Temporary Restorations Research Articles

Immediate versus early loading of immediately placed bone-level tapered dental implants with hydrophilic surface in full arch maxillary rehabilitation: A pilot randomized clinical trial with 2-year follow-up.

This study aimed to compare implant stabilities between the immediate and early loaded, immediately placed bone-level tapered dental implants in the maxilla and to evaluate marginal bone loss (MBL), oral health-related quality of life (OHRQoL), and patient satisfaction at a 2-year follow-up. A pilot, prospective, randomized, controlled clinical trial was conducted on 24 maxillary failing dentition patients. The bone-level tapered implants of 12 patients were immediately loaded with temporary restorations, while the other 12 patients did not receive any kind of temporization. Implant-supported screw-retained complete porcelain-fused-to-metal prostheses were delivered to all patients in the seventh postoperative week. The insertion torque values of implants assigned to the immediate and early loading groups were 33.0 ± 4.87 and 29.26 ± 8.31 Ncm, respectively. The dynamics of implant stability changes from implant placement up to a 2-year follow-up were similar for both groups (Penguin®, p = 0.268; Ostell®, p = 0.552), while the MBL was at submillimeter level. The cumulative implant survival rate was 91.80% for immediately loaded implants and 97.22% for early loaded implants, without significant difference (p = 0.162). The total score on the Oral Health Impact Profile questionnaire significantly decreased over time in both groups, indicating improvement in OHRQoL (p < 0.001), and the high level of patient satisfaction remained after 2 years of function regardless of a loading protocol. Both loading protocols, immediate and early, of six immediately placed bone-level tapered dental implants are an adequate treatment choice for fixed rehabilitation of the maxillary failing dentition.

Increasing Vertical Dimension of Occlusion (VDO): Review.

The need to increase the Vertical Dimension of Occlusion (VDO) to restore lost dental function or optimise specific dental treatments is a common occurrence in daily dental practice. The common belief that the Vertical Dimension at Rest (VDR) is fixed hinders the development of restorations with a VDO that encroaches on or surpasses the interocclusal rest space (IRS), thereby preventing potential tissue damage to the masticatory apparatus. Recent studies have shown that the mandible rest position falls within a range termed as the "comfort zone". The range of this zone may vary from one person to another and within the same person over time due to factors such as age or health status. In this review, we have concluded that a permanent increase in the VDO, once indicated, is a safe procedure for dentulous patients. However, it is important to minimise the extent of the increase to simplify the prosthodontics treatment process. An inter-incisal increase exceeding 5 mm is seldom needed. Moreover, it is important to consider the functional, aesthetic, and biological elements associated with VDO. The biological and functional environment closely related to the VDO had great adaptive capacities, which have for a historically been underestimated. Patient adaptation has been observed in dentate patients, edentulous patients, and even cases involving implant-supported prostheses. Muscle relaxation and changes in muscle length are likely the primary adaptation mechanisms, rather than the restoration of the original VDO through dentoalveolar maturation. Intervention with a fixed restoration is more predictable and results in a higher and more rapid level of adaptation. Finally, the increase should include the entire arch to prevent relapse of the VDO to its previous value, and changes in VDO should be assessed by utilising temporary diagnostic restorations for a period before implementing definitive prostheses, in order to evaluate the adaptive muscle response.

Biological Effects of PMMA and Composite Resins on Human Gingival Fibroblasts: An In Vitro Comparative Study.

