[Restorative treatment of generalized tooth wear]. / Restauratieve behandeling van gegeneraliseerde gebitsslijtage.

A 24-year-old patient with generalized tooth wear was referred to the Radboud Tooth Wear Project. The tooth wear had a chemical aetiology, caused by gastro-oesophageal reflux and resulting in functional problems of the masticatory system and a reduced quality of life. The treatment of the patient was minimally invasive, with directly applied composite restorations on all teeth, by means of which an increase of vertical dimension of occlusion was introduced. The restorative treatment was not preceded by testing of the new vertical dimension of occlusion. The patient was able to function well again after restorative treatment.

Randomized controlled trial on the performance of direct and indirect composite restorations in patients with severe tooth wear.

OBJECTIVE: The study aimed to evaluate survival and failure behavior of Direct Composite Restorations (DRC) and Indirect Composite Restorations (ICR) on molars and anterior teeth, in a Randomized Controlled Trial (RCT). METHODS: Patients with generalized severe tooth wear were included, and randomly assigned to one of 2 protocols: (1) DCR: All teeth were restored with directly applied micro-hybrid composite restorations (Clearfil AP-X, Kuraray) for load bearing areas and nano-hybrid composite restorations (IPS Empress Direct, Ivoclar Vivadent) for buccal veneers; (2) ICR: First molars were restored with indirect composite 'tabletop' restorations and maxillary anterior teeth were restored with indirect palatal veneer restorations (Clearfil Estenia C&B, cemented with Panavia F, Kuraray). Remaining teeth were restored directly. Restorations were evaluated after 3 years, focusing on clinical acceptability. Statistical analysis was performed using Kaplan Meier curves, Annual Failure Rates (AFRs), and univariate Cox regression analyses (p < 0.05). RESULTS: 41 patients (age: 36.6 ± 6.6y) were evaluated after 3 years (40.0 ± 2.2 m). 408 restorations on first molars and palatal veneers on maxillary anterior teeth were part of this RCT, with 220 DCRs and 188 ICRs. No differences in survival between treatment modality for palatal veneers for any failure criteria were found. Tabletop restorations on first molars showed a considerable higher failure rate for ICR compared to DCR (p = 0.026, HR: 3.37, 95%CI = 1.16-9.81). SIGNIFICANCE: In this RCT, directly applied composite restorations showed superior behavior compared to the indirect composite restorations, when used in the molar region.

[Impact of the coronavirus on Dutch oral health care and practice]. / Impact van het coronavirus op de praktijkvoering van de Nederlandse mondzorg.

Among dental hygienists and dentists in the Netherlands, the impact of the SARS-CoV-2 pandemic on oral healthcare practices from March to July 2020 was investigated. Of the 1,700 healthcare providers approached, 433 completed questionnaires could be used. The results show that the pandemic has had a profound impact on both the accessibility of oral healthcare and on care provided in oral healthcare practices. Extra attention was paid to hygiene and infection prevention: the types of personal protective equipment and the protocols and procedures were adjusted by many oral healthcare providers. The confirmed prevalence of oral healthcare providers with COVID-19 in this study was 1.6%. However, testing was not available to all respondents with complaints during this initial period. Over half of the respondents estimated that even with additional measures there is an increased risk of infection to oral healthcare providers during their work. The efficacy of the various additional measures in oral healthcare practices related to COVID-19 is still unknown.

[Risk factors for class II dental restoration survival:a practice-based study]. / Risicofactoren voor klasse II-restauratieoverleving: een praktijkgebaseerd onderzoek.

The aim of this practice-based cohort study was to determine the performance and influence of possible variables in class II restorations related to practice, patient, tooth, and restoration. To do this, electronic patient files from 11 general practices in the Netherlands were collected, and 31,472 restorations placed between January 2015 and October 2017 were analysed. The observation time of restorations varied from 0 to 2.7 years, resulting in a mean annual failure rate (AFR) of 7.8% at 2 years. However, wide variation in AFRs existed among the operators, varying between 3.6% and 11.4%. An excess of patient-related variables, such as age, general health, periodontal status, caries risk and the presence of parafunctional habits and tooth or restoration-related factors, increases the risk of reintervention. Restorations placed due to fracture were more prone to fail than restorations placed due to caries. This study demonstrated that a wide variety of risk factors on the practice, patient, and tooth levels influences the survival of class II restorations.

Risk Factors for Dental Restoration Survival: A Practice-Based Study.

