Comparison of the Apical Sealing Ability of Calcium Silicate-Based Sealer and Resin-Based Sealer Using the Fluid-Filtration Technique.

OBJECTIVE: The aim was to evaluate the apical sealing ability of tricalcium silicate-based (MTA Fillapex®) and resin-based (AH Plus®) sealers at 24 h, 7 days and 4 weeks. MATERIALS AND METHODS: Thirty-four extracted human upper anterior teeth were used. All the teeth were sectioned to leave the root 15 mm long, and then all the roots were instrumented using a set of ProTaper® rotary instruments. Four roots were selected randomly as controls, and the remaining 30 were randomly divided into 2 groups of 15 each: MTA Fillapex and gutta-percha (group 1) and AH Plus and gutta-percha (group 2) using a warm vertical compaction technique. The apical sealing ability of the filled root canal was measured using the fluid-filtration method with 200 mm Hg (26.67 KPa) above atmospheric pressure at 24 h, 7 days and 4 weeks. The apical microleakage of the 2 groups was compared using Student's t test. p < 0.05 was considered statistically significant. RESULTS: The mean apical microleakage in group 1 at 24 h, 7 days and 4 weeks was 1.01 ± 0.24, 0.43 ± 0.07 and 0.24 ± 0.08 nl/s. The corresponding values in group 2 were 1.15 ± 0.40, 0.32 ± 0.09, and 0.38 ± 0.10 nl/s. MTA Fillapex had significantly more leakage than AH Plus at 7 days, but at 4 weeks, MTA Fillapex showed a significantly better sealing ability than AH Plus (p < 0.05). CONCLUSIONS: In this study, the tricalcium silicate-based sealer promoted proper sealing when used for filling the root canals.

Effect of occlusal calculus utilized as a potential "biological sealant" in special needs patients with gastric feeding tubes: a qualitative in vitro contrast to pit and fissure sealant restorations.

The aim of this case report and in vitro investigation was to evaluate the marginal microleakage of intact occlusal calculus of primary molars extracted from a special needs patient who received nutrition via a gastric feeding tube. An adolescent with a history of developmental disturbance presented for routine dental care in a hospital facility. Prophylaxis was performed, and 2 mandibular permanent molars were restored. Five primary molars were extracted due to mobility and delayed retention. Heavy deposits of intact calculus were present on the occlusal surfaces of the primary teeth. The extracted teeth were immersed in methylene blue dye solution, invested in acrylic resin, sectioned into blocks, and photographed at 20× and 40× magnification. Previously photographed calculus-free molars with pit and fissure sealants were reviewed and served as contrasting "restorations." The occlusal calculus on the primary teeth extracted from the patient absorbed the dye, while the comparison teeth containing pit and fissure sealants exhibited varying degrees of marginal dye penetration (microleakage). No marginal microleakage was noted in the calculus specimens, indicating that this substrate may serve as a "natural" occlusal surface sealant and that its removal from occlusal surfaces during routine oral prophylaxis may be unnecessary.

Influência da contaminação cavitária na adaptação marginal das restaurações de resina composta / Influence of cavity contamination on marginal adaptation of composite resin restorations

Objetivo: avaliar a influencia da contaminação cavitária na adaptação marginal das restauraçõesde resina composta e a associação da lisozima ao sistema adesivo. Materiais e Métodos:Foram selecionados 40 terceiros molares permanentes e confeccionados preparos cavitários classeV com pontas diamantadas cilíndricas 1090 (4 mm de largura, 6 mm de comprimento e 1,5 mmde profundidade). Todos os dentes foram esterilizados e divididos aleatoriamente em 4 grupos(n=10): G1: sistema adesivo (SA) e restauração com resina composta (RC); G2: cavidadescontaminadas com 10 μl de Streptococcus mutans (0,5 de Mc Farland), SA e RC; G3:sistema adesivo associado com lisozima (ADL) e RC e G4: cavidades contaminadas com 10 μlde Streptococcus Mutans (0,5 de Mc Farland), ADL e RC. A lisozima foi adicionada ao SA com ummicrobrush embebido no SA e na lisozima em pó. Os dentes foram impermeabilizados e imersosem azul de metileno por 4 horas a 37ºC. Os dentes foram seccionados e fotografados. Resultados:A avaliação da microinfiltração foi feita por dois avaliadores utilizando o Programa Tpsdig. Paraavaliar a calibração entre os examinadores, foi utilizado o teste de Correlação de Pearson. As médiasdas porcentagens de fendas e bolhas foram submetidas ao teste de Kruskal Wallis com 5% designificância. Conclusão: a contaminação cavitária com Streptococcus mutans acarretou na formaçãode fendas entre a resina composta e as margens cavitárias. A lisozima associada ao sistemaadesivo não influenciou na formação de fendas e bolhas nas restaurações de resina composta.

