PURPOSE:To investigate the effect of cleaning procedures (ultrasonic, autoclaving) and aging methods (24 hours, 90 days, and thermocycling) on the shear bond strength (SBS) between alumina-particle air-abraded titanium (Ti) and zirconia (Zr; 3Y-, 4Y-, and 5Y-TZP) specimens luted with phosphate monomer-containing adhesive systems and resin-based composite. MATERIALS AND METHODS:Lab-side-fabricated test specimens were prepared by bonding different Zr plates to Ti cylinders using a resin-based composite. The cleaning procedures included ultrasonic cleaning and purging (UUP) or two stages of purging and autoclaving (PPA). The specimens were then aged for 24 hours, 90 days, or had to endure thermocycling. RESULTS:Autoclaving significantly improved SBS (F [27,231] = 17.265, P < .001) compared to no cleaning and three-stage disinfection. CONCLUSIONS:No differences were identified with regard to Zr or aging methods. Bond strength initially benefits from autoclaving but continuously approaches the comparative values over longer periods.

Introduction: To simulate removing luting agent remnants from crowns fixed onto implant-abutment analogs using a standardized machine-driven protocol including a scaler and air polishing or sonic. Material and methods: A motor-driven device was constructed that controlled the rotational speed of the specimens, machining distance, contact pressure, and working time. A standardized layer of cement (Provicol, VOCO; Cuxhaven, G; Ketac Cem, 3MEspe; Seefeld, G; or Rely X Unicem, 3MEspe, Seefeld, G) was placed onto the finishing line of the crowns luted onto titanium-abutment analogs. The cement layer was scaled with a fresh titanium scaler maneuvered by the motor-driven device and treated with air polishing or sonic. Protocol 1: Scaling only for 20s, 40s, or 60s; n=20; protocol 2: 40s of scaling plus 20s of air polishing; protocol 3: 20s of scaling plus 40s of air polishing; protocol 4: 20s of scaling plus 40s of sonic; protocol 5: 40s of scaling plus 20s of sonic; protocols 2-5: n=10. Cement remnants were counted digitally as "percentage of remnants". Statistics: mean, standard deviation, Bonferroni post hoc tests; alpha=0.05. Results: Ketac Cem was easily removed by scaling only and Provicol by scaling and air polishing, but the selfadhesive resin composite cement Rely X Unicem was not removable with the device. Only remnants of Provicol could be significantly reduced by further treatment after scaling (p<0.001). Conclusion: The presented motor-driven device enables reproducible investigations of various cleaning protocols and is thus useful to create an overview of cleaning protocols needed for the different types of cement.

OBJECTIVES:The aim of this in-vitro pilot study was to establish a splint testing method and compare insertion/removal performance of dental splints. MATERIALS AND METHODS:56 identical lower jaw splints (n = 8 per group) were manufactured from 2x methacrylate (MA) hand-cast (reference material), deep-drawn Polyethyleneterephthalate, combined deep-draw MA hand-cast, 2x CAD/CAM-milled MA and 3D-printed MA systems. After 10 days water storage (37 °C), cyclic pull-off and insertion performance on a metal jaw was investigated. Statistics; Shapiro-Wilk-test, one-way-ANOVA; post-hoc-Bonferroni, Kaplan-Meier-survival, α = 0.05. RESULTS:Mean insertion/pull-off cycles varied significantly (p = 0.000) between 864 cycles (MA) and 202640 cycles (Deep Draw MA). Fracture of the splints was characterized by brittle individual fractures in the 31-34 region and most fractures in region 35 (44 of 56 splints). Finite element analysis confirmed the type and location of failure. CONCLUSIONS:Deep-draw, cast methacrylate and combined systems showed longer insertion/pull-off system cycles in comparison to printed or milled splints. Insertion/pull-off performance showed differences between the tested splint systems and indicates the influence of the processing. CLINICAL RELEVANCE:The presented in-vitro test allowed for estimating the clinical insertion/pull-off performance of dental splints.