The use of temporary resin for provisional restorations is a fundamental step to maintain the position of prepared teeth, to protect the pulpal vitality and the periodontal health as well as the occlusion. The present study aimed at evaluating the biological effects of two resins used in dentistry for temporary restorations, Coldpac (Yates Motloid) and ProTemp 4™ (3M ESPE ™), and their eluates, in an in vitro model of human gingival fibroblasts (hGFs). The activation of the inflammatory pathway NFκB p65/NLRP3/IL-1β induced by the self-curing resin disks was evaluated by real-time PCR, Western blotting and immunofluorescence analysis. The hGFs adhesion on resin disks was investigated by means of inverted light microscopy and scanning electron microscopy (SEM). Our results suggest that hGF cells cultured in adhesion and with eluate derived from ProTemp 4™ (3M ESPE ™) resin evidenced a downregulation in the expression of the inflammatory mediators such as NFκB p65, NLRP3 and IL-1β compared to the cells cultured with Coldpac (Yates Motloid) after 24 h and 1 week of culture. Furthermore, the cells cultured with ProTemp 4™ (3M ESPE ™) after 24 h and 1 week of culture reported a higher cell viability compared to the cells cultured with Coldpac (Yates Motloid), established by MTS cell analysis. Similar results were obtained when hGFs were placed in culture with the eluate derived from ProTemp 4™ (3M ESPE ™) resin which showed a higher cell viability compared to the cells cultured with eluate derived from Coldpac (Yates Motloid). These results highlighted the lower pro-inflammatory action and improved cell biocompatibility of ProTemp 4™ (3M ESPE ™), suggesting a better performance in terms of cells-material interaction.

Clinical Longevity of Obturators in Patients with Jaw Defects: a Retrospective Cohort Study.

The primary objective of the present retrospective clinical study was to determine the survival time of obturators while analyzing possible influencing factors. This retrospective clinical cohort study analyzed the influence of various clinical factors on the survival probability of obturators and their follow-up outcomes using Kaplan‒Meier analysis. A total of 76 patients with 115 obturators were included in the study (47 men and 29 women, mean age 58.1 ± 18.1years). The mean observation time was 3.0 ± 4.5years (maximum 26.3years). A total of 40.9% (47) of all obturators observed had to be replaced. The survival rate after 5years was 79.5% for telescopic-crown-retained tooth-supported obturators, 86.9% for telescopic-crown-retained implant-supported obturators, 58.8% for removable full denture obturators, 22.1% for clasp-retained obturators and 0.0% for splints. The type of attachment, attendance at a regular follow-up and defect cause significantly influenced the survival of the obturators (p < .05). The findings obtained in this study support the recommendation of using implant-supported obturators. Telescopic-crown attachments, either tooth- or implant-supported, seem to be favorable in terms of survival time. Attendance at a strict follow-up program seems to have a major influence on the longevity of the obturators. The use of implant-supported obturators to cover permanent oral and maxillofacial defects is highly recommended. Additionally, the use of telescopic-crown attachments seems to be favorable in terms of survival time. Clasp-retained obturators and surgical splints should be used primarily for temporary restorations due to their shorter survival times.

Fully digital workflow of occlusal reconstruction treatment in a patient with congenital dentition defects.

Occlusal reconstruction is a critical intervention for patients with dental hard tissue defects, temporomandibular joint (TMJ) disorders, and jaw position abnormalities. Clinical efficiency and outcomes of these procedures have improved with advances in digital technologies. This case report aims to illustrate a comprehensive digital workflow for occlusal reconstruction in a patient with congenital dentition defects, emphasizing the application of digital technologies to enhance treatment outcomes. A 28-year-old woman with previously installed porcelain-fused-to-metal bridge restorations presented with a fractured prosthesis and TMJ symptoms. A multidisciplinary approach was adopted involving the use of digital facebow, intraoral scanners, digital smile design, and CAD/CAM technologies. The process included the extraction of defective restorations, temporary restorations to refine jaw position, and final permanent restorations. The digital workflow facilitated precise diagnostics and treatment, culminating in the successful installation of permanent restorations. Regular follow-ups at one- and three-months post-treatment confirmed stable occlusal function and high patient satisfaction. This case report showcases the potential of multiple digital technologies to streamline complex dental treatments and achieve high-quality results. The integration of digital technologies in occlusal reconstruction treatments offers significant benefits in terms of precision, patient comfort, and esthetic outcomes.

