Implant-supported Prostheses Research Articles

The Technique and Material Used to Join Transfers Affect the Accuracy and Final Fit of Implant-Supported Prostheses-In Vitro Study.

This study evaluated the linear dimensional change of polymerization of three materials and two techniques of the union of molding transfers for implant-supported prostheses used in the open-tray technique. A nylon maxilla-shaped matrix was made, two osseous integrated implants were installed, and, over these two, straight conical mini-pillars were installed. Open-tray impression transfers were attached to the mini-pillars, and a silicone guide was made to standardize the connections between the transfers. The samples were divided into six groups (n = 20): PA (Pattern Resin LS, chemically activated acrylic resin in the single step technique); DU (Durallay, chemically activated acrylic resin in the single step technique); BI (Protemp4, bisacrylic resin in the single step technique); PAC (Pattern Resin LS in sectioning and joining of segments technique); DUC (Durallay, in sectioning and joining of segments technique); and BIC (Protemp4, in sectioning and joining of segments technique). The linear dimensional change values that occurred among these transfers were measured in a profile projector (VB300; Starret) coupled to the Quadra Check device, with a resolution of 0.001 mm, performed by a single calibrated operator. Data were submitted to a two-way analysis of variance and Tukey's test (p < 0.01). Statistically significant mean values were found in all comparisons. The PA showed the lowest mean values (µm) of linear dimensional change, both in the single-step technique and in the sectioning and joining technique, in the following order: BI 255.73 (3.81), DU 173.75 (2.30), PA 95.97 (3.20), BIC 23.82 (1.71), DUC 20.85 (2.53), and PAC 13.27 (2.09). The single-step technique showed the worst results, regardless of the material. The sectioning and joining technique reduced the dimensional change in all materials, and the Pattern Resin LS showed the lowest shrinkage mean values, followed by Durallay and Protemp4.

Mechanical and modal analysis of different implant strategies for loss of three teeth with bone atrophy in the maxillary posterior region

Purpose: This study aimed to evaluate the stress distribution and secondary stability involved in five implant strategies, including implant-supported prostheses (ISP) and tooth-implant-supported prostheses (TISP), used for bone atrophy in the maxillary posterior region with teeth loss using finite element analysis, and to explore the more desirable implant methods. Methods: Five implant strategies were made to analyze and compare: M1, implant-supported prosthesis consisting of a short implant with a regular implant; M2, implant-supported prosthesis consisting of a tilted implant with a regular implant; M3, cantilever structure; M4, tooth-implant-supported prosthesis consisting of a short implant with a regular implant; M5, tooth-implant-supported prosthesis consisting of a regular implant, and M6, with only the natural teeth as a control group. Dynamic loading of the above models was performed in finite element analysis software to assess the stress distribution of the bone tissue and implants using the von Mise criterion. Finally, the secondary stability of different models was evaluated by modal analysis. Results: The maximum stress distribution in the cortical bone in M1(60 MPa) was smaller than that in M2(97 MPa) and M3(101 MPa), The first principal strain minimum was obtained in M2 (2271 μ ε ). M4 (33 MPa, 10085 Hz) with the best mechanical properties and highest resonance frequency. But increased the loading on the natural teeth. Conclusions: Short implants and tilted implants are both preferred implant strategies, if cantilever construction is necessary, a tooth-implant-supported prosthesis consisting of a short implant and a regular implant is recommended.

Long-Term Outcomes of Dental Rehabilitation and Quality of Life after Microvascular Alveolar Ridge Reconstruction in Patients with Head and Neck Cancer.