Selecting the sterilization method is important because sterilization can alter the surface chemistry of implant materials, including zirconia, and influence their cellular biocompatibility. Studies on the biological effects of sterilization on implant materials are lacking.The purpose of this in vitro study was to evaluate the biocompatibility of gamma-ray irradiated 3 mol% yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP) compared with unirradiated titanium, 3Y-TZP, and pure gold.Disk-shaped specimens each of commercially pure grade 4 titanium, 3Y-TZP, gamma-rayed 3Y-TZP, and pure gold were prepared and evaluated for osteogenic potential by using a clonal murine cell line of immature osteoblasts derived from mice (MC3T3-E1 cells). The surface topography (n=3), chemical analysis of the disks (n=3), and cell morphology cultured on these surfaces were examined using scanning electron microscopy, confocal laser scanning microscopy, and energy dispersive spectroscopy. Cellular biocompatibility was analyzed for 1 and 3 days after seeding. Cell adhesion and spreading were evaluated using confocal laser scanning microscopy (n=3). Cell proliferation was evaluated using methyl thiazolyl tetrazolium assay (n=3). Kruskal–Wallis and Bonferroni corrections were used to evaluate the statistical significance of the intergroup differences (α=.05).Gamma-ray sterilization of 3Y-TZP showed significantly higher surface roughness compared with titanium and gold (P<.002). On day 1, the proliferation and adhesion of MC3T3-E1 cells cultured on gamma-rayed 3Y-TZP were significantly higher than those cultured on gold (P<.05); however, cell spreading was significantly lower than that of titanium on days 1 and 3 (P<.05). On day 3, cell proliferation of gamma-rayed 3Y-TZP was significantly lower than that of unirradiated 3Y-TZP (P<.05). Cell adhesion of gamma-rayed 3Y-TZP was slightly lower than that of zirconia and titanium but without significant difference (P>.05).Gamma-rayed zirconia exhibited increased surface roughness compared with titanium and significantly decreased bioactivity compared with titanium and zirconia. The use of gamma-ray sterilization on zirconia is not promising regarding biocompatibility, and the effect of this sterilization method on implant materials warrants further investigation.

Objectives: Comparison of in-vitro fatigue and wear performance of 3Y-, 4Y-, 5Y-TZP and lithiumdisilicate ceramic, multilayer/monolayer 4Y-TZP and variation of wall thickness at 5Y-TZP. Method and materials: Crowns (n = 96; 6 groups a 16) were made of 3Y-TZP-LA, 4Y-TZP (multilayer and monolayer), 5Y-TZP (0,5mm/1 mm wall thickness) and lithiumdisilicate. 8 per group were stored in water (24hrs), 8 underwent TCML (1.200.000 x 50N; 2x3000x5 degrees/55 degrees C; H2O, 2min cycle). Fracture force was determined by static loading (v = 1 mm/min, steel sphere with tin foil, diameter = 12 mm). Pin-on-block wear test was performed (steatite antagonist d = 3 mm; 50N, 120,000 cycles, 1.2Hz, lateral motion: 1 mm, antagonist lift: 1 mm, n = 8). Roughness, wear depth [pm] and antagonist wear were determined (3-D-laser-microscope, KJ3D, Keyence, J). Statistics: one-way-ANOVA; Bonferroni-post-hoc-test; alpha = 0.05. Results: Fracture forces varied between 1211N (5Y,TCML) and 3952N (4Y-Mult,TCML). Individual significant differences (p <= 0.025) were found between materials. Increase of wall thickness (5Y; 0.5 mm/1.0 mm) lead to a non-significant (p >= 0.442) increase of fracture force. 4Y and 4Y-multilayer zirconia showed no significantly different (p >= 0.073) fracture forces. Zirconia mean wear (3Y:10.0 +/- 3.9 pm, 4Y:19.8 +/- 3.8 pm, 5Y:10.9 +/- 6.8 pm) was not significantly (p = 1.000) different. Lithiumdisilicate ceramic (149.3 +/- 45.4 pm) and human enamel (434.2 +/- 131.3 pm) provided significantly (p <= 0.002) higher wear. Antagonistic wear against lithiumdisilicate (17.5 +/- 3.9%) and human enamel (6.7 +/- 3.0%) was significantly (p <= 0.007) lower than against zirconia (4Y:31.9 +/- 8.0% 5Y:27.6 +/- 5.8%). Conclusion: Fracture force of 5Y-TZP differs from 4- or 3-Y-TZP. Mechanical characteristics and dimensional requirement of 5Y-TZP are comparable to lithiumdisilicate. Monoor multilayer 4Y-TZP provided comparable fracture forces. Wear was comparable between zirconia systems and lower in comparison to lithiumdisilicate or enamel.

