Screw Retention Research Articles

Advancing 3D Dental Implant Finite Element Analysis: Incorporating Biomimetic Trabecular Bone with Varied Pore Sizes in Voronoi Lattices.

The human mandible's cancellous bone, which is characterized by its unique porosity and directional sensitivity to external forces, is crucial for sustaining biting stress. Traditional computer- aided design (CAD) models fail to fully represent the bone's anisotropic structure and thus depend on simple isotropic assumptions. For our research, we use the latest versions of nTOP 4.17.3 and Creo Parametric 8.0 software to make biomimetic Voronoi lattice models that accurately reflect the complex geometry and mechanical properties of trabecular bone. The porosity of human cancellous bone is accurately modeled in this work using biomimetic Voronoi lattice models. The porosities range from 70% to 95%, which can be achieved by changing the pore sizes to 1.0 mm, 1.5 mm, 2.0 mm, and 2.5 mm. Finite element analysis (FEA) was used to examine the displacements, stresses, and strains acting on dental implants with a buttress thread, abutment, retaining screw, and biting load surface. The results show that the Voronoi model accurately depicts the complex anatomy of the trabecular bone in the human jaw, compared to standard solid block models. The ideal pore size for biomimetic Voronoi lattice trabecular bone models is 2 mm, taking in to account both the von Mises stress distribution over the dental implant, screw retention, cortical bone, cancellous bone, and micromotions. This pore size displayed balanced performance by successfully matching natural bone's mechanical characteristics. Advanced FEA improves the biomechanical understanding of how bones and implants interact by creating more accurate models of biological problems and dynamic loading situations. This makes biomechanical engineering better.

The Preliminary Development of a Friction-Based Lateral Screw-Retained Dental Crown—A Comparison between the Prototype Surface Treatment and the Retention Strength

This study aims to develop a novel retention method combining the retrievability of the screw retention method with the ideal occlusal table and the aesthetic capability of cement retention. Coping was developed to have lateral screw access, allowing the screw to lock the coping using lateral forces from screw tightening and friction between the tip of the screw and the sandblasted surface of an abutment. Sandblasting parameters varied based on particle size. The results show a positive correlation to surface roughness and indicate a positive correlation to retention force. The highest surface roughness and retention force result was shown by groups that were sandblasted using 686 μm of aluminum oxide. Experiments on the tightening strength of 48 subjects measured in simulated conditions similar to the assembly conditions of lateral screw retention implants resulted in a mean of 69.75 Nmm with the highest and lowest values of 120.67 Nmm and 34.67 Nmm. This result became the basis of tightening torque variation. Each group’s retention capability is measured and compared to cement-retained dental implants. The results show that the tightening torque correlates positively with retention force, with the highest average retention score showed by lateral screws retained under a tightening torque of 200 Nmm—317.87 N higher than cement-retained screws.

Clinical and radiographic results of crestal vs. subcrestal placement of implants in posterior areas: A split-mouth randomized controlled clinical trial.

The objective of this study was to evaluate the peri-implant soft tissue and marginal bone loss (MBL) around implants with platform-switching and internal conical connection placed at crestal and subcrestal levels in posterior areas. Nineteen partially edentulous patients with at least two adjacent missing teeth in posterior areas unilaterally or bilaterally were included. Forty-two implants were placed randomly at the crestal or subcrestal (1 mm) level in a split-mouth design. Implant-supported fixed dental prostheses with screw retention were delivered after 4 months of healing. Clinical and radiological measurements were performed at implant placement (T0), restoration delivery (T1), and 1-year follow-up after loading (T2). MBL was calculated as the change in distance from the implant-abutment interface to the first radiographically visible bone-implant contact. A repeated-measures mixed ANOVA followed by a paired Student's t-test with the Bonferroni correction was used for statistical analysis. p < 0.05 was considered statistically significant. Eighteen patients with thirty-eight implants completed the study at T2. The MBL was lower in the subcrestal group than in the crestal group (0.04 ± 0.08 vs. 0.17 ± 0.17 mm, p = 0.004). The peri-implant probing depth (PD) was 2.31 ± 0.48 mm in the subcrestal group and 1.92 ± 0.43 mm in the crestal group; this difference was statistically significant (p = 0.002). Intragroup comparison showed no significant differences in MBL, or PD around the crestal group and subcrestal group from T1 to T2. After 1 year of functional loading, subcrestal placement of implants with platform-switching and internal conical connection showed lower MBL and was associated with greater PD and peri-implant soft tissue height than implants placed at the crestal level.