Background/Objectives: Dental rehabilitation after extended tumour resection and jaw reconstruction is challenging. The present study aimed to report the prosthetic outcome and quality of life (QoL) in patients with head and neck cancer (HNC) after microvascular alveolar ridge reconstruction. Methods: The prosthetic outcomes of all consecutive patients with HNC who underwent microvascular alveolar ridge reconstruction at the University Hospital Salzburg between 2011 and 2018 were investigated. Oral health-related QoL (OHrQoL) and overall QoL were assessed using the validated Oral Health Impact Profile-49 (OHIP-49) and Short Form-36 questionnaires. Results: During the study period, 115 consecutive patients with head and neck cancer underwent microvascular jaw reconstruction. Among them, 23.3% and 27.4% received conventional tissue-borne prostheses and implant-supported prostheses, respectively, while 48.7% did not undergo dental rehabilitation. The prosthetic outcome was not associated with tumour stage (p = 0.32). Oral health-related quality of life (OHrQoL) was best in patients with implant-supported dental rehabilitation (OHIP-49 median score = 7) and worst in those with conventional removable dentures (OHIP-49 median score = 54). The corresponding OHIP-49 median score for patients who could not undergo dental rehabilitation was 30.5. All Short Form-36 subscale scores were equal to or higher than the malignancy norm scores. Conclusions: After microvascular jaw reconstruction, approximately one-third of the HNC patients received adequate implant-supported dental rehabilitation. However, the risk of dental rehabilitation failure was 50%. The different prosthetic outcomes affected OHrQoL, but not overall QoL.

Calibrated intraoral scan protocol (CISP) for full-arch implant impressions: An in vitro comparison to conventional impression, intraoral scan, and intraoral scan with scan-aid.

To assess a newly developed intraoral scan protocol in enhancing the accuracy of complete-arch implant impressions. Four impression approaches were applied to the same maxillary edentulous model with 6 implants: (1) intraoral scan (IOS), (2) intraoral scan with scan aid (IOS-SA), (3) calibrated intraoral scan protocol (CISP), and (4) conventional splinted open-tray impression (CONV). Each approach was repeated 10 times, and a direct scan of the model with a desktop scanner was used as a reference model. The alignment of scans and the reference model was conducted by two methods: (a) aligning all scan bodies to evaluate the overall fit, and (b) aligning the first and second scan bodies to simulate the Sheffield fit test for passive fitting of multiple implant-supported prostheses. Linear deviations from the reference model (trueness) and within each group (precision) were analyzed using Python scripts. When aligned by all scan bodies, the CISP group exhibited comparable mean trueness (38.33 μm) and precision (45.97 μm) to the CONV group (44.30 and 47.92 μm respectively), both of which significantly outperformed the IOS group (86.82 and 83.17 μm, respectively). Furthermore, in the virtual Sheffield fit test, the CISP group achieved the highest levels of mean trueness at the end span (121.7 μm), making a linear deviation reduction of 36.7%, 60%, and 41.4% when compared to the CONV, the IOS, and the IOS-SA groups, respectively. Moreover, the CISP group (104.3 μm) displayed a remarkable 65, 182, and 86 μm advantage in precision over the CONV, IOS, and IOS-SA groups, respectively. CISP demonstrated comparable accuracy to the gold standard, the conventional splinted open-tray impression. Furthermore, it excelledin the virtual passive fitting test.

A systematic review on prosthodontic rehabilitation of hemimandibulectomy patients

To restore oral function after tumor excision, practitioners must undertake the enormous challenge of restoring hemimandibulectomy deficits. Depending on the type and extent of mandibular reconstruction (Cantor-Curtis classification), there are many prosthetic treatment options available for the rehabilitation of acquired hemimandibulectomy abnormalities. The objective of this systematic study is to evaluate the range of prosthodontic rehabilitation techniques in relation to the kind of repair and severity of mandibular surgical abnormalities. The databases incorporated for literature search were Google Scholar and Medline (PubMed). Relevant search terms for hemimandibulectomy and reconstruction with prosthetic rehabilitation were used. Two reviewers independently assessed the articles using eligibility criteria; published case reports and case series in the English language and depicting prosthodontic treatment modality of patients greater than 13 years were included. A total of 212 records were identified from the database search of which 29 duplicates were removed.The remaining articles were assessed for eligibility, and 50 articles (comprising 50 cases) were finally included in the study. This review identified a number of prosthetic options, including some novel prosthetic techniques, guiding flange, twin occlusion, palatal ramp, conventional to hybrid partial and complete dentures, and implant-supported prosthesis.The prosthetic options covered in this review included implant-supported prosthesis, guide flange, dual occlusion, palatal ramp, conventional, hybrid, and full dentures, as well as a few cutting-edge prosthetic techniques.As they plan and manage sequential therapy for hemimandibulectomy cases in their daily practice, practitioners and prosthodontists will find this helpful.

