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Aim To assess in vitro the workflow for alveolar ridge augmentation with customised 3D printed block grafts and simultaneous computer-assisted implant planning and placement. Methods Twenty resin mandible models with an edentulous area and horizontal ridge defect in the region 34–36 were scanned with cone beam computed tomography (CBCT). A block graft for horizontal ridge augmentation in the region 34–36 and an implant in the position 35 were digitally planned. Twenty block grafts were 3D printed out of resin and one template for guided implant placement were stereolithographically produced. The resin block grafts were positioned onto the ridge defects and stabilised with two fixation screws each. Subsequently, one implant was inserted in the position 35 through the corresponding template for guided implant placement. Optical scans of the study models together with the fixated block graft were performed prior to and after implant placement. The scans taken after block grafting were superimposed with the virtual block grafting plan through a best-fit algorithm, and the linear deviation between the planned and the achieved block positions was calculated. The precision of the block fixation was obtained by superimposing the 20 scans taken after grafting and calculating the deviation between the corresponding resin blocks. The superimposition between the scans taken after and prior to implant placement was performed to measure a possible displacement in the block position induced by guided implant placement. The (98–2%)/2 percentile value was determined as a parameter for surface deviation. Results The mean deviation in the position of the block graft compared to the virtual plan amounted to 0.79 ± 0.13 mm. The mean deviation between the positions of the 20 block grafts measured 0.47 ± 0.2 mm, indicating a clinically acceptable precision. Guided implant placement induced a mean shift of 0.16 ± 0.06 mm in the position of the block graft. Conclusions Within the limitation

OBJECTIVE To assess time efficiency and the efficacy of the prosthetic manufacturing for implant crown fabrication in a centralized workflow applying computer aided design and computer aided manufacturing (CAD-CAM). MATERIAL AND METHODS Fifty-nine patients with one posterior implant each, were randomly allocated to either a centralized digital workflow (c-DW, test) or a laboratory digital workflow (l-DW, control). Patients were excluded from efficiency and efficacy analyses, if any additional restoration than this single implant crown had to be fabricated. A customized titanium abutment and a monolithic zirconia crown were fabricated in the c-DW. In the l-DW, models were digitalized for CAD-CAM fabrication of a monolithic zirconia crown using a standardized titanium base abutment. Time for impression, laboratory operating and delivery time were recorded. The efficacy of the prosthetic manufacturing was evaluated at try-in and at delivery. Data was analyzed descriptively. Statistical analyses using student's unpaired t- and paired Wilcoxon were performed (p < 0.05). RESULTS At impression taking, 12 patients (c-DW) and 19 patients (l-DW) were included. The impression time was 9.4±3.5 min (c-DW) and 15.1 ± 4.6 min (l-DW) (p < 0.05). The laboratory operating time was 130 ± 31 min (c-DW) and 218.0±8 min (l-DW) (p < 0.05). The delivery time was significantly longer in the c-DW (5.9 ± 3.5 1 days) as compared to the l-DW (0.5±0.05 days). At try-in and at delivery, efficacy of prosthetic manufacturing was similar high in both workflows. CLINICAL RELEVANCE The c-DW was more time efficient compared to the lab-DW and rendered a similar efficacy of prosthetic manufacturing.

OBJECTIVES: The load-bearing capacity of ultra-thin occlusal veneers made of 3D-printed zirconia were compared to the ones obtained by fabricating these reconstructions by CAD/CAM milling zirconia or heat-pressing lithium-disilicate. METHODS: On 60 extracted human molars, the occlusal enamel was removed and extended into dentin. Occlusal veneers of 0.5 mm thickness were digitally designed. The specimens were divided into 3 groups (n = 20 each) differing in the restorative material and the fabrication technique of the occlusal veneer. (1) 3DP: 3D-printed zirconia (Lithoz); (2): CAM: milled zirconia (Ceramill Zolid FX); (3) HPR: heat-pressed lithium disilicate (IPS e.max Press). After conditioning procedures, the restorations were adhesively bonded onto the conditioned tooth. Thereafter, all specimens were aged in a chewing simulator by exposure to cyclic fatigue and temperature variations. Subsequently the specimens were statically loaded and the load which was necessary to decrease the maximum load by 20% and initiate a crack (F$_{initial}$) and the load which was needed to fracture the specimen (F$_{max}$) were measured. Differences between the groups were compared applying the Kruskal-Wallis (KW) test and the Wilcoxon-Mann-Whitney-Test (WMW: p < 0.05). RESULTS: The median F$_{initial}$ values for the groups 3DP, CAM and HPR were 1'650 N, 1'250 N and 500 N. The differences between all three groups were statistically significant (KW: p < 0.0001). The median F$_{max}$ values amounted to 2'026 N for the group 3DP, 1'500 N for the group CAM and 1'555 N for the group HPR. Significant differences were found between 3DP and CAM (WMW: p = 0.0238). SIGNIFICANCE: Regarding their load-bearing capacity, 3D-printed or milled zirconia, as well as heat-pressed lithium disilicate, can be recommended as restorative material for ultra-thin occlusal veneers to prosthetically compensate for occlusal tooth wear. Despite statistically significant differences between the restoration mate