Objective: evaluate the influence of cavity contamination on marginal adaptation of compositerestorations and the association of lysozyme to the adhesive system. Materials and Methods:Were selected 40 permanent third molars and made cavity preparations class V with cylindricaldiamond burs 1090 (4 mm wide, 6 mm long and 2 mm deep). All teeth were sterilized and randomlydivided into 4 groups (n = 10): G1: adhesive system (SA) and restoration with compositeresin (CR); G2: cavity contaminated with 10 μl of Streptococcus mutans (0.5 McFarland), SA andRC; G3: adhesive system associated with lysozyme (ADL) and RC and G4: cavity contaminated with10 μl of Streptococcus mutans (0.5 Mc Farland), ADL and RC. Lysozyme was added to the SA witha microbrush embedded in the SA and powdered lysozyme. The teeth were sealed and immersedin a methylene blue for 4 hours at 37 ° C. The teeth were sectioned and photographed. Results:The evaluation of microleakage was made by two reviewers using the Tpsdig Program. To assessthe calibration of examiners, we used the Pearson correlation test. The mean percentages of cracksand bubbles were submitted to Kruskal Wallis test at 5% significance level. Conclusion: the cavityStreptococcus mutans contamination resulted in the formation of cracks between the compositeresin and the cavity margins. Lysozyme associated with the adhesive system did not influence theformation of cracks and bubbles in the composite restorations.

Secondary caries and microleakage.

OBJECTIVES: To critically appraise experimental ex vivo research that has focused on secondary caries, and to offer possible explanations for the seemingly poor correlation to clinical observations. METHODS: The literature relating to the etiopathogenesis or prevention of secondary caries gained from experimental ex vivo research was reviewed, with particular emphasis on microleakage and artificial caries-like lesions. RESULTS: It is doubtful whether a caries wall lesion can exist independently of an outer enamel caries lesion. Microleakage experiments apparently continue to emerge regardless of multiple reviews questioning the reliability and validity of the method. Several of the approaches used to generate artificial caries-like lesions are very aggressive. Remarkably little discussion has evolved about how these aggressive approaches create microenvironments that do not occur in reality. Corrosion- and biodegradation products may influence the biofilm qualitatively and quantitatively and it is difficult to replicate these variables in any ex vivo environment. Clinical data sampling method, patient demography as well as study methodology influences the incidence and prevalence estimates of secondary caries. Clinical results based on clinical work in settings where cost per unit time is of nominal concern do not provide any indications on how the restorative material will perform when placed by the average dentists in the mouths of their spectrum of patients during a busy workday. SIGNIFICANCE AND RECOMMENDATIONS: The term "wall lesion" including its variants is ill defined, has been, and is still being used indiscriminately. Stakeholders should avoid using this ambiguous label due to its connotation to an entity that does not exist per se.

Use of calcium-containing endodontic sealers as apical barrier in fluid-contaminated wide-open apices.