Assessment of Patient Satisfaction and Oral Health-Related Quality of Life Following Full Mouth Rehabilitation with Implant-Supported Prostheses.

The concept of success is typically established by the researcher or the practitioner rather than the patient, who has the greatest stake in the outcome of the prosthodontics therapy. To assess patient satisfaction and oral health-related quality of life (OHRQoL) in following full mouth rehabilitation with implant-supported prostheses (ISP). Thirty-two patients who underwent full mouth rehabilitation with ISP were included in this study. The Oral Health Impact Profile-14 (OHIP-14) questionnaire was used for the assessment of patient satisfaction and OHRQoL following full mouth rehabilitation with ISP. The functional limitation among study participants before, 1 month, and 3 months after ISP was 2.1 ± 1.3, 1.5 ± 0.8, and 1.4 ± 0.9, respectively. There was a significant reduction in functional limitation, psychological disability, and social disability before and 3 months after ISP. There is a significant improvement in patient satisfaction and OHRQoL in following full mouth rehabilitation with ISP.

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.

Clinical Evaluation of the Long-Term Survival and Success Rates of Different Types of Implant-Supported Prostheses.

Dental implants have been essential to the therapy of patients who are partially edentulous. Clinical evaluation of the long-term survival and success rates of different types of implant-supported prostheses. Patients who had a healthy edentulous ridge of three missing teeth in the posterior jaw in which two or three dental implants were placed having any of three prostheses, namely, three-unit fixed dental prostheses (FPD) on two implants, three splinted crowns on three implants, and three splinted crowns on three implants were included. The survival rate in all patients with dental implants having different types of prostheses was 94.9%. The survival rate in FPD, three splinted crowns, and three nonsplinted crowns was 100, 88.5, and 93.6% respectively. FPD loaded on two dental implants was found to have a greater long-term survival rate and success rate with a lower frequency of peri-implantitis and prosthodontic complications.

Full-mouth Rehabilitation with Fixed Implant-supported Prosthesis: A Case Report

Full-mouth Rehabilitation with Fixed Implant-supported Prosthesis: A Case Report

Electromyographic Evaluation of Masseter and Temporalis Muscle Activity in Distal Extension Edentulous Patients After Replacing with Implants—A Prospective Clinical Trial

Aim: To assess the changes in muscle activity after replacing the missing teeth or teeth with implants in distal extension edentulous patients and to evaluate the patient’s satisfaction levels. Materials and Methods: This was a single-group experimental study, based on convenience sampling with a sample size of 40 patients. Only unilateral mandibular distal extension edentulous sites were included and endo-osseous dental implants were placed in delayed protocol. Electrical activities of the masseter and temporalis muscles were recorded at rest and clench before, immediately, and one month after the cementation using electromyography. Patient satisfaction was analyzed through a questionnaire. Descriptive statistics an inferential statistics with repeated measures of ANOVA followed by the Bonferroni post hoc test were done to analyze the study data. P value &lt; .05 would be considered statistically significant for all the analyses. Results: Right temporalis showed significantly higher surface electromyography (sEMG) activity at one-month post cementation than baseline at rest and clench. Similarly, the left temporalis has shown significant sEMG activity at one-month post cementation than baseline at clench. However, there was no statistical difference with the right and left masseter. The implant-supported prosthesis was well received by the majority of patients. Conclusion: Definitive improvement in the electrical activity of the temporalis before and after the replacement of prosthesis was noticed with positive patient satisfaction levels with implant-supported prosthesis.

