Primary stability and osseointegration comparing a novel tapered design tissue-level implant with a parallel design tissue-level implant. An experimental in vivo study.

OBJECTIVES: The aim of the present study was to compare a novel tapered, double-threaded self-tapping tissue-Level design implant (TLC) to a well-established parallel walled tissue-level (TL) implant in terms of primary and secondary stability over time. MATERIALS AND METHODS: Test TLC (n = 10/per timepoint) and control TL (n = 10/per timepoint) implants were placed in the mandible of minipigs and left for submerged healing for 3, 6, and 12 weeks. Maximum insertion torque and implant stability quotient (ISQ) were measured for each implant at placement. Osseointegration and cortical bone maintenance were histologically evaluated by measuring total bone-to-implant contact (BIC) and first bone-to-implant contact (fBIC). RESULTS: A significantly higher maximum insertion torque was measured for the test implant TLC compared to the control TL implant (57.83 ± 24.73 Ncm and 22.62 ± 23.16 Ncm, respectively; p < .001). The mean ISQ values were comparable between the two implant types (75.00 ± 6.70 for TL compared to 75.40 ± 3.20 for TLC, p = .988). BIC was comparable between both implant types at each of the evaluated time points. The fBIC was found to be significantly more coronal at 12 weeks for the TLC implant compared to the TL implant (0.31 ± 0.83 mm for TLC compared to -0.22 ± 0.85 for TL, p = .027). CONCLUSION: The novel tapered tissue level design implant showed improved primary stability and an overall improved crestal bone height maintenance compared to the parallel walled design at 12 weeks.

Extrusion-based 3D printing of osteoinductive scaffolds with a spongiosa-inspired structure.

Critical-sized bone defects resulting from trauma, inflammation, and tumor resections are individual in their size and shape. Implants for the treatment of such defects have to consider biomechanical and biomedical factors, as well as the individual conditions within the implantation site. In this context, 3D printing technologies offer new possibilities to design and produce patient-specific implants reflecting the outer shape and internal structure of the replaced bone tissue. The selection or modification of materials used in 3D printing enables the adaption of the implant, by enhancing the osteoinductive or biomechanical properties. In this study, scaffolds with bone spongiosa-inspired structure for extrusion-based 3D printing were generated. The computer aided design process resulted in an up scaled and simplified version of the bone spongiosa. To enhance the osteoinductive properties of the 3D printed construct, polycaprolactone (PCL) was combined with 20% (wt) calcium phosphate nano powder (CaP). The implants were designed in form of a ring structure and revealed an irregular and interconnected porous structure with a calculated porosity of 35.2% and a compression strength within the range of the natural cancellous bone. The implants were assessed in terms of biocompatibility and osteoinductivity using the osteosarcoma cell line MG63 and patient-derived mesenchymal stem cells in selected experiments. Cell growth and differentiation over 14 days were monitored using confocal laser scanning microscopy, scanning electron microscopy, deoxyribonucleic acid (DNA) quantification, gene expression analysis, and quantitative assessment of calcification. MG63 cells and human mesenchymal stem cells (hMSC) adhered to the printed implants and revealed a typical elongated morphology as indicated by microscopy. Using DNA quantification, no differences for PCL or PCL-CaP in the initial adhesion of MG63 cells were observed, while the PCL-based scaffolds favored cell proliferation in the early phases of culture up to 7 days. In contrast, on PCL-CaP, cell proliferation for MG63 cells was not evident, while data from PCR and the levels of calcification, or alkaline phosphatase activity, indicated osteogenic differentiation within the PCL-CaP constructs over time. For hMSC, the highest levels in the total calcium content were observed for the PCL-CaP constructs, thus underlining the osteoinductive properties.

Piranha-etched titanium nanostructure reduces biofilm formation in vitro.