PURPOSE: The sealing of wide-open apex roots is still a challenge and requires the use of apical barrier techniques. The aim was to evaluate ex vivo the sealing and the apical morphology of 3 commercial calcium oxide (CaO)-containing sealers - namely, 2 zinc oxide-based (CRCS and Sealapex) and a calcium silicate MTA-based (TechBiosealer Endo) - placed in wet root canals with artificial wide-open apices.
 METHODS: Thirty human single-rooted teeth were shaped with Protaper and an artificial open apex (diameter size 110) was created. Each root was inserted in a custom-designed support containing simulated body fluid (Hank's balanced salt solution, HBSS) at the bottom simulating the presence of periapical fluid in the canal. Each sealer (TechBiosealer Endo, CRCS, Sealapex) was compacted to the apical 5 mm and the filled roots stored in HBSS at 37°C. The sealing was evaluated as microinfiltrated fluid since 24 hours up to 6 months using a high-precision digital fluid flow meter. The sealers were also studied for setting time in HBSS, calcium releasing (statistical analysis by 2-way ANOVA followed by Student-Newman-Keuls test, P<0.05) and surface morpho-chemistry by ESEM-EDX and OM analysis.
 RESULTS: All sealers showed a stable seal. TechBiosealer Endo maintained a better seal than the other materials (P<0.05) and ESEM-EDX and OM analyses showed the presence of apatite deposits.
 CONCLUSIONS: The clinical use of hydraulic hydrophilic MTA-based sealers can be recommended to stop/reduce the fluid flow rate through the apex. The artificial apical barrier in wet wide apices is a suitable technique able to seal wet root canals.

Análise do efeito do dimetacrilato contra a infiltração bacteriana pela interface implante/componente protético através da PCR Real Time: um estudo in vivo / Assessment of dimethacrylate as a sealant at the implant/abutment interface against bacterial leakage through Real Time PCR: an in vivo study

A interface do implante com o componente protético geralmente apresenta lacunas que servem de nichos para a colonização bacteriana. A proposta deste estudo é verificar a eficácia do dimetacrilato na vedação desta interface. Foram utilizados 20 implantes ósseos Bone Level® Straumann, indicados para reabilitação protética unitária cimentada. Os pilares protéticos foram instalados nos grupos controle e experimental, adicionando-se o dimetacrilato à interface da conexão protética. Foram realizadas uma coleta inicial e uma coleta ao final do período de 90 dias no interior de cada implante, e através da técnica de PCR quantitativo foi analisada a infiltração e a detecção das espécies bacterianas Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia. No Grupo Controle, todas as amostras apresentaram quantificação de microrganismos, confirmando infiltração bacteriana. No Grupo Experimental, apenas 30% das amostras apresentou quantificação após o período estudado. Assim, a ausência de bactérias no Grupo Experimental foi associada ao tratamento com o dimetacrilato para o período. Quando considerada a presença de pelo menos uma das bactérias específicas estudadas nas amostras, a diferença também foi estatisticamente significante. Entretanto, mais estudos devem ser desenvolvidos a fim de verificar se a vedação será eficiente por períodos mais longos.

The implant/prosthetic component interface often has gaps that serve as niches for bacterial colonization. The purpose of this study is to verify the effectiveness sealing this interface with dimethacrylate. Twenty two Straumann ® Bone Level implants was installed in areas with indication for single cemented prosthetic rehabilitation. The prosthetic components were installed in the control and experimental groups following the fabricant instructions, and adding the dimethacrylate in the interface of the experimental group. An initial collection and a second collection at the end of 90 days within each implant were performed, and after that, the technique of quantitative PCR was developed to analyze whether there was infiltration and detection of four bacterial species: Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia. In the control group, all samples showed quantification of microorganisms, confirming bacterial percolation. In the control group, only 30% of the samples submitted quantification after the study period. Thus, the absence of bacteria in the experimental group was associated with the treatment for the period dimethacrylate. Considering the presence of at least one specific bacteria in the samples studied, the difference was also statistically significant. However, more studies should be conducted to verify that the seal will be effective for longer periods.

Hydrodynamic flow through loading and in vitro secondary caries development.