A New Full Digital Workflow for Fixed Prosthetic Rehabilitation of Full-Arch Edentulism Using the All-on-4 Concept.

(1) Background: Recent digital workflows are being developed for full-arch rehabilitations supported by implants with immediate function. The purpose of this case series is to describe a new digital workflow for the All-on-4 concept. (2) Methods: The patients were rehabilitated using the All-on-4 concept with a digital workflow including computerized tomography scanning, intra-oral scanning, and CAD-CAM production of the temporary prosthesis, with the 3D printing of stackable guides (base guide, implant guide, and prosthetic guide). The passive fit of the prostheses and the time to perform the rehabilitations were evaluated. (3) Results: The digital workflow allowed for predictable bone reduction, the insertion of implants with immediate function, and the connection of an implant-supported prosthesis with immediate loading. The time registered to perform the full-arch rehabilitations (implant insertion, abutment connection, prosthesis connection) was below 2 hours and 30 min. No passive fit issues were noted. (4) Conclusions: within the limitation of this case series, the digital workflow applied to the All-on-4 concept using stackable base-, implant-, and prosthetic guides constitutes a potential alternative with decreased time for the procedure without prejudice of the outcome.

Rehabilitation of mandibular resected patients using fixed immediately loaded corticobasal implant -supported prostheses. A case series

Introduction and importanceAliments such as congenital conditions, pathological, and iatrogenic circumstances may result in mandibular defects that can severely disturb the patients' oral health, functions (mastication, speech), aesthetics, and quality of life and present a rehabilitating challenge. Case presentationwe present a multidisciplinary treatment approach for three cases presented with mandibular resection as a consequence of cystic, benign, and malignant tumour eradication that were rehabilitated with immediately loaded fixed corticobasal implant-supported prostheses and a follow-up period of 5,5 and 4 years.The reported cases present with excellent implant survival, along with healthy peri-implant tissues, stable prostheses, enhanced speech, chewing ability, aesthetics, superior patient satisfaction, and improved overall self-esteem. Clinical discussionA multidisciplinary oral and maxillofacial team is mandatory for the successful rehabilitation of patients with mandibular resection and to restore soft and hard tissue loss. The reported treatment modality offers the patient immediate fixed implant-supported prostheses omitting the need for a bone grafting procedure, with optimum peri-implant tissue health, excellent biomechanical and prosthetic results, and significant improvement in function and satisfaction. ConclusionCorticobasal fixed implant-supported prostheses can be a reliable treatment modality for mandibular resection, resulting in notable enhancements in the patients' oral health, appearance, mastication, speech, and self-esteem.

Shock Absorption Capacity of High-Performance Polymers for Dental Implant-Supported Restorations: In Vitro Study.

Restorative materials might significantly affect load transmission in peri-implant bone. The aim of the present study is to evaluate the shock absorption capacity of two different polymeric materials to be used for implant-supported prostheses. A masticatory robot was used to compare the shock absorption capacity of veneered and non-veneered polyetherketoneketone (PEKK), Pekkton®ivory (Cendres+Mètaux), and the glass fiber-reinforced composite (GFRC), TRINIATM (Bicon). Five identical sample crowns for each of the three groups were tested. Forces transmitted at the simulated peri-implant bone were recorded and statistically analyzed. The statistical analysis of forces transmitted at the simulated dental implant revealed significant differences between the materials tested and between these materials and zirconia, glass ceramic, composite resin, and acrylic resin. Only differences between PEKK and veneered PEKK and between PEKK and one of the previously tested composite resins were not statistically significant. PEKK samples demonstrated significantly greater shock absorption capacity compared to GFRC. PEKK revealed optimal shock absorption capacity. Further studies are needed to evaluate its efficacy in the case of long-span prostheses with reduced prosthetic volume.