OBJECTIVES: Nano-modified surfaces for dental implants may improve gingival fibroblast adhesion and antibacterial characteristics through cell-surface interactions. The present study investigated how a nanocavity titanium surface impacts the viability and adhesion of human gingival fibroblasts (HGF-1) and compared its response to Porphyromonas gingivalis with those of marketed implant surfaces. MATERIAL AND METHODS: Commercial titanium and zirconia disks, namely, sandblasted and acid-etched titanium (SLA), sandblasted and acid-etched zirconia (ZLA), polished titanium (PT) and polished zirconia (ZrP), and nanostructured disks (NTDs) were tested. Polished titanium disks were etched with a 1:1 combination of 98% H2SO4 and 30% H2O2 (piranha etching) for 5 h at room temperature to produce the NTDs. Atomic force microscopy was used to measure the surface topography, roughness, adhesion force, and work of adhesion. MTT assays and immunofluorescence staining were used to examine cell viability and adhesion after incubation of HGF-1 cells on the disk surfaces. After incubation with P. gingivalis, conventional culture, live/dead staining, and SEM were used to determine the antibacterial properties of NTD, SLA, ZLA, PT, and ZrP. RESULTS: Etching created nanocavities with 10-20-nm edge-to-edge diameters. Chemical etching increased the average surface roughness and decreased the surface adherence, while polishing and flattening of ZrP increased adhesion. However, only the NTDs inhibited biofilm formation and bacterial adherence. The NTDs showed antibacterial effects and P. gingivalis vitality reductions. The HGF-1 cells demonstrated greater viability on the NTDs compared to the controls. CONCLUSION: Nanocavities with 10-20-nm edge-to-edge diameters on titanium disks hindered P. gingivalis adhesion and supported the adhesion of gingival fibroblasts when compared to the surfaces of currently marketed titanium or zirconia dental implants. CLINICAL RELEVANCE: This study prepared an effective antibacterial nanoporous surface, assessed its effects against oral pathogens, and demonstrated that surface characteristics on a nanoscale level influenced oral pathogens and gingival fibroblasts. CLINICAL TRIAL REGISTRATION: not applicable.

Accuracy of a dynamic navigation system for dental implantation with two different workflows and intraoral markers compared to static-guided implant surgery: An in-vitro study.

PURPOSE: To investigate the accuracy of a miniaturized dynamic navigation system with intraoral markers and two different workflows for dental implantation and to compare with static computer-assisted implant surgery (sCAIS) surgery. MATERIALS AND METHODS: Two operators performed a total of 270 implant insertions in polyurethane mandibular models under simulated clinical conditions. Implants were placed after CBCT-based virtual planning in three different groups: two workflows utilizing dynamic computer-assisted implant surgery (dCAIS; DG1: marker in CBCT; DG2: 3D-printed marker) and the others with sCAIS (TG: template guided). Postoperative surface scans were matched to the planning data and allowed an evaluation of the angular and spatial deviation between the planned and the actually achieved implant position. Descriptive statistics were followed by a Mixed Model Analysis to determine the influence of the operator, the method, and operating area on different accuracy parameters and the random effect of the model number. RESULTS: The mean angular deviation ranged from 2.26° (DG1) to 2.96° (TG). The mean 3D deviation at the implant's tip ranged from 1.08 mm (TG) to 1.51 mm (DG2) and at the implant's base from 0.69 mm (TG) to 1.49 mm (DG2). The operator showed no significant influence on the accuracy. The method showed significant influence on singular parameters and the operating area on all spatial accuracy parameters. CONCLUSIONS: Dynamic navigation systems with intraoral markers enable accurate implant positioning, which is comparable to the static-guided implant surgery. 3D-printed markers provide less accurate results compared to prefabricated markers, attached before CBCT scan.

General and dental injuries sustained at concerts: A questionnaire-based study.