This in vitro study investigated the effect of hydrodynamic flow through mechanical loading on development of secondary caries lesions. Forty-eight bovine tooth specimens (enamel and dentin; sizes 3.2 x 3.2 x 2.0 mm) were restored with resin-composite on polystyrene bars; 18 samples were bonded, and 30 were not bonded. Specimens were suspended in a lactic acid solution (pH = 5; 14 days) in a modified brushing machine, and artificial caries lesions were formed. During caries development, specimens were mechanically loaded at the surface of the polystyrene bar, bent so that the tooth- composite interfaces were subjected to opening forces (16x/min). Loads applied were either none (Control Bonded, CB, n = 6; and Control Non-bonded, CNB, n = 6), 200 gr (NB200, n = 12), or 350 gr (NB350 and B350, both n = 12). Before and after caries development, specimens were imaged with transverse wavelength-independent microradiography (T-WIM), and lesion depth (LD) and mineral loss (ML) were calculated at 4 different locations. An independent t test was used to compare the LD and ML at the 4 different locations. A statistically significant effect of the level of loading (comparing groups NB200 and NB350) and of bonding (comparing groups NB350 and B350) could be observed, with a higher load and absence of bonding leading to more advanced lesions.

Prediction and diagnosis of clinical outcomes affecting restoration margins.

The longevity of dental restorations is largely dependent on the continuity at the interface between the restorative material and adjacent tooth structure (the restoration margin). Clinical decisions on restoration repair or replacement are usually based upon the weakest point along that margin interface. Physical properties of a restorative material, such as polymerisation shrinkage, water sorption, solubility, elastic modulus and shear strength, all have an effect on stress distribution and can significantly affect margin integrity. This review will focus on two aspects of margin deterioration in the oral environment: the in vitro testing of margin seal using emersion techniques to simulate the oral environment and to predict clinical margin failure and the relationship between clinically observable microleakage and secondary caries. The many variables associated with in vitro testing of marginal leakage and the interpretation of the data are presented in detail. The most recent studies of marginal leakage mirror earlier methodology and lack validity and reliability. The lack of standardised testing procedures makes it impossible to compare studies or to predict the clinical performance of adhesive materials. Continual repeated in vitro studies contribute little to the science in this area. Clinical evidence is cited to refute earlier conclusions that clinical microleakage (penetrating margin discoloration) leads to caries development and is an indication for restoration replacement. Margin defects, without visible evidence of soft dentin on the wall or base of the defect, should be monitored, repaired or resealed, in lieu of total restoration replacement.

10-year clinical outcomes of fixed dental prostheses with zirconia frameworks.

OBJECTIVES: The aim of this prospective clinical study was to assess the long-term clinical survival rate and the technical and biological complication rates of zirconia-based posterior FDPs. MATERIALS AND METHODS: Forty-five patients in need of one or more posterior FDPs received 57 three- to five-unit zirconia-based FDPs. The frameworks were fabricated by means of a prototype computer-aided manufacturing (CAM) system (direct ceramic machining, DCM), first processing zirconia in the white stage. The frameworks were veneered with a prototype veneering ceramic.The FDPs were adhesively placed. At baseline, 6 months, and 1,2, 3, 5, 8 and 10 years of function, the FDPs were examined for technical and/or biological complications. Furthermore, the periodontal health of the abutment teeth (test) and untreated control teeth was analyzed. Statistical analysis was performed applying descriptive statistics, Kaplan-Meier survival and multiple mixed effects regression tests. RESULTS: Twenty-one patients with 26 FDPs were examined at a mean observation time of 10.7 +/- 1.3 years. A total of 16 FDPs were lost to follow-up. Fifteen FDPs had to be replaced due to technical/biological complications; hence, the 10-year survival rate of the FDPs was 67%. Three framework fractures occurred, resulting in a 10-year survival rate for the zirconia frameworks of 91.5%. Chipping/fracture of the veneering ceramic was detected in 16 FDPs over 10 years (complication rate 32%). A significant correlation of the span of the FDPs and the incidence of chipping was observed: 4- and 5-unit FDPs had a 4.9 times higher probability for chipping than 3-unit FDPs. Marginal discrepancy/degradation was found in 90.7% of the FDPs over 10 years. At 11 of the FDPs (complication rate 27%), secondary caries occurred. No difference of the periodontal health was found around test and control teeth. CONCLUSION: The zirconia frameworks exhibited very good long-term stability. However, the zirconia-based FDPs frequently exhibited problems such as marginal deficiency or chipping of the veneering ceramic. Both problems may be associated with the prototype status of the system.

