Salivary Urease and ADS Enzymatic Activity as Endogenous Protection against Dental Caries in Children.

UNLABELLED: The aim of this cross sectional study was to evaluate the ureolytic and arginolytic activities of saliva in children and associate them with their caries status. STUDY DESIGN: 65, 8 year old children, were randomly selected. The ureolytic and arginolytic activity of non stimulated saliva was studied and associated with DMFT and dmft index. Saliva of children were sampled under fasting conditions; Children refrained from any oral hygiene procedures during the 12 hours that preceded the sample collection. Caries activity was scored and divided in 3 groups: Group A: Index zero: without lesions; Group B: Moderate Index: 1 to 3 enamel caries lesions; and Group C: High Index: more than 4 dentin caries lesions. RESULTS: DMFT scores were moderate: 0.4(±0.79) and dmft: 2.78(±2.45). Results expressed in µmol/min/mg/protein, for urease activity were statistically significant (p=0.048): Group A= 0.69 (±0.7); Group B= 0.45 (±0.43); and Group C= 0.39 (±0.55). The arginine deiminase activity was not statistically significant (p=0.16): Group A= 2.53 (±1.42), Group B= 2.31 (±1.57) and Group C= 1.97 (±2.0). CONCLUSION: Higher levels of ureolytic (statistically significant) and arginolytic activity (trend) in saliva were associated with lower DMFT/dmft scores in 8 year old children. There was a higher production of ammonia from the arginine deiminase system than the urease enzyme in saliva (p>0.05).

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.

Differences between reported and actual restored caries lesion depths: results from The Dental PBRN.

OBJECTIVE: The objectives of this research were to: (1) quantify the discordance between the caries lesion depth at which dentists restored initial lesions during a clinical study ("actual depth") and the lesion depth that they reported during a hypothetical clinical scenario ("reported depth"); (2) test the hypothesis that certain practitioner, practice, patient, and caries lesion characteristics are significantly associated with this discordance. METHODS: Practitioner-investigators who perform restorative dentistry in their practices completed an enrollment questionnaire and participated in 2 consecutive studies on caries diagnosis and treatment. The first study was a survey asking about caries treatment. The second study collected data on restorations placed in routine clinical practice due to caries in patients over 19 years of age on occlusal surfaces only or proximal surfaces only. We report results on 2,691 restorations placed by 205 dentists in 1,930 patients with complete data. RESULTS: Discordance between actual depth and reported depth occurred in only about 2% of the restorations done due to proximal caries, but about 49% of the restorations done due to occlusal caries. Practice type, restorative material used and the diagnostic methods used were significantly associated with discordance. CONCLUSION: Dentists frequently restored occlusal caries at a shallower depth as compared to their reported depth, but the discordance was very small for proximal lesions. Discordance for occlusal caries was more common when radiographs were not taken or if a resin restoration was placed.

The Evidence-practice Gap in Minimal Intervention Dentistry: An International Comparison Between Dentists in Japan and Brazil.

OBJECTIVES: This study was designed to: 1) evaluate and compare the evidence-practice gap (EPG) in minimal intervention dentistry (MID) in Japan and Brazil by measuring concordance between dentists' clinical practice and published evidence; and 2) identify dentists' factors associated with the EPG in both countries. METHODS: We performed a cross-sectional study using a web-delivered questionnaire among 136 Japanese and 110 Brazilian dentists. The questionnaire consisted of three questions concerning "restoration diagnosis and treatment," "deep caries diagnosis and treatment," and "caries risk assessment" regarding MID. A chi-square test was used to analyze differences in concordance among clinical practice and evidence from the literature between Japanese and Brazilian dentists. Logistic regression analyses were performed to analyze dentists' factors associated with overall concordance for all three questions. RESULTS: Overall concordance was significantly higher in Brazil (55%) than in Japan (38%) (p<0.01). Concerning how evidence was obtained, textbooks, nonacademic journals, and seminars and workshops were used as information sources more frequently by Japanese than Brazilian dentists (p<0.001), whereas scientific journal articles in English were used more frequently by Brazilian dentists (p<0.001). On logistic regression analysis, overall concordance was higher for Japanese dentists who frequently obtained evidence from scientific journal articles in English (p<0.05), whereas Brazilian dentists who frequently obtained evidence from the Internet were associated with lower overall concordance (p<0.05). CONCLUSIONS: Because overall concordance was significantly higher in Brazil than in Japan, Japan may have a greater EPG in MID practice. Specific characteristics of Japanese and Brazilian dentists showed significant associations with overall concordance.