Fiber-reinforced composite full-arch prosthetic reconstructions supported by three standard, short or extra-short implants: a two-center retrospective study.

To evaluate the survival of implants and prostheses, and marginal bone level of fiber-reinforced composite implant supported fixed complete prostheses supported by 3 implants. Patients with fiber-reinforced composite fixed prostheses supported by 3 standard-length, short or extra-short implants were included in this retrospective cohort study. Kaplan-Meier survival was computed for implants and prostheses. Univariate and multivariate Cox proportional hazard regressions, clustered by patient, were used to analyze bone level differences as a function of different study covariates. Linear regressions were used to investigate the relationship between distal extension lengths and bone levels. Forty-five patients with 138 implants were followed for up to 10years after prosthesis insertion (mean 52.8; SD 20.5months). Kaplan-Meier survival analysis showed overall survival rates of 96.5% for implants and of 97.8% for prostheses. The 10-year success rate for prostheses was 90.8%. Extra-short implants survived at similar rates to short and standard implants. Marginal bone levels surrounding implants remained stable over time, even showing slight bone gain on average (mean + 0.1mm/year; SD ± 0.5mm/year) Acrylic denture teeth, overdentures on the opposing arch, and implant placement in the posterior maxilla were correlated with bone gain. Screw retention, opposed to telescopic retention, was correlated with bone loss. Longer distal extensions were correlated with bone gain on the implants closest to the distal extensions. Fiber-reinforced composite fixed prostheses supported by only 3 implants, most of which were extra-short, presented high survival rates with stable bone levels. An encouraging prognosis can be expected for restoration of atrophic maxillary and mandibular arches, when restored with fixed fiber-reinforced composite frameworks with long distal extensions and supported on only 3 short implants.

Changes in Peri-Implant Soft Tissue Thickness with Bone Grafting and Dermis Allograft. Part III: A Case Series Using a Novel, Hybrid Implant Design with a Subcrestal Angle Correction.

This comparative case series presents 16 consecutively placed and temporized immediate implants in the maxillary esthetic zone. The implants have a novel, inverted body-shift design, intended to achieve high levels of primary stability via the tapered apical portion. The coronal narrow cylinder provides greater space between the implant platform and facial socket wall and adjacent teeth/implants, allowing a greater opportunity for augmentation. The restorative platform also features a subcrestal angle correction, which facilitates screw retention. The wider, facial platform-shift thus creates more room for augmentation via dual-zone bone grafting and the application of a dermal allograft, which yields greater soft tissue thickness after initial healing. This case series aimed to evaluate soft tissue thickness and compare the results to two previously published cohorts where implant design served as the only variable between groups.

Single-Unit Short Implants in the Molar Region: A Retrospective Study with a Minimum 3-Year Follow-up.

The high biomechanical loads in molar region wounds challenge the indication for short implants to be used as a single-unit implant. This study reports on the outcomes of single-unit short implants (≤ 8.0 mm) in the maxillary and mandibular molar regions. Forty-nine short implants were placed in 48 patients to replace a missing molar tooth. Two-piece restorations with screw retention were fabricated. During the follow-up, implant survival and marginal bone loss (MBL) were assessed. The known implant length was used as a reference to calibrate the linear measurements on digital periapical radiographs, and descriptive statistical analysis was performed. The implants were followed over a period of 47 ± 12 months. No implant failure was recorded, and no prosthesis failure was observed. The average MBL was 0.15 ± 0.5 mm. The mean crown height space was 13 ± 3 mm. The overall crown-to-implant ratio was 1.7 ± 0.4. Two technical complications occurred due to the loosening of the unit abutment. After screw re-tightening, no more screw loosening was observed. This study supports the use of short implants as a single-unit implant in the maxillary and mandibular molar regions.

