Resin Prosthesis Research Articles

Maxillary Rehabilitation using the All-on-Four Technique and Computer-Guided Surgery: A Case Report

The aim of this study was to evaluate the clinical and radiographic outcomes of the All-on-4 technique in fully edentu-lous maxilla using R2GATE software for flapless, computer-guided surgery and immediate loading. Ten adult patients with fully edentulous maxilla, aged between 35 and 60 years, were included in the study between April 2021 and April 2022. The surgical procedure was performed under local anesthesia and followed the All-on-4 approach with immediate loading of implants using a screw-retained provisional acrylic resin prosthesis on the same day. Final prosthesis was de-livered four months after the surgery. Clinical and radiographic outcomes were evaluated at four- and twelve-months post-operation. The study reported a 95% implant survival rate using the All-on-4 technique. The mean marginal bone level was recorded at 0.35 mm and 0.66 mm during the 4 and 12-month follow-up periods, respectively. Fixed provi-sional prosthesis fracture, abutment, and prosthesis screw loosening were the most frequent mechanical complications reported. Within the limitations of this study, the use of computer-guided surgery in the All-on-4 technique seemed to be a promising treatment option with high implant survival rates that may help reduce post-surgical discomfort and me-chanical complications in the rehabilitation of the edentulous maxilla.

Dental implants in patients with ectodermal dysplasia: a computer guided quad zygomatic case report and literature review

Ectodermal dysplasia (ED) is a genetic disorder affecting anatomical structures with an ectodermal origin. The consequent alveolar bone anomalies and lack of teeth require a multidisciplinary approach to rehabilitate patients function and esthetics. To avoid bone grafting procedures the application of zygomatic implants was suggested for the upper jaw treatment. The advancements in three-dimensional (3D) radiology and the introduction of digital implant planning software could enhance the approach to zygomatic implants in ED patients. The present case report describes the quad zygomatic implant treatment of the edentulous maxilla of an ED patient by means of computer guided implant surgery. The patient reported previous failure of bone grafting procedures in the upper jaw. The implants were immediately loaded with a screw-retained complete-arch resin prosthesis. The patient was followed up for 1 year with no biological nor mechanical complications reported, but a slight bone resorption in the anterior zone was observed. Zygomatic implants could be a potential alternative treatment to bone grafting in upper jaw and the digital implant planning could enhance the surgical procedure.

Retention of titanium copings to implant-supported fixed dental prostheses.

The aim of this in vitro study was to assess the effects of using different cements and titanium copings designs on the retention of implant-supported fixed dental prostheses (IFDPs) using a pull-out test. Fifty zirconia (ZirCAD; Ivoclar Vivadent) and 20 prepolymerized denture acrylic resin (AvaDent) rectangular (36mm × 12mm × 8mm) specimens were milled to mimic the lower left segmental portion of the All-on-Four IFDPs. Cylindrical titanium copings (Variobase; Straumann) (V) were used in 2 prepolymerized denture acrylic resin groups (n = 10) while conical titanium copings (Straumann) (C) were used as a control group for zirconia with 4 groups using cylindrical titanium copings. Before cementation, the outer surfaces of all titanium copings and the intaglio bonding surface of prosthetic specimens were airborne-particle abraded. All specimens were cemented following the manufacturer's recommendations and instructions according to the experimental design. After artificial aging (5000 cycles of 5°C 55°C, dwelling time 20s; 150 N, 1.5Hz in a 37°C water bath), all specimens were subjected to retention force testing using a pull-out test using a universal testing machine and a custom fixture with a crosshead speed 5mm/min. Modes of failure were classified as Type 1, 2, or 3. Retention force values were analyzed by the t-test for the prepolymerized denture acrylic resin specimen groups, and 1-way ANOVA and the Tukey test for the zirconia groups at α = 0.05. Mean and standard deviation retention force values varied from 101.1±67.1 to 509.0±65.2 N for the prepolymerized denture acrylic resin specimen groups. The zirconia groups ranged from 572.8±274.7 to 1416.1 ±258.0 N. There is no statistically significant difference in retention force values between V and C specimens cementing to zirconia with Panavia SA cement (Kuraray Noritake) (p = 0.587). The retention forces and failure modes were influenced by the cement used (p < 0.05). Modes of failure were predominantly Type 2 (mixed failure) and Type 1 (adhesive fracture from prosthetic materials) except for the quick-set resin group (Type 3, adhesive failure from coping). When bonding IFDPs onto titanium copings, quick-set resin provided significantly higher retention force for prepolymerized denture acrylic resin prostheses. Conical and cylindrical titanium copings performed similarly when cemented to zirconia with Panavia SA cement under the same protocol. The stability of the bonded interface and retention forces between zirconia prostheses and titanium copings varied from the cement used.