To improve patient dental care, it is necessary to identify possible risk factors for the failing of restorations. This practice-based cohort study investigated the performance and influence of possible risk factors at the level of the practice, patient, tooth, and restoration on survival of direct class II restorations. Electronic patient files from 11 Dutch general practices were collected, and 31,472 restorations placed between January 2015 and October 2017 were analyzed. Kaplan-Meier statistics were performed; annual failure rates (AFRs) were calculated; and variables were assessed by multivariable Cox regression analysis. The observation time of restorations varied from 0 to 2.7 y, resulting in a mean AFR of 7.8% at 2 y. However, wide variation in AFRs existed among the operators, varying between 3.6% and 11.4%. A wide range of patient-related variables is related to a high risk for reintervention: patient age (elderly: hazard ratio [HR], 1.372), general health (medically compromised: HR, 1.478), periodontal status (periodontal problems: HR, 1.207), caries risk and risk for parafunctional habits (high: HR, 1.687), restorations in molar teeth (HR, 1.383), restorations placed in endodontically treated teeth (HR, 1.890), and multisurface restorations (≥4 surfaces: HR, 1.345). Restorations placed due to fracture were more prone to fail than restorations placed due to caries. When patient-related risk factors were excluded, remaining risk factors considerably changed in their effect and significance: the effect of operator, age of the patient, and endodontic treatment increased; the effect of the diagnosis decreased; and the socioeconomic status became significant (high: HR, 0.873). This study demonstrated that a wide variation of risk factors on the practice, patient, and tooth levels influences the survival of class II restorations. To provide personalized dental care, it is important to identify and record potential risk factors. Therefore, we recommend further clinical studies to include these patient risk factors in data collection and analysis.

[European statement of consensus regarding the treatment of severe tooth wear]. / Europese consensusverklaring over de behandeling van ernstige gebitsslijtage.

In 2016, a European consensus meeting was held regarding the treatment of severe tooth wear. This meeting resulted in the publication of the European statement of consensus on the treatment of severe tooth wear in 2017. In the statement, new definitions of physiological and pathological tooth wear are described, recommendations for diagnosis and taking preventive measure are presented, and advice for counseling and monitoring is offered to better elucidate the underlying aetiological factors causing tooth wear in the patient. The decision whether restorative treatment is appropriate is multifactorial and partially dependent on the severity and the consequences of the wear and on the aesthetic and functional wishes of the patient. Restorative intervention should be delayed as long as possible, but when such intervention is indicated, the preference is for minimally invasive techniques using direct, indirect or hybrid treatment methods.

Clinical performance of full rehabilitations with direct composite in severe tooth wear patients: 3.5 Years results.

OBJECTIVES: To evaluate the mid-term clinical performance of direct composite restorations placed in patients with pathological tooth wear needing full rehabilitation with an increase of vertical dimension of occlusion. METHODS: In a prospective trial 34 patients (34.0 ±â€¯8.4 years; 25 males, 9 females) were treated with a minimal invasive additive technique using composite restorations. The restorative treatment protocol was to provide all teeth with composite build-up restorations in an increased vertical dimension of occlusion (VDO) using the DSO-technique. Recall appointments were planned after 1 month, 1 and 3 years after treatment. Restorations were scored for clinically acceptability (FDI-criteria) and scores 4 and 5 were recorded as clinically unacceptable. Frequencies of failures and Kaplan Meier survival curves are presented and effect of relevant variables was calculated with a multifactorial Cox regression (p < 0.05). RESULTS: 1256 Restorations were placed, 687 anterior, 324 premolar, and 245 molar restorations. After a mean observation time of 39.7 months a total of 69 failures were observed, of which 61 restorations were repaired (score 4) and 8 were replaced (score 5). Most common reasons for failure were (chip) fractures (n = 43) and caries (n = 11). Placement of anterior restorations in two sessions led to significant 4.6 times more failures then placed in one session. CONCLUSIONS: In patients with severe tooth wear a full rehabilitation, in an increased vertical dimension of occlusion, direct composite resin restorations show a 94.8% success and 99.3% survival rate after a period of 3.5 years.

Clinical studies in restorative dentistry: New directions and new demands.

Clinical research of restorative materials is confounded by problems of study designs, length of trials, type of information collected, and costs for trials, despite increasing numbers and considerable development of trials during the past 50 years. This opinion paper aims to discuss advantages and disadvantages of different study designs and outcomes for evaluating survival of dental restorations and to make recommendations for future study designs. Advantages and disadvantages of randomized trials, prospective and retrospective longitudinal studies, practice-based, pragmatic and cohort studies are addressed and discussed. The recommendations of the paper are that clinical trials should have rational control groups, include confounders such as patient risk factors in the data and analysis and should use outcome parameters relevant for profession and patients.

Longevity of Anterior Composite Restorations in a General Dental Practice-Based Network.

