Effectiveness of adhesive containing MDPB: A practice-based clinical trial.

OBJECTIVES: This prospective practice-based trial assessed the longevity of composite restorations made with an adhesive containing an antibacterial monomer compared to a conventional adhesive. METHODS: 9 general practices in the Netherlands were provided with two composite resin adhesives, each for a period of 9 months. Adhesive P contained the quaternary ammonium salt MDPB, and Adhesive S was a control. Patient's age and caries risk, as well as tooth type/number, reason for restoration placement, used restorative material and adhesive, and restored surfaces were recorded. All interventions carried out on these teeth in the 6 years after restoration were extracted from the electronic patient records, along with their date, type, reason, and surfaces. Two dependent variables were defined: general failure, and failure due to secondary caries. All data handling and multiple Cox regression analysis were carried out in R 4.0.5. RESULTS: 11 dentists from 7 practices made 10,151 restorations over a period of two years in 5102 patients. 4591 restorations were made with adhesive P, whereas 5560 were made with adhesive S. The observation period was up to 6.29 years, median observation time was 3.74 years. Cox regression showed no significant difference between the two adhesive materials when corrected for age, tooth type and caries risk, for general failure nor failure due to caries. SIGNIFICANCE: No difference in restoration survival could be shown between composite restorations made using an adhesive containing MDPB and control. Restorations made with the adhesive containing MDPB also did not fail more or less frequently due to secondary caries. This trial is registered on clinicaltrials.gov with identifier NCT05118100.

[Minimally invasive caries management in children: when to use what treatment]. / Minimaal invasief cariësmanagement bij kinderen: wanneer welke strategie?

Children are born with healthy mouths. The goal of primary prevention is to maintain this healthy situation. Starting primary prevention as early as possible, preferably at the moment of eruption of the primary teeth, is recommended. Estimating the caries risk, for example, with the help of a system such as the NOCTP method, is an important tool for deciding the check-up interval, bitewing interval and other care interventions. Prevention is always key. Active lesions may require another treatment, too, in addition to prevention. Inactive lesions as well as cleansable cavitated lesions do not require invasive treatment. Non-cleansable cavitated lesions are candidates for invasive treatment such as slicing as part of a non-restorative caries treatment (NRCT), Hall crowns or conventional restorations. The child's well-being is always the most important factor in choosing the right treatment.

[The anticaries effect of antibacterial bonding in vitro is lost with aging]. / Het cariësremmende effect van antibacteriële bonding in vitro gaat verloren door veroudering.

This in vitro study investigated whether aging of restorative materials influences secondary caries development. The research question was whether antibacterial bonding maintained its effectiveness after aging. 60 enamel-dentine blocks were restored using 3 different restorative materials (n = 20 per material): composite with conventional bonding, composite with antibacterial bonding and amalgam. Half of the samples in each group (n = 10) were artificially aged through exposure to a sucrose biofilm model. Lesion depth was subsequently measured using transversal microradiography. Aging led to deeper lesions in the composite with antibacterial bonding group (CAB), compared to fresh samples. These fresh samples showed lesions less deep than fresh samples of composite with conventional bonding. After aging, this effect was absent. Within the limitations of this short-term in vitro study, it can be concluded that aging of restorative materials can influence caries progression. Antibacterial bonding materials lose their effectiveness over time.

The effect of occlusal loading on cervical gap deformation: A 3D finite element analysis.

OBJECTIVES: Secondary caries can be accelerated by hydrodynamic flow in a gap between the tooth and restorative material. This study investigated whether occlusal loading can lead to increased hydrodynamic flow by deforming a gap between tooth and restorative material. METHODS: 3D finite element analysis was employed to model a molar containing a restoration with an interfacial gap. The model was loaded using direct cusp-to-restoration contact and using a rubber tube model simulating a food bolus. The object exerting pressure was moved across the molar from buccal to lingual side. The applied forces were 50, 100, 200 and 400N. The elastic modulus of the restoration material was varied between 5, 10, 15.9 and 25GPa to resemble different kinds of composite. The primary outcome parameter was the volume of the gap under occlusal pressure. RESULTS: Occlusal loading resulted in deformation of the gap area. Maximum deformation was seen when loading was applied in the middle of the restoration. Higher forces and lower restoration stiffness led to more deformation of the gap. Maximum deformation with a force of 100N and composite modulus of 15.9GPa was -0.0083mm3 (1.12%). SIGNIFICANCE: Deformation of the gap between tooth and restorative material could lead to increased hydrodynamic flow and faster secondary caries lesion formation. The measured deformation is small. Further research needs to show whether gap compression through occlusal loading affects secondary caries formation to a clinically relevant degree.

