Longevity of gold restorations in posterior teeth: A retrospective study up to 10-years.

OBJECTIVE: In this retrospective clinical study, we investigated the long-term survival and success of indirect gold restorations, placed by undergraduate students. MATERIAL AND METHODS: The study included 72 gold restorations in 45 patients, placed in a five-year period between 2009 and 2013. Two experienced dentists performed the evaluation following the FDI criteria after 5 to 10 years. Kaplan-Meier test was used for longevity analysis of success and survival. Data were tested for normality with Shapiro-Wilk test. Cox regression analysis, with significance level appointed at p ≤ .05, was performed using success and survival of restorations as dependent variables. Annual failure rates (AFRs) were calculated. RESULTS: Overall, 72 indirect gold restorations prepared in posterior teeth were assessed, with an observation time from 63 months to 117 months. The mean service time was 88.1 months and the median 87 months. No failures, but 2 repairs, were observed during the first five years. From 5 to 10 years 1 replacement and 1 more repair occurred. The survival and success rates of gold restorations were calculated at 9 years with 98.6% and 91%, respectively. Restorations placed on premolars had higher survival and success rates compared to molars. Three cases were categorized as repairs: in two cases, a root canal treatment was needed and, in one other, an occlusal perforation of the restoration was observed. CONCLUSIONS: Posterior indirect gold restorations placed by dental undergraduate students showed a highly predictable clinical performance in terms of success and survival. These results are comparable with survival rates reported in literature for restorations cemented in general dental practices. CLINICAL SIGNIFICANCE: Casted gold restorations placed from dental students in an undergraduate setting show high survival rates, similar to professional dentists.

A comprehensive in vitro comparison of the biological and physicochemical properties of bioactive root canal sealers.

OBJECTIVES: To evaluate the biological and physicochemical features of bioactive root canal sealers. MATERIALS AND METHODS: Human periodontal ligament fibroblasts (hPDLF) and human osteoblasts (hOB) were exposed to eluates of three bioactive root canal sealers, GuttaFlow® bioseal (GF), BioRoot™ RCS (BR), and TotalFill® BC Sealer (TF), and the epoxy resin-based sealer AH plus® (AH). Cytotoxicity and cellular inflammatory response were evaluated. The osteogenic potential was examined using human mesenchymal stem cells (hMSC). Film thickness, flowability, and pH were assessed. Root canal treatment was performed on human extracted teeth to evaluate the sealers' tightness towards bacterial penetration. The antibacterial activity against common pathogens in primary root canal infections was tested. RESULTS: AH was severely cytotoxic to hPDLF and hOB (p < 0.001). The bioactive sealers were generally less cytotoxic. IL-6 levels in hPDLF were elevated in the presence of AH (p < 0.05). AH and GF suppressed IL-6 production in hOB (p < 0.05). AH and BR stimulated the PGE2 production in hPDLF and hOB (p < 0.05). BR was the only sealer that led to calcium deposits in hMSC (p < 0.05). TF and AH showed the lowest film thickness and the highest flowability. Bacterial tightness was best in teeth filled with AH and BR. All sealers showed similar antimicrobial activity, but the overall antimicrobial efficacy was moderate as the bacteria were reduced by just one log scale (p < 0.05). CONCLUSIONS: This study revealed favorable in vitro results regarding the biocompatibility of the bioactive root canal sealers. CLINICAL RELEVANCE: Bioactive root canal sealers may be a useful alternative to epoxy resin-based sealers.

Longevity of lithium disilicate indirect restorations in posterior teeth prepared by undergraduate students: A retrospective study up to 8.5 years.

