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A comparative study was done regarding patient satisfaction between telescopic retained implant supported and retained over-denture prosthesis on four implants and a screw retained hybrid prosthesis rehabilitation also retained by four implants in patients with a completely edentulous mandible. Twenty patients were evaluated in this study, split into two groups. Regarding the evaluation of the patient satisfaction it was tested using a quantitative method, by asking the twenty patients different questions in a questionnaire. After an appropriate follow –up period from 2 weeks, to 12 months in both groups (telescopic retained overdenture and screw retained hybrid restoration), the results revealed the following; there was no statistically significant difference after 3 months as well as from 3 to 6 months and also from 6 to 9 months. Also there was a none statistically significant difference from 9 to 12 months, regarding patient satisfaction. In conclusion patients were equally satisfied with both prosthetic options.

With the help of dental implants, an oral rehabilitation can be performed not only very complex, but also very complete of various types of edentulous spaces. After insertion of the dental implants, they can be subsequently prosthetically restored through a wide range of implant-supported prosthetic restorations. In this material, we tried to highlight some particular aspects from the point of view of the laboratory stages of dental technique, which intervene in the technological flow of making implant-supported prosthetic restorations from ceramic masses on Zirconia structure.

Objectives 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 7-13 years. Material and methods 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 ≥1 mm were assessed. Peri-implantitis rates at 13 years were also calculated. Results 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 ± 1.03 mm, respectively. MBL ≥1 mm 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 ≥1 mm. 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. Conclusions It was concluded that FSI-FDP and FTI-FDP implants exhibited comparable MBL; however, the risk of MBL ≥1 mm in FTI-FDPs was lower than in FSI-FDPs. Besides, implant-abutment connection was the risk indicator of MBL ≥1 mm. In peri-implantitis rate, FSI-FDPs and FTI-FDPs behave similarly.

The aim of the study is to compare the prosthetic maintenance requirements between implant-retained ball overdentures versus fixed screw-retained implant prosthesis. Clinical and radiographic changes in peri-implant tissue with using PGE2 as a peri-implant crevicular fluid (PICF) biomarker were also evaluated. 54 completely edentulous patients were enrolled: group I, 27 patients were rehabilitated with fixed screw retained restorations; group II, 27 patients with ball retained implant overdenture. Prosthodontic complications were calculated. The clinical parameters were recorded and PICF was collected at baseline, 6- and 12-months postoperatively. There was no statistically significance difference between group I and group II regarding the frequency of maintenance of prosthetic parts of both types of restorations. There was a statistically significance difference between group I and group II regarding the frequency of maintenance of implant components. At 6‐ and 12‐month observation periods, group I showed statistically significant lower mean plaque index, gingival index, and pocket depth compared with group II (P .05). There was no difference in the frequency of maintenance of prosthetic parts between fixed screw retained restorations and ball retained over denture while the fixed screw retained restorations showed lower rate of maintenance of implant components. The screw retained group was more vulnerable than the ball group with respect to maintaining peri-implant tissue health.

Aim This clinical technique report aimed to describe a composite resin repair technique performed in an implant-supported prosthesis. Background Veneering ceramic fracture or chipping is one of the most frequent clinical failures in dentistry. Therefore, the use of less time- and cost-consuming ceramic repair techniques is helpful in clinical practice. Technique Briefly, to treat the ceramic surface, the glaze was removed at the margins of the fracture area, then, air-abrasion and acid-etching were performed. To promote chemical adhesion, a silane coupling agent and adhesive system were applied over the ceramic surface, and the composite resin was applied by incremental technique. Finally, the polish was performed. Conclusion In conclusion, the applied composite resin repair of feldspathic porcelain chipping in implant-supported prosthesis was a simple, easy, affordable, and minimally invasive treatment. Clinical significance The causes of veneer materials failures in metal-ceramic crowns are considered a challenge for the dentist and a problem that displeases patients. Repairs are indicated to prevent cracks from spreading and to prevent the accumulation of biofilm on the damaged surface. Therefore, different repair protocols have been proposed to enhance the esthetic, functionality, and longevity of the implant-supported prosthesis. Additionally, the success of the clinical cases depends on the capability to identify ceramic failures and the ability to indicate/perform the correct repair protocol. Since the described repair technique of the fractured screw-retained implant-supported prosthesis was a simple, easy, affordable, and minimally invasive treatment, with excellent esthetic and masticatory results, it represents an interesting clinical option.

