Influence of Denture Cleansers on the Retention Loss of Attachment Systems Retained Implant Overdenture.

Background: This study aimed to evaluate the effects of different denture cleansing solutions (DCSs) on the retention of Locator and Locator R-Tx attachment systems of implant retained overdentures (IRO). Methods: Two part acrylic resin blocks were fabricated, upper part contained metal housing and plastic inserts and lower part contained implant analogs and abutments. Eighty pink plastic inserts (40/attachment, 10/solution) were immersed in Corega, Fittydent, sodium hypochlorite, and water for a time simulating upto 1-year of clinical usage. Acrylic blocks were held on a universal testing machine for a pull-out test to record the dislodgement force. Measurements were conducted after 6 months (T1) and 12 months (T2). One-way ANOVA followed by Tukey's HSD test was used to analyze the results (α = 0.05). Results: For both attachments, retention significantly decreased after immersion in different solutions at T2 (P < 0.001). Locator R-Tx attachment in NaOCl showed a significant decrease in retention compared with other solutions at T1. At T2, there was a significant decrease in retention for all DCS compared with water (P < 0.001). Locator R-TX showed higher retention values per solution compared to Locator attachment (P < 0.001). In terms of retention loss %, NaOCl recorded the highest (61.87%) loss, followed by Corega (55.54%) and Fittydent (43.13%), whereas water demonstrated the best retention (16.13%) in both groups. Conclusion: Locator R-TX has better retention with different DCS immersion. The loss of retention varied with different types of DCS and NaOCl recorded the highest retention loss. Therefore, denture cleanser selection must be guided by the type of IRO attachment.

Evaluation of two implant-supported fixed partial denture abutment designs: Influence on screw surface characteristics.

PURPOSE: To compare screw surface characteristics between hemi-engaging and non-engaging implant-supported fixed partial denture (FPD) designs after cyclic loading. MATERIALS AND METHODS: Twenty-four implants measuring 4.3 × 10 mm were mounted on acrylic resin blocks. Specimens were divided into two groups. An experimental group included twelve 3-unit FPD with a hemi-engaging design; a control group included twelve 3-unit FPDs with the conventional design of two non-engaging abutments. Both groups were subjected to two types of cycling loading (CL), first axial loading, and then lateral loading at 30°. Load was applied to the units one million times (1.0 × 106 cycles) for each loading axis. Data on screw surface roughness in three locations and screw thread depth were collected before (BL) and after (AL) each loading type. Screw surface roughness was measured in µm using a mechanical digital surface profilometer and optical profiler. To evaluate screw thread depth in µm, an upright optical microscope Axio-imager 2 was used. To confirm readings made from the optical microscope, four random samples were selected from each group for scanning electron microscopy (SEM) analysis. The effect of cyclic loading was evaluated by averaging values across the two screws within each specimen, then calculating difference scores (DL) between BL and AL (DL = AL - BL). Additional difference scores were computed between the non-engaging screws in each experimental group specimen, and one randomly selected non-engaging screw in each control specimen. This difference was referred to as the non-engaging DL. Statistical significance was assessed using Mann-Whitney U tests (α = 0.05). RESULTS: Comparisons of DL and non-engaging DL by loading type revealed one significant difference regarding surface roughness at the screw thread. Significantly greater mean changes were observed after axial loading compared to lateral loading regarding both DL (axial M = -0.36 ± 0.08; lateral M = -0.21 ± 0.09; U = 20; p = 0.003) and non-engaging DL (axial M = -0.40 ± 0.22; lateral M = -0.21 ± 0.11; U = 29; p = 0.013). No significant differences in screw surface roughness in other sites or thread depth were found between the experimental and control abutment designs in DL or in non-engaging DL. No significant differences were found for DL (axial U = 13, p = 0.423; lateral U = 9, p = 0.150;) or non-engaging DL (axial U = 13, p = 0.423; lateral U = 18, p = 1.00). CONCLUSIONS: Results suggest that overall, changes in screw surface physical characteristics did not differ between hemi-engaging and non-engaging designs after evaluating screw surface roughness and thread depth before and after axial and lateral cyclic loading.

