSION: It is possible to measure depth and width of occlusal caries lesions by means of histological and radiographic technique with acceptably high reproducibility using this method.

Factors associated with inter-municipality differences in dental caries experience among Danish adolescents. An ecological study.

BACKGROUND: Caries on children and adolescents in Denmark has declined significantly over the last 30 years. Our first analysis in 1999, however, disclosed huge inter-municipality disparities in mean DMFS values as well as in prevalence of caries on Danish children; that fluoride in the water supply and the length of the education of the mothers could explain up to 45% of the above-mentioned disparity and that very few municipalities were positive outliers, i.e. were providing significant better caries results than expected from the background variables. Three of the aims of this second analysis were to repeat the analyses done on the 1999 sample, but now on a 2004 sample and then compare it with the results from 1999. A fourth aim was by means of an interview of CDOs to determine their interpretation of relevant conditions in the public dental health service in relation dental health outcome. METHODS: A total of 204 (99%) and 191 (93%) municipalities were involved in 1999 and 2004, respectively. Unit of analysis were the municipalities. Mean DMFS of 15-year-olds was used as outcome variable. Eight background variables were accounted for during the analysis: For the fourth aim, a sample of CDOs representing municipalities with positive (n = 10), with no change (n = 10), or with negative change (n = 10) in mean DMFS, relative to all municipalities, between 1999 and 2004 was selected. RESULTS: The inter-municipality variation in mean DMFS 1999 was 0.88 to 8.73 and in 2004 was 0.56 to 6.19. The analyses found that fluoride level of the drinking water and mothers' length of education were significant variables explaining about 44% of the variations in mean DMFS in both years. Only one municipality was characterized as a positive outlier in 1999 as well as in 2004. The dose-response relations between increasing fluoride concentrations in the water supply and DMF-S values diminished in both years at a level above 0.35 ppm. The structured interview disclosed that municipalities with significant improvement in mean DMFS from 1999 to 2004 had established goals and were committed to the prevention of dental caries at the individual level. Instability in manpower; number of children in the service and economy was associated to municipalities with negative changes in caries experience.

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.

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.

Influence of different variables on the inter-municipality variation in caries experience in Danish adolescents.

This investigation sought to estimate the influence a number of variables had on the inter-municipality variation in caries experience across Denmark. Unit of measurement was the municipality with public clinics. Mean DMF-S and %DMF-S = 0 of 15- and 18-year-olds in 1999 were obtained from 204 and 143 municipalities, respectively, out of a total number of 206 municipalities with public clinics. The independent variables were: cost per child per year; children/dentist ratio; auxiliary personal/dentist ratio; fluoride concentration in the water supply [F]; average personal income; % of mothers of the 15- and 18-year-olds with < or =10 years education (EDU-15 or EDU-18); proportion of immigrants; and size of the municipality. Multiple regression analyses disclosed that [F] (p < 0.001) and EDU-15 (p < 0.001) were significant variables among the 15-year-olds explaining 45% of the variation in mean DMF-S and 31% of the variation in % DMF-S = 0. With respect to the 18-year-olds, [F] (p < 0.001) and average personal income (p < 0.001) explained 53% of the variation in mean DMF-S and 30% of the variation in %DMF-S = 0. Few municipalities were characterized as outliers with significantly lower or higher observed caries experience than expected. It is concluded that there is room for other explanatory factors--first and foremost the professional effort made in the individual Public Dental Health Service to control caries.

Comparison of two measurement techniques for clinical wear.