BACKGROUND AND AIMS: Bone augmentation procedures to enable dental implant placement are frequently performed. The remit of this working group was to evaluate the current evidence on the efficacy of regenerative measures for the reconstruction of alveolar ridge defects. MATERIAL AND METHODS: The discussions were based on four systematic reviews focusing on lateral bone augmentation with implant placement at a later stage, vertical bone augmentation, reconstructive treatment of peri-implantitis associated defects, and long-term results of lateral window sinus augmentation procedures. RESULTS: A substantial body of evidence supports lateral bone augmentation prior to implant placement as a predictable procedure in order to gain sufficient ridge width for implant placement. Also, vertical ridge augmentation procedures were in many studies shown to be effective in treating deficient alveolar ridges to allow for dental implant placement. However, for both procedures the rate of associated complications was high. The adjunctive benefit of reconstructive measures for the treatment of peri-implantitis-related bone defects has only been assessed in a few RCTs. Meta-analyses demonstrated a benefit with regard to radiographic bone gain but not for clinical outcomes. Lateral window sinus floor augmentation was shown to be a reliable procedure in the long-term for the partially and fully edentulous maxilla. CONCLUSIONS: The evaluated bone augmentation procedures were proven to be effective for the reconstruction of alveolar ridge defects. However, some procedures are demanding and bear a higher risk for postoperative complications. This article is protected by copyright. All rights reserved.

The use of a caries infiltrant before application of a conventional adhesive did not impair bonding to sound and demineralised enamel and might be beneficial as a pretreatment in demineralised enamel.

OBJECTIVES: To assess the bonding potential of a universal composite resin cement and an adhesive/composite system to differently pre-treated PEEK surfaces. METHODS: One hundred and fifty PEEK disks were embedded in epoxy resin, polished (P4000 grit) and treated as follows (n=30/group): (A) no treatment, (B) acid etching with sulfuric acid (98%) for 1 min, (C) sandblasting for 10s with 50 microm alumina, (D) sandblasting for 10s with 110 microm alumina and (E) silica coating using the Rocatec system (3M ESPE). Polished and sandblasted (50 microm alumina) cp titanium (grade 4) served as a control. Acrylic hollow cylinders were either luted with a universal composite resin cement (RelyX Unicem) or an unfilled resin (Heliobond) and a hybrid composite (Tetric) to the specimens. Bond strength was measured in a shear test and failure modes were assessed. Statistic analysis was performed with one-way ANOVA followed by a post hoc Scheffé test and unpaired t-tests. RESULTS: With the universal composite resin cement, no bond could be established on any PEEK surfaces, except specimens etched with sulfuric acid (19.0+/-3.4MPa). Shear bond strength to titanium was significantly lower (8.7+/-2.8MPa, p<0.05). Applying the adhesive/composite system, shear bond strength values on pre-treated PEEK ranged from 11.5+/-3.2MPa (silica coating) to 18.2+/-5.4MPa (acid etched) with no statistically significant differences (p>0.05). No bond was obtained on the polished surface. SIGNIFICANCE: Bonding to PEEK is possible when using a bonding system. No adherence can be achieved with the tested universal composite resin cement except on an etched surface. The results strongly encourage further research in PEEK application in dentistry.

Aim: The aim of this randomized-controlled clinical study was to examine stability changes of palatal implants with chemically modified sandblasted/acid-etched (modSLA) titanium surface compared with a standard SLA surface, during the early stages of bone healing. Materials and methods: Forty adult volunteers were recruited and randomly assigned to the test group (modSLA surface) and to the control group (SLA surface). The test and control implants had the same microscopic and macroscopic topography, but differed in surface chemistry. To document implant stability changes resonance frequency analysis (RFA) was performed at implant insertion, at 7, 14, 21, 28, 35, 42, 49, 56, 70 and 84 days thereafter. RFA values were expressed as an implant stability quotient (ISQ). Results: Immediately after implant installation, the ISQ values for both surfaces tested were not significantly different and yielded mean values of 73.8+/-5 for the control and 72.7+/-3.9 for the test surface. In the first 2 weeks after implant installation, both groups showed only small changes and thereafter a decreasing trend in the mean ISQ levels. In the test group, after 28 days a tendency towards increasing ISQ values was observed and 42 days after surgery the ISQ values corresponded to those after implant insertion. For the SLA-control group, the trend changed after 35 days and yielded ISQ values corresponding to the baseline after 63 days. After 12 weeks of observation, the test surface yielded significantly higher stability values of 77.8+/-1.9 compared with the control implants of 74.5+/-3.9, respectively. Conclusion: The results support the potential for chemical modification of the SLA surface to positively influence the biologic process of osseointegration and to decrease the healing time. To cite this article: Schätzle M, Männchen R, Balbach U, Hämmerle CHF, Toutenburg H, Jung RE. Stability change of chemically modified SLA titanium palatal implants. A randomized controlled clinical trial