Fixed prosthetic rehabilitation of a patient with Papillon-Lefevre syndrome supported by a Quad Zygoma Approach: A clinical report.

Papillon-Lefevere syndrome (PLS) is a rare disorder with severe oral manifestations resulting in premature tooth loss at an early stage of life. As a result, extensive bone resorption pattern in the maxilla negates conventional implant treatment in the majority of cases. This clinical report describes a prosthetic rehabilitation revision of a 26-year-old female diagnosed with PLS using an implant supported fixed complete denture with a quad zygoma approach. A 1 year follow-up is also presented.

Effect of treated zirconium dioxide nanoparticles on the flexural properties of autopolymerized resin for interim fixed restorations: An in vitro study.

STATEMENT OF PROBLEM: Fractures of interim fixed restorations are a common complication. The autopolymerized polymethyl methacrylate resin materials used for interim fixed restorations have limited mechanical properties, but whether adding treated zirconium dioxide nanoparticles improves mechanical properties is unclear. PURPOSE: The purpose of this in vitro study was to evaluate the effect of treated zirconium dioxide nanoparticles on the flexural strength and elastic modulus of autopolymerized polymethyl methacrylate resin. MATERIAL AND METHODS: A split-metal mold (60×10×3.3 mm) was used to fabricate 40 autopolymerized acrylic resin specimens. The specimens were divided into 4 groups (n=10) according to zirconium dioxide nanoparticle concentration: control (unmodified resin) and zirconium dioxide nanoparticle contents of 1, 2.5, and 5 wt%. The specimens were mixed and polymerized according to the manufacturer's instructions and stored in distilled water for 48 ±2 hours at 37 °C. The flexural strength and elastic modulus were evaluated based on the 3-point bend test where data were analyzed by using 1-way analysis of variance and Tukey post hoc tests (α=.05). RESULTS: The flexural strength of the 1-wt% zirconium dioxide nanoparticle specimens was significantly higher than that of the control group (P<.001) but did not significantly increase further with the higher nanoparticle content (P>.05). Elastic modulus significantly decreased with 2.5-wt% zirconium dioxide nanoparticles (P=.019), while no significant changes were found with other test groups (P>.05). CONCLUSIONS: The addition of treated zirconium dioxide nanoparticles at low concentrations increased the flexural strength of autopolymerized polymethyl methacrylate resins used in fixed interim restorations.

Preload evaluation of 2 implant-supported fixed partial denture abutment designs.

STATEMENT OF PROBLEM: A hemi-engaging abutment design has been suggested to improve the stability of the implant-to-abutment interface compared with that of a fully nonengaging design to restore implant-supported fixed partial denture. However, controversy persists regarding the benefit of using a hemi-engaging abutment design and prompts the need for specific mechanical testing on the effect of these designs on screw preload under simulated clinical conditions. PURPOSE: The purpose of this in vitro study was to determine whether significant differences in preload values of the screw before and after cyclic loading exist between hemi-engaging and nonengaging abutment fixed partial denture designs. MATERIAL AND METHODS: Twenty-four conical connection implants measuring 4.3×10 mm (Nobel Biocare Replace Conical Connection; Nobel Biocare) were mounted in acrylic resin blocks. Specimens were divided into 2 groups. An experimental group included 12 three-unit fixed partial dentures with a hemi-engaging design; a control group included 12 three-unit fixed partial dentures with the conventional design of 2 nonengaging abutments. A digital screw torque meter was used to measure screw torque values per the manufacturer's recommendation of 35 Ncm. Reverse torque value was measured before cyclic loading and referred to as initial preload. After cyclic loading, reverse torque value was measured and referred to as final preload. The effect of cyclic loading was evaluated by averaging the reverse torque value across the 2 screws in each specimen and then calculating the changes between the initial preload and final preload. The difference between initial and final preload was referred to as reverse torque difference. An additional reverse torque difference, referred to as reverse torque difference-nonengaging, was calculated for the nonengaging screws in each experimental specimen and for 1 randomly selected screw of the 2 in each control specimen. Preload efficiency before and after cyclic loading was also calculated. All groups went through cyclic loading using a universal testing machine. The specimens went through axial loading first, and then the reverse torque value was measured. Twenty-four new abutment screws were then used, and the specimens then went through lateral loading at 30 degrees. Load was applied to the units (1.0×106 cycles) for each loading axis. The statistical significance of differences between the axial and lateral reverse torque difference and between the 2 groups of reverse torque difference and reverse torque difference-nonengaging were assessed using Mann-Whitney U tests (α=.05). RESULTS: A comparison of reverse torque difference between loading types revealed no significant difference (P=.773). Therefore, data for the 2 loading types were combined before comparing the reverse torque difference and reverse torque difference-nonengaging values between the 2 groups based on abutment design (12 hemi-engaging designs in the experimental group and 12 fully nonengaging designs in the control group). The experimental group mean reverse torque difference was -0.65 ±1.95 Ncm (range -4.0 to 2.4 Ncm), and the control group mean reverse torque difference was -2.5 ±5.44 Ncm (range -15.3 to 5.3 Ncm). No significant difference was found (P=.340). Furthermore, no significant difference was found between the reverse torque difference for the nonengaging screw in each of the 12 implants with a hemi-engaging design versus 1 randomly selected nonengaging screw in each of the 12 implants with a fully nonengaging design (P=.355). CONCLUSIONS: No significant difference was found in screw preload between a hemi-engaging and a full nonengaging 3-unit fixed partial denture supported by conical connection implant configurations before and after cyclic loading.