Tooth loss is a common problem in adults. the negative effects of tooth loss are decreased chewing and speech function, reduced aesthetics, and migration of adjacent teeth. Many types of dental prosthetics can be used to prevent these negative effects, such as removable partial dentures, adhesive resin dentures, fixed partial dentures, and dental implants each prosthesis had its advantages and disadvantages. In this case report the clinician will discuss about single tooth implants. The aim of this case report is to provide information about the procedure for placement single tooth implants to the posterior mandibular teeth using the screw retained implant technique.

Total rehabilitation is one of the most sophisticated kinds of dental implant-supported prosthetics. The usage of multiunit abutment system allows the clinician an accurate and passive fitting of screw-retained full-arch construction. In addition, it retains a condition of soft and bone tissues around prosthetic construction. The aim of this case is to demonstrate a modern approach in planning and realisation of full-mouth screw-retained dental implant prosthetics. A 59-year-old patient had an extraction of all failed teeth on upper and lower jaws with immediate 16 implant placement (8 implants on maxilla and 8 implants on mandible) using surgical template. Multiunit abutments were installed intraoperatively. Temporary constructions were fixed immediately after surgery. After 3 months of dental impressions, plaster models and their scan were prepared to make final screw-retained zirconium dioxide constructions. Reevaluation of functional and aesthetic result of the treatment was made after 12 months.

A reabilitação oral implanto suportada, pode ser feita mediante coroas aparafusadas (CA) ou cimentadas (CC). O objetivo deste trabalho consiste em analisar algumas características mecânicas e biológicas de ambas as opções tais como: o índice de placa (IP), índice de sangramento (IS), mucosite, periimplantite, perda óssea (PO), fratura (F), chipping e o desaperto do parafuso. Realizou-se uma pesquisa bibliográfica na pubmed usando uma restrição temporal de 10 anos incidindo nos estudos clínicos, em inglês e em humanos. Relativamente aos resultados: o IP foi superior em CC devido à dificuldade de remoção e como consequência acumula mais placa bacteriana. Em relação ao IS foi igual nas CC e CA, a mucosite e a perimplantite foi mais frequente em CC derivado à inflamação dos tecidos, devido ao excesso de cimento. O aspeto biológico PO foi mais frequente em CA. O desaperto do parafuso e a F da cerâmica foi mais frequente em CA, em relação ao chipping foi mais frequente em CC, sendo que os valores não são estatisticamente significativos. Cada método de retenção tem as suas vantagens e desvantagens fazendo com que a sua escolha dependa das caraterísticas e necessidades de cada paciente. Com este trabalho foi possível concluir que não é possível determinar qual a melhor alternativa protética para as próteses fixas sobre implantes. A resposta a esta discussão só é possível de ser obtida após uma exaustiva avaliação de cada caso de reabilitação, ponderando as vantagens e desvantagens de cada técnica, não havendo uma resposta geral para qual o melhor tipo de retenção, podendo levar a diferentes tipos de conclusões. Implant-supported oral rehabilitation can be performed using screw-retained or cemented crowns. The objective of this work is to analyze some mechanical and biological characteristics of both options, such as: plaque index, bleeding index, mucositis, periimplantitis, bone loss, fracture, chipping, and screw loosening of the prosthetic abutment. A literature search was performed at pubmed using a 10-year time restriction focusing on clinical trials in English. Regarding the results. The PI was higher in CC because they are difficult to remove and, as a consequence, accumulate more bacterial plaque. In relation to IS, it was the same in CC and AC, and the lack of oral hygiene was due to the accumulation of cement. In this study, we also evaluated mucositis and periimplantitis, where tissue inflammation was more frequent in CC due to excess cement. The PO biological aspect was more frequent in CA. In the present studies, screw loosening and ceramic F was more frequent in AC, compared to chipping it was more frequent in CC, but always bearing in mind that, in general, the values are not statistically significant. Each retention method has its advantages and disadvantages, so that the choice of the best method depends on the characteristics and needs of each patient. With this work, it was possible to conclude that it is not possible to specify the best prosthetic alternative for fixed prostheses on implants. The answer to this discussion can only be obtained after an exhaustive evaluation of each rehabilitation case, weighing the advantages and disadvantages of each technique, with no general answer for which is the best type of retention, which may lead to different types of conclusions .