Role of hermetic coronal seal on the long term success of apexification in immature permanent teeth induced by calcium hydroxide based regenerative materials- A pilot study

: Calcium hydroxide with or without iodoform is commonly used for apexification in immature permanent teeth. Before permanent restoration, temporary restorative material is used for ensuring coronal seal at the tooth orifice. An ideal coronal sealing agent prevents micro-leakage and maintains aseptic root canal environment. : This study aims at assessing the role of coronal seal on the long term success of apexification in immature permanent teeth by calcium hydroxide.: 51 children between the age group of 8-10 years having open apex in permanent upper anterior(s) secondary to trauma were divided into three groups, each receiving calcium hydroxide based material for apexification. Children were evaluated clinically and radiographically and followed up for a period of nine months. Cavit was used as temporary restoration in all three groups. Cases with loss of coronal seal, failure in apexification and clinical flare ups were identified. The data were statistically analyzed by Z-test and Chi-square test.: Presence of good coronal seal was directly related with successful and uneventful apexification. Loss of coronal seal was mostly related with increased evidence of clinical flare up and failure in or delayed apexification. Both the results were found to be statistically significant.: Temporary restorative materials providing meticulous coronal seal is as important as the permanent restoration, for the long term success of apexification.

Coronal leakage of a new temporary restorative material: An invitro study

This invitro study aims to assess the potency of new temporatory restorative material Orafil LC with other temporary restoratives: Zinc oxide eugenol and Cavit G in preventing microleakage during the inter-appointment period of endodontic treatment.Endodontic access cavity was prepared on 60 premolar teeth and restored with 3 different temporary restorative materials in the respective groups. (n=20)The teeth were stored in methylene blue stain and were sectioned to be observed under a compound microscope at 1,2,3 and 7 days to access coronal microleakage and further investigations were under a scanning electron microscope. All the tested materials showed microleakage with maximum leakage in Zinc oxide eugenol followed by Cavit G and Orafil LC. Orafil LC showed the least microleakage.Orafil LC showed least microleakage when compared with other temporary restorative materials used in this study

Digital Protocol to Record Occlusal Analysis in Prosthodontics: A Pilot Study.

Background: Digital technologies enable the accurate replication of occlusion, which is pivotal for stability in maximum intercuspation and dynamic occlusion. CAD softwares generates standardized occlusal morphologies requiring significant adjustments. The consideration of individual mandibular movements during restoration leads to better functional integration. This pilot study evaluates the efficacy of a novel, fully digital protocol for occlusal analysis recording in prosthodontics. Methods: Patients needing single or multiple metal-free restorations were included. Teeth underwent horizontal finish line preparation, while restorations on implants were either directly screwed or used multi-unit abutments. A digital impression (Trios 3 Intraoral Scanner) captured the mouth's elements. Dynamic occlusion was recorded via Patient Specific Motion (PSM). After the placement and functionalization of temporary restorations, subsequent scans included various elements, and CAD software (Dental system) was used for the restoration design. Restorations were milled in monolithic zirconia, pressed from CAD/CAM-milled wax, and sintered. Results: An evaluation of 52 restorations in 37 patients indicated high accuracy in restorations manufactured via the fully digital workflow. Monolithic zirconia was predominantly used. Subtractive (17.3%) and additive (7.7%) occlusal adjustments were mainly chairside. Conclusion: This study underscores the efficacy of meticulous verification measures and a centric contact system in reducing the need for clinical occlusal refinements in prosthetic restorations.

Influence of fabrication method on the marginal fit of temporary restorations.

Computer-aided manufacturing (CAM) technology allows the use of different manufacturing techniques. This in vitro study aimed to evaluate the marginal fit of temporary restorations manufactured using conventional chairside methods, milling, and three-dimensional printing. Fifteen 3-element temporary restorations specimens were produced and categorized into three groups: non-digital, obtained using the conventional chairside method (GC); milled (GM); and three-dimensionally printed (GP). Marginal fit was assessed using scanning electron microscopy (SEM) performed under two conditions: one with only the central screw tightened, and the other with all three screws tightened. Horizontal misfit values were categorized as over-, equal-, and under-extended and qualitatively analyzed. Statistical analysis was performed using the Tukey-Kramer test (α=0.05). In the vertical assessment, three-dimensionally printed restorations demonstrated greater misfit than restorations obtained by milling and the conventional chairside method (P<0.05). In the horizontal assessment, the misfit in the GP group was significantly higher than that in the GM and GC groups. Restorations obtained using the conventional chairside method and milled provisional restorations showed more favorable results than three-dimensionally printed restorations.

