Biomedical subjects

Sven Reich

Publications and source records attributed to Sven Reich.

8 recordsLinked to original sources

PubMed2026

Marginal fit and five-year outcomes of posterior monolithic zirconia restorations: A randomized paired and observational clinical study.

OBJECTIVES: The aim of this study was to evaluate the marginal fit and five-year clinical performance of posterior 5 mol% yttria-partially stabilized zirconia restorations. A randomized paired comparison with lithium disilicate crowns was performed for marginal fit. METHODS: A total of 65 posterior restorations were placed in 38 patients, including 32 zirconia crowns, 17 lithium disilicate crowns, and 16 zirconia partial coverage restorations. In the randomized paired comparison, 17 patients received one lithium disilicate crown and one zirconia crown. Additional zirconia crowns (n=15) and zirconia partial coverage restorations (n=16) were included in a prospective observational cohort. The primary outcome was marginal fit within the randomized cohort. Marginal and internal fit were assessed using the replica technique. Marginal and internal gap values were compared using the Wilcoxon signed-rank test; clinical outcomes were analyzed descriptively, and Kaplan-Meier estimates were calculated for survival and complication-free survival. Clinical performance was assessed using CDA criteria, periodontal parameters, complication recording, and patient-reported outcomes. Clinical examinations were performed at baseline and at 12, 24, 36, 48, and 60 months. RESULTS: Mean marginal gap values at the crown margin were 46 ±33 µm for lithium disilicate crowns and 50 ±32 µm for zirconia crowns (p>0.05). No restoration required replacement, resulting in 100% restoration survival after a median follow-up of 60 months (range: 57-64 months). Most complications were biological or functional, including endodontic, periodontal, occlusal, and proximal-contact-related events. One zirconia partial coverage restoration exhibited a small ceramic fracture managed by polishing. The Kaplan-Meier probability of complication-free survival was 76.4% for zirconia crowns, 66.7% for lithium disilicate crowns, and 87.5% for zirconia partial coverage restorations. CONCLUSIONS: In the randomized paired comparison, 5 mol% yttria-partially stabilized zirconia crowns showed marginal gap values similar to lithium disilicate crowns. All restorations remained in situ during the observation period. Lower complication-free survival was mainly related to biological and functional events and should be interpreted separately from restoration survival. CLINICAL SIGNIFICANCE: Clinical evidence for posterior 5 mol% yttria-partially stabilized zirconia restorations remains limited. This study provides mid-term clinical data on crowns and partial coverage restorations. In the randomized full-crown comparison, marginal fit was similar to that of lithium disilicate crowns, supporting the clinical consideration of monolithic zirconia restorations for posterior teeth.

Humans↗

PubMed2006

Evaluation of two different teaching concepts in dentistry using computer technology.

The common teaching goal of two different phantom head courses was to enable the students to provide an all-ceramic restoration by the means of computer technology. The aim of this study was to compare these two courses with regard to the different educational methods using identical computer software. Undergraduate dental students from a single year were randomly assigned to two different courses. One course was a conventional teacher-centred course [TRAD]. The other course contained problem-based learning (PBL) oriented structured modules [HYBRID]. The students completed an evaluation based on a 25 item seven-point Likert scale. Two independent evaluators assessed the practical work. Differences between TRAD and HYBRID were tested for significance using the Mann-Whitney U-test (at p < or = 0.05). Both courses were rated as demanding. The HYBRID group rated those items significantly better, which focused on course atmosphere and student-teacher relationship. The TRAD group felt that their course was more satisfying. Practical results of the two groups did not differ significantly. Within the limits of the study it was revealed, that the HYBRID group was less satisfied with the own success although the learning conditions were rated better. This could be interpreted in two ways: (1) the PBL oriented course lead the students to more self skepticism to their own work or (2) due to increased intellectual demands and the lack of detailed guidelines the course was felt as more burdening.

Attitude of Health Personnel↗

PubMed2006

Enhanced sympathetic cardiac modulation in bruxism patients.

Sleep bruxism, an oral parafunction including teeth clenching and grinding, might be related to increased stress. To evaluate sympathetic cardiac activity in bruxism patients, we monitored cardiac autonomic modulation using spectral analysis of heart rate variability and compared results to those of age-matched healthy volunteers. In bruxism patients, sympathetic cardiac activity was higher than in volunteers. The increased sympathetic tone suggests increased stress and might be related to occlusal disharmonies.

Adult↗

PubMed2005

Dentist-time expenditure for two different adhesive all-ceramic systems.

OBJECTIVES: The purpose of this clinical investigation was to compare a chair-side adhesive all-ceramic system to a laboratory processed adhesive all-ceramic system with respect to quality and time expenditure for the dentist. METHODS: The same dentist treated 10 patients, who were each to receive two large posterior single tooth restorations of similar location and extent. One restoration was made in the laboratory by using the IPS Empress system [LAB], the other one was done chair-side by utilizing the Cerec system [CHAIR]. The time expenditure was measured for [LAB] and [CHAIR] and compared by the Wilcoxon signed rank test. The restorations were also evaluated according to the USPHS criteria. RESULTS: The mean time expenditure for the dentist with low-level assistance was 111:03 min [S.D.+/-24:09 min] for [LAB] and 115:31 min [S.D.+/-15:54 min] for [CHAIR]. Time expenditure with medium level assistance for the operator was 100:53 min [S.D.+/-23:59] for [LAB] and 105:50 [S.D.+/-15:28] for [CHAIR]. Assuming a high level of assistance, the mean time values were 53:11 min [S.D.+/-14:29] for [LAB] and 54:29 min [S.D.+/-09:21] for [CHAIR]. The baseline investigation according to the modified USPHS criteria did not reveal any differences between [CHAIR] and [LAB]. CONCLUSION: There were no statistical significant differences with respect to time expenditure or quality between [LAB] and [CHAIR] in this study.

