[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.

[Measuring tooth wear with regular intra-oral 3D scanners: for still in the future, or is it already possible?] / Serie: Innovatieve technieken en ontwikkelingen in de mondzorg. Meten van gebitsslijtage met reguliere 3D-scanners: toekomstmuziek, of al mogelijk?

Quantitative tooth wear measurement is a method of increasing importance when measuring tooth wear progression. The Radboud university medical center has developed a protocol that measures height and volumetric differences on regular 3D-scans. Intra-oral scans were made on patients with tooth wear and superimposed. To assess reliability the precision , as well as intra- and inter-rater precision of the protocol was tested. T-tests were performed to determine the structural and random error. Our findings indicate that the method is precise enough to measure height differences in patients with severe tooth wear progression, or tooth wear with an interval longer than 1 year. The method is not precise enough to measure volumetric changes.

[Cup-shaped tooth wear defects: more than erosive challenges?] / Komvormige defecten in occlusale vlakken van molaren: meer dan alleen erosieve belasting?

The underlying mechanism of the development of cups and grooves on occlusal tooth surfaces is still unclear. The aim of this study was to evaluate factors contributing to in-vitro cup formation, and to elucidate the clinical process. Extracted human molar teeth were exposed to acidic aqueous solutions at pH of 4.8 and 5.5 in combination with different loading conditions: no load (0N, control), 30N or 50N. Before and after 3 months exposure, the samples were scanned using a non-contact profilometer. A statistically significant difference between a loading of 0N and 50N was found at pH 4.8 (p < 0.002). Cup shaped lesions had formed only at pH of 4.8, in the 30N and 50N groups. The study showed that a cup can arise fully in enamel and that this requires simultaneous acidic and mechanical loading.

[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.

[Combined orthodontic and restorative treatment]. / De gecombineerde orthodontisch restauratieve behandeling.

In patients with agenesis or enamel anomalies in anterior teeth combined orthodontic and restorative treatment is often necessary to achieve an optimal aesthetic result. How both can best be achieved, but also how to maintain the result, requires communication between the dentist and the orthodontist. The orthodontic treatment plan needs to be established in cooperation with the dentist who will carry out the restorative treatment while the patient is at a young age. Since with these young patients, who are still growing craniofacially and whose teeth are still developing, possible future restorative and/or orthodontic treatment, as well as the means of orthodontic retention, need to be included in the treatment plan. In cleft palate patients, it is also important that methods of orthodontic retention of maxillary arch width are given timely attention in the restorative treatment plan because it is especially vulnerable to relapse.

[Intra-oral restoration and correction of single- and multi-unit dental prostheses]. / Intraorale reparatie en correctie van kronen en bruggen.

In cases of a fracture of the porcelain or non-aesthetic margin of a correctly functioning single- or multi-unit dental prosthesis, an intra-oral restoration or correction using a resin composite can generally be chosen. To establish adhesion to metal, porcelain, resin and composite, macro-mechanical, micromechanical and/or chemical retention methods are available. In order to achieve macro-mechanical retention, the preparation ofpits, grooves and/or undercuts is necessary. Micromechanical retention indicates surface roughening of the prosthodontic material at microscopic level through etching or sand-blasting. For chemical retention methods, special primers are used which may react chemically with the several prosthodontic materials. The treatment of choice is determined by the prosthodontic material and the feasibility of the retention method.

An in vitro evaluation of the fatigue behavior of resin composite materials as part of a translational research cycle.

PURPOSE: This study aimed to reproduce and translate clinical presentations in an in vitro set-up and evaluate laboratory outcomes of mechanical properties (flexural strength, fatigue resistance, wear resistance) and link them to the clinical outcomes of the employed materials in the Radboud Tooth Wear Project (RTWP). MATERIALS AND METHODS: Four dental resin composites were selected. 30 discs (Ø12.0 mm, 1.2 mm thick) were fabricated for each of Clearfil TM AP-X (AP), Filtek TM Supreme XTE (FS), Estenia TM C&B (ES), and Lava Ultimate (LU). Cyclic loading (200 N, 2 Hz frequency) was applied concentrically to 15 specimens per group with a spherical steatite indenter (r = 3.18 mm) in water in a contact-load-slide-liftoff motion (105 cycles). The wear scar was analysed using profilometry and the volume loss was digitally computed. Finally, all specimens were loaded (fatigued specimens with their worn surface loaded in tension) until fracture in a biaxial flexure apparatus. The differences in volume loss and flexural strength were determined using regression analysis. RESULTS: Compared to AP and FS, ES and LU showed a significantly lower volume loss (p < 0.05). Non-fatigued ES specimens had a similar flexural strength compared to nonfatigued AP, while non-fatigued FS and LU specimens had a lower flexural strength (p < 0.001; 95 %CI: -80.0 - 51.8). The fatigue test resulted in a significant decrease of the flexural strength of ES specimens, only (p < 0.001; 95 %CI: -96.1 - -54.6). CLINICAL RELEVANCE: These outcomes concur with the outcomes of clinical studies on the longevity of these composites in patients with tooth wear. Therefore, the employed laboratory test seems to have the potential to test materials in a clinically relevant way.