OBJECTIVES: To analyze retrospectively the clinical performance and survival of lithium disilicate inlays, partial crowns and crowns placed by undergraduate students. METHODS: 250 lithium disilicate posterior restorations (IPS™Emax Press) were evaluated. Mean service time was 6.6 years (79 months) with a maximum observation time of 8.5 years (102 months). Clinical performance was assessed using FDI Criteria. Descriptive statistics were used to display the distribution of the criteria. Success and survival of the restorations were calculated with the Kaplan Meier method. A Cox regression analysis was performed to detect influencing parameters for the survival or the success of the restorations. RESULTS: Survival and success rates of lithium disilicate indirect restorations were calculated at 6.6 years with 96.3 % and 93.8 %, respectively. After 8.5 years the survival rate was calculated with 94 % and the success rate with 83.8 %. 10 out of 250 restorations (4%) failed, while the main reasons for failure were fracture of material, debonding/loss of restoration, endodontic complications as well as recurrence of caries. A Cox regression analysis failed to show a correlation between restoration failure and the experience level of the students, an existing root canal treatment, type of tooth, bruxism or the use of rubber dam. CONCLUSIONS: Lithium disilicate indirect posterior restorations demonstrate a high success and survival rate after a mean service of 6.6 years when placed by undergraduate students with different levels of experience. Co-factors influencing the survival or success rate of these restorations could not be identified. CLINICAL SIGNIFICANCE: Lithium disilicate restorations show a good clinical performance up to 8.5 years when prepared by undergraduate students.

Efficiency of occlusal and interproximal adjustments in CAD-CAM manufactured single implant crowns - cast-free vs 3D printed cast-based.

PURPOSE: The aim of this study was to evaluate the efficiency of occlusal and interproximal adjustments of single implant crowns (SIC), comparing a digital cast-free approach (CF) and a protocol using 3D printed casts (PC). MATERIALS AND METHODS: A titanium implant was inserted at position of lower right first molar in a typodont. The implant position was scanned using an intraoral scanner and SICs were fabricated accordingly. Ten crowns (CF; n = 10) were subject to a digital cast-free workflow without any labside occlusal and interproximal modifications. Ten other identical crowns (PC) were adjusted to 3D printed casts before delivery. All crowns were then adapted to the testing model, simulating chair-side adjustments during clinical placement. Adjustment time, quantity of adjustments, and contact relationship were assessed. Data were analyzed using SPSS software (P < .05). RESULTS: Median and interquartile range (IQR) of clinical adjustment time was 02:44 (IQR 00:45) minutes in group CF and 01:46 (IQR 00:21) minutes in group PC. Laboratory and clinical adjustment time in group PC was 04:25 (IQR 00:59) minutes in total. Mean and standard deviation (±SD) of root mean squared error (RMSE) of quantity of clinical adjustments was 45 ± 7 µm in group CF and 34 ± 6 µm in group PC. RMSE of total adjustments was 61 ± 11 µm in group PC. Quality of occlusal contacts was better in group CF. CONCLUSION: Time effort for clinical adjustments was higher in the cast-free protocol, whereas quantity of modifications was lower, and the occlusal contact relationship was found more favourable.

Development and evaluation of an interdisciplinary teaching model via 3D printing.

The investigation aimed to assess the feasibility of creating an interdisciplinary training model simulating endodontic, restorative as well as implantologic treatment procedures by using 3D printing technology. A CBCT scan of the mandible of a real patient was initially taken. The generated DICOM-data were converted to a STL-file, which was further processed to design spaces for exchangeable replica teeth, a bone segment and an adapter to fix the model in a mannequin's head. After the manufacturing process, the model was evaluated by dental students performing a root canal treatment, the insertion of a glass fibre post and the insertion of an implant. The workflow allowed a simple and cost-effective way of manufacturing a single model, which is suitable for several training scenarios in the fields of endodontics, prosthodontics and implantology. The model was rated as being comparable to the real patient situation and offers repetitive treatment simulations. The present workflow is a feasible way of using DICOM-data and 3D printing for an interdisciplinary training model. The dental schools can design models according to their own curriculum and put the focus on a patient centered education.

A detailed report on the measures taken in the Department of Conservative Dentistry and Periodontology in Munich at the beginning of the COVID-19 outbreak.