This study investigated the handling properties and clinical performance of two commercially available resin materials with slight differences in filler composition for the fabrication of fixed interim restorations. In a dental university setting, patients requiring prosthetic treatment were supplied with fixed interim restorations fabricated from two commercially available resin materials. To clarify the handling properties of the resin materials, dentists and undergraduate students completed a questionnaire. Prior to insertion of the definitive restoration, the interim restorations were analyzed by calibrated examiners using a modification of the United States Public Health Service criteria. Eighty-two fixed interim restorations with a mean clinical service period of 44.5 (±28.3) days were included, including 39 single crowns, 30 fixed denture prostheses, 10 blocked crowns, and 3 partial coverage restorations. No significant differences between the two materials in the rating of their handling properties were identified, with the exception of the parameter "surface". Failures due to fractures were observed in 13% of the interim restorations. No significant differences between the materials in the rating of the clinical performance were identified. These results indicate that slight changes in the filler composition of commercial formulations account for few differences in handling properties and clinical performance.

BACKGROUND:The lateral pterygoid muscle (LPM) has been described in many anatomical and functional studies. The morphology of the LPM is still under debate because of its deep location in the infratemporal fossa and the difficulties to approach this area with different anatomical methods. Although it has been generally accepted that this muscle is mainly composed of two separate parts, other forms have been described in the past. OBJECTIVES:To conduct a systematic literature review regarding the anatomy and variations of the LPM. METHODS:We included studies published in English, German or French employing anatomical and imaging methods or a combination of the two methods. The cadavers used in the dissections had to be human and without any pathological alterations. Studies were only included when focusing on the anatomy of the LPM or its morphological variations or when taking the frequency of variations into account. We searched 26 biomedical databases including MEDLINE, EMBASE, BIOSIS Previews and Science Citation Index Expanded (part of Web of Science) through October 2014. The review was followed by the dissection of a hemisected head in two different planes. RESULTS:We identified 4279 records (2200 after deduplication) in the databases searches plus 17 articles from manual searches. 81 studies out of these articles were included in this review. 69 articles used anatomical methods, 5 imaging methods and 7 studies a combination of the two methods. 11 studies took into account that the LPM may have variations and also considered the relative frequency of each variation. The frequency of one-headed LPMs ranged between 7.7% and 26.7%, of two-headed LPMs between 61.4% and 91.1% and of three-headed LPMs between 4.0% and 35.0%. Our own dissection showed a three-headed version of the LPM. DISCUSSION:In anatomical studies, different preparation techniques seem to be the main reason for diverging results.

PURPOSE To investigate the fatigue and fracture resistance of computer-aided design and computer-aided manufacturing (CAD/CAM) ceramic molar crowns on dental implants and human teeth. MATERIALS AND METHODS Molar crowns (n=48; n=8/group) were fabricated of a lithium-disilicate-strengthened lithium aluminosilicate glass ceramic (N). Surfaces were polished (P) or glazed (G). Crowns were tested on human teeth (T) and implant-abutment analogues (I) simulating a chairside (C, crown bonded to abutment) or labside (L, screw channel) procedure for implant groups. Polished/glazed lithium disilicate (E) crowns (n=16) served as reference. Combined thermal cycling and mechanical loading (TC: 3000×5℃/3000×55℃; ML: 1.2×106 cycles, 50 N) with antagonistic human molars (groups T) and steatite spheres (groups I) was performed under a chewing simulator. TCML crowns were then analyzed for failures (optical microscopy, SEM) and fracture force was determined. Data were statistically analyzed (Kolmogorow-Smirnov, one-way-ANOVA, post-hoc Bonferroni, α=.05). RESULTS All crowns survived TCML and showed small traces of wear. In human teeth groups, fracture forces of N crowns varied between 1214±293 N (NPT) and 1324±498 N (NGT), differing significantly (P≤.003) from the polished reference EPT (2044±302 N). Fracture forces in implant groups varied between 934±154 N (NGI_L) and 1782±153 N (NPI_C), providing higher values for the respective chairside crowns. Differences between polishing and glazing were not significant (P≥.066) between crowns of identical materials and abutment support. CONCLUSION Fracture resistance was influenced by the ceramic material, and partly by the tooth or implant situation and the clinical procedure (chairside/labside). Type of surface finish (polishing/glazing) had no significant influence. Clinical survival of the new glass ceramic may be comparable to lithium disilicate.