Objectives: The purpose of this randomized clinical trial was to compare the required time of potential clinical adjustments of posterior screw-retained monolithic zirconia implant retained crowns based on intraoral optical scanning (IOS) or conventional impressions. Materials and methods: Patients with posterior tissue level implants (Straumann RN) replacing solitary teeth were recruited. Of all patients, impressions were taken with both an IOS (3M™ TDS) and a conventional (polyether) pick-up impression. Randomization was performed after impression taking and patients were to receive either a crown based on the digital or the conventional impression. The time required for adjustments at placement was recorded. Additionally, restoration survival and mechanical complications with a follow-up of one year were documented. Results: Thirty two patients with 45 implants were included: 23 restorations in the test (IOS) and 22 in the control (conventional) group. The average adjustment time was 3.35 min (SD ± 3.38, range: 0–11 min) for the digital versus 6.09 min (SD ± 4.63, range: 0–18 min) for the conventional impressions (p =.039). A proper fit (no adjustments required) was achieved 39,1% in the digital and 18,2% conventional group respectively. All 45 restorations could be placed within the two planned appointments and only two minor mechanical complications occurred during the first year of function. Conclusions: The use of IOS resulted in shorter adjustment times at try-in than conventional impressions for solitary CAD/CAM implant restorations. Screw-retained solitary monolithic zirconia restorations on ti-base abutments show low complication- and survival rates in the short term.

OBJECTIVES To analyse whether there is a difference in marginal bone levels (MBL) and the respective changes between cemented and screw-retained reconstructions at 3 and 5 years of loading. METHODS Radiographic data from 14 prospective multicentre clinical trials following implant loading with fixed cemented (CEM) or screw-retained (SCREW) reconstructions with a 3- to 5-year follow-up were retrieved from a database. MBL and MBL changes were assessed at initiation of implant loading (BL), at 3 (FU-3) and 5 years (FU-5) thereafter. The presence of peri-implantitis was also determined. RESULTS Data from 1,672 implants at BL, 1,565 implants at FU-3 and 1,109 implants at FU-5 were available. The mean MBL amounted to 0.57 mm (SD 0.87) at BL, 0.55 mm (SD 0.86) at FU-3 and 0.65 mm (SD 1.18) at FU-5. At FU-3, the mean MBL was 0.44 mm (SD 0.65) in group CEM and 0.63 mm (SD 0.99) in group SCREW showing a significant difference between the groups (intergroup

Implant design factors and the abutment connection are correlated with crestal bone stability. The aim of the present study was to evaluate a new type of screw-retained prostheses delivered on tissue-level implants with conical external vertical seal and internal hexagon connection. Implants 4.25 mm in diameter and 10 mm in length (Prama, Sweden and Martina) were placed in partially edentulous patients needing at least one implant in the healed site, having sufficient bone volume. The implant neck was positioned above the bone crest. A healing abutment was placed according to a one-stage approach. Outcome measures were implant and prosthesis survival rate, any complications, marginal bone loss (MBL), periodontal parameters, and pink esthetic score (PES). Overall, 13 patients (4 women and 9 men, mean age 50 ± 22 years) with the same number of implants were treated and followed for one year after loading. At the 12-month follow up, no implant and no prosthesis failed, and no complications were experienced. The mean MBL experienced at the one year follow-up was 0.65 ± 0.48 mm. One year after loading, 2 out of 13 implants present bleeding on probing (15.4%), 4 out of 13 patients presented with plaque at the one year of follow-up (30.8%) and the PES was 10.5 ± 2.3 mm. Within the limitations of the present study, the analyzed implants seem to be a viable treatment option for the rehabilitation of a single tooth gap.

Clinical oral implants research 32(12), 1484-1495 (2021). doi:10.1111/clr.13849, Published by Wiley-Blackwell, Oxford

Objectives: This research aimed to compare the oral health-related quality of life (OHRQoL) between fully dentate subjects and edentulous patients wearing implant-supported fixed partial dentures (i-FPDs). The clinical conditions of both types of restorations were evaluated. Methods: Participants were assigned to: Group-1 (SR, n = 50): screw-retained i-FPD wearers; Group-2 (CR, n = 50): cement-retained i-FPD wearers; and Group-3 (ND, n = 50): dentate subjects with a healthy natural dentition (controls). Patients answered the OHIP-14sp and QoLIP-10 questionnaires. Data related to sociodemographics, prosthesis features, peri implant status, complications, and subjective evaluations, were compiled. Potential modulators of the OHRQoL and the i-FPDs’ clinical conditions were assessed using non-parametric tests (α= 0.05). Results: ND individuals were the least satisfied (OHIP-14sp; p< 0.001). Both prosthodontic groups reported similar levels of wellbeing, excluding the speaking difficulties, which were lower for SR wearers as shown by both scales (p = 0.001). The most discontented patients (OHIP-14sp) were: women (p = 0.022), under 65 years (p = 0.03), without partner (p< 0.001) and having a crown (p = 0.033). The level of education/schooling also affected the OHIP-14sp scores (p< 0.001). Implant mobility and peri implantitis were more frequent among CR wearers (p-values= 0.008 and 0.05, respectively). Conclusions: The OHRQoL of both prosthodontic groups was comparably higher than that of the dentate subjects, who were the most nonconformist. The self-perceived satisfaction was mainly modulated by sociodemographic factors. Clinical significance: Overall, the retention system did not impact the OHRQoL, prosthetic problems, and subjective evaluations of i-FPD wearers. However, the cementation may increase the risk of peri implant diseases.