Impact of Polymerization Technique and ZrO2 Nanoparticle Addition on the Fracture Load of Interim Implant-Supported Fixed Cantilevered Prostheses in Comparison to CAD/CAM Material.

ZrO2 nanoparticles (ZNPs) have excellent physical properties. This study investigated the fracture load of implant-supported, fixed cantilevered prosthesis materials, reinforced with ZNPs and various polymerization techniques, compared with conventional and CAD/CAM materials. Sixty specimens were made from two CAD/CAM; milled (MIL) (Ceramill TEMP); and 3D-printed (NextDent Denture 3D+). Conventional heat-polymerized acrylic resin was used to fabricate the other specimens, which were grouped according to their polymerization technique: conventionally (HP) and autoclave-polymerized (AP); conventionally cured and reinforced with 5 wt% ZNPs (HPZNP); and autoclave reinforced with 5 wt% ZNPs (APZNP). The specimens were thermocycled (5000 cycles/30 s dwell time). Each specimen was subjected to static vertical loading (1 mm/min) using a universal Instron testing machine until fracture. Scanning electron microscopy was used for fracture surface analyses. The ANOVA showed significant fracture load differences between all the tested groups (p = 0.001). The Tukey post hoc tests indicated a significant difference in fracture load between all tested groups (p ˂ 0.001) except HP vs. HPZNP and AP vs. MIL. APZNP had the lowest mean fracture load value (380.7 ± 52.8 N), while MIL had the highest (926.6 ± 82.8 N). The CAD/CAM materials exhibited the highest fracture load values, indicating that they could be used in long-term interim prostheses. Autoclave polymerization improved fracture load performance, whereas ZrO2 nanoparticles decreased the fracture load performance of cantilevered prostheses.

Management of Buccal Screw Access Hole Positioning for Implant Fixed Complete Dentures: A Report of Two Patients and a Proposed Decision Tree.

The present report demonstrated the use of two methods to correct the positioning of buccal screw access holes in both implant- and abutment-level implant-supported fixed complete dentures in two patients. The report suggests that nonaxially tightened abutments (in this report, dynamic abutments), angled multi-unit abutments, and the use of a milled framework with individual crowns aid in masking buccal screw access holes while maintaining the benefits of a screw-retained design. A decision tree is also proposed to facilitate the workflow when faced with such clinical scenarios.

Healing of soft tissue lacerations in diabetic-induced rats.