BACKGROUND/AIM: Evidence on the risk of injury at concerts is scant. The aim of this study was to collect data on general and dental injuries incurred by concertgoers in Switzerland and to investigate whether the frequency of accidents was related to music genre, gender and consumption of alcohol. MATERIALS AND METHODS: A questionnaire-based, cross-sectional study comprising 451 concertgoers in Switzerland was conducted on the timeframe January 2019 to February 2021. The survey gathered data on general and dental injuries, alcohol consumption and drug use. The statistical analysis included Fisher's exact tests, chi-squared tests, rank sum tests and logistic regressions (α = .05). RESULTS: There were 28.8% of respondents who reported an injury incurred at a concert. Contusion was the most prevalent injury, accounting for 33.8% of all injuries. Legs were the most commonly injured body part (34.6%). Injuries to their mouth/lips/teeth were reported by 17.7% of respondents. Dental injuries, accounting for 4.6% of all reported injuries, comprised four tooth fractures, one lateral luxation and one avulsion. The risk of injury while attending punk rock concerts was 8.6 times higher than for pop concerts (p < .001). In comparison with pop concerts, metal and rock concerts had an increased risk of injury by factors of 5.1 and 2.3, respectively (p ≤ .029). Neither gender nor drug use had a significant effect on the injury risk (p ≥ .3). Heavy alcohol consumption (>5 standard glasses) increased the risk of injury by a factor of 2.3 (p = .028). CONCLUSIONS: This study suggests that concert attendees at rock, metal and punk concerts face an increased risk of injury, which is likely due to the frequency of aggressive dance styles such as moshing. Heavy alcohol consumption leads to a greater risk of injury at concerts.

Cytokines Activate JAK-STAT Signaling Pathway in MG-63 Cells on Titanium and Zirconia.

Although titanium has been traditionally used as the gold standard for dental implants, recent years have seen the widespread application of zirconia implants given their superiority with regards to reduced bacterial adhesion, inflammation and cellular-interaction in terms of bio-compatibility. The JAK-STAT signaling pathway plays an important role in bone remodeling and formation. The aim of the study was to investigate the activation of the JAK-STAT pathway through different cytokines in osteoblast-like cells (MG-63) on zirconia in comparison to titanium discs. IFN-γ induced the very strong activation of STAT1 protein, IFN-α activated both STAT1 and STAT3 molecules, IL-6 activated STAT3 and IL-4 induced the activation of STAT6 on both surfaces. The activation of STAT proteins was confirmed by western blot, immunofluorescence and flow cytometry using phospho-specific anti-STAT antibodies, which recognize only phosphorylated STAT proteins. The incubation of MG-63 cells with IFN-γ caused the upregulation of MHC class I and class II proteins when MG-63 cells were grown on zirconia and titanium discs. In sum, the present study shows that the JAK-STAT pathway is activated in MG-63 cells when they are incubated on titanium or zirconia surfaces.

Esthetic and functional outcomes of narrow-diameter implants compared in a cohort study to standard diameter implants in the anterior zone of the maxilla.

OBJECTIVE: The aim of this study was to evaluate functional and esthetic clinical outcomes and patient satisfaction with narrow-diameter implants in comparison to standard-diameter implants in the anterior zone of the maxilla in a follow-up examination after 1 to 6 years. METHOD AND MATERIALS: The study was designed as a retrospective cohort study investigation including 27 patients receiving a 3.3-mm diameter single implant (NDI, n = 14) or a standard-diameter 4.1-mm single implant in the anterior zone of the maxilla (SDI, n = 16). Descriptive and analytical statistics were performed comparing both groups with regard to clinical examination including esthetic outcome, sulcus fluid flow-rate, crown esthetics, patients' satisfaction on visual analog scales, occurrence of biologic or technical complication, probing pocket depths (Fisher exact test), pink esthetic score (PES) and Periotest (Mann-Whitney U test). The level of significance was set at α = .05. RESULTS: The mean observation period was 4.8 years after crown insertion in the NDI group, and 4.9 years in the SDI group. Significant differences were observed for Periotest values in favor of the 4.1-mm implants (P = .014). No differences were found with regards to esthetics (PES; P = .27) or sulcus fluid flow-rate (P = 0.73) and probing pocket depths (P = .35). Overall patient satisfaction was high for both groups with visual analog scale scores of 9.3 ± 1.1 for NDI and 9.4 ± 1.0 for SDI (P = .39). CONCLUSION: Clinical outcome with narrow-diameter implants was comparable to standard-diameter implants in the anterior zone of the maxilla with similar esthetic assessments and patients' satisfaction.

Novel Titanium Nanospike Structure Using Low-Energy Helium Ion Bombardment for the Transgingival Part of a Dental Implant.