This practice-based study investigated the performance of a large set of anterior composite restorations placed by a group of 24 general practices. Based on data from electronic patient files, the longevity of 72,196 composite restorations was analyzed, as placed in 29,855 patients by 47 general dental practitioners between 1996 and 2011. Annual failure rates (AFRs) were calculated, and variables associated with failure were assessed by multivariate Cox regression analysis with shared frailty for 2 age groups (5 to 24 y and ≥25 y). The observation time of restorations varied from 2 wk to 13 y, with a mean of 4.8 y, resulting in a mean AFR of 4.6% (95% confidence interval [95% CI], 4.5% to 4.6%) at 5 y. Among dentists, a relevant variation in clinical performance of restorations was observed, with an AFR between 2% and 11%. The risk for restoration failure increased in individuals up to 12 y old, having a 17% higher risk for failure when compared with the age group of 18 to 25 y (hazard ratio, 1.17; 95% CI, 1.03 to 1.34), and for the age group >65 y, having a 81% higher risk for failure when compared with 25 to 35 y (hazard ratio, 1.81; 95% CI, 1.66 to 1.98). In both multivariate models, there was a difference in longevity of restorations for different teeth in the arch, with fillings in central incisors being the most prone to failure and replacement. It was concluded that anterior composite restorations placed by general dental practitioners showed an adequate clinical performance, with a relevant difference in outcome among operators.

[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.

Ten-Year Survival of Class II Restorations Placed by General Practitioners.

The aim of this retrospective practice-based study was to investigate the survival of direct class II restorations placed by a group of general dental practitioners (GDPs) and to analyze the effect of practice-, patient-, and tooth/restoration-related factors. Electronic patient files of 24 general dental practices were used for collecting the data for this study. From the patient files, survival rates of 222,836 composites, amalgams, glass ionomers, and compomers placed in 61,121 patients by 67 GDPs between 1999 and 2011 were analyzed by Kaplan-Meier statistics and a multiple Cox regression. The investigated group of GDPs placed restorations with a satisfactory survival (mean AFR10, 4.9%; 95% confidence interval, 2.1 to 7.7), although a wide variation in annual failure rate (AFR) existed between the different operators, varying between 2.6% and 7.0%. Restorations placed in young adults (21-30 y old) survived longest, whereas they showed a shorter survival in children (hazard ratio [HR], 1.553) and the elderly (HR, 1.593). Restorations in molar teeth, restorations placed in endodontically treated teeth, and multisurface restorations are more at risk for reintervention. However, restoration size (included surfaces) has a greater impact on restoration survival in premolar teeth. For the future, improved data collection at the practice/operator, patient, and tooth/restoration level (e.g., risk assessment and diagnoses) will provide the opportunity to evaluate even more extensively the risk factors involved. Knowledge Transfer Statement: The results of this study give insight into the long-term survival of direct dental restorations and the influencing practice-, patient-, and tooth/restoration-related variables.

Restoration materials and secondary caries using an in vitro biofilm model.

This in vitro study investigated whether restoration materials and adhesives influence secondary caries formation in gaps using a short-term in vitro biofilm model. Sixty enamel-dentin blocks were restored with 6 different restoration materials with or without adhesives (n = 10 per group) with a gap: 1) Clearfil AP-X composite, 2) Clearfil AP-X composite + SE Bond, 3) Clearfil AP-X composite + ProtectBond, 4) Filtek Silorane composite, 5) Filtek Silorane composite + Silorane System adhesive, or 6) Tytin amalgam. Specimens were subjected to an intermittent 1% sucrose biofilm model for 20 days to create artificial caries lesions. Lesion progression in the enamel-dentin next to the different materials was measured in lesion depth (LD) and mineral loss (ML) using transversal wavelength independent microradiography (T-WIM). A regression analysis was used to compare the LD and ML of the different restoration materials at 4 measurement locations: 1 location at the surface of the enamel, 1 location at the wall of the enamel, and 2 locations at the wall of the dentin. A statistically significant effect of AP-X composite with Protect Bond was found for LD and ML at the WallDentin1 location, leading to less advanced wall lesions. An additional finding was that gap size was also statistically significant at the 2 wall locations in dentin, leading to increasing lesion progression with wider gaps. In conclusion, adhesives can influence wall lesion development in gaps. Protect Bond showed significantly less caries progression compared to bare restoration materials or other adhesives in this short-term in vitro biofilm model.

Longevity of posterior composite restorations: a systematic review and meta-analysis.