A threshold gap size for in situ secondary caries lesion development.

OBJECTIVES: This study investigated the influence of very small gaps in secondary caries (SC) development and additionally linked the threshold gap size with the caries activity level from volunteers. METHODS: For 21 days, 15 volunteers wore a modified occlusal splint loaded with dentin-composite samples restored with different interfaces: bonded (B = samples restored with complete adhesive procedure), no-bonded (NB = restored with composite resin without adhesive procedure), and 30, 60 and 90 µm (no adhesive procedure and with intentional gap). The splint was dipped in a 20% sucrose solution (10 min) 8 x per day. Samples were imaged with transversal wavelength independent microradiography (T-WIM) and lesion depth and mineral loss were calculated. Average wall lesion depth from each volunteer was determined and according to the values the volunteers were grouped as high, mid and low caries activity levels. RESULTS: No wall lesion formation was observed in B and NB groups. In general, intentional gaps led to SC lesion depth progression independent of caries activity level of volunteers. No substantial wall lesions were found for two volunteers. A trend for deeper lesion in larger gaps was observed for the high activity group. CONCLUSION: Very small gaps around or wider than 30 µm develop SC independent of the caries activity level of the patient and SC wall lesion progression seemed to be related to individual factors even in this standardized in situ model. SIGNIFICANCE: Independently of caries activity level of the patient, the threshold gap size for secondary caries wall lesion seems to be 30 µm at most.

Secondary caries development and the role of a matrix metalloproteinase inhibitor: A clinical in situ study.

OBJECTIVES: This in situ study aimed to investigate whether the dentin treatment with MMPs inhibitor (CHX 2%) could influence the development of secondary caries wall lesions in different dentin-composite interfaces. MATERIAL AND METHODS: For 21 days, 15 volunteers wore a modified-occlusal splint loaded with dentin-composite samples treated or not with CHX and restored according 4 different interface conditions: Bonding (B = samples restored with complete adhesive procedure), no bonding (NB = restored with composite resin without adhesive procedure), 100 µm (no adhesive procedure and with intentional gap) and 100 µm + B (adhesive material on composite side and intentional gap). Eight times per day, the splint with samples was dipped in a 20% sucrose solution for 10 min. Before and after caries development, samples were imaged with T-WIM and lesion depth (LD) and mineral loss (ML) were calculated. RESULTS: Linear mixed effect analysis showed that dentin treatment with CHX did not significantly affect the caries lesion progression (LD and ML; p ≤ 0.797). Dentin wall lesions were observed in the 100 µm and 100 µm + B groups independently of MMP inhibitor treatment. CONCLUSION: The treatment of dentin with MMP inhibitor was not able to slow down the secondary caries wall lesion development in this in situ study. SIGNIFICANCE: The dentin treatment with 2% CHX did not prevent secondary caries wall lesion initiation.

[Preventive dentistry 5. Secondary caries]. / Preventieve tandheelkunde 5. Secundaire cariës.

Secondary caries is reported as one of the most important reasons for replacing restorations. The patient's general caries risk plays an important role in the development of secondary caries. The connection, at the patient level, between various factors, the risk of caries and restoration factors, such as the presence of a gap and the kind of restoration material, deserves additional investigation. The minimum gap width in which secondary caries can develop is most likely less than 100 µm and could depend on the patient's caries risk. Composite restorations seem more susceptible to secondary caries than amalgam restorations in patients with high caries risk. So far, there is no unambiguous explanation for this difference. The prevention of secondary caries is comparable to that of primary caries and stresses the importance of fluoride, diet and oral hygiene.