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.

Causes of the Evidence-practice Gap and Its Association with the Effects of Minimal Intervention Dentistry Education to Clinicians.

OBJECTIVES: To identify causes of the evidence-practice gap (EPG) in dentistry in Japan and analyze whether these causes are associated with: (a) improvement of EPG in minimal intervention dentistry (MID) following an educational intervention and (b) specific dentist characteristics. METHODS: We conducted a mixed-methods questionnaire survey among 197 Japanese dentists that integrated both quantitative and qualitative data. Causative factors for the EPG identified in the quantitative survey were clarified by qualitative analysis. We measured the EPG in a baseline survey using an EPG measurement tool based on MID. To examine how feedback using the latest scientific evidence affected change in the EPG, we measured the EPG again immediately after feedback was provided to participating dentists. RESULTS: Qualitative analysis classified all dentists into one of four "EPG cause" groups, namely "evidence-", "dentist-", "patient-", and "health insurance system-related" causes. Quantitative analysis confirmed that improvement in the EPG following the feedback intervention was indeed associated with group classification. The highest concordance was found for the "evidence-related" group while the lowest concordance was in the "dentist-related" group (p=0.004). Concordance improved after evidence feedback in all groups but was lowest in the "dentist-related" group. More dentists reported practice busyness in the "dentist-related" group. CONCLUSIONS: In this study, we identified four groups of causes of EPG among Japanese dentists. The degree of concordance between evidence and clinical practice was the lowest in the "dentist-related" group, and the results of this study are expected to provide useful information for the development of intervention methods for closing the EPG in the future.

Methods used by Dental Practice-based Research Network (DPBRN) dentists to diagnose dental caries.

OBJECTIVES: To (1) identify the methods that dentists in The Dental Practice-Based Research Network (DPBRN) use to diagnose dental caries; (2) quantify their frequency of use and (3) test the hypothesis that certain dentist and dental practice characteristics are significantly associated with their use. METHODS: A questionnaire about methods used for caries diagnosis was sent to DPBRN dentists who reported doing some restorative dentistry; 522 dentists participated. Questions included the use of dental radiographs, the dental explorer, laser fluorescence, air-drying and fiber-optic devices and magnification as used when diagnosing primary, secondary/recurrent or non-specific caries lesions. Variations on the frequency of their use were tested using multivariate analysis and Bonferroni tests. RESULTS: Overall, the dental explorer was the instrument most commonly used to detect primary occlusal caries and caries at the margins of existing restorations. In contrast, laser fluorescence was rarely used to help diagnose occlusal primary caries. For proximal caries, radiographs were used to help diagnose 75%­100% of lesions by 96% of the DPBRN dentists. Dentists who use radiographs most often to assess proximal surfaces of posterior teeth were significantly more likely to also report providing a higher percentage of patients with individualized caries prevention (p=.040) and seeing a higher percentage of pediatric patients (p=.001). CONCLUSION: The use of specific diagnostic methods varied substantially. The dental explorer and radiographs are still the most commonly used diagnostic methods..

Could alkali production be considered an approach for caries control?

This study investigated the relationship of arginine deiminase (ADS) and urease activities with dental caries through a case-control study. ADS and urease activities were measured in dental smooth-surface supragingival plaque and whole saliva samples from 93 subjects, who were in three different groups: caries-free (n = 31), caries-active (n = 30), and caries-experienced (n = 32). ADS activity was measured by quantification of the ammonia generated from the incubation of plaque and saliva samples in a mixture containing 50 mM arginine-HCl and 50 mM Tris-maleate buffer, pH 6.0. ADS-specific activity was defined as nanomoles of ammonia generated per minute per milligram of protein. Urease activity was determined by quantification of ammonia produced from 50 mM urea. For bacterial identification and enumeration real-time qPCR analysis was used. Groups were compared using Kruskal-Wallis tests. Spearman correlations were used to analyze plaque metabolic activity and bacterial relationships. The results revealed significantly higher ammonia production from arginine in saliva (1.06 vs. 0.18; p < 0.0001) and plaque samples (1.74 vs. 0.58; p < 0.0001) from caries-free subjects compared to caries-active subjects. Urease levels were about 3-fold higher in the plaque of caries-free subjects (p < 0.0001). Although higher urease activity in saliva of caries-experienced and caries-free subjects was evident, no significant difference was found between the groups.