The aim of this meta-analysis, based on individual participant data from several studies, was to investigate the influence of patient-, materials-, and tooth-related variables on the survival of posterior resin composite restorations. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted a search resulting in 12 longitudinal studies of direct posterior resin composite restorations with at least 5 years' follow-up. Original datasets were still available, including placement/failure/censoring of restorations, restored surfaces, materials used, reasons for clinical failure, and caries-risk status. A database including all restorations was constructed, and a multivariate Cox regression method was used to analyze variables of interest [patient (age; gender; caries-risk status), jaw (upper; lower), number of restored surfaces, resin composite and adhesive materials, and use of glass-ionomer cement as base/liner (present or absent)]. The hazard ratios with respective 95% confidence intervals were determined, and annual failure rates were calculated for subgroups. Of all restorations, 2,816 (2,585 Class II and 231 Class I) were included in the analysis, of which 569 failed during the observation period. Main reasons for failure were caries and fracture. The regression analyses showed a significantly higher risk of failure for restorations in high-caries-risk individuals and those with a higher number of restored surfaces.

Gap size and wall lesion development next to composite.

This in situ study investigated whether there is a relationship between gap size and wall lesion development in dentin next to 2 composite materials, and whether a clinically relevant threshold for the gap size could be established. For 21 days, 14 volunteers wore a modified occlusal splint containing human dentin samples with 5 different interfaces: 4 gaps of 50 µm, 100 µm, 200 µm, or 400 µm and 1 non-bonded interface without a gap. Eight times a day, the splint with samples was dipped in a 20% sucrose solution for 10 minutes. Before and after caries development, specimens were imaged with transversal wavelength-independent microradiography (T-WIM), and lesion depth (LD) and mineral loss (ML) were calculated at the 5 different interfaces. After correction for the confounder location (more mesial or distal), a paired t test clustered within volunteers was performed for comparison of gap widths. Results showed no trend for a relationship between the corrected lesion depth and the gap size. None of the differences in lesion depth for the different gap sizes was statistically significant. Also, the composite material (AP-X or Filtek Supreme) gave no statistically significant differences in lesion depth and mineral loss. A minimum gap size could not be established, although, in a non-bonded interface without a measurable gap, wall lesion development was never observed.

Indirect restorations for severe tooth wear: fracture risk and layer thickness.

OBJECTIVES: This in vitro study investigated static failure risk related to restoration layer thickness for different indirect materials and compare them to direct composites. METHODS: Two ceramics (IPS e-max CAD, EmpressCAD (Ivoclar Vivadent)), two indirect composites (Estenia (Kuraray), Sinfony (3M)) and two direct composites (Clearfil AP-X (Kuraray), Tetric EvoCeram (Ivoclar Vivadent)) were chosen. Of each material, 25 discs varying in thickness (0.5-3.0mm) were prepared and cemented to bovine dentine. For measuring compressive strength, samples were placed in a universal testing device. Each sample was uniaxially loaded until failure occurred. For each material a regression model based on the Weibull distribution was used to estimate the relation between restoration layer thickness and failure. Using these models, the chance of failure, standard error and 95% confidence interval for that chance is estimated. Groups of materials were compared as well. RESULTS: Except for Tetric Evoceram, all materials show a significant positive association between layer-thickness and compressive strength, with an increased strength of increased thickness. ProCAD performed significantly worse than all other materials, especially when compared to the other ceramic material (IPS e-max CAD) (p=0.001). CONCLUSION: For most tested materials, a thicker layer offers more strength, however, this property seems to be material/brand specific. CLINICAL RELEVANCE: As direct composites showed the best results within the limitations of this in vitro study, dentists should consider these materials as a good choice for restoring severe tooth wear, and may offer superior performance compared to indirect composites and ceramics. For some brands of materials thicker layers result in a stronger restoration.

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.

The influence of approximal restoration extension on the development of secondary caries.

OBJECTIVES: To evaluate whether occlusoproximal restorations with cervical margins apical to the cemento-enamel junction (CEJ) are more prone to failure than restorations with margins coronal to the CEJ, in particular failure due to secondary caries. METHODS: A method was developed for scoring cervical margin extension on bitewings, and validated in vitro. Records from patients with at least one occlusoproximal restoration replaced due to secondary caries were selected from an existing database. Cervical margins of approximal restoration sites were scored on bitewings in relation to the CEJ (supra vs. sub CEJ). For all restorations dates of placement, replacement and reason for failure were recorded. Survival times were calculated and Cox-regression analysis was applied to assess influence of selected variables on survival of restorations: extension of cervical margins, number of restored surfaces, restoration material and age of the patient. RESULTS: Records of 84 patients with 1912 restoration sites were examined, 655 failed; 399 supra CEJ and 256 sub CEJ. 257 restorations failed because of secondary caries. Restorations ending below the CEJ showed significantly increased risk for failure (HR=1.28, p=0.020), however, no relation with secondary caries was found (p=0.130). Amalgam restorations showed decreased risk for secondary caries (HR=0.51, p<0.001). CONCLUSION: Occlusoproximal restorations with cervical margins apical to the CEJ do not fail more often due to secondary caries. However, those restorations did show larger risk of failure overall compared to restorations with margins coronal to the CEJ. Resin composite restorations showed increased risk for secondary caries compared to amalgam restorations. CLINICAL SIGNIFICANCE: Within the limitations of this study, no association was found clinically between extension of restoration margins below the CEJ and the occurrence of secondary caries.