The aim of this study was to examine the effects of surface pre-treatment on CAD/CAM materials including ceramics, zirconia, resin-infiltrated ceramic, and resin-based composite.

PURPOSE:To evaluate the fatigue and fracture resistance of anterior implant-supported and tooth-supported crowns made of different monolithic ceramics.MATERIALS AND METHODS:Anterior crowns were fabricated of lithium disilicate or one of two zirconia ceramics and were tested as tooth-supported (reference) or as implant-supported crowns with chairside or labside (screw channel) procedures. After thermocycling and mechanical loading (TCML), crowns were loaded to fracture.RESULTS:All crowns survived TCML. Implant-supported crowns (chairside and labside) showed higher fracture values than tooth-supported crowns. Fracture resistance was comparable or higher for zirconia than for lithium disilicate crowns.CONCLUSION:Implant-supported ceramic crowns may withstand clinical anterior loading forces.

PURPOSE:To compare the debonding and fracture force of different CAD/CAM composite crowns with respect to the influence of water storage (0d vs. 90d/37 °C) and types of cementation (adhesive vs. self-adhesive). METHODS:Extracted human molars were prepared with a worst-case preparation scenario providing a nonretentive design (height ~4 mm; angle ~15°) and reduced fitting (250 µm). After digitalization, 72 crowns (n = 8 per group; circular wall thickness 1.5 mm / occlusal thickness ~2.5 mm) were milled from the composites (CS, LU), one experimental composite (EX), a resin-infiltrated ceramic (VE), and a feldspar ceramic reference (VM). The crowns were adhesively bonded (Scotchbond Universal + Rely X Ultimate, 3M), and two groups (EX, VE) were additionally cemented with a self-adhesive cement (RelyX Unicem, 3M). After 90-d water storage, thermal cycling and mechanical loading (TCML) were performed. Restorations, which failed during storage or TCML, were analyzed using scanning electron microscopy, and surviving restorations were loaded to fracture. To evaluate storage effects, two materials (EX, LU) were investigated without water storage. RESULTS:CS (7×) and LU (2×) exhibited debonding during 90-d storage. LU (5×) debonded during TCML. Cement remained on the inner sides of the crowns in all cases. EX and VE survived storage and TCML without failure or debonding. Two specimens of VM exhibited cracks after TCML. Fracture forces varied between 720 N and 2155 N. Solely the results between VE and VM were not significantly different (p = 0.204). Debonding effects due to water storage were material dependent. Fracture forces in tendency (p > 0.117) were higher for self-adhesive cementation. CONCLUSIONS:Debonding and stability of CAD/CAM crowns were material dependent. Water storage affected debonding, and cementation marginally influenced performance and fracture force.

Objectives: The deviation and spread of values measured by tensile strength tests should be significantly reduced by optimized axially pull-off-device. Material and methods: Factors like geometry, roughness, surface texture and fit of the specimens, the luting procedure (mixing ratio, compacting pressure) were standardized and the precision of the axially load transmission during the tensile force application optimized. Copings of CoCr-alloy were luted using a provisional zinc-oxide eugenol and a glass-ionomer cement (n = 20 per group each) on 4 degrees, respectively 8 degrees titanium implant abutment analogs. 24 h after luting the copings were pulled off with the improved (IPD) and the previous non improved device (NIPD). Means, std. dev. and t-tests were calculated. Results: The stress- strain curves produced by the IPD showed a clear and linear relationship between stress and strain. The curves of the NIPD were ragged and chaotic. For both luring agents the means of the retentive force were considerable higher (p > 0.000) with IPD. However, the standard deviation was unimproved for the zinc oxide eugenol cement: IPD: 27%; NIPD: 27%, but significantly improved with glass ionomer: IPD: 16%, NIPD: 28%. Conclusion: The results from luting agents, which react like a solid body, may benefit from the optimized pull-off-device. Despite the fact that many factors in this investigation have been controlled, unknown flow characteristics of non-Newtonian-fluids like luting agents may have a considerable influence on the standard deviation of pull-off tests.