Evaluation of separating media for autopolymerizing acrylic resin fabricated on 3D-printed acrylate-based resin dental casts

Statement of problemLimited data are available regarding the most suitable separating medium for fabricating dental acrylic resin prostheses or appliances on 3-dimensional (3D)-printed resin casts. PurposeThe purpose of this in vitro study was to investigate and evaluate different separating media in terms of the ease of removal and detail reproduction of an autopolymerizing acrylic resin fabricated on acrylate-based 3D-printed resin casts. Material and methodsA cube-shaped cast was designed with a built-in truncated cone-shaped hole and a V-shaped groove at the base. Seventy-five casts were 3D-printed using acrylate-based resin and assigned to 5 groups according to the applied separating media: Siliform BEA (silicone-based), IMPRIMO 3D (alginate-based), 3D Modellisolierung (wax-based), TECHNOSIL (alginate-based), and none (control). After the application of the separating media, the truncated cone-shaped holes in the specimens were filled with autopolymerizing acrylic resin. The efficacy of the separating media was evaluated according to the ease of removal on a scale of 1 to 3 and accurate detail reproduction of the V-shaped groove on a scale of 1 to 3 under ×6 magnification. The nonparametric Kruskal-Wallis rank test was used to identify significant differences among the separating media (α=.05). ResultsSignificant differences were found among the groups (P<.001). Siliform BEA and 3D Modellisolierung had the best mean rank in both the ease of removal and detail reproduction scores, which were significantly different from those of the alginate-based separating media (IMPRIMO 3D and TECHNOSIL) and the control group (P<.01). ConclusionsThe dedicated silicone- and wax-based separating media for 3D-printed casts exhibited the most favorable performance in terms of ease of removal and detail reproduction.

Fit analysis of stereolithography-manufactured three-unit resin prosthesis with different 3D-printing build orientations and layer thicknesses

Statement of problemPrinting conditions can affect the fit of a 3-dimensionally (3D) printed prosthesis. Therefore, it is important to determine the optimal printing conditions for stereolithography (SLA)-manufactured prostheses. PurposeThe purpose of this study was to analyze the fit according to the build orientations and layer thicknesses in SLA-manufactured 3-unit resin prostheses. Material and methodsSLA 3D printed prostheses were produced in 5 build orientations (0, 30, 45, 60, and 90 degrees) and 2 layer thicknesses (50 and 100 μm). Milled prostheses were fabricated from the same design. The mounted prostheses on the master model were scanned with microcomputed tomography (μCT). Data were processed with the NRecon software program. For quantitative analysis, marginal and internal fits were measured by using the imageJ software program in terms of the following metrics: absolute marginal discrepancy, marginal gap, cervical area, midaxial wall area, line-angle area, and occlusal area. Internal gap volume was also measured with the CTAn software program. For statistical analysis, ANOVA and Tukey HSD tests were used (α=.05). For qualitative analysis, μCT cross-sections were compared among groups, and intaglio surfaces were imaged with a scanning electron microscope. ResultsA layer thickness of 50 μm with build orientations of 45 and 60 degrees exhibited smaller mean gap values (P<.05) than the other conditions for all measurements except line-angle area and occlusal area. The scanning electron microscope images showed voids on the intaglio surfaces for the 0- and 90-degree groups. ConclusionsFor SLA 3D printed resin prostheses, a difference in fit occurred based on the printing conditions, although both 3D printed and milled prostheses showed a clinically acceptable fit. When an SLA 3D printed prosthesis is manufactured under appropriate conditions, a clinically acceptable fit can be obtained.