Experience of oral rehabilitators on the techniques and materials used in temporary restorations

Provisional restorations are temporary dental interventions that protect the tooth from thermal and chemical changes, in addition to restoring its anatomy and aesthetic functionality for a short period. These are performed with different techniques and materials, selected according to the patient's clinical situation and the dentist's criteria. Using a qualitative descriptive approach, a structured interview with open questions was conducted with 10 oral rehabilitators, using intentional non-probabilistic sampling. It was found that provisional restorations should provide a good seal, isolate the preparation from the buccal environment, and be comfortable and esthetic. The materials used must be easy to clean, resistant, bioactive, and promote dental remineralization, supporting occlusal loads and thermal changes to guarantee pulp protection and occlusal functions. Its proper use ensures the quality of the final restoration and allows effective oral hygiene. The materials are selected by the dentist according to the patient's needs, such as their economic situation and the condition of the tooth, and the experience with provisional restorations has been positive, allowing quality results. To avoid complications, a temporary that is easy to handle is required, which guarantees a good seal and facilitates cleaning

Мініінвазивні методи відновлення зубів в терапевтичній стоматології

Abstract. Photopolymer composite materials have unprecedented adhesion to hard tooth tissues and correspond to the optical properties of enamel and dentin. Due to these characteristics, photopolymers are widely used in aesthetic dentistry. The purpose of this work is to evaluate the results of the step-by-step acquisition by the dentist of the manual skills of using photopolymer materials. Methods of working with dental materials on models and in the oral cavity were used. The results showed that the technique of working with modern photopolymers requires excellent manual skills, mastering them and their improvement continues constantly with the appearance of new, more advanced tools and methods of treatment in dentistry. One of the effective ways of mastering innovative work methods is the production of temporary restorations from various materials. Conclusions. During the training stages of the dentist, in cases of remote temporary filling, a mini-invasive effect can be used, since it practically does not lead to the risk of damage to the tooth and involves the manufacture of an aesthetic restoration in the future in accordance with the protocol for the treatment of permanent teeth. Key words: photopolymer materials, minimally invasive treatment, manual skills, aesthetic restoration, adhesion.

Impact of different CAD software programs on marginal and internal fit of provisional crowns: An in vitro study

Statement of the problemDifferent CAD software programs used for designing crowns show variations in marginal and internal fit. Marginal and internal discrepancies may cause poorly fitting crowns. PurposeThe aim of this study was to compare the marginal and internal fit of single crown temporary restorations designed using three different CAD software programs. Materials and methodsDentbird, Exocad and Inlab 20 were used to design temporary single crowns using the same cement gap. Three experimental groups (n = 10/group) were formed based on the CAD software used. Geomagic Control X three-dimensional analysis software was used to compare the marginal and internal fit among the groups. Measurements were obtained at nine different thickness points. IBM SPSS Statistics, version 22 was used for all statistical analyses. ResultsAmong the CAD software programs tested, Dentbird produced the best internal fit on the buccal surface and the best marginal fit on both buccal and mesial surfaces. Exocad achieved the best values on the distal surface for both internal and marginal fit, while Inlab showed the best values on the mesial surface for internal fit and on the palatal surface for marginal fit. ConclusionsThe Dentbird CAD software program provided the most accurate fit values that closely matched the design. The marginal and internal fit oftemporary crowns may vary depending on the CAD software used.