OBJECTIVES: The corona disease (COVID-19) is developing into one of the greatest challenges for healthcare professionals around the world. In this article, we report the detailed actions taken in the Department of Conservative Dentistry and Periodontology, University Hospital, Ludwig-Maximilians-University (LMU), Munich, Germany, during the early phase of the COVID-19 pandemic. MATERIAL AND METHODS: After a joint on-site inspection of the dental clinic with the Department of Clinical Microbiology and Hospital Hygiene, existing clinical and hygiene protocols were adapted for COVID-19 patients. RESULTS: A comprehensive summary of the preparation of the facilities as well as pre- treatment, treatment and posttreatment protocols are described and arising problems are being discussed. CONCLUSIONS: The importance of rigorous hygiene and treatment protocols as well as a sufficient supply of PPE for dental offices and hospitals is highlighted. The measures reported may be subject to change due to the dynamics of the pandemic. CLINICAL RELEVANCE: The modes of transmission of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (e.g., droplets, aerosols, and fomites) can pose a risk for dental healthcare professionals and patients alike. The presented measures may guide dental faculties and dental practices during the early stage of the COVID-19 crisis.

Six-year results of a randomized controlled clinical trial of two glass ionomer cements in class II cavities.

OBJECTIVES: Long-term survival of two highly viscous glass ionomer cements (Fuji IX GP Fast and Equia Fil) over a period of 6 years in vivo. METHODS: A total of 85 two- or three-surface class II restorations, comprising 43 Equia Fil / Equia Coat and 42 Fuji IX GP Fast / Fuji Coat LC, were placed in 34 patients. The restorations were re-evaluated after 6 years using the FDI criteria. The statistical analysis was performed with Fisher's exact test, the Wilcoxon signed-rank test, the Mann-Whitney U test and the Kaplan-Meier method. RESULTS: Forty-four restorations (22 Equia Fil and 22 Fuji IX GP Fast) could be assessed at the 6-year follow-up. During the whole study period, eight failures, four for each material, were observed. The main reasons for failure were material fractures and retention loss, which were partly combined with poor marginal adaptation or poor proximal anatomical form. Two failures may be attributed to insufficient application of the materials, as suspected according to the radiographs. The Kaplan-Meier survival proportion for Equia Fil restorations at 6 years was 86.5% and that for Fuji IX GP Fast at 6 years was 86.8% (log-rank p = 0.907). During the period from 3 to 6 years, only one filling in each group failed. CONCLUSION: Both materials showed acceptable and comparable survival rates after 6 years. CLINICAL SIGNIFICANCE: Highly viscous glass ionomer cement can be an acceptable restoration material for smaller class II cavities.

Temperature changes on the root surface during application of warm vertical compaction using three different obturation units.

This study aimed to determine the temperature increase on the root surface during warm vertical compaction using three different obturation systems. Forty-five human single-rooted premolars were randomly assigned to one of three experimental groups of 15 teeth each for obturation with a System B unit, an Elements Obturation Unit, or a B&L SuperEndo Alpha II unit. All teeth were filled using the continuous wave of condensation technique with a set temperature of 200 °C. The temperature measurements were made with an infrared camera at 3 s (T0) and 1 min (T1) following activation of the heat plugger. T0 ranged between 48.1 and 84 °C depending on the obturation system. The mean value for T0 showed significant differences between various obturation systems (p = 0.001). The temperature increase on the root surface during the application of vertical compaction shows considerable variability depending on the obturation system.

Corrigendum: A 3-year controlled randomized clinical study on the performance of two glass-ionomer cements in Class II cavities of permanent teeth.

OBJECTIVE: To compare the clinical performance of two glass-ionomer cements in combination with two light-cured coatings in Class II cavities. METHOD AND MATERIALS: In total, 43 Equia Fil/Equia Coat and 42 Fuji IX GP Fast/Fuji Coat LC restorations were placed, in 34 patients. Only Class II cavities with two- or three-surface restorations were included. The clinical performance was evaluated at baseline, after 1, 2, and 3 years using the FDI criteria. For the statistical analysis, Fisher exact test, Wilcoxon signed-rank test and Mann-Whitney U test were applied. The success and survival of the restorations were calculated with the Kaplan-Meier method and a log-rank test was used to detect significant differences between the tested materials. RESULTS: At the 3-year recall, no significant differences could be detected between the two glass-ionomer cements for any of the evaluated criteria (Mann-Whitney U test, P > .05). When comparing the baseline with the recall data at 3 years for each material separately, significant changes could be observed in both materials for the criteria "surface luster," "fracture of material and retention," and "approximal anatomical form" (Wilcoxon signed-rank test, P < .05). Additionally, the Equia Fil restorations showed a notable change for the criteria "marginal adaptation" (Wilcoxon signed-rank test, P = .039). At the 3-year follow up, the Equia Fil and the Fuji IX GP Fast restorations exhibited an overall survival rate of 89.3% and 88.0%, respectively. Three fillings in each group failed. CONCLUSION: The two glass-ionomer cements tested performed similarly in Class II cavities in adult patients, with a moderate failure rate after 3 years. (Original article published in Quintessence Int 2019;50:592-602; doi: 10.3290/j.qi.a42692).