AIM(S): The aim of the study was to fabricate a nanospike surface on a titanium alloy surface using a newly established method of low-energy helium ion bombardment. Various methods to achieve nanospike formation on titanium have been introduced recently, and their antibacterial properties have been mainly investigated with respect to Escherichia coli and Staphylococcus aureus. Oral pathogens such as Porphyromonas gingivalis play an important role in the development of peri-implantitis. For that reason, the antibacterial properties of the novel, nanostructured titanium surface against P. gingivalis were assessed, and a possible effect on the viability of gingival fibroblasts was evaluated. MATERIALS AND METHODS: Helium sputtering was employed for developing titanium surfaces with nanospikes of 500 nm (ND) in height; commercially available smooth-machined (MD) and sandblasted and acid-etched titanium disks (SLA) were used as controls. Surface structure characterization was performed through scanning electron microscopy (SEM) and atomic force microscopy (AFM). Following incubation with P. gingivalis, antibacterial properties were determined via conventional culturing and SEM. Additionally, the viability of human gingival fibroblasts (HGFs) was tested through MTT assay, and cell morphology was assessed through SEM. RESULTS: SEM images confirmed the successful establishment of a nanospike surface with required heights, albeit with heterogeneity. AFM images of the 500 nm nanospike surface revealed that the roughness is dominated by large-scale hills and valleys. For frame sizes of 5 × 5 µm and smaller, the average roughness is dominated by the height of the titanium spikes. ND successfully induces dysmorphisms within P. gingivalis cultures following the incubation period, while conventional culturing reveals a 17% and 20% reduction for ND compared to MD and SLA, respectively. Moreover, the nanospike surfaces did not affect the viability of human growth fibroblasts despite their sharp surface. CONCLUSION(S): This study successfully developed a novel titanium-nanospike-based structuration technique for titanium surfaces. In addition, the nanospikes did not hinder gingival fibroblast viability. Enhanced antimicrobial effects for such a novel nanospike-based resurfacing technique can be achieved through further optimizations for nanospike spacing and height parameters.

Surgical therapy of peri-implantitis with adjunctive hydroxyapatite and enamel matrix derivative: a 1-year retrospective case series.

This case series retrospectively investigated the one-year surgical outcome of regenerative peri-implantitis therapy using a hydroxyapatite (HA) bone substitute material in combination with enamel matrix derivate (EMD) and collagen membrane for guided bone regeneration (GBR). Data-sheets of patients were screened to detect patients who received identical regenerative peri implantitis-therapy with surface decontamination and GBR applying HA, EMD and a collagen membrane under broad- spectrum antibiotic regime. For inclusion, information on pre- and postoperative clinical and radiographic parameters (probing pocket depth (PPD), bleeding on probing (BOP), suppuration (SUPP) and the radiological bone level (RBL)) had to be available for statistical analysis. Data of a total of 11 patients (20 implants) were extracted out of 202 (336). All implants were still in function after one year. Bone defects decreased by an average of 1.3 mm mesially and 0.9 mm distally, respectively. Mean PPD was reduced from 4.9 mm to 2.7 mm. BOP decreased from 90% to 20%. Suppuration decreased from 65% to 0%. Based on the success criteria applied, 15 of the 20 (75%) implants included were considered as successfully treated after 1 year. Regenerative peri-implantitis therapy according to the presented concept showed promising clinical and radiographic outcomes after one year. To estimate the beneficial effects of the combined use of HA, EMD and collagen membranes, further long term investigations with a control group are needed.

Effect of a Nanostructured Titanium Surface on Gingival Cell Adhesion, Viability and Properties against P. gingivalis.