Surface roughness of etched composite resin in light of composite repair.

OBJECTIVES: In search for clinically effective composite repair protocols, the effect of various etching protocols on the surface roughness of composite resins with different filler composition were investigated. METHODS: Of two composite resins (hybrid-filled Clearfil AP-X; nano-filled Filtek Supreme XT) specimens of 3mm thick with a diameter of 7 mm were prepared (n=24). The top surface was polished with 4000-grit SiC-abrasive paper and subjected to one of eight surface treatments: (n=3): negative control (NC), 37% phosphoric acid for 20s (37PA-20s), 3% hydrofluoric acid for 20s (3HF-20s), for 120 s (3HF-120 s), 9.6% hydrofluoric acid for 20s (9.6HF-20s), for 120 s (9.6%HF-120 s), 37PA-20s followed by 9.6%HF for 120 s (37PA-20s/9.6HF-120 s) and 9.6%HF for 120 s followed by 37PA-20s (9.6HF-120s/37PA-20s). Roughness (S(a)) was measured using a 3D noncontact optical interferometer (WYKO) and surface topography imaged by SEM. Multilevel models were used to estimate the variances within a sample and between samples in each group. Using the resulting overall variances and the means for each group, the eight groups were compared consecutively using t-tests (p<0.05). RESULTS: The hybrid-filled composite resin demonstrated a significantly rougher surface than the nano-filled (p<0.05). For both composites 9.6%HF-120 s, 37PA-20s/9.6HF-120 s and 9.6%HF-120 s/37PA-20s resulted in a large increase in roughness compared to the other groups (p<0.05). For the hybrid-filled, the succeeding groups (37PA-20s, 3HF-20s, 3HF-120 s and 9.6HF-20s) resulted in a statistically significant increase in surface roughness (p<0.02). For the nano-filled only a statistically significant increase in roughness was found between 3HF-20s and 3HF-120 s (p<0.001) and between 9.6HF-20s and 9.6HF-120 s (p<0.001). SEM surface characterization revealed that the hybrid-filled composite resin was much more affected by etching than the nano-filled. SIGNIFICANCE: Composite resins should not be seen as a group of materials having identical properties when it comes to repair. The effect of etching will depend on the composition of the filler particles.

Is there one optimal repair technique for all composites?

OBJECTIVES: The aim of this study was to investigate the effectiveness of a variety of techniques to bond new composite to artificially aged composite of different compositions. METHODS: Composite resin blocks were made of five different commercially available composites (n=30) (Clearfil AP-X, Clearfil PhotoPosterior, Photo Clearfil Bright, Filtek Supreme XT and HelioMolar). After aging the composite blocks (thermo-cycling 5000×), blocks were subjected to one of 9 repair procedures: no treatment (control), diamond bur, sandblasting alumina particles, CoJet™, phosphoric acid, 3% hydrofluoric acid 20s or 120s, 9.6% hydrofluoric acid 20s or 120s. In addition, the cohesive strength of the tested composites was measured. Two-phase sandwiches ('repaired composite') were prepared using each of the 9 repair protocols, successively followed by silane and adhesive (OptiBond FL) treatment, prior to the application of the same composite. Specimens were subjected to micro-tensile bond strength testing. Data were analyzed using ANOVA and Tukey's HSD (p<0.05). RESULTS: For all composites the lowest bond strength was obtained when no specific repair protocol (control) was applied; the highest for the cohesive strength. Compared to the control for the microhybrid composite (Clearfil AP-X) five repair techniques resulted in a significantly higher repair strength (p<0.05), whereas for the nano-hybrid composite (Filtek Supreme XT) and hybrid composite containing quartz (Clearfil PhotoPosterior) only one repair technique significantly increased the bond strength (p<0.01). SIGNIFICANCE: None of the surface treatments can be recommended as a universally applicable repair technique for the different sorts of composites. To optimally repair composites, knowledge of the composition is helpful.