OBJECTIVES: Clinical wear of restorations is generally evaluated by marginal integrity over time. In this study, both a subjective and an objective method for wear assessment are compared, and the relative advantages and disadvantages of each are considered. METHODS: A surface evaluation technique for quantitative measurement of wear, as developed at the University of Minnesota (UMN) has been compared to the commonly employed method of wear assessment used by Leinfelder (LF). Measurements were made by comparing suitable casts of restored teeth before and after clinical function. Semi-quantitative wear assessment was studied in comparison with detailed quantitative information about the topology of the pre- and post-wear occlusal surfaces obtained from stylus profilometry and processed by imaging techniques. Fourteen model sets of baseline, 2, 3 and 5 year old Class II composite restorations from a Danish clinical trial were evaluated using both techniques. RESULTS: In general, after 5 years of function, the digitizing method (UMN) generated wear values that were twice as high, indicating that general wear of restorative materials is underestimated by the LF-method. CONCLUSIONS: The comparison clearly revealed the advantages and limitations of each technique. Evaluation of wear by means of the LF technique provides global semi-quantitative data on restoration margins relative to enamel, underestimating general wear of the restorative material. Advanced 3-D measuring techniques such as the UMN method provide extensive quantitative data regarding wear patterns of the entire occlusal surface, i.e. restoration and enamel. Such a highly accurate technique is capable of differentiation between wear behavior of restorative materials early on in clinical studies. In addition, through its digital alignment procedure, the UMN method provides data on accuracy of the replication process used in clinical studies.

Detection, diagnosing, monitoring and logical treatment of occlusal caries in relation to lesion activity and severity: an in vivo examination with histological validation.

The aims of the present study were to investigate the ability of 3 experienced clinicians to detect occlusal carious lesions, assess their depth, diagnose their activity and define a logical management for each lesion. The material consisted of 35 third molars scheduled for extraction or surgical removal making it possible to validate the accuracy of the clinical recordings histologically. Examinations were carried out at baseline and after 4 months in order to monitor lesion progression. At the first visit a radiograph was taken; the number of filled surfaces was counted and the oral hygiene assessed generally and by disclosing occlusal plaque of the tooth under examination. After cleaning the occlusal surface caries was recorded in a selected investigation site using a visual ranked caries scoring system, as well as an electrical conductance recording (ECM). Apart from counting fillings and taking new radiographs the same procedure was performed at the second visit, which then was followed by extraction of the tooth. After sectioning the tooth lesion depth was recorded, and lesion activity, based on acid production, was assessed using methyl red dye. Lesion activity was also judged by means of polarized light microscopic examinations of the sections. Results showed strong relationships between the visual, ECM and radiographic assessments and both lesion depth and lesion activity. In contrast, all other parameters were poorly related to lesion activity. Changes in visual assessments and in conductance readings from first to second examination were poorly associated with lesion activity. In conclusion, clinicians are able to detect lesions, predict activity and severity and define a logical management of occlusal caries on the basis of a single examination.

Longevity and cariostatic effects of everyday conventional glass-ionomer and amalgam restorations in primary teeth: three-year results.

The aim of this study was to compare the longevity and cariostatic effects of everyday conventional glass-ionomer and amalgam restorations in primary teeth. The materials consisted of 515 Ketac-Fil glass-ionomer restorations and 543 Dispersalloy amalgam restorations prepared in 666 children, from 3 to 13 years of age, by 14 dentists within the Danish Public Dental Health Service in the municipalities of Vaerløse and Hillerød. The restorations, of which 79% were of the Class II type, were in contact with 593 unrestored surfaces in adjacent primary and permanent teeth. After 3 years, 6% of the patients had dropped out of the study, and 33% of the teeth were exfoliated with the restoration in situ. A further 37% of the glass-ionomer and 18% of th amalgam restorations were recorded as failed (p < 0.001). The frequency of failures was highest for Class II glass-ionomer restorations, which showed a 50% median survival time of only 34 1/2 months, because of many fractures, while the 75% survival time for Class II amalgam restorations just exceeded the actual 36 months (p < 0.001). Caries progression was most often recorded in surfaces adjacent to amalgam restorations, and 21% of these surfaces needed restorative treatment vs. 12% of the surfaces adjacent to glass-ionomer restorations (p < 0.001). The three-year results indicated that conventional glass ionomer is not an appropriate alternative to amalgam for all types of restorations in primary teeth. In particular, the short longevity of Class II glass-ionomer restorations could not be compensated for by the reduced caries progression and need for restorative therapy of adjacent surfaces.

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.

The age of restorations in situ.