BACKGROUND/AIM: Prevalence and incidence of diabetes are increasing and many dental trauma patients today have diabetes. The implications of delayed wound healing, associated with diabetes mellitus, on oral mucosal wound healing have not been investigated extensively. The aim of this study was to investigate the implications of diabetes mellitus on the cellular, vascular, and fibroblastic changes induced by laceration on the oral mucosa of Wistar rats. MATERIALS AND METHODS: Sixteen female Wistar rats were randomly assigned into two groups: 1. Experimental Streptozotocin-induced diabetic group (8 rats). 2. Control group (8 rats). A standardized laceration injury was induced from the corner of the mouth to the mid-check penetrating through dermal and oral mucosal contaminated by saliva. Samples were taken from the rats after sacrificing them on days 1,3,7, and 10. Inflammation was evaluated both qualitatively and quantitatively. Two investigators evaluated samples in a blinded manner. RESULTS: Histology reports indicated delayed wound healing patterns in diabetic rats through days 1, 3, 7, and 10 when compared to controls. Inflammation was also noted to be consistently present more often in diabetic rats. Furthermore, polymorphonuclear cell count was consistently higher in diabetic rats. CONCLUSION: The results suggest that oral mucosa wound healing is delayed in diabetic Wistar rats compared to non-diabetic rats in terms of wound closure, angiogenesis, and polymorphonuclear cells number. Furthermore, it is also suggested that wound healing is impaired both in the early and late stages of soft tissue wound healing.

Outcomes Assessment of Treating Completely Edentulous Patients with a Fixed Implant-Supported Profile Prosthesis Utilizing a Graftless Approach. Part 2: Patient-Related Outcomes.

PURPOSE: To assess outcomes of treating completely edentulous patients with a fixed implant-supported profile prosthesis, utilizing a graftless approach, for the maxilla and for the mandible, with an emphasis on patient-related outcomes, specifically maximum occlusal force, patient satisfaction, and impact on quality of life. MATERIALS AND METHODS: This was a cross-sectional study with the following inclusion criteria: completely edentulous patients rehabilitated with a fixed implant-supported profile denture, utilizing a graftless approach. Patients fulfilling the inclusion criteria were asked to participate in the study during their follow-up visits; hence, a consecutive sampling strategy was used. To measure maximum occlusal force, a digital occlusal force gauge was used. Subjects were asked to answer a paper survey distributed in the clinic. The survey contained general demographic questions, visual analog scale (VAS) categories, and Oral Health Impact Profile-14 (OHIP-14). RESULTS: The mean VAS score was 8.9 out of a possible 10. The mean OHIP-14 score was 7.5 out of a possible 56. The mean maximum occlusal force recorded in the anterior region was 108 Ncm. The mean maximum occlusal force recorded in the posterior region was 205 Ncm. CONCLUSION: Results indicated that patients treated with a graftless approach reported high satisfaction and impact on quality of life. Regarding maximum occlusal force values, significant differences between men and women were reported. The impact on quality of life seemed to improve when patients presented completely edentulous at the time of treatment as opposed to terminal dentition. Finally, significant positive correlations were detected between satisfaction and impact on quality of life, impact on quality of life and posterior maximum occlusal force, anterior and posterior maximum occlusal force, and complications and anterior maximum occlusal force.

Outcomes Assessment of Treating Completely Edentulous Patients with a Fixed Implant-Supported Profile Prosthesis Utilizing a Graftless Approach. Part 1: Clinically Related Outcomes.

PURPOSE: To assess outcomes of treating completely edentulous patients with a fixed implant-supported profile prosthesis utilizing a graftless approach for the maxilla and for the mandible, with emphasis on clinically related outcomes, specifically implant and prosthesis survival. MATERIALS AND METHODS: This was a retrospective study with the following inclusion criteria: completely edentulous patients rehabilitated with a fixed implant-supported profile denture utilizing a graftless approach. Patients fulfilling the inclusion criteria were asked to participate in the study during their follow-up visits, and hence a consecutive sampling strategy was used. Data regarding implant and prosthesis cumulative survival rates (CSRs) were gathered and calculated. RESULTS: Thirty-four patients were identified with a total of 220 implants placed. An overall CSR of 98.2% was recorded with an observation of up to 10 years. For tilted, axial, and zygomatic implants, CSRs of 96.9%, 98.0%, and 100%, respectively, were observed for up to 10 years. For provisional prostheses, CSRs of 92.3% at 1 year, and 84.6% at 2 years were observed. For final prostheses, a CSR of 93.8% was observed at 10 years. CONCLUSION: The results suggest that treating completely edentulous patients with a fixed profile prosthesis utilizing a graftless approach in the maxilla and the mandible can be a reliable treatment option.