Risk factors for screw breach and iatrogenic nerve injury in percutaneous posterior pelvic ring fixation

BackgroundPercutaneous screw fixation of the posterior pelvic ring is technically demanding and can result in cortical breach. The purpose of this study was to examine risk factors for screw breach and iatrogenic nerve injury. MethodsA retrospective review at a single level-one trauma center identified 245 patients treated with 249 screws for pelvic ring injuries with postoperative computed tomography (CT) scans. Cortical screw breach, iatrogenic nerve injury, and associated risk factors were evaluated. ResultsThere were 86 (35%) breached screws. The breach rate was similar between screw types (33% S1-iliosacral (S1-IS), 44% S1-transsacral (S1-TS), 31% S2-IS, and 30% S2-TS) and was not associated with patient characteristics, Tile C injuries, or corridor size or angle. The overall rate of screw revision for screw malpositioning was 1.2% (3/249). Iatrogenic nerve injuries occurred in 8 (3.2%) of the 249 screws. Screws that caused iatrogenic nerve injuries had greater screw breach distances (5.4 vs. 0 mm, MD 5, CI 2.3 to 8.7, p < 0.0001), were more likely to be S1-IS screws (88% vs. 47%, PD 40%, CI 7 to 58%, p = 0.006), more likely to be placed in Tile C injuries (75% vs. 44%, PD 31%, CI -3 to 55%, p = 0.04), and there was a trend for having a screw corridor size <10 mm (75% vs. 47%, PD 28, CI -6 to 52%, p = 0.06). Of the 7 iatrogenic nerve injuries adjacent to screw breaches, two nerve injuries recovered after screw removal, three recovered with screw retention, and two did not recover with screw retention. ConclusionScrew breaches were common and iatrogenic nerve injuries were more likely with S1-IS screws. Surgeons should maintain a high degree of caution when placing these screws and consider removal of any breached screw associated with nerve injury.

Evaluation of clinical and radiographic outcome of friction fit conical abutment system in implant-supported dental prostheses: An in vivo study.

The purpose of this clinical study was to analyze the clinical feasibility of friction fit conical abutment system in implant-supported fixed dental prostheses as an alternative to cement and screw retention. This was an in vivo longitudinal study. A total of 10 prostheses were designed as 3- or 4-unit fixed dental prostheses supported by two implants. All the subjects selected were evaluated for pocket probing depth (PPD) and marginal bone loss at the time of implant placement (T1), at the time of placement of friction fit prostheses (T2), and 12 months after placement of friction fit prostheses (T3). Marginal bone loss at T2 and T3 was measured with respect to bone levels at T1 and T2, respectively. The patient satisfaction was assessed at T2 and T3 using FDI clinical criteria and scoring system (modified by Monaco et al.). Shapiro-Wilk test was employed to test the normality of data. Paired sample t-test was performed for quantitative variables. A total of twenty implants were inserted in ten partially edentulous spaces; the average patient age was 50.2 years. No significant difference was seen between T2 and T3 for PPD. Comparison of marginal bone loss using paired t-test showed a statistically highly significant difference at T2 and T3 with higher value at T2. No prostheses were dislodged during postprosthetic follow-up. The survival rate was 100% for both the abutments and implants. No change in surface luster was observed 12 months following prosthetic rehabilitation in any case. No prostheses or framework fracture was reported and all patients were satisfied with the prosthesis received. Friction fit conical abutment system can act as a novel approach for the retention of implant-supported fixed dental prostheses.

Prospective clinical study on the influence of implant crown and bridge prostheses characteristics on peri-implant disease