Influence of volumetric shrinkage and curing light intensity on proximal contact tightness of class II resin composite restorations: in vitro study.

BACKGROUND: Proximal contact tightness of class II resin composite restorations is influenced by a myriad of factors. Previous studies investigated the role of matrix band type and thickness, consistency of resin composite, and technique of placement. However, the effect of volumetric shrinkage of resin and intensity of curing light has yet to be determined. Thus, the aim of this study was to identify the influence of these factors on the proximal contact tightness when restoring class II cavity preparations in vitro. METHODS: Sixty artificial molars were restored with either a low-shrinkage (Filtek Silorane, 3M ESPE) or a conventional (Z100, 3M ESPE) composite and polymerized with low-intensity (Smartlite IQ2, Dentsply) or high-intensity light curing units (Demi(TM), Kerr). Proximal contact tightness was measured using the Tooth Pressure Meter. Data were statistically analyzed using one-way analysis of variance and Tukey post hoc test. RESULTS: Use of low-shrinkage composite (Filtek Silorane) resulted in significantly tighter proximal contacts compared to the use of conventional composite (Z100) when cured with the same polymerization unit (p<0.001). Moreover, the low-intensity curing unit (IQ2) resulted in significantly tighter contacts than the high-intensity unit when material is constant (p<0.001). CONCLUSIONS: Low-shrinkage resin composite and low curing light intensity is associated with tighter proximal contact values.

Creating tight proximal contacts for MOD resin composite restorations.

OBJECTIVE: The purpose of this study was to compare proximal contact tightness (PCT) of MOD resin composite restorations placed with different matricing protocols. METHODS: Forty-five ivorine lower right first molars with standardized MOD cavities were equally divided into three groups according to the restoration protocol. Group 1: Sectional matrix (Standard matrix, Palodent, Dentsply) secured with a wedge (Premier Dental Products Co.) and separation ring (BiTine I, Palodent, Dentsply, York, PA, USA) was used to restore the mesial surface first and then removed and repeated for the distal surface. Group 2: Identical to group 1, but separation rings were placed at both the mesial and distal sides (BiTine I+II, Palodent) prior to restoration. Mesial surface was restored followed by distal. Group 3: Walser matrix (O-form, Dr. Walser Dental GmbH) was used. Following composite resin restoration, PCT was measured using the tooth pressure meter. Data were analyzed using analysis of variance and a Tukey post hoc test (p<0.05). RESULTS: PCT values for mesial contacts were 2.99 ± 0.47N for group 1, 4.57 ± 0.36N for group 2, and 3.03 ± 0.79N for group 3. For the distal contacts, the values were 4.46 ± 0.44N for group 1, 5.12 ± 0.13N for group 2, and 0.76 ± 0.77N for group 3. Significantly tighter contacts were obtained for mesial and distal contacts for group 2 compared to groups 1 and 3 (p<0.05). For groups 1 and 3, mesial contacts were not significantly different (p=0.993), while distal contacts for group 1 were significantly tighter (p<0.001). CONCLUSION: Within the limitations of this study, tighter contacts can be obtained when sectional matrices and separation rings are applied to both proximal surfaces prior to placement of the resin composite in MOD cavities.

Influence of microcapsule parameters and initiator concentration on the self-healing capacity of resin-based dental composites.