A 3-year controlled randomized clinical study on the performance of two glass-ionomer cements in Class II cavities of permanent teeth.

OBJECTIVE: To compare the clinical performance of two glass-ionomer cements in combination with two light-cured coatings in Class II cavities. METHOD AND MATERIALS: In total, 43 Equia Fil/Equia Coat and 42 Fuji IX GP Fast/Fuji Coat LC restorations were placed, in 34 patients. Only Class II cavities with two- or three-surface restorations were included. The clinical performance was evaluated at baseline, after 1, 2, and 3 years using the FDI criteria. For the statistical analysis, Fisher exact test, Wilcoxon signed-rank test and Mann-Whitney U test were applied. The success and survival of the restorations were calculated with the Kaplan-Meier method and a log-rank test was used to detect significant differences between the tested materials. RESULTS: At the 3-year recall, no significant differences could be detected between the two glass-ionomer cements for any of the evaluated criteria (Mann-Whitney U test, P > .05). When comparing the baseline with the recall data at 3 years for each material separately, significant changes could be observed in both materials for the criteria "surface luster," "fracture of material and retention," and "approximal anatomical form" (Wilcoxon signed-rank test, P < .05). Additionally, the Equia Fil restorations showed a notable change for the criteria "marginal adaptation" (Wilcoxon signed-rank test, P = .039). At the 3-year follow up, the Equia Fil and the Fuji IX GP Fast restorations exhibited an overall survival rate of 86.21% and 84.0%, respectively. CONCLUSION: The two glass-ionomer cements tested performed similarly in Class II cavities in adult patients, with a moderate to high failure rate after 3 years.

Clinical evaluation of the bulk fill composite QuiXfil in molar class I and II cavities: 10-year results of a RCT.

OBJECTIVE: The objective of this RCT was to compare the 10-year clinical performance of QuiXfil with that of Tetric Ceram in posterior single- or multi-surface cavities. METHODS: 46 QuiXfil (Xeno III) and 50 Tetric Ceram (Syntac classic) composite restorations were placed in 14 stress bearing class I and 82 class II cavities in first or second molars. Clinical evaluation was performed at baseline and after up to 10 years by using modified US Public Health Service criteria. At the last recall period, 26 QuiXfil and 30 Tetric Ceram restorations in 11 stress bearing class I and 45 class II cavities, were assessed. RESULTS: Ten failed restorations were observed during the follow-up period, four Tetric Ceram restorations failed due to secondary caries (2), tooth fracture (1) and bulk fracture combined with secondary caries (1) whereas six QuiXfil restorations failed due to secondary caries (1), tooth fracture (2), secondary caries combined with restoration fracture (1), restoration fracture (1) and postoperative sensitivity (1). Fisher's exact test yielded no significant difference between both materials (p=0.487). SIGNIFICANCE: Both materials, bulk fill QuiXfil restorations and Tetric Ceram restorations, showed highly clinical effectiveness during the 10-year follow-up.

Evaluation of the interface between gutta-percha and two types of sealers using scanning electron microscopy (SEM).