Objectives: To investigate the edge force of CAD/CAM materials as a function of (a) material, (b) thickness, and (c) distance from the margin. Methods: Materials intended for processing with CAD/CAM were investigated: eight resin composites, one resin-infiltrated ceramic, and a clinically proven lithiumdisilicate ceramic (reference). To measure edge force (that is, load to failure/crack), plates (d=1 mm) were fixed and loaded with a Vickers diamond indenter (1 mm/min, Zwick 1446) at a distance of 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1.0 mm from the edge. Edge force was defined as a loading force at a distance of 0.5 mm. The type of failure was determined. To investigate the influence of the thickness, all data were determined on 1-mm and 2-mm plates. To test the influence of bonding and an underlying dentin, individual 1-mm plates were bonded to a 1-mm-thick dentin-like (concerning modulus of elasticity) resin composite. Results: For the 1-mm plates, edge force varied between 64.4 +/- 24.2 N (Shofu Block HC) and 183.2 +/- 63.3 N (ceramic reference), with significant (p <= 0.001) differences between the materials. For the 2-mm plates, values between 129.2 +/- 32.5 N (Lava Ultimate) and 230.3 +/- 67.5 N (Cerasmart) were found. Statistical comparison revealed no significant differences (p>0.109) between the materials. Brilliant Crios (p=0.023), Enamic (p=0.000), Shofu Blocks HC (p=0.009), and Grandio Bloc (p=0.002) showed significantly different edge force between the 1-mm-and 2-mm-thick plates. The failure pattern was either cracking, (severe) chipping, or fracture. Conclusions: Material, material thickness, and distance from the edge impact the edge force of CAD/CAM materials.

Purpose: High wear resistance of denture teeth preserves good occlusal relationship and sufficient parafunctional stability. This in-vitro investigation aimed to determine and compare the wear performance of different artificial denture teeth. Methods: Denture teeth of fifteen commercial products (n = 8/group) were loaded in a pin-on-block design using steatite antagonists (d = 3 mm). Cyclic loading (50 N) was applied for 120,000 loadings (f = 1.2 Hz) with simultaneous thermal cycling (distilled water, 5 degrees C/55 degrees C, 2 min/cycle). A loading cycle consisted of a vertical 1 mm impact and a subsequent lateral 1 mm sliding movement. Worn areas were digitalized (3-D-laser-scanning-microscope). Maximum and mean wear depth and surface roughness were determined and statistically compared (one-way Anova, Tukey-HSD test, alpha = 0.05). Worn surfaces and cut specimens were investigated with scanning electron microscopy (SEM). Results: Maximum wear varied between 475.1 mu m and 1232.2 mu m. Mean wear was between 241.1 mu m and 753.6 mu m with significant differences (p < 0.001) between individual materials. Mean and maximum wear showed a significant correlation (Pearson's correlation coefficient: 0.942). Surface roughness increased between unworn to worn surface by 1.2 mu m (Ra, p = 0.387) and by 41.7 mu m (Rz, p = 0.000). All materials provided round or drop-shaped wear traces. Superficial analysis showed no cracks, chipping or fractures in the worn areas. Detailed evaluation of cut specimens with SEM exposed cracks on the bottom of the wear traces. Conclusions: Denture teeth showed significantly different in-vitro wear performance and increased roughness in the wear trace. Differences may be attributed to the composition of the materials, regarding both filler and polymer structure. The selection of teeth might contribute to enhanced in-vivo performance of the denture. (c) 2017 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Zusammenfassung In der vorliegenden Untersuchung wurde die mundgesundheitsbezogene Lebensqualität von älteren Patienten in Abhängigkeit vom Ausmaß einer Xerostomia, der Speichelfließrate und dem Zahnstatus untersucht. Die Ergebnisse zeigen, dass die Lebensqualität signifikant durch das Vorliegen einer Xerostomie beeinträchtigt wird. Da die Prävalenz von Hyposalivation bei älteren Patienten eher gering zu sein scheint, sollten therapeutische Strategien darauf abzielen, die subjektive Empfindung von Mundtrockenheit zu lindern.