OBJECTIVE: Fracture is one of the main causes for failure of resin-based composite restorations. To overcome this drawback, self-healing resin-based composites have been designed by incorporation of microcapsules. However, the relationship between their self-healing capacity and microcapsule and resin parameters is still poorly understood. Therefore, the objective of this study was to systematically investigate the effect of initiator concentration (in the resin) and microcapsule size and concentration on the self-healing performance of commercially available flowable resin-based composites. METHODS: Poly(urea-formaldehyde) (PUF) microcapsules containing acrylic healing liquid were synthesized in small (33±8µm), medium (68±21µm) and large sizes (198±43µm) and characterized. Subsequently, these microcapsules were incorporated into a conventional flowable resin-based composite (Majesty Flow ES2, Kuraray) at different contents (5-15wt%) and benzoyl peroxide (BPO) initiator concentrations (0.5-2.0wt%). Fracture toughness (KIC) of test specimens was tested using a single edge V-notched beam method. Immediately after complete fracture (KIC-initial), the two fractured parts were held together for 72h to allow for healing. Subsequently, fracture toughness of the healed resin-based composites (KIC-healed) was tested as well. RESULTS: The fracture toughness of healed dental composites significantly increased with increasing microcapsule size and concentration (2wt% BPO, p<0.05). The highest self-healing efficiencies (up to 76%) were obtained with microcapsules sized 198±43 um. SIGNIFICANCE: commercially available resin-based composites can be rendered self-healing most efficiently by incorporation of large microcapsules (198±43µm). However, long-term tests on fatigue and wear behavior are needed to confirm the clinical efficacy.

Wear behavior of a microhybrid composite vs. a nanocomposite in the treatment of severe tooth wear patients: A 5-year clinical study.

OBJECTIVE: This study aimed to compare the wear behavior of a microhybrid composite vs. a nanocomposite in patients suffering from severe tooth wear. METHODS: A convenience sample of 16 severe tooth wear patients from the Radboud Tooth Wear Project was included. Eight of them were treated with a microhybrid composite (Clearfil APX, Kuraray) and the other eight with a nanocomposite (Filtek Supreme XTE, 3M). The Direct Shaping by Occlusion (DSO) technique was used for all patients. Clinical records were collected after 1 month (baseline) as well as 1, 3 and 5 years post-treatment. The maximum height loss at specific areas per tooth was measured with Geomagic Qualify software. Intra-observer reliability was tested with paired t-tests, while multilevel logistic regression analyses were used to compare odds ratios (OR) of "large amount of wear". RESULTS: Intra-observer reliability tests confirmed that two repeated measurements agreed well (p > 0.136). For anterior mandibular teeth, Filtek Supreme showed significantly less wear than Clearfil APX; in maxillary anterior teeth, Clearfil APX showed significantly less wear (OR material = 0.28, OR jaw position = 0.079, p < 0.001). For premolar and molar teeth, Filtek Supreme showed less wear in bearing cusps, whereas Clearfil APX showed less wear in non-bearing cusps (premolar: OR material = 0.42, OR bearing condition = 0.18, p = 0.001; molar: OR material = 0.50, OR bearing condition = 0.14, p < 0.001). SIGNIFICANCE: Nanocomposite restorations showed significantly less wear at bearing cusps, whereas microhybrid composite restorations showed less wear at non-bearing cusps and anterior maxillary teeth.

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.

An investigation into the impact of tooth wear on the oral health related quality of life amongst adult dental patients in the United Kingdom, Malta and Australia.

OBJECTIVE: To investigate the relationship between levels of tooth wear scored using the Basic Erosive Wear Examination (BEWE) and the impact on the quality of life of adult dental patients. METHODS: BEWE assessments were performed on 319 new dentate adult patients attending the practices of 5 trained recruiters based in primary care in Malta (120), Australia (118) or the UK (81). Oral impacts on the quality of life were measured using a shortened form of the Oral Health Impact Profile (OHIP-26). Regression analysis were performed, adjusted for age, to estimate the relationship between the variables. Data were expressed as Confidence Intervals (95 % CI), p-values (values <0.05 were considered statistically significant) and adjusted R2 values. RESULTS: Overall, the sample had a mean age of 42.6 ±â€¯17.1 (range, 18-93 years), a mean cumulative BEWE score of 6.7 ±â€¯4.4 and a mean total OHIP-26 score of 1.84 ±â€¯0.59. For the cumulative sextant BEWE scores, 68.0 % of the participants scored ≤ 8, 24.5 % between 9 and 13 and 7.5 %, ≥ 14. A significant association was found between increasing BEWE score and the overall OHIP-26 total score (effect = 0.028; p = 0.002), implying a higher BEWE to be associated with a larger impact of oral conditions on daily life. CONCLUSION: Higher levels of tooth wear were significantly associated with a deteriorating oral-health related quality of life amongst the participants. CLINICAL RELEVANCE: When treatment planning for patients with tooth wear, it is appropriate to consider the psycho-social impact of the condition alongside other clinical findings.