Recurrent apical periodontitis and late endodontic treatment failure related to coronal leakage: a case report.

INTRODUCTION: This article describes a case of late failure after endodontic retreatment as characterized by recurrent post-treatment apical periodontitis. METHODS: At the time of the initial treatment, the patient presented with acute apical abscess associated with a tooth with pulp necrosis caused by trauma. Four years later, the tooth was retreated because of persistent disease. The follow-up examination 28 months after retreatment showed complete healing. RESULTS: The patient returned 11 years and 7 months later for bleaching of the discolored tooth, and although the periodontal tissues were clinically and radiographically normal, a fracture line was observed on the mesial aspect of the pulp chamber. Extraction was indicated, but the patient only returned 5 years and 9 months later. Then a radiograph showed recurrent post-treatment apical periodontitis. The tooth was extracted, and histopathologic and histobacteriologic analyses revealed bacterial colonies along the fracture line and colonizing ramifications and accessory canals at the apical root canal system. CONCLUSIONS: Coronal leakage can be regarded as the most reasonable explanation for resurgence of the disease. However, a predisposing overlapping condition in the form of root fracture conceivably favored the penetration of bacteria from saliva and plaque biofilm along the filled root canal.

Effect of gap geometry on secondary caries wall lesion development.

OBJECTIVE: To investigate how the size of the space between restoration and dentinal wall of the tooth affects the development of secondary caries lesions, especially wall lesions. METHODS: Tooth-resin composite specimens were mounted on custom-made gap model stages and divided into 4 groups (n = 10): group 1 with a 30-µm gap throughout both enamel and dentin, group 2 with a 30-µm enamel gap and 530-µm dentinal gap, group 3 with 525-µm gaps in both enamel and dentin, and group 4 with 525-µm and 1,025-µm gaps in enamel and dentin, respectively. Specimens were gas sterilized and incubated in a cycling microbial caries model for 8 days and analyzed with confocal microscopy for lesion size at the enamel outer lesion (EOL), enamel wall lesion (EWL), dentin wall lesion A (DWL-A) next to the dentin-enamel junction (DEJ) and dentin wall lesion B (DWL-B) at 750 µm from the DEJ. RESULTS: No difference in EOL or EWL size was found between the groups. DWL-A and DWL-B were larger in group 3 than groups 1 and 2. A larger DWL-B was found in group 3 than group 4. CONCLUSIONS: The presence of additional space at the dentinal wall area did not affect secondary caries development as long as the enamel gap was small. However, with enamel gaps of approximately 500 µm, the presence of the additional gap space at the dentinal wall led to the development of smaller dentinal wall lesions at the deeper parts of the simulated cavity. In uniform gaps, the size of the interface was positively correlated with the size of the dentinal wall lesions.

Short-term treatment of periapical lesion of anterior tooth affected by microleakage using Nd:YAG laser. Case report.

Tooth-colored restorations are the first choice for anterior restorations. However, microleakage is a significant problem at the margins of anterior cavities restored with resin composites. Microleakage can cause pulpal irritation and periapical inflammation. Today, laser irradiation is used frequently for dental treatments. Nd:YAG laser has been used successfully in endodontic treatments. A 17-year-old male presented to our clinic with a maxillary right lateral incisor that resulted in microleakage of an old composite resin restoration. Clinical examination revealed swelling and abcess formation on the palatal mucosa. The radiographic examination was performed and an inflammation around the apex was diagnosed. Root canal preparation, canal sterilization by Nd:YAG laser and root canal filling were performed at the same visit. The patient was observed for two months. In the case presented here, short-term treatment of a periapical lesion of an anterior tooth affected by microleakage using the Nd:YAG laser is discussed.