Objective: To investigate the influence of different characteristics of implant-supported fixed dental prostheses on the incidence of peri-implant disease. Methods: Prospective cohort was established for patients who received implant-supported fixed dental prostheses at the Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University between June 2014 and September 2015. Several patient-related factors, implant prostheses factors, and oral hygiene maintenance factors were collected. The Log-rank test was used to compare the peri-implant disease rates of various factors, and the Cox proportional hazards model was used to conduct multivariate study on single factor significant factors to analyze the impact on the incidence of peri-implant disease. Results: A total of 214 subjects and 351 implants were included in the cohort, the follow-up period was (11.0±3.5) months. Finally, 43.0% (92/214) of patients and 37.3% (131/351) of implants developed peri-implant diseases. The incidence of peri-implant mucositis and peri-implantitis was 41.1% (88/214) and 4.2% (9/214) at the subject level,and 34.2% (120/351) and 3.1% (11/351) at the implant level. Among the factors associated with the implant prosthesis, single factor Log-rank analysis showed that prostheses retention methods, proximal contact of the prostheses, occlusion situation were statistical significance (P<0.05). Multivariate analysis using Cox proportional hazards model showed that screw retention (hazard ratio=2.38, 95%CI: 1.42-3.99), proximal contact loss of the prostheses (hazard ratio=2.36, 95%CI: 1.31-4.27) were independent risk factors for peri-implant disease (P<0.05). Conclusions: Factors such as prostheses retention mode and proximal contact characteristics have important influence on the health status of the implant.

Survey of Dental Implant and Restoration Selection by Prosthodontists in Dubai.

Background With various surgical and prosthetic component designs being introduced in dental implants, decisions have to be made when choosing a system and a certain prosthodontic protocol. A survey of implant prosthodontic specialists has not been previously performed in the Middle East. Aim This study aimed to determine selection criteria and choice of dental implants and restorations by prosthodontic specialists in the Emirate of Dubai, United Arab Emirates. Materials and Methods A validated 16-item questionnaire was used in the survey which included demographic information, implant training and experience, implant treatment planning, implant restoration, and implant system preference. The research protocol was approved by the Research and Ethics Committees of Hamdan Bin Mohammed College of Dental Medicine and Dubai Health Authority. Prosthodontists were identified from regulatory authority websites and contacted by e-mail with the questionnaire attached. Results A total of 84.6% (77) of the registered prosthodontists in Dubai completed the questionnaire with 66.2% reported practicing implant dentistry. Out of which, 54.9% reported surgically placing dental implants and 45.1% restore them only prosthetically. Prefabricated metal abutments were the most commonly selected abutments for single crowns (76.0%) and for fixed dental prostheses (66.7%). Screw retention is preferred mostly for single crowns (68.0%) and fixed dental prostheses (74.0%). Locators were the most commonly selected type of attachment for implant-retained/supported overdentures (49.0%). Conventional loading was the most selected type of loading in all oral conditions. Conclusion Within the limitations of this study, it can be concluded that most prosthodontists in Dubai practice implant dentistry and more than half surgically place dental implants. Prefabricated metal abutments are the most selected type of abutments. Most prosthodontists use screw-retained implant restorations and prefer locator attachments for implant-retained/supported overdentures. Conventional loading is the most preferred implant loading method in all oral conditions. Implant company/system selections are various and there is no major preference for a certain system. The majority of prosthodontists select implant systems based on implant features, literature review, and simplicity of restorative kit.

Clinical Application of PEEK as a Provisional Fixed Dental Prosthesis Retained by Reciprocated Guide Surfaces of Healing Abutments During Dental Implant Treatment.

The aim of this study was to evaluate the clinical use of a high-performance polymer, polyether ether ketone (PEEK), as a material for use in provisional fixed dental prostheses (FDPs) that can be retained by reciprocated guide surfaces of hexagonal-shaped healing abutments during dental implant treatment. Patients requiring teeth replacement with dental implants for partially and fully edentulous cases in the maxilla and mandible were included. The provisional FDP was fabricated with hex castable copings and PEEK granules using the lost wax technique. The common path of insertion was established by reducing the coping that is in obstruction to the healing abutment. Retention was provided by the reciprocated guide surfaces of multiple hexagonal-shaped healing abutments. Twenty-three custom provisional PEEK FDPs supported by 166 implants in 20 partially and fully edentulous patients were provided during the treatment period. The mean functional periods of the provisional PEEK FDPs for maxillary and mandibular cases were 6.95 ± 0.84 months and 1.90 ± 0.62 months, respectively. All provisional PEEK FDPs functioned as intended for the entire treatment period. There were a total of 10 complications: 4 cases had resin and denture veneers debond from the PEEK framework; 3 partially edentulous cases required supplementary screw retention; and 3 implants in separate cases did not osseointegrate, requiring extended use of the provisional prosthesis. Two provisional mandibular PEEK FDPs with prolonged usage (over 2 years) were excluded from calculations. No fracture of the PEEK framework was observed. The results from this study suggest that PEEK can be a suitable material for use in provisional FDPs during dental implant treatment. Prosthetic complications were frequent but were resolved intraorally. The reciprocated guide surfaces of multiple hexagonal-shaped healing abutments can provide adequate retention and resistance for edentulous cases during the implant treatment period. However, in partially edentulous cases, a prosthesis without cross-arch stabilization supplementary screw retention was required.