Marginal fit of 3-unit implant-supported fixed partial dentures: Influence of pattern fabrication method and repeated porcelain firings.

Marginal fit significantly impacts the long-term success of dental restorations. Different pattern fabrication methods, including hand-waxing, milling, or 3D printing, may affect restorations accuracy. The effect of porcelain firing cycles on the marginal fit of metal-ceramic restorations remains controversial, with conflicting findings across studies. The aim was to evaluate the potential effects of multiple porcelain firings (3, 5, 7 cycles) as well as pattern fabrication method (conventional hand-waxing, milling, and 3D printing) on the marginal adaptation of 3-unit implant-supported metal-ceramic fixed partial dentures. It was hypothesized that neither the wax pattern fabrication method nor repeated ceramic firings would significantly affect the marginal adaptation of metal-ceramic crowns. In this in-vitro study, 30 Cobalt-Chromium alloy frameworks were fabricated based on pattern made through three techniques: conventional hand-waxing, CAD-CAM milling, and CAD-CAM 3D printing (n = 10 per group). Sixteen locations were marked on each abutment to measure the vertical marginal gap at four stages: before porcelain veneering and after 3, 5, and 7 firing cycles. The vertical marginal gap was measured using direct microscopic technique at ×80 magnification. Mean vertical marginal gap values were calculated and two-way ANOVA and Tukey's post hoc tests were used for inter-group comparisons (α = 0.05). The 3D printing group showed significantly lower (P<0.001) mean vertical marginal gaps (60-76 μm) compared to the milling (77-115 μm) and conventional hand-waxing (102-110 μm) groups. The milling group exhibited a significant vertical gap increase after 3 firing cycles (P<0.001); while the conventional (P = 0.429) and 3D printing groups (P = 0.501) showed no significant changes after 7 firing cycles. Notably, the vertical marginal gap in all groups remained below the clinically acceptable threshold of 120 μm. CAD-CAM 3D printing provided superior marginal fit compared to CAD-CAM milling and conventional hand-wax pattern fabrication methods. The impact of porcelain firing on the mean marginal gap was significant only in the milling group. All three fabrication techniques yielded clinically acceptable vertical marginal adaptation after repeated firings. Additive manufacturing holds promise to produce precise implant-supported prostheses.

Prosthetic framework improvement using lattice structure: A comparative finite element study of a mandibular implant-supported prosthesis

Objectives:An alternative option was proposed regarding the prosthetic rehabilitation of a fully edentulous mandible using only four implants. The aim was to reduce the stiffness of the prosthetic framework. To that end, the alternative option consists of a prosthetic framework optimized with a porous structure. Mechanical differences were analyzed between non-prosthetic mandible and restored mandible either with a conventional bulk titanium framework or with this alternative option. The non-prosthetic mandible corresponds to the mandible in its natural state, without prosthesis. This will be considered as the reference for comparison with restored models (mandible with prosthesis). Methods:Three models are used: the first one is the non-prosthetic mandible, the second one is the restored mandible with conventional bulk titanium prosthetic framework, and the third one is the alternative option. Prosthetic framework was optimized with the use of a lattice structure. A numerical analysis was performed (with Abaqus Standard software®) to obtain the effective parameters corresponding to equivalent homogeneous behavior. In the 3 models, physiological boundary conditions were used, considering the activity of several muscles of the masticatory system during three main tasks of mastication (incisive clenching, maximum intercuspation and unilateral molar clenching). Results:Numerical simulations allowed to obtain mandibular global kinematics, local displacement at the bone–implant interface and the state of strain at the bone–implant interface, for each masticatory tasks. For this comparative study, the non-prosthetic mandible model was used as a reference to observe the benefits of using a lattice prosthetic framework compared to a conventional bulk titanium framework. Conclusion:Compared to conventional titanium framework, the lattice prosthetic one appeared to be more respectful of the natural mandible kinematics, given by the reference model. It also resulted in strain values within the physiological loading range.