The effect of proximal contour on marginal ridge fracture of Class II composite resin restorations.

OBJECTIVES: To compare the marginal ridge fracture strength of Class II composite resin restorations placed with a straight or contoured matrix band using composite resins with different modulus of elasticity. METHODS: In 60 artificial first molars standardized MO-preparations were ground. Two matrix systems were used: (1) A straight matrix (Standard Tofflemire Matrix, KerrHawe) in Tofflemire retainer (Produits Dentaire). (2) A contoured matrix (Standard matrix, Palodent, Dentsply). In both groups, a wooden wedge and separation ring (Composi-Tight Gold, GDS) were placed and the matrix was burnished against the adjacent tooth. Three composite resins together were used (Filtek Supreme: e-modulus 13.3 GPa (3M ESPE), Clearfil AP-X: 16.6 GPa (Kuraray) and Clearfil Majesty Posterior: 22.0 GPa (Kuraray)), resulting in six groups (n=10). Teeth were mounted into a MTS servo hydraulic testing machine (Mini Bionix II, MTS, USA) with stylus placed on the marginal ridge. Samples were loaded at a crosshead speed of 1.0mm/min until fracture occurred. Fracture resistance data were statistically analyzed using ANOVA and Scheffé's post hoc test for multiple comparison of groups (p<0.05). RESULTS: Contoured proximal surfaces (365.5+/-87.6N) resulted in significant stronger marginal ridges compared to straight surfaces (290.5+/-64.2N) (p<0.001). Clearfil AP-X (378.1+/-94.63N) provided a higher resistance to fracture than Filtek Supreme (301.4+/-67.3N) (p=0.001) and Clearfil Majesty Posterior (304.5+/-70.6N) (p=0.002). No differences were found between Filtek Supreme and Clearfil Majesty Posterior (p=0.890). CONCLUSION: Within the limitations of this in vitro study it was shown that use of a contoured matrix results in a stronger marginal ridge of a Class II composite resin restoration.

A guide to managing tooth wear: the Radboud philosophy.

This paper explains a conservative, pragmatic and minimally invasive intervention concept for the treatment of severe tooth wear patients based on the Radboud Tooth Wear Project in the Netherlands. Guidelines and flowcharts for management of severe tooth wear patients and rehabilitation in increased vertical dimension of occlusion are presented. We concluded that: (a) Restorative treatment is not always indicated, even for patients with severe tooth wear. (b) If the patient has no complaints, counselling and monitoring is probably the best option. (c) Minimally invasive and adhesive restorative strategies are preferred when severe tooth wear patients are to be treated in increased vertical dimension, especially when young patients are involved. (d) Clinical evidence for a suitable restorative treatment protocol is limited to five-year follow up for direct composites. This material seems to be suitable for rehabilitation in increased vertical dimension on the middle long term. Clinical results for indirect techniques are not available yet. (e) Restorations, including those that are considered 'definitive' may prove to have a limited lifetime in patients with severe tooth wear due to bruxism and erosion. Explanation of the possible treatment options and expected complications should be included in the informed consent.

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.

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.

The long-term effect of a composite resin restoration on proximal contact tightness.

OBJECTIVE: The aim of this study was to investigate changes in proximal contact tightness up to 6 months after the restorative treatment. MATERIALS AND METHODS: In a randomised clinical trial Class II composite resin restorations were placed in 52 patients. Proximal contact tightness was measured before, directly after, and 6 months after treatment. These data were analysed statistically using linear regression and t-tests. RESULTS: Proximal contacts, that increased in tightness as result of the treatment tend to loose tightness after a 6-months period but remain tighter than before treatment. Proximal contacts, that decreased after treatment hardly change after 6 months. CONCLUSIONS: A change in contact tightness after restorative treatment will not always remain stable over time.