Aluminum Silicates↗

PubMed2005

Clinical fit of all-ceramic three-unit fixed partial dentures, generated with three different CAD/CAM systems.

In this study, the hypothesis was tested that the marginal and internal fit of CAD/CAM fabricated all-ceramic three-unit fixed partial dentures (FPDs) can be as good as in metal-ceramic FPDs. Twenty-four all-ceramic FPDs were fabricated and randomly subdivided into three equally sized groups. Eight frameworks were fabricated using the Digident CAD/CAM system (DIGI), another eight frameworks using the Cerec Inlab system (INLA). Vita Inceram Zirkonia blanks were used for both groups. In a third group frameworks were milled from yttrium-stabilized Zirconium blanks using the Lava system (LAVA). All frameworks were layered with ceramic veneering material. In addition, six three-unit metal-ceramic FPDs served as control group. All FPDs were evaluated using a replica technique with a light body silicone stabilized with a heavy body material. The replica samples were examined under microscope. The medians of marginal gaps were 75 microm for DIGI, 65 microm for LAVA and INLA and 54 microm for the conventional FPDs. Only the DIGI data differed significantly from those of the conventional FPDs. Within the limits of this study, the results suggest that the accuracy of CAD/CAM generated three-unit FPDs is satisfactory for clinical use.

Aluminum Oxide↗

PubMed2004

Submental cutaneous sinus tract as a result of progressive peri-implantitis: a case report.

BACKGROUND: The aim of the present case report was to define diagnosis and treatment options of a submental cutaneous sinus tract as a result of a progressive peri-implantitis around mandibular dental implants in a patient with a history of oral squamous cell carcinoma. METHODS: Before the removal of the submental fistula, a panoramic radiograph and a computed tomography of the head and neck were assessed to identify the implants responsible for the cutaneous sinus tract and to exclude the presence of a tumor recurrence and lymph node metastases. The involved implants were removed, as there was a communication along them between the oral cavity and the cutaneous sinus tract resulting from progressive peri-implantitis. A histological examination of the excised fistula was carried out. RESULTS: The histological examination excluded a recurrence of the oral squamous cell carcinoma. The fistula completely consisted of granulation tissue without epithelialization. After affected implants were removed, the wound healing was uneventful. CONCLUSIONS: A panoramic radiograph is mandatory to identify the involved implants. Computed tomography, and excision of the fistula and a histological examination should be performed only in patients with a history of oral squamous cell carcinoma. Since the cutaneous sinus tract showed no epithelialization, it healed spontaneously after the removal of the responsible implants. Because of the large bony defect caused by progressive peri-implantitis leading to a communication of the oral cavity with the cutaneous sinus tract, more conservative treatment options with preservation of the implants could not be adopted in the present case.

Carcinoma, Squamous Cell↗

PubMed2002

The effect of multicolored machinable ceramics on the esthetics of all-ceramic crowns.

STATEMENT OF PROBLEMS: Computer-aided design/computer-assisted machining systems offer the possibility of fabricating restorations from one machinable ceramic block. Whether multishaded blocks improve esthetic results and are a viable alternative to individually stained ceramics has not been fully determined. PURPOSE: The aim of this investigation was to examine the effect of multishaded blocks on the esthetic appearance of all-ceramic CEREC crowns and compare these crowns with single-shade and stained restorations. MATERIAL AND METHODS: Ten subjects were included in this study. For each subject, 6 different crowns were milled with the use of a CEREC machine. One crown was milled from each of the following machinable ceramic materials: CEREC Vitablocs Mark II in classic colors; Vitablocs Mark II in 3D-Master colors; Vitablocs Mark II in either classic or 3D-Master colors, with additional staining; Megadenta Bloxx multishaded; Mark II experimental multilayer; and an experimental multilayer leucite ceramic. Three independent examiners assessed the esthetic appearance of crowns fabricated to match each subject's anterior tooth shade. A scale of 1 to 6 was used to score the shade match and esthetic adaptation of each crown, with 1 representing excellent characteristics and 3.5 serving as the threshold for clinical acceptability. The examiners' scores were averaged, and the mean values were analyzed with the Wilcoxon signed rank test (P<or=.05). RESULTS: Only individually stained Mark II restorations achieved a mean score below the threshold of 3.5 for all 10 subjects. These restorations were significantly more esthetic (P<or=.05) than restorations fabricated from all other materials except the Mark II experimental multilayer ceramic. The second best results were obtained for crowns made from single-shaded Mark II 3D-Master blocks: 6 out of 10 restorations were scored below 3.5. Two of the layered materials (Mark II experimental and Bloxx) followed with 5 acceptable restorations out of 10. CONCLUSION: Within the limitations of this study, the results provide no evidence that multicolored machinable ceramics improve the esthetics of all-ceramic crowns.

Aluminum Silicates↗

PubMedDate not supplied

Scanning electron microscope evaluation of CEREC II and CEREC III inlays.

In response to an increased public demand for esthetic restorations, dentists are using computer-aided design/computer-aided manufacture (CAD/CAM) technology to fabricate inlay/onlay, crown, and laminate veneers. This study evaluated the fit at the gingival margin of surface inlay restorations milled by the CEREC II as well as the more recently developed CEREC III. The marginal fit of inlays milled by the CEREC III was more accurate than the fit of those milled by the CEREC II, although both were within the ADA specifications of 50 micro.

Acetone↗