Fiber-Reinforced Composites for Full-Arch Implant-Supported Rehabilitations: An In Vitro Study.

Background: Fiber-reinforced composites (FRCs) have been proposed as an alternative to traditional metal alloys for the realization of frameworks in full-arch implant-supported prostheses. The aim of the present in vitro study was to evaluate the deflection under load of seven prostheses endowed with frameworks made of different materials, including different types of fiber-reinforced composites (FRCs). Methods: A master cast with four implant analogues in correspondence with the two lateral incisors and the two first molars was used to create full-arch fixed prostheses with the same shape and different materials. Prostheses were made of the following different materials (framework+veneering material): gold alloy+resin (Au+R), titanium+resin (Ti+R), FRC with multidirectional carbon fibers+resin (ICFRC+AR), FRC with unidirectional carbon fibers+composite (UCFRC+C), FRC with glass fibers+resin (GFRC+AR), FRC with glass fibers+composite (GFRC+C), and resin (R, fully acrylic prosthesis). Flexural tests were conducted using a Zwick/Roell Z 0.5 machine, and the deflection of the lower surface of the prosthesis was measured in order to obtain load/deflection graphs. Results: Greater rigidity and less deflection were recorded for UCFRC+C and GFRC+C, followed by Ti+R and Au+R. The greatest deformations were observed for resin alone, ICFRC+R, and GFRC+R. The results were slightly different in the incisal region, probably due to the greater amount of veneering material in this area. Conclusions: When used to realize full-arch frameworks, Au and Ti allow for predictable mechanical behavior with gradual deformations with increasing load. UCFRC also demonstrated good outcomes and less deflection than ICFRCs when loaded. The GFRC full-arch framework may be a valid alternative, although it showed greater deflections. Further studies are needed in order to evaluate how different prosthesis designs and material thicknesses might affect the outcomes.

Analysis of Satisfaction Levels in Completely Edentulous Patients Treated with Different Configurations of Implant- Supported Prostheses.

To evaluate and compare patient satisfaction levels in edentulous patients treated with different configurations of implant-supported prostheses as well as previous prosthesis experiences before implant treatment. A study population of 142 patients was identified and separated into four treatment groups: group 1 comprised 43 patients treated with an implant-supported overdenture in the mandible and conventional complete denture in the maxilla; group 2 comprised 32 patients treated with implant-supported overdentures in the maxilla and mandible; group 3 comprised 26 patients treated with an implant-supported overdenture in the mandible and a fixed prosthesis in the maxilla; and group 4 comprised 41 patients treated with implant-supported maxillomandibular fixed restorations. Questionnaires asking about masticatory performance, pronunciation, comfort, and social ability were used to evaluate treatment outcomes. The patients in group 4 were significantly more satisfied regarding masticatory performance than other treatment modalities. Visual analog scale (VAS) scores for comfort and social ability were similar in groups 3 and 4 and significantly higher than those in groups 1 and 2. The patients who used a conventional removable prosthesis before implant treatment were more satisfied with their implant-supported prosthesis regarding social ability (P &#61; .03). The treatment design of an implant-supported fixed prosthesis in the maxilla and implant overdenture in the mandible provided a comparable level of satisfaction with maxillomandibular fixed prosthesis for edentulous patients. This combination served as a practical solution especially for patients with mandibular atrophy who would require extensive surgeries to support maxillomandibular fixed prostheses. In the maxilla, patient satisfaction with an implantsupported overdenture was not superior to that with a conventional prosthesis. Note that previous removable prosthesis experience may influence social comfort for patients.

Milled PMMA: A Material for Long-Term Implant-Supported Fixed Complete Dental Prostheses.