Implant therapy has evolved into an important part of daily dental practice. Appropriate knowledge of diagnostic and therapeutic options with dental implant therapy is, therefore, mandatory for dental students. The present consensus paper describes the theoretical knowledge as a foundation to the teaching of implant dentistry at the undergraduate level. Students need a solid basic knowledge about biological prerequisites and clinical procedures leading to successful implant treatment and, in particular, an understanding of the importance of embedding implants into the overall treatment concept. Among others this includes aspects of bone and soft tissue integration of dental implants, as well as aspects of materials that are used in implant dentistry. The students should also be able to differentiate between low, medium and high-risk situations, which assumes that they have knowledge about a proper clinical examination. Furthermore, the students need to be able to inform the patient about the different treatment options and their advantages and disadvantages. Frequently, a choice has to be made between an FDP anchored on teeth and an implant-borne reconstruction. This is highly influenced by the long-term prognosis of the different treatment options. In order to perform implant placement in uncomplicated cases and to give appropriate patient information, adequate knowledge of surgical procedure and surgical complications is mandatory. Furthermore, the dentist needs to be competent in evaluating clinical situations and in advising patients about the suitability of the different options, e.g. removable or fixed reconstructions. It is possible that peri-implant tissue destruction may be a more common finding during long-term service of implant-borne reconstructions than was previously believed. The dentist needs knowledge about etiology and pathogenesis of peri-implantitis and should know how to provide an effective maintenance care programme. In cases of peri-implantit

The aim of this study was to test the color-change effect of all-ceramic restorations compared with porcelain-fused-to-metal (PFM) restorations on marginal peri-implant soft tissue. Thirty patients were randomly divided into 2 groups of 15 subjects each. The all-ceramic group received all-ceramic crowns on aluminum oxide-based abutments, while the PFM group received crowns on titanium or gold abutments. A reflectance spectrophotometer was used to measure the color difference (deltaE(Implant)) between the midfacial peri-implant mucosa before and after restoration insertion. The color difference (deltaE(Tooth-implant)) between the midfacial peri-implant mucosa and the gingival margin of the corresponding neighboring tooth was tested. The mucosal thickness was measured midfacially around the implant (MT(Implant)) and neighboring tooth (MT(Tooth)). deltaE(Implant) values were similar for the all-ceramic (7.4 +/- 2.7) and PFM groups (7.6 +/- 2.8). The all-ceramic group induced significantly less visible mucosal color change (3.4 +/- 1.4) compared to the PFM group (5.2 +/- 2.3). The MT(Implant) value of the all-ceramic group was 3.4 +/- 0.8 mm, while that of the PFM group was 2.9 +/- 0.9 mm, which was not significantly different. Significant differences were found when comparing MT(Implant) (3.1 +/- 0.9) and MT(Tooth) (1.2 +/- 0.3) values for test and control groups. All-ceramic restorations revealed a better color match to the neighboring teeth than PFM restorations.

OBJECTIVES: The flexural strengths of veneering ceramics for zirconia were compared. METHODS: With 10 different veneering ceramics for zirconia (test group) and three different veneering ceramics for the metal-ceramic technique (control group) three-point flexural strength and biaxial flexural strength according to ISO 6872: 1995 as well as four-point flexural strength according to EN 843-1: 2005 were measured (n=10). Statistical analysis was performed with one-way ANOVA and post hoc Scheffé test (SPSS, p<0.05). RESULTS: For the test group, three-point flexural strength ranged between 77.8+/-8.7 and 106.6+/-12.5MPa without any statistically significant differences, biaxial flexural strength between 69.1+/-4.8 and 101.4+/-10.5MPa with three homogeneous groups and four-point flexural strength between 59.5+/-6.2 and 89.2+/-9.5MPa with five homogeneous groups. The control group showed three-point flexural strength values ranging from 93.3+/-13.5 to 149.4+/-20.5MPa, biaxial flexural strength values from 93.4+/-10.0 to 141.2+/-11.6MPa, and four-point flexural strength values from 82.7+/-8.5 to 116.9+/-9.8MPa. In every case, the results of the four-point flexure test were significantly lower than those obtained in the three-point flexure test. The three-point flexural strengths of the test group are similar to those of two ceramics of the control group. The flexural strength of one ceramic of the control group significantly exceeded the strengths of all other ceramics investigated. CONCLUSION: Three-point flexural strength values of veneering ceramics for zirconia are similar to those of veneering ceramics for the metal-ceramic technique. The four-point flexure test among all three tests showed highest discrimination between the different ceramic materials.