Infiltração bacteriana na interface implante/pilar: considerações ao implantodontista / Bacterial leakage of the implant-abutment interface: what the implantologist should know

Diversos estudos têm mostrado altas frequências de sucesso na reabilitação oral por meio de implantes dentários. Entretanto, podem ocorrer fracassos por complicações logo após a sua instalação ou, posteriormente, quando a prótese sobre o implante já está em função há algum tempo. As falhas tardias podem ocorrer em situações nas quais a osseointegração de um implante previamente estável e em função é perdida por sobrecarga e/ou infecção, sendo que, um dos fatores de infecção é a infiltração de bactérias através de falhas existentes na conexão implante/pilar. Com essas considerações, o objetivo deste trabalho foi, de por meio de uma revisão de literatura discorrer sobre a infiltração de fluídos e bactérias no interior dos implantes, que ocorre devido à falha na conexão implante/pilar protético. Concluiu-se que mesmo com o desenvolvimento de novos implantes e pilares e a tentativa de alguns autores de buscarem o vedamento dessa microfissura a infiltração bacteriana entre implante/pilar não foi evitada.

Many studies have shown high rates of successful oral rehabilitation with implants. However, complications may occur immediately after the implant is placed or some time later, when the prosthesis has already been used for some time. These complications may lead to implant failure. Late failures can happen in situations where the osseointegration of a previously stable and functional implant is lost because of an overload and/or an infection. One of the causes of infection is the infiltration of bacteria in failures present in the implant-abutment interface. With this in mind, the purpose of this study was to address the infiltration of liquids and bacteria inside the implant due to failures in the implant-abutment interface based on a literature review. In conclusion, despite the development of new implants and abutments and the attempts of some authors to seal microfissures, bacterial infiltration in the implant-abutment interface still occurred.

Dental barotrauma.

PURPOSE: The aim of this study was to review the current knowledge regarding dental barotrauma. METHODS: A search using the PubMed Bibliographic Index and Index-Medicus was performed to identify articles in English that were published between 1930 and 2007. The reference lists of the resulting articles were searched to find publications relating to dental barotrauma. RESULTS: Only a few scientific publications reported this phenomenon. Moreover, a significant part of the relevant literature was from more than 60 years ago. There was no published study on the current incidence rate of this phenomenon. CONCLUSION: Besides other oral manifestations of barometric pressure changes, such as barodontalgia (barometric pressure-related oral pain), a clinician should be familiar with this entity and take preventive measures as well as periodically examine his or her patients who fly planes or scuba dive. The clinician should also search for occult pathologies such as leaking restorations or secondary caries lesions. In addition, the clinician should be aware of the possible influence of pressure changes on the retention of prosthetic devices and plan treatment accordingly.

[Validity of decision criteria for replacement of fillings]. / Die Validität von Entscheidungskriterien bei der Füllungserneuerung.

One of the main treatments in dental practice is the exchange of restorations due to secondary or residual caries. Thereby, only restorations indeed infected with secondary or residual caries should be renewed. The aim of the study was to check the validity of different criteria for the replacement of fillings. Three hundred seventeen replacements of dental restorations were evaluated retrospectively by using an examination form. Different clinical parameters were correlated with the finding of caries after removal of the old restoration. Clinical findings were differentiated between caries soft to probing, caries only stainable with caries detector and caries-free cavities. Sixty-seven percent of the cavities showed caries that could be probed, 16.1% were just stainable with caries detector and 17% were caries-free. In general, results of previous replacements of fillings were a valid criterion. Other indicators for caries-free cavities were properly placed fillings with a correctly reconstructed morphology, fillings without marginal defects, a low age of the filling and a positive impression of the patients' general hygiene. Indicators for cavities with secondary caries were marginal gaps, pain within the respective section of the jaw, a high number of filled surfaces and a bad impression of the general hygiene. Systematic diagnostic criteria should be adopted in decision making on replacement of fillings in order to avoid new restorations of caries-free cavities.