OBJECTIVES: The transgingival part of titanium implants is either machined or polished. Cell-surface interactions as a result of nano-modified surfaces could help gingival fibroblast adhesion and support antibacterial properties by means of the physico-mechanical aspects of the surfaces. The aim of the present study was to determine how a nanocavity titanium surface affects the viability and adhesion of human gingival fibroblasts (HGF-1). Additionally, its properties against Porphyromonas gingivalis were tested. MATERIAL AND METHODS: Two different specimens were evaluated: commercially available machined titanium discs (MD) and nanostructured discs (ND). To obtain ND, machined titanium discs with a diameter of 15 mm were etched with a 1:1 mixture of 98% H2SO4 and 30% H2O2 (piranha etching) for 5 h at room temperature. Surface topography characterization was performed via scanning electron microscopy (SEM) and atomic force microscopy (AFM). Samples were exposed to HGF-1 to assess the effect on cell viability and adhesion, which were compared between the two groups by means of MTT assay, immunofluorescence and flow cytometry. After incubation with P. gingivalis, antibacterial properties of MD and ND were determined by conventional culturing, live/dead staining and SEM. Results: The present study successfully created a nanostructured surface on commercially available machined titanium discs. The etching process created cavities with a 10-20 nm edge-to-edge diameter. MD and ND show similar adhesion forces equal to about 10-30 nN. The achieved nanostructuration reduced the cell alignment along machining structures and did not negatively affect the proliferation of gingival fibroblasts when compared to MD. No differences in the expression levels of both actin and vinculin proteins, after incubation on MD or ND, were observed. However, the novel ND surface failed to show antibacterial effects against P. gingivalis. CONCLUSION: Antibacterial effects against P. gingivalis cannot be achieved with nanocavities within a range of 10-20 nm and based on the piranha etching procedure. The proliferation of HGF-1 and the expression levels and localization of the structural proteins actin and vinculin were not influenced by the surface nanostructuration. Further studies on the strength of the gingival cell adhesion should be performed in the future. CLINICAL RELEVANCE: Since osseointegration is well investigated, mucointegration is an important part of future research and developments. Little is known about how nanostructures on the machined transgingival part of an implant could possibly influence the surrounding tissue. Targeting titanium surfaces with improved antimicrobial properties requires extensive preclinical basic research to gain clinical relevance.

Consumer vs. High-End 3D Printers for Guided Implant Surgery-An In Vitro Accuracy Assessment Study of Different 3D Printing Technologies.

This study evaluates the accuracy of drill guides fabricated in medical-grade, biocompatible materials for static, computer-aided implant surgery (sCAIS). The virtually planned drill guides of ten completed patient cases were printed (n = 40) using professional (Material Jetting (MJ)) and consumer-level three-dimensional (3D) printing technologies, namely, Stereolithography (SLA), Fused Filament Fabrication (FFF), and Digital Light Processing (DLP). After printing and post-processing, the drill guides were digitized using an optical scanner. Subsequently, the drill guide's original (reference) data and the surface scans of the digitized 3D-printed drill guide were superimposed to evaluate their incongruencies. The accuracy of the 3D-printed drill guides was calculated by determining the root mean square (RMS) values. Additionally, cast models of the planned cases were used to check that the drill guides fitted manually. The RMS (mean ± SD) values for the accuracy of 3D-printed drill guides were-MJ (0.09 ± 0.01 mm), SLA (0.12 ± 0.02 mm), FFF (0.18 ± 0.04 mm), and DLP (0.25 ± 0.05 mm). Upon a subjective assessment, all drill guides could be mounted on the cast models without hindrance. The results revealed statistically significant differences (p < 0.01) in all except the MJ- and SLA-printed drill guides. Although the measured differences in accuracy were statistically significant, the deviations were negligible from a clinical point of view. Within the limits of this study, we conclude that consumer-level 3D printers can produce surgical guides with a similar accuracy to a high-end, professional 3D printer with reduced costs.

Real-Time Guided Endodontics with a Miniaturized Dynamic Navigation System Versus Conventional Freehand Endodontic Access Cavity Preparation: Substance Loss and Procedure Time.