This study aims to investigate bacterial adhesion on different titanium and ceramic implant surfaces, to correlate these findings with surface roughness and surface hydrophobicity, and to define the predominant factor for bacterial adhesion for each material.

Objective. To investigate the fatigue and fracture resistance of different CAD/CAM-materials as implant- or tooth-supported molar crowns with respect to the clinical procedure (screwed/bonded restoration).Methods. 168 crowns were fabricated from different CAD/CAM-materials (n = 8/material): ZLS (zirconia-reinforced lithium silicate ceramic; Suprinity, Vita-Zahnfabrik), COB (composite; Brilliant Crios, Coltene), COL (composite; Lava Ultimate, 3M Espe), PMV/PPV (polyether ether ketone (PEEK) + milled composite veneer/composite paste veneer; BioHPP + HIPC veneer/Crealign veneer, Bredent), COH (composite; Block HC, Shofu), and ZIR (zirconia; IPS e.max ZirCAD, Ivoclar-Vivadent) as reference. Three groups were designed simulating the following clinical procedures: (a) chairside procedure ([CHAIR] implant crown bonded to abutment), (b) labside procedure ([LAB] abutment and implant crown bonded in laboratory, screwed chairside), and (c) reference ([TOOTH] crowns bonded on human teeth). Combined thermal cycling and mechanical loading (TCML) were performed simulating a 5-year clinical situation. Fracture force was determined and failures were documented. Data were statistically analyzed (Kolmogorov-Smirnov-test, one-way-ANOVA; post-hoc-Bonferroni, alpha = 0.05). Results. All crowns of group LAB-PPV showed cracks after TCML. The other groups survived fatigue testing without failures. Fracture forces varied between 921.3 N (PPV) and 4817.8 N (ZIR) [CHAIR], 978.0 N (COH) and 5081.4 N (ZIR) [LAB], 746.7N (PPV) and 3313.5 N (ZIR) [TOOTH]. Significantly (p <0.05) different fracture values were found between materials in all three groups. Only ZLS crowns provided no significant (p > 0.05) differences between the individual groups.Significance. Different ceramic and resin-based materials partly performed differently in implant or tooth situations. Individual resin-based materials (PPV, COB, COH) were weakened by inserting a screw channel. Most CAD/CAM-materials may be clinically applied in implant-supported crowns without restrictions. (C) 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

PURPOSE:To investigate the force absorption capacity of implant-supported crowns made of different restorative materials and connected to abutments with different luting agents. MATERIALS AND METHODS:Molar crowns were milled of different computer-aided design/computer-aided manufacture materials (n = 8 crowns per material): polymethyl methacrylate, polyether ether ketone, composite, lithium disilicate, titanium, and zirconia. Crowns were mounted on titanium implant replicas using different luting agents: uncemented, temporarily cemented (zinc oxide-eugenol cement), conventionally cemented (zinc oxide phosphate cement), and adhesively bonded. As a reference, one implant replica was tested without a crown. Force absorptions of the different combinations of crown materials and luting agents were determined by applying an increasing force (0 to 250 N) on the occlusal crown surface and measuring the resulting force below the implant. Mean curves of applied and resulting forces up to 200 N were determined (six measurements per group), and slopes were calculated. Statistical analysis was performed (one-way analysis of variance, Bonferroni post hoc test, α = .05). RESULTS:Significant (P < .001) differences in the applied and resulting forces were found between the crown materials that were uncemented, temporarily cemented, cemented, and adhesively bonded. Materials with higher moduli of elasticity (ceramics, titanium) showed steeper slopes of the force curves and lower shock-absorbing capacity than resin-based materials, but were influenced more by the luting agents. The damping effects of resin-based materials were higher in combination with all cementation and luting modes. CONCLUSION:Shock absorption tests exhibited a strong material-dependent damping behavior of implant-supported crowns. The shock-absorbing capacity of crown materials with high moduli of elasticity may benefit from conventional cementation.