Influence of microleakage, surface roughness and biofilm control on secondary caries formation around composite resin restorations: an in situ evaluation

This study was carried out to evaluate in situ the influence of microleakage, surface roughness and biofilm control on caries formation around composite resin restorations. During 28 days, 12 volunteers wore palatal devices containing bovine enamel slabs restored with composite resin. Restorations were made without leakage, when the adhesive system was applied, or with leakage, when adhesive system was omitted. Half of the restorations in each group were finished and the remaining were finished and polished. In one side of the palatal device, biofilm was left to accumulate over the restored slabs, and in the other side dental slabs were brushed, to allow biofilm removal. There was an extraoral application of 20 percent sucrose solution (8x/day) over the enamel slabs. The formation of caries lesions (white spots) was evaluated by visual inspection under stereomicroscopy. Additionally, the dental slabs were sectioned and observed under polarized light microscopy. Data were submitted to Kruskal-Wallis test and Spearman's correlation test at 5 percent significance level. Polishing and bonding were not significant factors regarding white spot formation (p>0.05). Biofilm control (brushing) was associated with reduction of caries formation close to the restorations (p<0.01). Polarized light microscopy confirmed the visual inspection findings. These results suggest that while microleakage and surface roughness did not influence caries lesion formation, biofilm control may prevent the enamel demineralization.

Influence of microleakage, surface roughness and biofilm control on secondary caries formation around composite resin restorations: an in situ evaluation.

This study was carried out to evaluate in situ the influence of microleakage, surface roughness and biofilm control on caries formation around composite resin restorations. During 28 days, 12 volunteers wore palatal devices containing bovine enamel slabs restored with composite resin. Restorations were made without leakage, when the adhesive system was applied, or with leakage, when adhesive system was omitted. Half of the restorations in each group were finished and the remaining were finished and polished. In one side of the palatal device, biofilm was left to accumulate over the restored slabs, and in the other side dental slabs were brushed, to allow biofilm removal. There was an extraoral application of 20% sucrose solution (8x/day) over the enamel slabs. The formation of caries lesions (white spots) was evaluated by visual inspection under stereomicroscopy. Additionally, the dental slabs were sectioned and observed under polarized light microscopy. Data were submitted to Kruskal-Wallis test and Spearman's correlation test at 5% significance level. Polishing and bonding were not significant factors regarding white spot formation (p>0.05). Biofilm control (brushing) was associated with reduction of caries formation close to the restorations (p<0.01). Polarized light microscopy confirmed the visual inspection findings. These results suggest that while microleakage and surface roughness did not influence caries lesion formation, biofilm control may prevent the enamel demineralization.

Validity of staining and marginal ditching as criteria for diagnosis of secondary caries around occlusal amalgam restorations: an in vitro study.

This study determined the validity of marginal ditching and staining as criteria for the diagnosis of secondary caries around amalgam restorations. One hundred and twenty-four Class I amalgam restorations on extracted human teeth were submitted to standardized clinical examinations. A calibrated examiner recorded the presence of ditching in the tooth/restoration interface, the occurrence of bluish-grey staining on the occlusal surface, and their relationship with the presence and severity of secondary carious lesions. Examinations were repeated after 4 days to calculate the intra-examiner reliability. Stereomicroscopic inspection of the serial tooth sections was used as the gold-standard. Six teeth were lost during the study. Of the 118 remaining teeth, 19 (16%) showed occlusal bluish-grey staining and 26 showed more than 0.20 mm wide marginal ditches. Of the latter, 14 presented narrow ditches (0.20-0.45 mm), while 12 presented wide ditches (0.45 mm). The evaluation criteria presented low sensitivity and positive predictive values. Positive and negative likelihood ratios showed that the criteria exhibited, indistinctly, the same odds to determine a positive or negative result for a diseased or healthy tooth. It was concluded that marginal ditching and staining were not valid criteria for the diagnosis of secondary caries around occlusal amalgam restorations.