Common Temporization of Access Cavity and Pulp Spacers Practiced by Endodontists in Saudi Arabia: A Cross-sectional Study

Background: Temporary restorations are necessary for preventing coronal leakage during and after treatment completion and must provide an effective barrier against salivary contamination of the root canal system. Endodontic spacers also help remove temporary restoration by avoiding the chances of unwanted intact tooth structure loss and perforation on the floor of the pulp chamber and prevent temporary restorative materials entrapment into the root canals resulting in canal blockage. However, the cotton pellet placed between the temporary and the root canal orifice can compromise the coronal seal by the reduction in thickness of temporary restoration. Objective: The primary aim of this investigation was to determine the most common temporary restoration used during and after endodontic treatment. The secondary aim is to know the percent preference for restorations with double seal and the frequency of spacer used. Methods: Four hundred fifty online questionnaires comprising 15 (four demographic questions and eleven questions related to the study objective) were sent to endodontists in Saudi Arabia via WhatsApp and Twitter. Statistical significance was set at P&lt;0.05 when assessed using a chi-square test. Results: About 370 (82.22%) participants completed the survey. Glass ionomer cement (GIC) was most used as a temporary restoration among endodontists for both the anterior (53%) and posterior teeth (49.7%; P=0.001). In double seal, Cavit was most used as the temporary restoration, which was placed below the seal exposed orally 56.2% (P=0.001). GIC was most used as coronal seal material placed over Cavit in 71.9% of the participants (P=0.001). About 56.2% of the endodontists placed cotton pellets between visits but not after obturation (P=0.001). Polytetrafluoroethylene tape instead of cotton pellet was preferred by 30.3% of the participants (P=0.001). Conclusion: Glass ionomer cement (GIC) was most used as a temporary restoration. In double seal, GIC was most used as coronal seal material placed over Cavit. A pulp spacer was found to be the most commonly used between visits but not after obturation.

Microleakage of Restorative Materials Used for Temporization of Endodontic Access Cavities.

A tight temporary seal applied to an access cavity is thought to improve endodontic outcomes. This study aims to assess the bacterial and glucose microleakage of different types and combinations of temporary restorations. Human-extracted incisors were instrumented, dressed with a calcium hydroxide paste, and sealed with Cavit W (CW), CW/Ketac Molar (CW/KM), CW/Smart Dentin Replacement (CW/SDR), Intermediate restorative material/KM (IRM/KM), or Clip F (CF). Standardized 3D-printed hollow test specimens were manufactured and temporized in the same manner. The specimens were examined for bacterial and glucose leakage for 28 days. Data were analyzed using a Kaplan-Meier survival analysis. CW/SDR and CF showed the least bacterial and glucose leakage over time. CW, CW/KM, and IRM/KM had similarly high levels of glucose leakage, but CW/KM and IRM/KM provided a tighter seal against bacterial penetration than CW. CW/SDR and CF should be considered for the sealing of access cavities of teeth previously restored with methacrylate-based materials.

Patient Satisfaction with Anterior Interim CAD-CAM Rehabilitations Designed by CAD Technician versus Trained Dentist—A Clinical Preliminary Study

The objective of this study was to assess the impact of digital waxing expertise on patient satisfaction with anterior interim computer-aided design and computer-aided manufacturing (CAD-CAM) prosthetic rehabilitations designed either by a CAD and dental technician or by a dental clinician with basic CAD-CAM training. This in vivo preliminary study was conducted on a total of 18 patients receiving anterior CAD-CAM rehabilitations (at least from canine to canine) with fixed bridges and/or single crowns. Only patients that had conventional chairside temporary restorations were enrolled. Three within-patient groups were defined at different time points: group CONTROL refers to all 18 patients at their first appointment, when they were using their initial temporary conventional prostheses; group DENT refers to all patients immediately after trying in a set of CAD-CAM prostheses designed by a dental clinician (with basic one-week CAD-CAM training); and group CAD refers to all patients after trying in a set of CAD-CAM prostheses for the same tooth elements but designed by an experienced CAD technician (who was also an experienced dental prosthetic technician). All CAD-CAM restorations were milled in polymethyl methacrylate (PMMA) with high translucency and strength properties (Prime, Zirkonzahn). Satisfaction with comfort and esthetics was assessed for all patients for the three different time points (groups CONTROL, DENT and CAD). Statistically significant differences among groups were assessed with the Friedmann’s test. Group CAD significantly outperformed the other groups in both assessed variables (p = 0.001). The group DENT, in turn, outperformed group CONTROL for satisfaction with esthetics (p = 0.006) but not for comfort (p &gt; 0.05). In conclusion, CAD operator background and expertise level significantly affect patient self-reported outcomes for anterior CAD-CAM rehabilitations. Single crowns and fixed bridges digitally designed by an experienced professional trained in both CAD-CAM and dental technology will likely offer high satisfaction and comfort to patients receiving anterior prosthetic rehabilitations.