In a cross-sectional survey the age of restorations in situ was recorded in three patient groups. Group A were randomly examined regular attenders, group B were irregular attenders randomly chosen from patient treatment records, and in group C the age of posterior gold and composite resin restorations was recorded in selected regular attenders. The study material included 8310 restorations in group A, 1281 in group B, and 500 restorations in group C. The three materials amalgam, composite, and gold accounted for more than 90% of all restorations. In group A 3.3% of the restorations were scheduled for replacement. The most prevalent reasons for replacement were secondary caries, bulk fractures of the restoration, and tooth fractures. The median age of the failed restorations was fairly similar to the median age of the acceptable restorations in situ among the regular patients (group A). The data indicate median ages of 20 years for gold restorations, 12-14 years for amalgam restorations, and 7-8 years for composite resin restorations. The restoration ages were influenced by the type and size of the restoration, the restorative material used, and possibly also the intra-oral location of the restorations.

11-year assessment of Class-III resin restorations completed with two restorative procedures.

This randomized clinical trial was initiated to study the effect of two restorative procedures on the clinical quality and longevity of class-III resin restorations. The material consisted of 52 pairs of class-III restorations in the microfilled resin Silar completed with two modifications of the conventional acid-etch restorative procedure: A) beveling of the margins of the cavity preparations, and B) treatment of the etched butt-joint cavities before filling with the dentin-adhesive NPG-GMA/ethanol together with re-etching and surface coating of the finished restorations with low viscous resin. The restorations were examined at base line and after 2, 4, 6, and 11 years. The cumulative 11-year survival rate for both types of restorations was 84%. Marginal discolorations, marginal discrepancies, and secondary caries were most often recorded corresponding to the beveled type-A restorations, whereas the esthetic quality of the two types of restorations was almost identical. Surface discolorations were most often recorded among smokers, and significant correlations were found between the patients' consumption of alcoholic beverages and corpus discoloration, surface discoloration, and surface wear of restorations.

Resin restorations: leakage, bacteria, pulp.

Through the development of composite resin materials, the acid-etch technique and dentin adhesives, dentists can now complete perfect and permanent dental restorations--restorations with a color and shape approximating the natural tooth, with perfect marginal adaptation, and no harmful effects to the surrounding tissues, including the dental pulp. However, newer cross-sectional studies indicate that marginal defects are still the main cause of replacement of resin restorations, and that their clinical durability is shorter than that of other types. Moreover, there is no doubt that gap preventive treatments can intensify pulpal reactions to resin restorations if bacterial leakage occurs. The present thesis is based on nine previously published studies (I-IX). The aims of the studies were: to examine the possibilities of minimizing the occurrence of bacterial leakage around resin restorations through the use of various gap preventive procedures, to extend our understanding of their mode of action, and to investigate the pulpal reactions associated with restorations with and without bacterial leakage. The results of earlier research are reviewed, as well as the various methods for registration of gap occurrence around restorations. Studies I-IX are described briefly and followed by a discussion of the results, a summary and some concluding remarks.

Progression of approximal caries in relation to iatrogenic preparation damage.

The aim of the present study was to evaluate the effect of iatrogenic preparation damage on the need for operative caries treatment of approximal surfaces, adjacent to Class II amalgam restorations. The material was collected by 77 dentists from the Public Dental Child Health Service in Denmark. It consisted of die-stone models of 187 first-time Class II preparations, adjacent to 190 unfilled approximal surfaces of 58 primary and 132 permanent teeth. The cavity preparations were performed in children between 4 and 17 years of age. They were all filled with amalgam. Information about operative treatment and exfoliation or extraction of the preparation teeth and the adjacent teeth during the following seven years was obtained from the patients' records. Stereomicroscopic examination of the models revealed preparation damage on 64% of the unfilled approximal surfaces in primary teeth and on 69% of the corresponding test surfaces in permanent teeth. During the observation period, operative treatment was performed on 10% of the undamaged test surfaces in primary teeth and on 35% of the damaged ones (p less than 0.05). The corresponding figures for test surfaces in permanent teeth were 6% and 15% (p less than 0.05). It is concluded that iatrogenic preparation damage is a frequent side-effect of operative intervention with approximal caries lesions, and represents a dental health problem, since the damage increases caries progression and the perceived need for restorative therapy of the adjacent teeth.