OBJECTIVES: The aim of the present study was to evaluate the adaptation of a calcium silicate bioceramic (BC) sealer with either BC or conventional gutta-percha compared with that of AH Plus sealer in different root canal sections. MATERIALS AND METHODS: Seventy-two extracted mandibular premolars were divided randomly into six groups. After standardised chemomechanical preparation, four groups were obturated with the BC sealer and BC gutta-percha or conventional gutta-percha, and the other two groups were obturated with AH Plus sealer and conventional gutta-percha either in lateral compaction or in a single cone technique. Each root was sectioned into three sections. An impression was made from each section, and replicas were then made for scanning electron microscopy (SEM) analysis. Areas and interfacial gaps were identified using image analysis software. In addition to descriptive and explorative data analyses, linear regression analysis was performed. RESULTS: All specimens had measurable interfacial gaps. Significantly fewer gaps were found between conventional gutta-percha and sealer compared to those observed when using the BC gutta-percha (p < 0.001). However, minor interfacial gaps between sealer and dentin were observed with the BC sealer (p = 0.04). The technique of obturation in different root canal sections did not significantly affect the sealer adaptability. CONCLUSION: The type of gutta-percha as well as the sealer had a noticeable impact on the adaptability. CLINICAL RELEVANCE: Different obturation techniques will result in similar outcomes. However, within the limitations of the study, there seems to be no advantage in using the BC gutta-percha.

Long-term outcome of MTA apexification in teeth with open apices.

OBJECTIVE: This retrospective study aimed to collect information about the long-term outcome of apexification treatment with mineral trioxide aggregate (MTA) of teeth with open apices. METHOD AND MATERIALS: A total of 98 teeth in 79 patients (m:f = 1:1.3) who had completed endodontic apexification treatment with MTA between September 2005 and January 2014 at a university dental clinic were considered. Both initial treatments and retreatments of former root canal treatments other than apexification were included. All patients were invited for a standardized follow-up visit. Data regarding age, sex, tooth type, reason for treatment, detailed treatment protocol, clinical and radiographic findings, treatment quality, and outcome were also collected from the patients' records. Descriptive statistical analysis was performed. RESULTS: In the majority of cases, endodontic treatment was related to trauma with fracture (45/98, 45.9%) and luxation injuries (20/98; 20.4%), followed by unknown causes (12/98; 12.2%), retreatments (7/98; 7.1%), hypophosphatasia (7/98; 7.1%), and caries (1/98; 1%). In the beginning, the Periapical Index (PAI) showed pathologic findings with a PAI > 2 in approximately 50% of cases, while 25% presented with minor or an absence of findings. At the end of the observation period, more than 90% showed clinical-radiographic success, whereas eight teeth were associated with an elevated PAI. Only 5% of cases needed further dental treatment, such as root-end surgery or retreatment of the root canal treatment. CONCLUSION: Within the limits of this retrospective investigation, clinical and clinical-radiographic success of the apexification treatment appears to make this a good and reliable treatment option for teeth with open apices.

Full-length amelogenin influences the differentiation of human dental pulp stem cells.

BACKGROUND: Amelogenin is an extracellular matrix protein well known for its role in the organization and mineralization of enamel. Clinically, it is used for periodontal regeneration and, due to its finding also in predentin and intercellular spaces of dental pulp cells, it has recently been suggested for pulp capping procedures. The aim of this study was to analyse in vitro the effect of the recombinant human full-length amelogenin on the growth and differentiation of human dental pulp stem cells (hDPSCs). METHODS: Human DPSCs were treated with a supplement of amelogenin at a concentration of 10 ng/ml, 100 ng/ml and 1000 ng/ml. The groups were compared to the unstimulated control in terms of cell morphology and proliferation, mineralization and gene expression for ALP (alkaline phosphatase), DMP1 (dentin matrix protein-1) and DSPP (dentin sialophosphoprotein). RESULTS: Amelogenin affects hDPSCs differently than PDL (periodontal ligament) cells and other cell lines. The proliferation rate at two weeks is significantly reduced in presence of the highest concentration of amelogenin as compared to the unstimulated control. hDPSCs treated with low concentrations present a downregulation of DMP1 and DSPP, which is significant for DSPP (p = 0.011), but not for DMP1 (p = 0.395). CONCLUSIONS: These finding suggest that the role of full-length amelogenin is not restricted to participation in tooth structure. It influences the differentiation of hDPSC according to various concentrations and this might impair the clinical results of pulp capping.