Protezat parciale termoplastike

Thermoplastic dentures are mainly used for the therapy of partial edentulism, but not only. They are made of flexible materials, that are more resistant to breaking, and thinner than classic resin prostheses or prostheses with metal con- struction. Due to their chemical composition and the man- ner of fabrication (by injection), they are suitable for cases that show allergies to the residual monomer of classic RPD or to allergens from the metals used for the fabrication of RMD with metal construction. They are more aesthetic because their clasps are made of the same material as the prosthesis, with the color of the tooth or gingiva. Not only RPD can be fabricated from thermoplastic materials, but also full dentures, clasps, fiber-reinforced fixed partial den- tures, temporary crowns and bridges, obturators, speech therapy devices, briquettes and orthodontic retainers, trays for taking a functional impression, occlusal splints, anti “sleep apnea” devices, gingival simulators and pros- thetic implant holders (abutments).

USE OF ACRYLIC RESIN PROSTHESES IN THE TREATMENT OF RHINOTHECAL FRACTURES.

This report describes the use of synthetic acrylic resin prostheses in five birds with rhinothecal fracture. Satisfactory biomechanical and clinical results were obtained in all cases, enabling early return to function of the beak. The patients, a roadside hawk (Rupornis magnirostris; case 1), a cockatiel (Nymphicus hollandicus; case 2), two turquoise-fronted parrots (Amazona aestiva; cases 3 and 4), and a maritaca (Pionus maximiliani; case 5), all suffered rhinothecal fractures with extensive bone loss, resulting in malnutrition, dehydration, and difficulty in handling food. An acrylic prosthesis was chosen in all cases, with the resin mold formed with two 1.0-mm pins in four cases, and cerclage wires in case 2. All birds made an excellent recovery and showed early use of the beak, with no complications for up to 15 mon. After 21 d of observation, the patients were moved to zoo enclosures for rehabilitation. The treatment of rhinothecal fractures is very challenging and requires a combination of orthopedic and dental techniques to provide full recovery of the species' natural functions.

Efficacy of a new membrane obturator prosthesis in terms of speech, swallowing, and the quality of life of patients with acquired soft palate defects: study protocol of the VELOMEMBRANE randomized crossover trial

BackgroundSoft palate defects created during oral cancer surgery may prevent complete palatal closure and trigger palatopharyngeal insufficiency. One current treatment employs a rigid obturator prosthesis; an extension of acrylic resin at the level of the hard palate ensures surface contact with the remaining musculature. Unfortunately, airflow escape often causes hypernasality, compromises speech intelligibility, and creates swallowing problems (including leakage of food and fluid into the nasal airway). We plan to test a new removable denture featuring a thick dental dam that serves as a membrane obturator. The principal objective of the clinical trial is a comparison of speech handicap levels after 1 month in patients with acquired velar insufficiencies who wear either the new device or a conventional, rigid obturator. The secondary objectives are between-device comparisons of the swallowing handicaps and the health-related qualities of life.MethodsThe VELOMEMBRANE trial is a superiority, open-labeled, two-way, random crossover clinical trial. Adult patients exhibiting velar or palatovelar substance loss after tumor excision and who are indicated for rigid obturator-mediated prosthetic rehabilitation will be recruited in two teaching hospitals in France. Fourteen participants will be randomly allocated to wear both prostheses for 1-month periods in either order. The new membrane obturator is a removable resin prosthesis incorporating a rigid extension that holds a dental dam to restore the soft palate. The primary outcome will be the extent of phonation-related disability (the overall score on the Voice Handicap Index [VHI]). The secondary outcomes will be the Deglutition Handicap Index and health-related quality of life scores of the European Organization for Research and Treatment of Cancer (EORTC).DiscussionHigh-quality evidence will be provided to document the utility of a new medical device that may greatly improve the management and quality of life of patients with acquired velar insufficiency.Trial registrationClinicalTrials.govNCT04009811. Registered on 4 July 2019

