Refine
Document Type
- Article (15)
Language
- English (15)
Has Fulltext
- yes (15)
Is part of the Bibliography
- no (15)
Keywords
- Acuris (2)
- clinical research (2)
- clinical study (2)
- dental implant (2)
- electrolytic cleaning (2)
- marginal bone loss (2)
- periimplantitis (2)
- Bacterial leakage (1)
- CAD/ CAM crown (1)
- CAD/CAM (1)
Institute
- Medizin (15)
Purpose: The aim of this study is to record material- and surface-dependent heat dissipation during the process of inserting implants into native animal bone. Materials and Methods: Implants made of titanium and zirconium that were identical in macrodesign were inserted under controlled conditions into a bovine rib tempered to 37 °C. The resulting surface temperature was measured on two bone windows by an infrared camera. The results of the six experimental groups, ceramic machined (1), sandblasted (2), and sandblasted and acid-etched surfaces (3) versus titanium implants with the corresponding surfaces (4, 5, and 6) were statistically tested. Results: The average temperature increase, 3 mm subcrestally at ceramic implants, differed with high statistical significance (p = 7.163 × 10−9, resulting from group-adjusted linear mixed-effects model) from titanium. The surface texture of ceramic implants shows a statistical difference between group 3 (15.44 ± 3.63 °C) and group 1 (19.94 ± 3.28 °C) or group 2 (19.39 ± 5.73 °C) surfaces. Within the titanium implants, the temperature changes were similar for all surfaces. Conclusion: Within the limits of an in vitro study, the high temperature rises at ceramic versus titanium implants should be limited by a very slow insertion velocity.
Purpose: All-ceramic restorations required extensive tooth preparation. The purpose of this in vitro study was to investigate a minimally invasive preparation and thickness of monolithic zirconia crowns, which would provide sufficient mechanical endurance and strength.
Materials and methods: Crowns with thickness of 0.2 mm (group 0.2, n=32) or of 0.5 mm (group 0.5, n=32) were milled from zirconia and fixed with resin-based adhesives (groups 0.2A, 0.5A) or zinc phosphate cements (groups 0.2C, 0.5C). Half of the samples in each subgroup (n=8) underwent thermal cycling and mechanical loading (TCML)(TC: 5℃ and 55℃, 2×3,000 cycles, 2 min/cycle; ML: 50 N, 1.2×106 cycles), while the other samples were stored in water (37℃/24 h). Survival rates were compared (Kaplan-Maier). The specimens surviving TCML were loaded to fracture and the maximal fracture force was determined (ANOVA; Bonferroni; α=.05). The fracture mode was analyzed.
Results: In both 0.5 groups, all crowns survived TCML, and the comparison of fracture strength among crowns with and without TCML showed no significant difference (P=.628). Four crowns in group 0.2A and all of the crowns in group 0.2C failed during TCML. The fracture strength after 24 hours of the cemented 0.2 mm-thick crowns was significantly lower than that of adhesive bonded crowns. All cemented crowns provided fracture in the crown, while about 80% of the adhesively bonded crowns fractured through crown and die.
Conclusion: 0.5 mm thick monolithic crowns possessed sufficient strength to endure physiologic performance, regardless of the type of cementation. Fracture strength of the 0.2 mm cemented crowns was too low for clinical application.
Diagnostic value of dynamic magnetic resonance imaging of temporomandibular joint dysfunction
(2021)
Background: To estimate the diagnostic value of dynamic magnetic resonance imaging (MRI) for the assessment of the temporomandibular joint (TMJ) compared to standard static MRI sequences in patients with TMJ dysfunction (TMD).
Methods and materials: This retrospective study included 71 patients with clinical diagnose of TMD. We acquired 5 static T1- and T2-weighted sequences in parasagittal and paracoronal views and one dynamic sequence (trueFISP) in parasagittal view for each TMJ. Image analysis included evaluation of morphology and function of intra-articular structures and rating of the dynamic images as more, equally, or less informative compared to static MRI sequences.
Results: Mean age was 35.0 ± 14.7 years and 50/71 (70.4%) were female. 127/142 (89.4%) TMJs were of diagnostic quality. 42/127 (33.1%) TMJs showed no disc displacement (DD), 56 (44.1%) had DD with disc reduction (DDwR), and 29 (22.8%) had DD without disc reduction (DDwoR). In 38/127 (29.9%) TMJs, dynamic images were rated “more informative”, in 84/127 (66.2%) “equally informative”, and in 5/127 (3.9%) “less informative” compared to solely static images. Overall, 27/71 (38.0%) patients benefited from additional dynamic sequences compared to solely static images. Dynamic images were “more informative” in TMJs with DDwR (23/56 [41.1%], p < 0.001) and in TMJs with DDwoR (13/29 [44.8%], p = 0.007), while it had no beneficial value for TMJ without DD. For evaluation of joint effusion, static T2-weighted images were rated better in 102/127 (80.3%) TMJs compared to dynamic images (<0.001).
Conclusion: Dynamic MRI sequences are beneficial for the evaluation of morphology and function of the TMJ compared to static sequences, especially in patients with temporomandibular disc displacement.