INTRODUCTION: This study aimed to evaluate substance loss and the time required for access cavity preparation (ACP) using the conventional freehand method (CONV) versus a miniaturized dynamic navigation system of real-time guided endodontics (RTGE) in an in vitro model using 3-dimensional-printed teeth. METHODS: Nine human anterior maxillary teeth were selected and micro-computed tomographic scanned. Root canals were virtually reduced to 2 mm below the cementoenamel junction. The teeth were digitally duplicated and mirrored to yield 6 different models with 6 single-rooted teeth each. The models were 3-dimensionally printed using radiopaque resin and consecutively mounted on a dental mannequin for ACP. Two operators with 12 and 2 years of clinical experience, respectively, received 6 models (36 teeth) each and performed ACP on half of the models using RTGE (after digital planning) and CONV on the other half 2 weeks later. The time was recorded. Postoperative substance loss was measured by cone-beam computed tomographic imaging. The differences in time and substance loss between the methods and operators were evaluated by the t test. RESULTS: Overall, substance loss was significantly lower with RTGE than CONV (mean = 10.5 mm3 vs 29.7 mm3), but both procedures took a similar time per tooth (mean = 195 vs 193 seconds). Operator 1 (more experienced) achieved significantly less substance loss than operator 2 with CONV (mean = 19.9 vs 39.4 mm3) but not with RTGE (mean = 10.3 vs 10.6 mm3). CONCLUSIONS: RTGE is a practicable, substance-sparing method performed in comparable time as CONV. Moreover, RTGE seems to be independent of operator experience.

Influence of a Novel Drill Design on Heat Generation During Conventional and Guided Implant Osteotomy.

PURPOSE: The aim of this in vitro study was to evaluate the temperature development of a novel, electropolished drill design during conventional and guided implant osteotomy in comparison to conventional drills under standardized conditions. MATERIALS AND METHODS: Single and sequential 12-mm-deep drilling protocols (guided and unguided) with a conventional (control groups) and novel drill (test groups) were performed in artificial bone blocks under external irrigation. Each drilling protocol was repeated 30 times with drill diameters of 2.2, 2.8, 3.5, and 4.2 mm. Temperature changes were recorded by an infrared camera, and the accumulated thermal energy was calculated. For group comparison, a one-way analysis of variance (ANOVA) and Tukey post hoc test were used with a level of significance set to = .05. RESULTS: The highest temperatures were measured up to 77.9°C for small-diameter drills in the control and test groups. The 3.5-mm and 4.2-mm novel drills showed significantly lower heat generation during guided and unguided osteotomy preparation for single and sequential drilling. The accumulated thermal energy during guided osteotomy preparation was significantly lower with the electropolished drills. CONCLUSION: The drill design has an important impact on heat development during osteotomy, which was most pronounced for guided osteotomy with conventional drills and for small-diameter osteotomies.

Suitability of Magnetic Resonance Imaging for Guided Endodontics: Proof of Principle.

INTRODUCTION: This proof-of-principle study aimed to demonstrate that magnetic resonance imaging (MRI) is sufficiently accurate for the detection of root canals using guided endodontics. METHODS: One hundred extracted human teeth (anterior and premolar) were mounted onto 5 mandibular and 5 maxillary models, fitted with splints designed to accommodate a thin layer of aqueous gel for indirect imaging, and scanned by MRI. After MRI and intraoral scans were aligned using planning software, access cavities were planned virtually, and templates were manufactured with computer-aided design/computer-aided manufacturing, the access cavities were prepared. Cone-beam computed tomographic scans were performed and matched with the virtual preoperative planning data to determine the accuracy of access cavity preparation in terms of deviation between planned and prepared cavities in the mesiodistal and buccolingual dimensions and angle. Descriptive statistical analysis was performed, and the mean values were compared using the t test. RESULTS: Ninety-one of 100 root canals were successfully scouted after MRI-guided access cavity preparation. The mean angle deviation was 1.82°. The mean deviation ranged from 0.21-0.31 mm at the base of the bur and from 0.28-0.44 mm at the tip of the bur. Preparation in the buccolingual dimension was significantly more precise in mandibular compared with maxillary teeth, and accuracy in the mesiodistal dimension was more precise in anterior teeth compared with premolars. CONCLUSIONS: This in vitro study demonstrated the suitability of MRI for guided endodontic access cavity preparation.

Thermal exposure of implant osteotomies and its impact on osseointegration-A preclinical in vivo study.