Correlations of oral bacterial arginine and urea catabolism with caries experience.

BACKGROUND/AIM: Alkali generation by oral bacteria plays a key role in plaque pH homeostasis and may be a major impediment to the development of dental caries. To determine if the capacity of oral samples to produce ammonia from arginine or urea was related to caries experience, the arginine deiminase system (ADS) and urease activity in saliva and dental plaque samples were measured in 45 adult subjects. METHODS: The subjects were divided into three groups according to caries status; 13 caries-free (CF) individuals (decayed, missing, and filled teeth = 0); 21 caries-active (CA) individuals (decayed teeth >or= 4); and 11 caries-experienced (CE) individuals (decayed teeth = 0; missing and filled teeth > 0). Real-time polymerase chain reaction was used to quantify the proportion of certain acid- or alkali-producing organisms in the samples. RESULTS: The amount of ammonia generated from the test substrates by plaque samples was generally higher than that produced by salivary samples in all groups. Significantly higher levels of salivary ADS activity and plaque urease activity were observed in CF subjects compared to CA subjects (P = 0.0004 and P = 0.014, respectively). The proportions of Streptococcus mutans from saliva and dental plaque of CA subjects were significantly higher than those from the CF group (P = 0.0153 and P = 0.0009, respectively). In the CA group, there was an inverse relationship between urease activity and the levels of S. mutans (P < 0.0001). CONCLUSION: This study supports the theory that increased caries risk is associated with reduced alkali-generating capacity of the bacteria colonizing the oral cavity; providing compelling evidence to further our understanding of oral alkali-generation in health and disease.

Caries Diagnosis in Dental Practices: Results From Dentists in a Brazilian Community.

The aim of this study was to assess practices related to diagnosis of dental caries among dentists (n=217) from Araraquara, São Paulo State, Brazil. Data on sociodemographic information and practitioner characteristics were collected using a pretested questionnaire, and data on practices related to caries diagnosis were gathered by using a translated and culturally adapted questionnaire from the US National Dental Practice-Based Research Network. Descriptive statistics and regression analyses were used for data analysis. Respondents reported using in most of their patients radiographs (Rx) to diagnose proximal caries (59%), explorer (Ex) for the diagnosis of occlusal caries (64%) and on the margins of existing restorations (79%), as well as air jet (AJ) with drying (92%). Magnification (M) (25%), fiber optic transillumination (FOTI; 14%), and laser fluorescence (LF) (3%) were used in the minority of patients. Regression analysis revealed that the following dentists' characteristics were significantly associated (p<0.05) with the use of diagnostic methods on a greater percentage of their patients: advanced degree (Rx, FOTI), higher percentage of patients with individualized caries prevention (Rx, FOTI, M), more years since dental school graduation (Ex, M), and work in an exclusively private practice model (LF). In conclusion, most Brazilian dentists from Araraquara reported they most commonly use visual, tactile, and radiographic imaging for the diagnosis of dental caries. Some dentists' characteristics, such as time from dental school graduation and having a postgraduation course, were associated with the use of certain diagnostic methods.

Prescription Drug Monitoring Program Use: National Dental PBRN Results.