Marginal bone loss and the risk indicators of fixed screw-retained implant-supported prostheses and fixed telescopic-retained implant-supported prostheses in full arch: A retrospective case-control study.

This study compared full-arch screw-retained implant-supported fixed dental prostheses (FSI-FDPs) and full-arch telescopic-retained implant-supported fixed dental prostheses with a professional retrieval system (FTI-FDPs) on marginal bone loss (MBL), the risk indicators and peri-implantitis rate after 7-13years. Sixty five edentulous patients were treated with 86 prostheses and 592 implants. The FSI-FDP group comprised 26 patients (32 prostheses, 202 implants), and the FTI-FDP group comprised 39 patients (54 prostheses, 390 implants). MBL and the risk indicators of MBL ≥1mm were assessed. Peri-implantitis rates at 13years were also calculated. Full-arch screw-retained implant-supported fixed dental prostheses and FTI-FDP implants exhibited comparable mean MBLs of 0.60±0.51 and 0.41±1.03mm, respectively. MBL ≥1mm was noted for 25% of FSI-FDP implants and 6.9% of FTI-FDP implants. Superstructure-abutment connection (screw retention:FSI-FDPs >telescopic retention:FTI-FDPs) and implant-abutment connection (External butt joint, Internal butt joint >Morse taper joint) were associated with MBL ≥1mm. Peri-implantitis rates at the implant level were 3.99% (95%CI=3.93-20.5) in FSI-FDP group and 3.85% (95%CI=3.85-34.3) in FTI-FDP group with no significance. It was concluded that FSI-FDP and FTI-FDP implants exhibited comparable MBL; however, the risk of MBL ≥1mm in FTI-FDPs was lower than in FSI-FDPs. Besides, implant-abutment connection was the risk indicator of MBL ≥1mm. In peri-implantitis rate, FSI-FDPs and FTI-FDPs behave similarly.

Preliminary Results Using a Friction-Fit Crown to Abutment Connection.

One of the chronic problems with traditional cement or screw retention of crowns to implants is the development of biologic and technical complications, including soft tissue complications, bone loss, screw loosening, loss of retention, and veneering material fractures. The purpose of this case series report is to document preliminary results, specifically crown retention, using a friction-fit connection of crown to abutment. A sample composed of patients who had one or more implants restored between July 1, 2019, and October 30, 2019, were enrolled in this retrospective case-control series. Each patient had their crown connected to the implant abutment using a friction-fit system. Patients were seen for routine follow-up for documentation of crown retention, and 24 crowns were followed. After 6 months of follow-up, 100% of the crowns retained retention and did not become loose under normal masticatory function. The use of a friction-fit connection provided excellent retention of the crown to the abutment over the 6-month follow-up period.

The ability to screw-retain single implant-supported restorations in the anterior maxilla: A CBCT analysis

Statement of problemEvidence to validate the routine use of angled screw-channel abutments in the anterior maxilla is sparse. If properly planned, they might provide surgical and prosthetic benefits. PurposeThe purpose of this observational study was to determine the prevalence of digitally placed implants in the anterior maxilla that would allow screw-retained implant-supported restorations with either a straight or an angled screw-channel abutment. Material and methodsTwo hundred cone beam computed tomography (CBCT) scans met the inclusion criteria for retrospective analysis and digital implant planning. Virtual implants were planned for randomly selected anterior maxillary teeth by using the anatomic crown and root position. Virtual abutments of varying angulation were attached to the implants to determine the ability to screw retain a restoration with either a straight or an angled screw-channel abutment. ResultsOne hundred fifty-two (76%) sites required an angled screw-channel abutment to enable screw retention. Forty-eight (24%) sites allowed screw retention with a straight abutment. The percentage of implants requiring angled or straight abutments varied significantly among anterior teeth (P<.005). One hundred nine (71.7%) angled screw-channel abutment sites required a 5-degree abutment, 41 (26.9%) required a 10-degree abutment, and 2 (1.3%) required a 15-degree abutment. Among the anterior teeth, lateral incisors presented a greater need for angled screw-channel abutments. None of the implants in the present study needed cement-retained restorations. ConclusionsAngled abutments allowed for screw-retained restorations on digitally planned implants in the anterior maxilla. The required angular correction to a screw-retained restoration was ≤15 degrees. Screw-retained restorations were frequently achievable (76%) with the use of angled screw-channel abutments or with straight abutments (24%), and lateral incisors presented a greater need for angled screw-channel abutments.