OBJECTIVES: Thermal and mechanical stresses during osteotomy preparation can impair implant osseointegration. This study investigated implant osseointegration following the measurement of temperature exposure during osteotomy drilling, varying drill design, sequence, and drill wear. MATERIALS AND METHODS: 36 tapered implants were placed in a mandibular minipig model after guided drilling of implant osteotomies using 4 different groups: (1) control drills with a conservative, sequential drilling sequence, (2) control drills using a shortened drill sequence (PF), (3) novel test drill displaying an optimized drill design and surface treatment, PF, and (4) aged test drill, PF. Intraosseous temperatures during drilling were measured using a temperature probe. BIC, fBIC, and tissue reactions were histomorphometrically derived after 2 and 8 weeks of healing. RESULTS: Compared to control drills (1) or (2), test drills (3) resulted in significantly lower maximum temperatures ((35.4 (CI 30.2-40.5)°C vs. (46.5 (CI 41.0-52.0)°C, p = .0021)) and shorter drill times ((4.5 (CI 1.6-7.3)sec vs. 10.3 (7.3-13.4)sec). Lower osteotomy temperature values and shorter drill times corroborated with significantly higher BIC after 2 and 8 weeks healing for the test (3) compared to control groups (2) (2 weeks: (44.9 (CI 34.1-55. 7)% vs. (31.3 (CI 20.5-42.2)%, p = <.0001 and 8 weeks: (73.7 ( CI 64.2-83.2)% vs. (66.2 (CI 57.0-75.4)%, p = <.0455). CONCLUSION: The improved osseointegration of implants placed after osteotomy preparation with novel test drills using a shortened drill sequence compared to standard drills and conventional drill protocols might be attributed to more favorable thermal profiles and less mechanical stress exerted on the bone surrounding the implant osteotomy.

Serious injuries and dental trauma in the line of police duty and their long-term consequences.

Confrontations between police officers and citizens have become almost commonplace in today's world. The propensity for violence towards police officers is an ongoing topic. Statistics show a clear increase in violent crimes of this nature. The aim of the present study was to evaluate police officers' risk of injury including orofacial involvement in the line of duty. One hundred and sixty-eight members of a regional police corps in northwestern Switzerland were interviewed with the help of an online questionnaire. The data were kept completely anonymous. Survey questions related to police officers' life on and off the job and focused on serious line-of-duty injuries (LODIs) that led to a loss of work time. LODIs resulting in work absences were not uncommon: 60.9% had been injured in the line of duty. During their free time, the officers showed a moderate risk-taking behavior (mean 50, IQR 30-67.2) and a slightly higher level of perceived risk of being injured while on duty (mean 59.1, SD 20). Most line-of-duty injuries occurred during the first 15 years of service. Among the injured police officers, the level of perceived threat of violence while on duty (mean 40, IQR 20-60) was higher than their non-injured colleagues (mean 50, IQR 21.2-60). The most commonly injured body parts were the hands (20.8%), head (14.9%) and knees (11.3%). Dental injuries were reported in only one case (0.6%). Greater work experience seems to improve the reactions and protective behavior of this occupational group in dangerous situations. Albeit the risk of being injured is high among police officers, dental trauma and orofacial involvement occurs rarely.

Dental trauma and tongue injuries in professional alpine ski racing-A worldwide survey.

BACKGROUND/AIM: Skiing is a sport with a medium risk of injuries, and injuries are increasingly common among professional alpine skiers. Examples of other medium-risk sports are for example handball, basketball, and karate. The aim of this study was to assess the frequency of dental trauma in professional alpine skiing and to determine whether the frequency of dental injuries is associated with a skier's performance level, alpine skiing discipline, and/or years of skiing experience. MATERIAL AND METHODS: A questionnaire consisting of 17 questions was distributed to professional male ski racers to gather information about their skiing discipline (category), performance level, and injuries, particularly dental trauma. RESULTS: A total of 161 out of 190 skiers returned the survey, with a response rate of 84.2%. Of these, 134 (83.2%) had suffered alpine ski racing-related injuries during their career and 38 (23.6%) reported skiing-related dental trauma-most commonly crown fractures (65.8%, n = 25), which mainly involved the maxillary or mandibular incisors (76.0%, n = 28). Ski racers with higher performance levels were more likely to experience dental injuries, but the difference in the frequency of dental trauma between participants in the speed versus technical category was not significant. Likewise, the number of years of ski racing experience did not impact the frequency of dental injuries. The participants rarely wore custom-made mouthguards (6.8%, n = 11). None of those who reported dental injuries were wearing a custom-made mouthguard when the injury occured. They preferred to wear chin guards, over-the-counter mouthguards, or no mouthguards. CONCLUSION: Professional alpine ski racing has a medium risk of dental trauma, which further increases with skier performance level. The participating skiers rarely wore custom-made mouthguards.