Oral rehabilitation of patients with Chediak-Higashi syndrome using zygoma and root form implant-supported fixed prostheses: A report of two patients.

Chediak-Higashi syndrome (CH-S) is a rare genetic immunodeficiency disorder. Fewer than 500 individuals with CH-S have been reported worldwide in the past 20 years. The dental management of patients in whom CH-S has been diagnosed has been rarely reported and only in the form of a case report. All reports addressed the severe periodontal disease found in those patients, and most studies concluded that periodontal treatment had an unfavorable prognosis. As a result, complete edentulism at an early age because of severe periodontal disease is expected. The purpose of this report was to present 2 patients with CH-S seeking oral rehabilitation after early tooth loss and severe bone resorption as a manifestation of severe periodontal disease. The treatment used bilateral zygoma implants and an all-on-4 concept. The complications encountered and management with a 5-year post-surgery follow-up are also presented.

Bone Reduction to Facilitate Immediate Implant Placement and Loading Using CAD/CAM Surgical Guides for Patients With Terminal Dentition.

The aim of this study is to present a method, using 3 computer-aided design/computer-aided manufacturing (CAD/CAM) surgical guides, to accurately obtain the desired bone reduction followed by immediate implant placements and loading for patients diagnosed with terminal dentition. Patients who had bone reduction, implants placed, and immediate loading using Anatomage Invivo 5 CAD/CAM surgical guides between the period 2013 and 2015 were evaluated retrospectively. Patients diagnosed with terminal dentition and treated using the "3-guide technique" were identified. Pre- and postsurgical images were superimposed to evaluate deviations of the bone reduction and deviations at the crest, apex, and angle of implants placed. Twenty-six implants placed in 5 patients were included in this study. The overall deviation means measured for bone reduction was 1.98 mm. The overall deviation means measured for implant placement at the crest, apex, and angle were 1.43 mm, 1.90 mm, and 4.14°, respectively. The CAD/CAM surgical guide fabrication is an emerging tool that may facilitate the surgical process and aid in safe and predictable execution of bone reduction and immediate implant placement. Using 3 CAD/CAM surgical guides, a method is presented to obtain the desired bone reduction followed by immediate implant placement and loading for patients diagnosed with terminal dentition. This method may improve guide stability for patients with terminal dentition undergoing complete implant-supported treatment by taking advantage of the teeth to be extracted.

Accuracy Assessment of Immediate and Delayed Implant Placements Using CAD/CAM Surgical Guides.

The aim of this study is to assess the accuracy of immediately placed implants using Anatomage Invivo5 computer-assisted design/computer-assisted manufacturing (CAD/CAM) surgical guides and compare the accuracy to delayed implant placement protocol. Patients who had implants placed using Anatomage Invivo5 CAD/CAM surgical guides during the period of 2012-2015 were evaluated retrospectively. Patients who received immediate implant placements and/or delayed implant placements replacing 1-2 teeth were included in this study. Pre- and postsurgical images were superimposed to evaluate deviations at the crest, apex, and angle. A total of 40 implants placed in 29 patients were included in this study. The overall mean deviations measured at the crest, apex, and angle were 0.86 mm, 1.25 mm, and 3.79°, respectively. The means for the immediate group deviations were: crest = 0.85 mm, apex = 1.10, and angle = 3.49°. The means for the delayed group deviations were: crest = 0.88 mm, apex = 1.59, and angle = 4.29°. No statistically significant difference was found at the crest and angle; however, there was a statistically significant difference between the immediate and delayed group at the apex, with the immediate group presenting more accurate placements at the apical point than the delayed group. CAD/CAM surgical guides can be reliable tools to accurately place implants immediately and/or in a delayed fashion. No statistically significant differences were found between the delayed and the immediate group at the crest and angle, however apical position was more accurate in the immediate group.