Effect of layer thickness and printing orientation on the color stability and stainability of a 3D-printed resin material

Statement of problemAlthough 3-dimensional (3D)–printed resin prostheses are widely used, studies on the effects of the manufacturing parameters of 3D printing on the color stability and stainability of these prostheses are lacking. PurposeThe purpose of this in vitro study was to investigate the effects of layer thickness and printing orientation on the color stability and stainability of a 3D-printed resin. In addition, the influence of roughness and water contact angle was evaluated. Material and methodsColor changes (ΔE00) in tooth-colored resin specimens produced by 3D printing with 2 different layer thicknesses and 3 different printing orientations and immersed in 3 types of aging media (distilled water, coffee solution, and wine) were evaluated (n=10). The CIELab color values were measured with a spectrophotometer at baseline and different time points (1, 3, 7, 15, and 30 days). The surface roughness (Ra) of resin specimens was measured at various time points (baseline, 7, 15, and 30 days) by confocal laser scanning microscopy after immersion in coffee solution (n=15). The water contact angle was determined by using the sessile drop method (n=10). The ΔE00 values were analyzed by using the 3-way repeated measures ANOVA followed by the Bonferroni test and Dunnett T3 test (α=.05). Ra values were analyzed by 3-way repeated measures ANOVA (α=.05). The water contact angle data were analyzed by 2-way ANOVA (α=.05). ResultsThe 3-way repeated measures ANOVA showed that layer thickness, printing orientation, and storage time significantly influenced the ΔE00 values of the 3D-printed resin specimens in each aging medium (P<.001). The ΔE00 values in the 0-degree subgroups were significantly lower than those in the 45- and 90-degree subgroups (P<.05). The ΔE00 values in the 25-μm thick groups were significantly higher than those in the 100-μm thick groups (P<.05). The ΔE00 values demonstrated an increase up to 15 days in all aging media. In distilled water, the ΔE00 values of the specimens increased or decreased depending on the groups, whereas in the coffee solution, the values decreased after 15 days (P<.001); in red wine, the values demonstrated a continuous increase up to 30 days in all groups (P<.001). The 3-way repeated measures ANOVA showed that the Ra values did not change significantly with immersion time (P=.444). The 2-way ANOVA showed that the water contact angle was not significantly affected by layer thickness (P=.921) or printing orientation (P=.062). ConclusionsLayer thickness and printing orientation affected the color stability and stainability of the 3D-printed resin. The discoloration of the 3D-printed resin differed with time, depending on the type of aging media used.

Cytotoxicity of Acrylic Resins, Particulate Filler Composite Resin and Thermoplastic Material in Artificial Saliva with and without Melatonin.

There is limited information on the effect of melatonin on the cytotoxicity of dental materials. The study evaluated the cytotoxic effects of heat- and auto-polymerized acrylic resin, particulate filler composite resin and a thermoplastic material on L-929 fibroblast cell viability at different incubation periods in artificial saliva without and with melatonin. Disk-shaped specimens were prepared according to each manufacturer’s instructions and divided into two groups to be stored either in artificial saliva (AS) and AS with melatonin (ASM). The measurements were performed using an MTT (3-(4,5)-dimethylthiazol-2-yl)-2,5-diphenyl tetrazoliumbromide) assay, in which the L-929 mouse fibroblasts cell culture was used. For the MTT test, extracts were examined at 1, 24, 72 h and 1 and 2 weeks. Data were analyzed using 3-way ANOVA and Tukey’s tests. No significant difference was found between groups AS and ASM (F = 0.796; p = 0.373). Incubation period significantly affected all materials tested (p < 0.001). Storing resin-based materials in artificial saliva with melatonin solution for 24 h may reduce cytotoxic effects on the fibroblast cells for which the highest effect was observed. Soaking resin prosthesis or orthodontic appliances in artificial saliva with melatonin at least 24 h before intraoral use or rinsing medium containing melatonin may be recommended for decreasing the cytotoxicity of dental resin materials.

