• Assess the effectiveness of sealing localized marginal defects of amalgam restorations that were initially scheduled for replacement of restorations.
• The hypothesis was that sealed defective margins of the amalgam restorations shows similar performance than replacement amalgam restorations.

Study Design

Were examined 157 patients with 586 amalgam restorations that were recruited at the Operative Dentistry Clinic, at the Dental School, University of Chile with the indication of amalgam replacements, of them, a cohort of thirty two patients (19 females and 13 males, mean age = 27 years old), with 73 Class I amalgam restorations, that presented one or more localized margin defects (Bravo or Charlie according to modified United State Public Health Service, USPHS criteria), were included in the study. The protocol was approved by the Institutional Research Ethics Committee of the Dental School at the University of Chile, Investigation Project, School of Dentistry (0205) and all patients signed the informed consent form and completed the registration form. Only Faculty members were accepted to provide the treatment.

Treatment Groups Criteria: 73 restorations with defective margins were evaluated in accordance with the modified USPHS criteria and assigned to either the sealant (n=26), repair (n=21) and control groups (n=26).

Restorations Assessment: The quality of the restorations were evaluated using the modified U.S. Public Health System/Ryge criteria. Two examiners assessed the restorations independently and by visual and tactile (mouth mirror number 5) examination using an explorer (N° 23) and indirectly by radiographic, examination, for interproximal observation (Bite Wing). All the restorations were examined at baseline and each year during four and ten years after treatment. The restorations assessment was carried out by five parameters: marginal adaptation (MA), roughness (R), secondary caries (SC), marginal stain (MS) and teeth sensitivity (TS). If any difference was recorded between the 2 independent examiners, and they did not reach an agreement, a third clinician was called to assist with the process decision. If the three clinicians they did not reach an agreement, the lower score was recorded. All three clinicians participated in calibration exercises at the beginning and before the last examination took place and the inter-examiner reliability results were Kappa=0.74 at the baseline and Kappa=0.87 at the ten year.

A change from Bravo to Alpha was considered an improvement and a change from Alpha to Bravo was considered downgrade.

Caries risk assessment: A graphical computed program (CARIOGRAM) was used for individual´s patients caries risk assessed, the program weighted the interaction between the following 10 caries related factors: Caries experience, related general disease, diet contents, diet frequency, plaque amount by Silness Löe Index, semi quantitative detection of mutans streptococci and lactobacilli in saliva by Caries Risk Test (CRT), fluoride program, amount of saliva stimulated secretion by CRT Buffer (Vivadent), saliva buffer capacity and clinical judgment. Patients were classifying in high, intermediate and low caries risk. Additionally the results also indicate where targeted actions to improve the situation will have the best effect.

Patients were recalled ten years after the treatment, for clinical assessment by the same examiners, applying the same criteria used at baseline. Failed restorations were removed from the study and treated according to the diagnosed needs.

Statistical analysis The ordinal dependent variable was changed in level of the modified USPHS criteria from the baseline value. The assigned score of each restoration reflected the worst result for any of the parameters. The results of each group in terms of degradation or upgrade were analyzed by Friedman range non-parametric test to compare the pre and postoperative conditions. Additionally, the performance of all groups was contrasted using the Mann Whitney test to determine the differences between the upgrade and downgrade of the restoration´s quality. The statistical significance was set at 95%, α=0.05 and β=0.80 for statistical analysis.

Inclusion criteria:

• Patients with amalgam restorations with marginal deficiencies that were judged to be suitable for sealing.
• Older than 18 years of age ¨
• More than 20 teeth in their mouth
• The restorations had to be in functional occlusion with an opposing natural tooth
• With at least one proximal contact area with and adjacent tooth
• Area out of the restoration´s failures in good condition
• Patients who agree and sign the informed consent for participating in the study.

Exclusion Criteria:

• Patients with contraindications for regular dental treatment based on their medical history
• Special aesthetic requirements that could not be solved by this alternative treatment
• Xerostomia or who were taking medication that significantly decreased salivary flow
• High caries risk
• Psychiatric or physical diseases, that interfered with teeth hygiene.

Patients of the Operative Dentistry Clinics, School of Dentistry, University of Chile