Optimization measurement for the ballscrew raceway profile based on optical measuring system

Given that the ballscrew raceway profile directly affects the service characteristics and precision retention of ball screws, this paper proposes an optimized continuous measuring method for the ballscrew raceway profile, without the need to adjust the sensor for the measurement of each raceway. Based on a comparison with existing measuring methods and principles, an optical measuring system is constructed, in which installation errors in the LED sensor and the linear calibration system, together with the straightness of the mobile platform, are obtained and analyzed. More importantly, in this work, we propose a transformation algorithm for the helix angle as well as an arc-selecting principle. Compared to the measurment results and time consumption of the profilometer, the maximum error for the measured radius and contact angle of the system proposed in this paper is 1.5 μm and 35′, and the measuring efficiency is increased by 15.8%, 58.6%, and 67.5% for 1, 5, and 20 continuous raceways, respectively, indicating effective performance in terms of accuracy, repeatability, and efficiency. Moreover, the system is also capable of measuring the pitch diameter and lead error of the ballscrew, which is significant in regard to classifying the accuracy of the ballscrew raceway profile, and improving machining precision.

Management of unfavorable implant positions and angulations in edentulous maxillae with different complete-arch fixed prosthetic designs: A case series and clinical guidelines

Implant-supported fixed prostheses in the edentulous maxilla can be difficult because of anatomic limitations and high esthetic demand. The choice between cement and screw retention depends on factors such as esthetics, occlusion, retrievability, and passivity. The choice is also often governed by the ability to manage technical or biologic complications. In the edentulous maxilla, because of the bone trajectory and resorption pattern, unfavorable implant angulations may be encountered. In such situations, a conventional screw-retained prosthesis is difficult to design. This article describes the restoration of edentulous maxillae for a series of patients with different complete-arch fixed prosthesis designs. The clinical guidelines, including indications, advantages, and limitations of each design, were discussed.

Complication rates for various retention types in anterior implant-supported prostheses: A retrospective clinical study

Statement of problemImplant-supported prostheses have typically been retained by cement or screws, each of which has advantages and disadvantages. Two new types of prosthesis with complementary advantages and disadvantages have been proposed: the screw- and cement-retained prosthesis, which combines cement and screw retention, and the antiloosening inner-post screw (ALIPS) type, which uses lateral screws. Both esthetic and functional factors should be considered for anterior prostheses; however, clinical studies of the complication rates of these designs are lacking. PurposeThe purpose of this retrospective clinical study was to evaluate the complications of dental implant-supported restorations with various prosthetic types in the anterior region and to analyze other factors that affect complications. Material and methodsThis study included 51 patients who had 83 implants placed in the anterior region by a single clinician between August 2009 and December 2016. Surgical and prosthetic features were recorded, and implant complications were analyzed. ResultsThere were 45 (55.4%) cement-retained implants, 5 (6.0%) screw- and cement-retained prosthesis implants, and 32 (38.6%) ALIPS-retained implants. Peri-implant mucositis was observed most frequently in the ALIPS type (21.9%), but the biological complications did not differ significantly with the prosthetic type. The most common mechanical complication was loss of retention in the cement type of prosthesis (30.4%) and screw loosening in the ALIPS type (43.8%). Implant complications varied with position (maxilla or mandible) and implantation timing (period from tooth extraction to implant placement). ConclusionsThe complications of implants placed in the anterior region were affected by different factors but did not differ significantly with the type of the retention.