Investigation of the marginal fit of a 3D-printed three-unit resin prosthesis with different build orientations and layer thicknesses.

PURPOSEThe purpose of this study was to analyze the marginal fit of three-unit resin prostheses printed with the stereolithography (SLA) method in two build orientations (45°, 60°) and two layer thicknesses (50 µm, 100 µm).MATERIALS AND METHODSA master model for a three-unit resin prosthesis was designed with two implant abutments. Forty specimens were printed using an SLA 3D printer. The specimens were printed with two build orientations (45°, 60°), and each orientation was printed with two layer thicknesses (50 µm, 100 µm). The marginal fit was measured as the marginal gap (MG) and absolute marginal discrepancy (AMD), and MG and AMD measurements were performed at 8 points per abutment, for 16 points per specimen. All statistical analyses were performed using SPSS software. Two-way analysis of variance (ANOVA) was separately performed on the MG and AMD values of the build orientations and layer thicknesses. Moreover, one-way ANOVA was performed for each point within each group.RESULTSThe margins of the area adjacent to the pontic showed significantly high values, and the values were smaller when the build orientation was 45° than when it was 60°. However, the margin did not differ significantly according to the layer thicknesses.CONCLUSIONThe marginal fit of the three-unit resin prosthesis fabricated by the SLA 3D method was affected by the pontic. Moreover, the marginal fit was affected by the build orientation. The 45° build orientation is recommended.

Temporary Implants and Particulate Dentin Graft Protecting Traditional Implants in Severe Periodontal Patient

Provisional implants (PIs) can offer a total contribution to a patient's esthetic comfort and chew during the integration of standard implants. Although temporary implants are not intended for osseointegration and have to withdraw at there or 4 months, most of them begin to move during this process, and most of them had extracted before standard implants integration. Resin fixed prosthesis attached to temporary implant abutments gives the patient stability, gives esthetics, and gives protection to traditional implants, compared to removable prostheses, which more quickly leads to the loosening and loss of these temporary implants. Temporary implants could be used with cemented or screwed resin prosthesis or with titanium framework, depending on the patient's bite, bruxism, or clenching. All PIs are made in one piece, titanium grade 5, with V threads and a Bioetched surface (rough surface) to increase the insertion torque and bone to implant contact in soft and hard bone. Temporary upper fixed denture, relined with resin, is the easiest solution for protecting and reducing the risk of failure of some of the standard implants. The possible solution in such cases is the use of temporary implants as support for the fixed structure, acting as protection of traditional implants and bone grafts. Our clinical case was made with six temporary implants TR® 2.7 mm diameter by 13 mm length, grinding extracted teeth using smart dentin grinder, and fixed temporary denture for 3 months. At 4 months, a complete zirconium denture was screwed in standard implants.

Implant survival and biologic complications of implant fixed complete dental prostheses: An up to 5-year retrospective study