Background: Phobic patients avoid dental treatment impairing their oral health and making it challenging to offer them prosthetic rehabilitation. This study evaluated patients’ experience of implant-supported prosthetic treatment after implantation performed under general anaesthesia due to dental phobia and severe pharyngeal reflexes (SPR). The effect of gender, age and location of implantation on patient satisfaction was tested.
Methods: Two hundred five patients underwent implantation under general anesthesia both in maxilla and mandible, respectively. After a trans-gingival healing period of 6–8 weeks, fixed implant bridges were inserted. Patients completed oral health impact profile questionnaire (OHIP-14). An additional set of six special questions was also developed and considered. Analysis of the OHIP-14 total score was made using logistics regression. Wald chi-square test was used to analyse the effect of age, gender and location of implantation. Effect sizes were estimated as odds-ratios and associated 95% Wald confidence intervals.
Results: Eighty two of 205 patients were included after prosthetic treatment. After start, 38 patients were excluded (4 died and 34 couldn’t be reached). OHIP-14-analyses were made by 43 patients (30–90 years). 67% of patients were totally satisfied with the whole implant rehabilitation (scoring 0). Mean of total score was 2.5. Only age affected significantly (p = 0.014) patients satisfaction. The obtained data indicate that younger patients (30–64 years) especially women are less satisfied (4.95) than older patients (0.3) for age group (65–90 years).Special questions’ data showed that 94.5% were satisfied with their treatment. 77.3% continued regular check-up after treatment and 96.9% would undergo the same treatment again. 95.5% would recommend implants to a friend of colleague.
Conclusion: Gender and location of implantation have no significant influence on patient satisfaction. Younger patients especially women are less satisfied than older patients. Phobic patients are totally satisfied with implant rehabilitation under general anaesthesia which means that this treatment can be considered as a treatment of choice giving these patients the same opportunity like others to improve their oral health and well-being.
Objectives: The present randomized clinical trial assesses the six-month outcomes following surgical regenerative therapy of periimplantitis lesions using either an electrolytic method (EC) to remove biofilms or a combination of powder spray and electrolytic method (PEC).
Materials and Methods: 24 patients with 24 implants suffering from peri-implantitis with any type of bone defect were randomly treated by EC or PEC. Bone defects were augmented with a mixture of natural bone mineral and autogenous bone and left for submerged healing. The distance from implant shoulder to bone was assessed at six defined points at baseline (T0) and after six months at uncovering surgery (T1) by periodontal probe and standardized x-rays.
Results: One implant had to be removed at T1 because of reinfection and other obstacles. None of the other implants showed signs of inflammation. Bone gain was 2.71 ± 1.70 mm for EC and 2.81 ± 2.15 mm for PEC. No statistically significant difference between EC and PEC was detected. Significant clinical bone fill was observed for all 24 implants. Complete regeneration of bone was achieved in 12 implants. Defect morphology impacted the amount of regeneration.
Conclusion: EC needs no further mechanical cleaning by powder spray. Complete re-osseointegration in peri-implantitis cases is possible.
The aim of this systematic review and meta-analysis was to compare the peri-implant vertical bone loss of immediate loading of implant crowns using the one abutment at one time (AOT) protocol and implants with abutment removal (AR). This systematic review with meta-analysis was reported according to the PRISMA statement, with guidance from the Cochrane Collaboration Handbook. A total of 103 publications were identified in the PubMed database and reference lists of examined articles. After the screening of titles and abstracts, the eligibility of eight full-text articles was assessed. Five studies published between 2010 and 2015 were included in the meta-analysis. There was less peri-implant vertical bone loss at implants using an AOT protocol than at implants using AR protocol (WMD -0.19, 95% CI -0.26 to -0.13; p<0.0001; random-effects model). In conclusion, the use of the AOT protocol with platform-switched Morse implants results in less bone loss than do AR procedures, but this effect may not be clinically relevant. The preservation of marginal bone level achieved with the AOT protocol may not enhance the aesthetics. These results should be interpreted with caution.
Purpose: Bacterial biofilms are a major problem in the treatment of infected dental and orthopedic implants. The purpose of this study is to investigate the cleaning effect of an electrolytic approach (EC) compared to a powder-spray system (PSS) on titanium surfaces. Materials and Methods: The tested implants (different surfaces and alloys) were collated into six groups and treated ether with EC or PSS. After a mature biofilm was established, the implants were treated, immersed in a nutritional solution, and streaked on Columbia agar. Colony-forming units (CFUs) were counted after breeding and testing (EC), and control (PSS) groups were compared using a paired sample t-test. Results: No bacterial growth was observed in the EC groups. After thinning to 1:1,000,000, 258.1 ± 19.9 (group 2), 264.4 ± 36.5 (group 4), and 245.3 ± 40.7 (group 6) CFUs could be counted in the PSS groups. The difference between the electrolytic approach (test groups 1, 3, and 5) and PSS (control groups 2, 4, and 6) was statistically extremely significant (p-value < 2.2 × 10−16). Conclusion: Only EC inactivated the bacterial biofilm, and PSS left reproducible bacteria behind. Within the limits of this in vitro test, clinical relevance could be demonstrated.