INTRODUCTION: The American Dental Association recommends that dentists use a prescription drug monitoring program (PDMP) prior to prescribing an opioid for acute pain management. OBJECTIVE: The objective of this study was to examine dentists' experiences using their state PDMP, as well as the impact that state-mandated registration policies, mandated use policies, and practice characteristics had on the frequency with which dentists used their PDMP. METHODS: We conducted a web-based cross-sectional survey among practicing dentist members of the National Dental Practice-Based Research Network ( n = 805). The survey assessed prescribing practices for pain management and implementation of risk mitigation strategies, including PDMP use. Survey data were linked with network Enrollment Questionnaire data to include practitioner demographics and practice characteristics. RESULTS: Nearly half of respondents ( n = 375, 46.6%) reported having never accessed a PDMP, with the most common reasons for nonaccess being lack of awareness ( n = 214, 57.1%) and lack of knowledge regarding registration and use ( n = 94, 25.1%). The majority of PDMP users reported the program to be very helpful (58.1%) or somewhat helpful (31.6%). Dentists reported that PDMP use most often did not change their intended prescribing behavior (40.2%), led them not to prescribe an opioid (33.5%), or led them to prescribe fewer opioid doses (25.5%). Presence of a mandated use policy was significantly associated with increased frequency of PDMP use across a variety of situations, including prior to 1) prescribing any opioid for pain management, 2) issuing refills, 3) prescribing to new patients, and 4) prescribing to patients deemed high risk. CONCLUSION: Findings suggest that the majority of dentists find PDMPs helpful in informing their opioid-prescribing practices. Whereas the existence of a state-mandated use policy is a consistent predictor of dentists' PDMP use, outreach and education efforts may overcome key barriers to use identified in this study. KNOWLEDGE TRANSFER STATEMENT: Findings from this national survey suggest that the majority of practicing dentists find PDMPs helpful in informing their opioid-prescribing practices; however, consistent PDMP use was not common. Whereas the existence of a state-mandated use policy is a consistent predictor of dentists' PDMP use, outreach and education efforts may overcome key barriers to use identified in this study.

Patient-Centered Dentinal Hypersensitivity Treatment Outcomes: Results from the National Dental PBRN.

Dentinal hypersensitivity (DH) can have a significant impact on oral health and functioning, and it is a clinical symptom commonly managed by dentists during routine clinical practice. DH symptoms are typically elicited by otherwise innocuous, nonpainful stimuli applied to exposed dentin (e.g., tactile stimuli, warming or cooling temperatures or air puffs). Treatment approaches have sought to directly target the dentinal pulp tissues or close dentinal tubules via dental office care and treatment services (fluoride varnishes, glutaraldehydes, bonding agents, sealants, oxalates, or lasers) or home care services (toothpastes or dentifrices containing fluoride or potassium nitrate compounds). The purpose of this prospective multicenter cohort study was to assess how community-based dentists from the National Dental Practice-Based Research Network (National Dental PBRN) manage DH and whether the effectiveness of DH treatments can be assessed in those settings. A total of 171 dentists recruited 1862 subjects with DH from their existing patients. Dentists then recommended and provided DH treatment as appropriate. Treatment choice was at the discretion of the dentists. Patients rated their DH pain at baseline and 1, 4, and 8 wk during the course of their treatments. They used pain intensity and unpleasantness visual analog scales and 4 labeled magnitude scales and rated their satisfaction with treatment after 8 wk. Patients were provided reminders postbaseline via email, texting, or voice mail. These patient-centered outcomes served as the principal measures for the assessment of treatment because treatments sought to alleviate DH symptoms. The patients with DH who reported pain reduction from dentist-provided treatments (glutaraldehyde/HEMA [hydroxyethyl methacrylate] compounds, oxalates, and bonding agents), dentists' advice and counseling regarding oral habits and diet, and patient-applied fluoride toothpaste reported a concomitant positive rating of satisfaction with DH treatments. The results from this study support the feasibility of engaging network practices to assess the effectiveness of clinical DH treatments. Knowledge Transfer Statement: National Dental PBRN dentists provide a range of procedures to treat dentinal hypersensitivity. In this large nonrandomized study designed to assess clinical care and to capture patient-reported outcomes, about 60% of patients reported improvement in pain. This study demonstrated the feasibility of engaging network dentists and their patients to assess treatment effectiveness. Future studies will explore the feasibility of imposing randomization and measuring patient compliance with treatment in the manner that this treatment is provided.

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.

How to Bridge Research Results to Everyday Clinical Care?

Laboratory and clinical studies are essential to the advancement of sciences. However, a significant gap exists between the research findings and clinical practice. Therefore, research findings can be of little importance if their outcome cannot be directly or indirectly applied to everyday clinical care or readily translated. This paper focuses on how we can shorten the gap between the generation of new knowledge and their implementation into everyday clinical care. A new model is discussed where clinicians are the ones generating the research idea are paired with researchers. They collaborate on studies whose results are readily applicable to everyday practice. Partnering with health providers on studies that address everyday clinical research questions is a potential solution to speed up the translation of the research findings. Generating clinically applicable results can better improve the health of the public. Quoting Dr. Lawrence W. Green: "If we want more evidence-based practice, we need more practice-based evidence." This paper presents the practice-based research model as a solution to address this knowledge gap.