Statement of problemLimited information is available on the association between prosthesis-associated risk factors and biologic complications for patients with implant fixed complete dental prostheses (IFCDPs). PurposeThe purpose of this retrospective study was to assess the implant survival and biologic complications of IFCDPs up to 5 years of follow-up. Material and methodsPatients who had received IFCDPs between August 1, 2009 and August 1, 2014 were identified through an electronic health record review. Those who consented to participate in the study attended a single-visit study appointment. Clinical and radiographic examinations, intraoral photographs, and peri-implant hard and soft tissues parameters were assessed. Only prostheses which could be removed during the study visit were included. Associations between biologic complications and prosthetic factors, such as time with prosthesis in place, prosthesis material, number of implants, cantilever length, and type of prosthesis retention, were assessed. ResultsA total of 37 participants (mean ±standard deviation age 62.35 ±10.39 years) with 43 IFCDPs were included. None of the implants had failed, leading to an implant survival of 100% at 5.1 ±2.21 years. Ten of the prostheses were metal-ceramic (Group MC) and 33 were metal-acrylic resin (Group MR). Minor complications were more frequent than major ones. Considering minor complications, peri-implant mucositis was found in 53% of the implant sites, more often in the maxilla (P=.001). The most common major biologic complication was peri-implantitis, which affected 4.0% of the implants, more often in the mandible (P=.025). Peri-implant soft tissue hypertrophy was present 2.79 times more often (95% CI: 1.35 – 5.76, P<.003) around implants supporting metal-acrylic resin prostheses than metal-ceramic ones, with the former type also showing significantly more plaque accumulation (P<.003). ConclusionsBiologic complications such as soft tissue hypertrophy and plaque accumulation were more often associated with metal-acrylic resin prostheses. Peri-implant mucositis occurred more often under maxillary IFCDPs, while peri-implantitis appeared more common around mandibular implants.

EVALUATION OF IMPACT STRENGTH OF HEAT CURE ACRYLIC RESIN REINFORCED WITH NYLON FIBER MESH WITH AND WITHOUT PRESTRESSING (IN VITRO STUDY)

INTRODUCTION: Acrylic resin prostheses are liable to high levels of forces due to their frequent removal by patients and accidental slippage. Hence, the impact strength of acrylic denture base material is of major significance in providing long-term functional prostheses.OBJECTIVES: The aim of this study was to evaluate the reinforcing effect of prestressed nylon fiber meshwork and the specimen thickness increase on the impact strength of heat cure acrylic resin.MATERIALS AND METHODS: 72 specimens were divided into 3 groups (I, II and III) which were heat cure acrylic resin (control), Nylon mesh reinforced acrylic resin and prestressed-nylon mesh reinforced acrylic resin. Each group was formed of 24 specimens, which were further subdivided into 3 subgroups (A, B and C) of different dimensions; 75 mm × 10 mm × 3 mm and 75 × 10 × 4 mm and 75 x 10 x 5 mm. Thus, the specimens were divided into 9 experimental subgroups (n=8 per subgroup). A Charpy’s impact tester was used to measure the impact strength of acrylic resin. The data were analyzed using Anova-test (p≤0.05).RESULTS: The mean impact strength of groups II and III was higher than the control group I impact strength. The difference between the reinforced groups and control group was statistically significant for all specimen thicknesses.CONCLUSIONS: The impact strength of heat cure acrylic resin was increased by the incorporation of nylon fiber mesh whether prestressed or not.

Investigation of Optimal Cement Space in 3D Printed 3-unit Resin Prosthesis: A Pilot Study

Investigation of Optimal Cement Space in 3D Printed 3-unit Resin Prosthesis: A Pilot Study

RESECTION OF A LARGE AMELOBLASTOMA: A CASE REPORT

Ameloblastoma is an odontogenic tumor that accounts for 1% of all facial tumors, is characterized by slow and painless growth, and is often diagnosed due to local volume increase or by routine radiography. A 34-year-old female patient attended the surgery service, reporting pain, dysphagia, dysphonia, and increased right hemiface volume for 10 years. Clinical examination revealed a large bulge in the right mandibular region, with firm consistency and palpation. Oral and lingual bulging caused tongue detachment, dental dislocation, and trauma in the lesion. Computed tomography revealed multilocular areas, bone expansion, and extension of the lesion to the contralateral molar region. An incisional biopsy was performed, which was diagnosed as a multicystic ameloblastoma with a plexiform pattern. The patient underwent immediate reconstruction of the area, using a customized acrylic resin prosthesis with a reconstruction plate 2.4. The patient is currently in the postoperative follow-up period, free of pain and rehabilitated with a total prosthesis.