Traditionally, metal-ceramics, metal-reinforced acrylics, and-more recently-full-contour or layered zirconia have been the materials of choice for definitive fixed implant-supported rehabilitations. Polymethyl methacrylate (PMMA) is commonly used in implant dentistry for the fabrication of implant-supported interim prostheses and as milled or 3D-printed prototypes. This article describes a novel protocol to prosthetically restore a completely edentulous patient following a digital workflow, with fixed, screw-retained, implant-supported prostheses fabricated from CAD/CAM milled PMMA, with no metal substructure. After a 2-year follow-up in terms of esthetics, phonetics, function, and biologic tissue response, the outcome remains functional and free of mechanical, biomechanical, or biologic complications. The aim of this article is to illustrate the feasibility of using milled PMMA as a viable definitive prosthetic material for the fixed implant rehabilitation of edentulous patients.

Does intra-oral scan improve the impression accuracy of full-arch implant-supported prostheses: A systematic review and meta-analysis.

The present study aimed to systematically review the studies comparing the accuracy of intraoral scan (IOS) and conventional implant impressions (CI) in completely edentulous patients. Electronic searches were performed in PubMed, Embase and Cochrane CENTRAL up to December 1, 2023. Clinical studies and in vitro studies reporting the accuracy of digital full arch impressions were included. The primary outcome is the 3-dimensional deviations between the study reference models. A risk of bias assessment was performed for clinical studies. A stratified meta-analysis and a single-armed meta-analysis were conducted. A total of 49 studies were included, with 8 clinical studies and 41 in vitro studies. For comparison between IOS and conventional impressions, studies were categorized into two groups based on the different measurement methods employed: RMS and CMM. In studies using RMS, the result favored the IOS in the unparalleled situation with the mean difference of -99.29 μm (95% CI: [-141.38, -57.19], I2 = 81%), while the result was opposite with the mean difference of 13.62 μm (95% CI: [10.97, 16.28], I2 = 26%) when implants were paralleled. For different brands of IOS, the accuracy ranged from 76.11 μm (95% CI: [42.36, 109.86]) to 158.63 μm (95% CI: [-14.68, 331.93]). Accuracy of intraoral scan is clinically acceptable in edentulous arches, especially for unparalleled implants. More clinical studies are needed to verify the present finding.

A One-Year Randomized Controlled Clinical Trial of Three Types of Narrow-Diameter Implants for Fixed Partial Implant-Supported Prosthesis in the Mandibular Incisor Area.

Narrow-diameter implants (NDI) serve as a solution for treating limited bone volume in the anterior mandible. This study aimed to evaluate the one-year clinical outcomes of various NDIs in the mandibular incisor area after immediate loading in partially edentulous patients. This single-center, prospective, single-blinded, randomized controlled trial study included 21 patients, with 7 patients in each of the following groups: control (BLT NC SLActive®; Straumann), experimental group 1 (CMI IS-III Active® S-Narrow; Neobiotech), and experimental group 2 (CMI IS-III Active® Narrow; Neobiotech). Using full digital flow, two fixtures were placed in each patient and immediately provisionalized on the day of surgery. Evaluations encompassed periapical radiographs, implant stability quotient (ISQ), implant stability test (IST) readings, per-implant soft tissue health, patient satisfaction surveys, and esthetic score assessments. Definitive prostheses were delivered twelve weeks post-surgery (CRiS, number: KCT0007300). Following exclusions due to low stability values (n = 2), fixture failure (n = 5), and voluntary withdrawal (n = 1), the implant success rate for patients completing all clinical protocols stood at 100%. The resulting patient failure rates in the control, experimental group 1, and experimental group 2 were 50.0%, 42.9%, and 14.3%, respectively. There were no significant differences between the groups in terms of marginal bone loss, soft tissue health, patient satisfaction, and esthetic scores. Narrow implants showed superior clinical outcomes, followed by S-Narrow and Straumann implants. Calculated one-year survival rates at the implant level were 66.7% for the control group, 85.7% for experimental group 1, and 100% for experimental group 2. All three types of NDIs showed acceptable clinical and radiographic results during the year-long observation period.