Judgment of the Quality of Restorative Care as Predictors of Restoration Retreatment: Findings from the National Dental PBRN.

The primary aim of this study was to test the hypothesis that a patient's subjective assessments of the dentist's technical competence, quality of care, and anticipated restoration longevity during a restorative visit are predictive of restoration outcome. This prospective cohort study involved 3,326 patients who received treatment for a defective restoration in a permanent tooth, participated in a baseline patient satisfaction survey, and returned for follow-up. Of the 4,400 restorations that were examined by 150 dentists, 266 (6%) received additional treatment after baseline. Reporting satisfaction with the technical skill of the dentist or quality of the dental work at baseline was not associated with retreatment after baseline. However, patients' views at baseline that the fee was reasonable (odds ratio [OR], 1.6) was associated with retreatment after baseline, whereas satisfaction at baseline with how long the filling would last (OR, 0.6) was associated with less retreatment. These findings suggest that retreatment occurs more often for patients who at baseline are satisfied with the cost or who at baseline have less confidence in the restoration. The authors found no associations between restoration retreatment and the patients' baseline evaluations of the technical skills of their dentists or perceptions of quality care. KNOWLEDGE TRANSFER STATEMENT: Dental patients' ratings of their dentist's skills were not related to a restoration needing retreatment. Patients focus on other aspects of the dental visit when making this judgment.

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.

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.

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.

Clinical evaluation of replacement of class V resin based composite restorations.

OBJECTIVES: The purpose of this clinical study was to evaluate any increase in size of Class V resin based composite restorations that required replacement. Emphasis was placed on measurements of the loss of tooth structure in areas distant from the site of failure. METHODS: 14 Class V restorations scheduled for replacement were recorded with pre-operative impressions and intra-oral photographs. Restorations were then removed and cavity preparations were completed. A second impression and photograph were taken and stone casts were prepared for each impression. The perimeter and area of each restoration and cavity preparation were measured with a video-based imaging system (Dage 725 CCD camera) equipped with a macro lens, at a fixed magnification of x 10-15. The initial measurements of the restoration image were compared to the measurements of the new cavity preparation, in both instances excluding the site of failure. Intra-class correlation coefficient (ICR) and paired t-test were used for statistical analysis. RESULTS: A significant difference between the pre and post-operative measurements for both area (P=0.0125) and perimeter (P=0.003) was found. CONCLUSION: The study showed that replacement of Class V resin based composite restorations resulted in increased size of the cavity preparation in areas distant from the site of failure.

Enamel and dentine shear bond strength of two resin modified glass ionomers and two resin based adhesives.

OBJECTIVES: The purpose of this in vitro study was to compare the shear bond strength to enamel and dentine of two resin modified glass ionomers (Fuji Bond L.C. and Vitrebond) and two resin based adhesives (Prime&Bond 2.1 and Scotchbond Multi-Purpose). METHODS: A total of 120 bond sites were prepared on either enamel (n = 60) or dentine (n = 60) on human molars by grinding the teeth flat with a 600 grit sandpaper. Each tooth substrate group was divided into four groups (n = 15) to match each material. Each of the four material systems was applied, according to the manufacturers instructions, to the bond sites. On top of the placed material, a microfilled composite was placed in a 2.5 mm diameter matrix and light-cured for 40 s. All specimens were thermocycled 500 times (5-55 degrees C). Shear bond strength values were determined 120 h after bonding using a Zwick testing machine. One-way ANOVA was used to determine whether significant differences (p < 0.05) existed among the material groups on enamel and dentine. Pairwise comparisons were used to determine significant differences (p < 0.05) among the four products. RESULTS: The ANOVA revealed strong significant differences on enamel (p = 0.0001) and dentine (p = 0.0172). The enamel bond strength values of the two resin based adhesives were significantly higher than one of the resin modified glass ionomers (Vitrebond), while the other resin modified glass ionomers did not differ from Scotchbond Multi-Purpose. On dentine, however, Vitrebond performed significantly better than the two resin based adhesives. CONCLUSIONS: The investigated resin modified glass ionomers bonded better to dentine surfaces than to enamel surfaces, while the investigated resin based adhesive systems bonded better to enamel than to dentine.