Application of the palatogram technique to improve speech with complete-arch fixed implant-supported zirconia prostheses

While maxillary complete-arch fixed implant-supported prostheses are a popular treatment for patients with complete edentulism or with a terminal dentition, how speech is best optimized with this treatment is unclear. One popular method used in complete denture therapy for immediate improvement of speech, as well as to reduce the speech adaptation period for patients, is the use of a palatogram technique. Contemporary biomaterials such as zirconia used for complete-arch fixed implant-supported prosthesis are difficult to adjust and modify. Therefore, the purpose of this article was to describe the application of the palatogram technique during the evaluation stage of the maxillary screw-retained milled prototype prosthesis (interim acrylic resin prosthesis) to improve the palatal contours and optimize contact areas of the tongue with the palatal aspect of the prosthesis. The modified interim prosthesis can then be used for copy milling the definitive zirconia prosthesis. This technique is useful when other prosthodontic factors related to speech, such as the occlusal vertical dimension and tooth positions, have already been optimized.

Use of the natural products from the leaves of the fruitfull tree Persea americana against Candida sp. biofilms using acrylic resin discs

The search for natural substances such as plant extracts with antimicrobial properties has considerably increased, given that biofilms constitute a barrier against antifungal therapy, where these can be formed on any surface, such as acrylic resin prosthesis. The objective of this study was to identify the chemical composition of the Persea americana Mill. leaf ethanol extract (EEFPa) using the UPLC-QTOF-MS/MS technique, to verify its antifungal activity through a sensitivity test according to the conditions described in the documents in M27-A3 (CLSI, 2008) and M60 (CLSI, 2017), to induce biofilm formation in acrylic resin discs and quantify their formation using tetrazolium salt reduction (MTT), as well as to treat these with the extract and fluconazole. Ten of the twelve compounds present in the extract were identified. In the sensitivity test the lowest minimum inhibitory concentration observed was 512 μg/mL, while fluconazole concentrations ranged from 64 to 1 μg/mL. During biofilm induction, all the isolates were able to form biofilms within 48 h. During biofilm treatment, the extract was less effective at biofilm reduction than Fluconazole. The EEFPa showed significant antifungal activity against some of the strains in this study, however the extract showed lower effect when compared to fluconazole against the biofilm formation.

Tapered Screw Implants With Different Machined Neck Designs: A 3-Year Split-Mouth Randomized Controlled Prospective Study.

Tapered Screw Implants With Different Machined Neck Designs: A 3-Year Split-Mouth Randomized Controlled Prospective Study.

Effects of Printing Parameters on the Fit of Implant-Supported 3D Printing Resin Prosthetics.

The purpose of the study was to investigate the influence of 3D printing parameters on fit and internal gap of 3D printed resin dental prosthesis. The dental model was simulated and fabricated for three-unit prostheses with two implants. One hundred prostheses were 3D printed with two-layer thicknesses for five build orientations using a resin (NextDent C&B; 3D systems, Soesterberg, The Netherlands) and ten prostheses were manufactured with a milling resin as control. The prostheses were seated and scanned with micro-CT (computerized tomography). Internal gap volume (IGV) was calculated from 3D reconstructed micro-CT data. IGV, marginal fit, and lengths of internal gaps were measured, and the values were analyzed statistically. For the 3D printed prostheses, IGV was smaller at 45°, 60°, and 90° compared to other build orientations. The marginal fit evaluated by absolute marginal discrepancy was smaller than other build orientations at 45° and 60°. IGV was smaller at 50 µm layer thickness than at 100 µm layer thickness, but the marginal fit was smaller at 100 µm layer thickness than at 50 µm layer thickness. The 3D printed prosthesis had smaller internal gap than the milled prosthesis. The marginal fit of the 3D printed resin prosthesis was clinically acceptable, and build orientation of 45° and 60° would be recommended when considering fit and internal gap.