Impact of the retention system of implant fixed dental restorations on the peri-implant health, state of the prosthesis, and patients’ oral health-related quality of life

ObjectivesTo investigate the impact of the retention system (screwed or cemented) of implant fixed dental prostheses (i-FDPs) on the peri-implant health, prosthesis’ state, patient self-evaluation of functionality and aesthetics, and oral health-related quality of life (OHRQoL). Methods35 participants were classified into two groups according to the retention system of their metal-ceramic i-FDPs. For the analysis of peri-implant health and prosthetic complications, the implant units were individually assessed. Group 1 (SPD; n = 22): implant units for screwed i-FDPs; and Group 2 (CPD; n = 36): implant units for cemented i-FDPs. Data related to socio-demographics, design and installation of the superstructures, peri-implant condition, prosthetic complications, functionality, and aesthetics, were gathered. Patients answered the Oral Health Impact Profile (OHIP-14sp) questionnaire. Descriptive and parametric probes were run to evaluate the impact scores considering the study variables (α = 0.05). ResultsThe plaque index, gingival index, functionality, aesthetics, and global evaluation made by the patient recorded significantly better results for the SPD group. The most affected OHIP-14sp domain was ‘Physical pain’, followed by ‘Psychological discomfort’, and ‘Functional limitation’. The subscales: ‘Functional limitation’, ‘Physical disability’, and ‘Social disability’, attributed significantly worst OHRQoL to CPD users. ConclusionA major presence of peri-implant disease, together with a worse functionality, aesthetics, and patient satisfaction were recorded in cemented i-FDPs with respect to the screwed ones. Clinical significanceThe retention system of i-FDPs can impact the peri-implant health, the subjective functional and aesthetic evaluation of the restoration, and the patients’ OHRQoL; the screw retention providing superior results than the cementation.

Implant supported rehabilitation on upper jaw with minor amount of fixtures (3 years follow up)

Активное вытеснение имплантационными конструкциями банальных из комплексной реабилитации пациентов сопряжено с очевидной тенденцией уменьшения количества опор таких протезов при высоких показателях сохраняемости как самих протезов, так и имплантатов. Материалы и методы. Фиксация протяженных имплантационных протезов с помощью винтов, несмотря на большие клинико-технологические сложности при их создании по сравнению с фиксирующимися цементом, обеспечивает возможность их регулярного демонтажа для проведения профессиональной гигиенической очистки и ремонта, а учитывая все бoльшую востребованность несъемных имплантационных протезов у пациентов преклонного возраста и одновременно с этим сложность поддержания ими самостоятельно индивидуальной гигиены на высоком уровне, в ортопедической стоматологии становится актуальным поиск вариантов для быстрого и регулярного демонтажа таких протезов. Результаты и обсуждение. В данной работе представлены 3-летние результаты (на примере выписок из историй болезни трех пациентов) имплантационного протезирования пациентов с использованием конструкций с малым количеством опор, фиксированных горизонтальными винтами. Представлена 100-процентная сохраняемость конструкций имплантационной системы «blueSKY fast & fixed» bredent Medical (Senden, Германия) с немедленной нагрузкой, при этом конструкции с четырьмя и шестью опорами показали схожие результаты. Выводы. Фиксация горизонтальными винтами открывает перспективы для регулярной (4—6 раз в год) очистки имплантационных протезов для сохранения здоровья периимплантатных тканей у пациентов преклонного возраста.

Fabricating a screw-retained, complete arch, fixed implant prosthesis using selective metal laser sintering: A clinical report

In contemporary prosthodontic practice, implant-supported therapy has consistently resulted in high success rates, with satisfactory and predictable outcomes for completely edentulous patients. Of the several options, complete-arch, fixed screw-retained solutions are generally considered to be the preferred treatment solution. Screw retention offers advantages such as predictable retrievability and potentially easy prosthodontic maintenance, as well as excess cement not being a concern. However, implant mispositioning and malalignment may often necessitate the use of cement-retained prostheses. This clinical report describes a method of fabricating a complete-arch, implant screw-retained, double framework metal-ceramic prosthesis, despite the unfavorable implant positioning, by using selective direct metal laser sintering technology.