Evaluation of the color stability of different temporary restorative materials

This study aimed to evaluate the color stability of different temporary restorative materials in contact with staining solutions, as well as to verify which one presents the highest resistance to staining. In this laboratory study, five types of temporary restorative materials were evaluated: self-curing acrylic resin, bis-acrylic resin, light-curing acrylic resin, CAD/CAM machinable, and 3D printed resin. Thirty samples of each material were produced in a circular mold measuring 10 mm diameter and 2 mm thickness. The materials were divided into subgroups (n=10) and immersed in solutions: Coffee, Coca-cola®, and distilled water (control). Color measurements were carried out at baseline, 1, 7, and 14 days using a digital spectrophotometer and the color parameters were calculated according to the CIEDE00 system. The color change data were subjected to two-way ANOVA (temporary material vs time) and post-hoc Tukey test (α = 0.05). The materials showed a color change only comparing baseline vs. one day, according to acceptability standard ΔE00 &gt; 1.8. Thus, we concluded that there was a difference in color stability already on the first day of immersion. In addition, the coffee solution showed the highest color variation when compared to the other solutions. Clinical applicability: Temporary restorations are widely used in prosthetic treatments and can remain in the mouth for a considerable period. They are responsible for aesthetic and function maintenance along the rehabilitation process. In addition, they provide data for the definitive prosthesis and should assure comfort and confidence to the patient. Thus, it is necessary that these materials are resistant and present such color stability that does not compromise the aesthetics during the treatment phase.

Microleakage Evaluation of Temporary Restorations Used in Endodontic Treatment-An Ex Vivo Study.

(1) Background: Coronal microleakage can lead to endodontic treatment failure. This study aimed to compare the sealing ability of different temporary restorative materials used during endodontic treatment. (2) Methods: Eighty sheep incisors were collected, uniformized in length, and access cavities were performed, except for in the negative control group, where the teeth were left intact. The teeth were divided into six different groups. In the positive control group, the access cavity was made and left empty. In the experimental groups, access cavities were restored with three different temporary materials (IRM®, Ketac™ Silver, and Cavit™) and with a definitive restorative material (Filtek Supreme™). The teeth were submitted to thermocycling, and two and four weeks later, they were infiltrated with 99mTcNaO4, and nuclear medicine imaging was performed. (3) Results: Filtek Supreme™ obtained the lowest infiltration values. Regarding the temporary materials, at two weeks, Ketac™ Silver presented the lowest infiltration, followed by IRM®, whereas Cavit™ presented the highest infiltration. At four weeks, Ketac™ Silver remained with the lowest values, whereas Cavit™ decreased the infiltration, comparable to IRM®. (4) Conclusion: Regarding temporary materials, Ketac™ Silver had the lowest infiltration at 2 and 4 weeks, whereas the highest infiltration was found in the Cavit™ group at two weeks and in the IRM® group at 4 weeks.

Cytotoxicity of 3D printed resin materials for temporary restorations on human periodontal ligament (PDL-hTERT) cells.