Resorbable synthetic scaffolds are promising for different indications, espe- cially in the context of bone regeneration. However, they require additional biological components to enhance their osteogenic potential. In addition to different cell types, autologous blood-derived matrices offer many advantages to enhance the regenerative capacity of biomaterials. The present study aimed to analyze whether biologization of a PCL-mesh coated using differently centrifuged Platelet rich fibrin (PRF) matrices will have a positive influence on primary human osteoblasts activity in vitro. A polymeric resorbable scaffold (Osteomesh, OsteoporeTM (OP), Singapore) was combined with differently centrifuged PRF matrices to evaluate the additional influence of this biologization concept on bone regeneration in vitro. Peripheral blood of three healthy donors was used to gain PRF matrices centrifuged either at High (710× g, 8 min) or Low (44× g, 8 min) relative centrifugal force (RCF) according to the low speed centrifugation concept (LSCC). OP-PRF constructs were cultured with pOBs. POBs cultured on the uncoated OP served as a control. After three and seven days of cultivation, cell culture supernatants were collected to analyze the pOBs activity by determining the concentrations of VEGF, TGF-β1, PDGF, OPG, IL-8, and ALP- activity. Immunofluorescence staining was used to evaluate the Osteopontin expression of pOBs. After three days, the group of OP+PRFLow+pOBs showed significantly higher expression of IL-8, TGF-ß1, PDGF, and VEGF compared to the group of OP+PRFHigh+pOBs and OP+pOBs. Similar results were observed on day 7. Moreover, OP+PRFLow+pOBs exhibited significantly higher activity of ALP compared to OP+PRFHigh+pOBs and OP+pOBs. Immunofluorescence staining showed a higher number of pOBs adherent to OP+PRFLow+pOBs compared to the groups OP+PRFHigh+pOBs and OP+pOBs. To the best of our knowledge, this study is the first to investigate the osteoblasts activity when cultured on a PRF-coated PCL-mesh in vitro. The presented results suggest that PRFLow centrifuged according to LSCC exhibits autologous blood cells and growth factors, seem to have a significant effect on osteogenesis. Thereby, the combination of OP with PRFLow showed promising results to support bone regeneration. Further in vivo studies are required to verify the results and carry out potential results for clinical translation.
Purpose: Scientific evidence is limited regarding the long-term (>10 years) outcomes of large enough numbers of implants (>500) to allow for reliable comparison of subgroups. The purpose of this study was to analyze the outcomes of dental implants placed in an active University Clinic setting and followed for up to 20 years.
Materials and Methods: Data documenting the implant placement, prosthetic reconstruction, and annual follow-up of patients treated at Frankfurt University were extracted from a Structured Query Language database and patients’ written records and evaluated statistically.
Results: Between April of 1991 and May of 2011, 12,737 ANKYLOS® (DENTSPLY Implants Manufacturing GmbH, Mannheim, Germany) implants were placed in 4,206 patients for a variety of clinical indications. The Kaplan–Meier cumulative survival rate (CSR) was 93.3% after 204 months. Most of the failures (198/1.6%) occurred during the first year after implant placement and before prosthesis delivery. A significantly higher (p < .001) number of implants placed in the mandible and in hard quality bone failed than those placed in the maxilla or in weak and normal quality bone. Female patients had significantly higher CSRs (93.7% 204 months) than male patients (92.8% 204 months/p = .029). The implants showed low rates of peri-implant bone loss after 204 months (horizontal: 21 mm: 85.7%, vertical: 21 mm: 85.2%).
Conclusion: ANKYLOS dental implants followed for up to 20 years have high CSRs and low rates of peri-implant bone loss.
Purpose: To evaluate the prevalence of peri‐implantitis (PI) and peri‐implant mucositis (PM) in a long‐term follow‐up with comparison among different PI and PM definitions, and to report on the incidence of PI.
Materials and Methods: In a retrospective clinical study five different PI and PM definitions were applied onto a population with 274 implants 17 to 23 years postimplant placement. Recommendations by the Eighth European Workshop on Periodontology (EWOP) were used as base reference. Clinical and radiological measurements were considered. Risk factors were evaluated in a regression analysis.
Results: After an average observation period of 18.9 years, 40.1% of the implants were diagnosed with PM and 15.0% with PI (Eighth EWOP). PI incidence reached 7.9% on implant level and 13.2% on patient level. Implants diagnosed with PI and progressive bone loss displayed exceptionally vertical bone defect configuration (BDC). Diabetes mellitus, smoking, regular maintenance, or a former periodontal infection did not show significant influence on the prevalence of peri‐implant diseases. Patients with bruxism displayed significantly less PM and PI.
Conclusions: Vertical BDC seems to correspond with active PI, wherefore we estimate such a defining factor of importance. Diagnosis of PM and evaluation of probing pocket depths might be only of descriptive interest as they could lead to false‐positive results.