[Guideline Antibiotics in oral surgery]. / Leitlinie Antibiotika in der Oralchirurgie.

Antibiotics can be used in oral surgery. The effective benefits are offset by the dangers of resistance and sensitization, which requires a strict indication. There are controversial views regarding indication, dosage and, above all, duration and timing of antibiotic medication in oral surgery.

Status report on dental implantology in Switzerland. An updated cross-sectional survey.

A status report of dental implantology in Switzerland has already been performed in 1994 and 2006. The present study, based on these former surveys, aimed to update these results for the year 2016. To this end, a questionnaire was sent to all dentists in Switzerland who were members of the Swiss Dental Society (SSO) at the time of the survey. The questionnaire asked for personal background data and obtained information about the dentists' knowledge and concepts when using implants, the extent to which they used implants and about specific implant systems, which were selected based on the previous surveys. Out of 3,168 questionnaires, 1,446 were returned (return rate: 45.6%). Approximately 91% of the responding dentists had a practical involvement in implantology (implant placement only, superstructure insertion only, or both). Just over half of them (53%) placed more than twenty implants per year. Good handling was chosen by all dentists (100%) as a selection criterion for the implant system they used preferably. The current data suggested that the range of indications had widened, yet that the edentulous mandible was still the indication of choice. The percentage of dentists engaged in dental implantology doubled from 1994 to 2006 (1994: 42.2%, 2006: 82.2%). An increase of almost 10% in dentists involved in dental implantology was also apparent from 2006 to 2016 (2006: 82.2%, 2016: 91%). Our data show that, whilst the relative number of implant users had greatly increased among Swiss dentists, their rationale to place implants has remained similar.

Stability of screw-retention in two-piece zirconia implants: An in vitro study.

OBJECTIVES: To compare the stability of a screw-retained connection in a novel two-piece zirconia implant to a conventional titanium-based connection in an in vitro chewing simulation including artificial ageing. MATERIAL AND METHODS: Incisor (I) and molar (M) shaped monolithic zirconia crowns were screw-retained on either two-piece zirconia (test) or two-piece titanium (control) implants resulting in 4 groups of 8 samples (titanium implants with incisor-shaped crowns (T-I), titanium implants with molar-shaped crowns (T-M), zirconia implants with incisor-shaped crowns (Z-I) and zirconia implants with molar-shaped crowns (Z-M). These were subjected to artificial ageing by thermal cycling (TC: 2 × 3000 × 5°C/55°C cycles of 2 min) and mechanical loading (ML: 1.2 × 106 cycles of 50 N, f = 1 Hz). Surviving samples additionally underwent a fracture force test. Kaplan-Meier plots were drawn, and two-way ANOVA was calculated taking anatomical localisation and material variables as factors. RESULTS: The mean corresponding survival times were lower for T-M (0.86 × 106  ± 0.31 × 106 cycles) and Z-I (0.84 × 106  ± 0.21 × 106 cycles) compared to T-I (1.14 × 106  ± 0.10 × 106 cycles) and Z-M (1.20 × 106  ± 0.10 × 106 cycles). In one-way ANOVAs for survival time dependent on either location or material, no statistically significant differences could be found (location: p = .31; material: p = .62) in one-way ANOVAs. The interaction of location and material showed significant differences (F = 21.3, p < .001). CONCLUSION: The connection of the tested screw-retained zirconia crowns in two-piece zirconia implants is comparable to standard titanium implants in the specific in vitro testing.