Various dental resin materials are available for the fabrication of temporary restorations using modern additive printing methods. Albeit these materials are placed for several months in intimate contact with dental hard and soft tissues, including the gingival crevice, there exists only insufficient evidence on the biocompatibility of these materials. This in vitro study aimed to delineate the biocompatibility of 3D printable materials on periodontal ligament cells (PDL-hTERTs). Samples of four dental resin materials for additive fabrication of temporary restorations using 3D printing (MFH, Nextdent; GC Temp, GC; Freeprint temp, Detax; 3Delta temp, Deltamed), one material for subtractive fabrication (Grandio disc, Voco) and one conventional temporary material (Luxatemp, DMG) were prepared with a standardized size according to the manufacturer's instructions. Human PDL-hTERTs were exposed to resin specimens or eluates of the material for 1, 2, 3, 6 and 9 days. For determination of cell viability, XTT assays were performed. In addition, the expression of the proinflammatory cytokines interleukin 6 and 8 (IL-6 and 8) was assessed in the supernatants with ELISA. Cell viability and the expression of IL-6 and 8 in presence of the resin material or their eluates was compared with untreated controls. Immunofluorescence staining for IL-6 and IL-8, as well as scanning electron microscopy of the discs after culturing, were performed. Differences between groups were analyzed with Student´s t-test for unpaired samples. Compared to untreated control samples, the exposure against the resin specimen induced strong reduction of cell viability in case of the conventional material Luxatemp (p<0.001) and the additive material 3Delta temp (p<0.001) irrespective of the observation period. On the contrary, the presence of eluates of the various materials induced only minor changes in cell viability. Considering IL-6 (day 2: p=0.001; day 6 and 9: p<0.001) and IL-8 (day 1: p=0.001; day 2, 3, 6, 9: p<0.001) their expression was strongly reduced in presence of the eluate of Luxatemp. Except for IL-6 at day 1 and 6 also the material 3Delta temp caused significant reduction of both proinflammatory mediators at any time point. The conventional material Luxatemp and the additive material 3Delta temp appear to severely affect cell viability when in direct contact with PDL-hTERTs. The other tested materials of this new category of additive materials and the subtractive material Grandio seem to induce only minor changes in direct contact with these cells. Therefore, they could serve as a viable alternative in the fabrication of temporary restorations.

Fracture Resistance Analysis of CAD/CAM Interim Fixed Prosthodontic Materials: PMMA, Graphene, Acetal Resin and Polysulfone

Four groups of ten samples were fabricated for each material. Each specimen was characterized by a compression test on a universal testing machine, all specimens were loaded to fracture and the value in Newtons (N) was recorded by software connected to the testing machine. The fracture mode was evaluated on all samples using a stereomicroscope. There were statistically significant differences (p value < 0.005) between PMMA and the other three materials (PMMA: 1302.71 N; GRA: 1990.02 N; RA: 1796.20 N; PS: 2234.97). PMMA presented a significantly lower value than the other materials, and PS showed the highest value. GRA and RA presented a similar range of values but they were still higher than those of PMMA. GRA, RA and PS are presented as valid options within the range of interim milled restorative materials and as alternatives to PMMA.

Retention force, translucency, and microstructural properties of translucent temporary luting cements: An in vitro study

The aim of the study was to investigate the retention behaviour (pull-off force include adhesive remnant index = ARI) as well as translucency of various temporary luting cements and use microstructure elucidation methods to formulate explanatory approaches to their mode of action.The retention force of the temporary luting cements Provicol QM Plus (P+), Provicol QM Aesthetic (Pae), Bifix Temp (BiT), and as a reference a glass ionomer cement Meron (M) with a direct (Structur 3/S3) or an indirect (Structure CAD/SCAD) resin-based composite restauration was investigated after accelerated aging (thermocycling). Additional investigation of the physical properties was performed regarding to translucency and surface free energy. The microstructure was evaluated by X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry and micro X-ray computed tomography.All tested temporary luting cements showed different pull-off forces in the range between 3.0 and 16.8 N in combination with S3 or SCAD after thermocycling. Only BiT with S3 showed pull-off forces of 129.2 N and complete retention on the restoration (ARI = 0), which was significant (p < .001) to all other samples. High translucency (BiT > Pae > M > P+) was observed for materials with lower crystalline content and low residual mass (usally resulting from higher organic content). M showed the highest surface free energy with a predominantly polar fraction, while BiT had a predominantly dispersive fraction. The highest porosity was observed in the coronal region of the restoration.The results suggest that translucency of temporary luting cements can be increased with higher organic and lower cryristall content. All combinations of cements and temporary restorations (direct/indirect; with the exception of BiT/S3) showed pull-off forces below 17 N (equivalent to a weight force of ∼1.7 kg), which allows manual detachment of the restoration by the dentist.