Objective. The introduction of CAD/CAM and the development of zirconia-based restorations have allowed clinicians to use less expensive materials and faster manufacturing procedures. The purpose of the study was to analyze the differences, in terms of mechanical and biological complication, in multiunit zirconia fixed dental prosthesis (FPDs) on posterior implants produced using a digital workflow. Method and Materials. This study was a retrospective investigation, and patients treated with screw-retained monolithic or partial veneer FPDs on dental implants were selected. Periapical radiographs were taken at baseline and at the 3-year follow-up. Complications were recorded and classified as technical and biological ones. Results. The study population included 25 patients. The occlusal and interproximal corrections were not clinically significant. In the study sample, the survival rate and success rate of the FPDs after 3 years were 100% and 96%, respectively. One implant failed immediately after placement. Conclusion. Monolithic zirconia FPDs and partial veneer FPDs showed a 100% survival rate, presenting an interesting alternative to metal ceramic restorations. The partial veneer FPDs had a higher technical complication rate than the monolithic FPDs; however, no statistically significant difference was found.

Conventionally casted frameworks have been considered the preferredsolutions for complete and partial restorations since the beginningof implantology. However, following technological development, thecomputer aided design/computer aided manufacturing (CAD-CAM)with milling the frameworks has been introduced as an alternativeoption with the potential of minimising inaccuracies, reducing theoperator dependence and offering a homogeneous structure with highmechanical properties. The CAD-CAM multi-unit reconstructionvaries with fixation type, implant framework connection, andprostheses material. However, the materials developed for theuse of CAD-CAM, may have different technical and biologicalcomplications with time.The present thesis aims to provide insights into the risk ofcomplications in screw-retained multi-unit frameworks manufacturedusing the CAD-CAM technique. An in vitro test (Study I) was performed to assess the effectsof misfit at implant-level FPDs and supporting bone levels on thegeneration of implant cracks. Three clinical studies were conducted:in Study II, partially edentulous patients were rehabilitated with eitheran abutment or implant level multi-unit Cobalt-Chromium metalceramicframework; in Study III, patients, edentulous in the maxilla,were treated with either four or six implants and rehabilitated witha fixed titanium metal-acrylic framework; in Study IV edentulouspatients were treated with removable overdentures retained bytitanium milled bars. In Study III and IV, Oral Health Related Qualityof Life was evaluated.The marginal bone level change was clinically not significantregardless of fixation type (Study II), retention (Study III-IV), andmaterial used (Study II-III-IV). No framework complications wereregistered. Patients reported a high level of satisfaction after thetreatment (Study III-IV). Based on the studies included in this thesis, the followingconclusions can be made: (i) the risk of implant cracks in screwretainedImplant Level (IL) Fixed Partial Denture (FPD) is low, evenwith a misfit; (ii) according to the 1-year data presented in Study II,abutment level (AL) retention is recommended for FPDs; (iii) the costeffectivefor a maxillary Fixed Complete Denture (FCD) supported byfour implants can be considered predictable and comparable to siximplants; (iv) implant-supported FCDs and Implant supported Over-Dentures (IOD) are associated with high rates of patient satisfaction,related to aesthetics and mastication function mainly resulting fromthe high stability of the prostheses; (v) the technical and biologicalcomplications reported in FPDs, FCDs and IODs were limited.However, a considerable percentage of prosthetic fractures andchippings were reported for FCDs at 1-year and 3-year follow-ups.Clinicians have to be aware that additional visits may be required formaintaining the prostheses.

The aim of this study was to assess the influence of moderate cigarette smoking on the clinical (bleeding on probing [BoP] and probing depth [PD]) and radiographic (crestal bone resorption [CBR]) parameters around cement- and screw-retained dental implants at 5-year follow-up. A questionnaire was used to collect information about age, gender, smoking history, duration of implants in function, jaw location of the implant, and daily toothbrushing and flossing. Peri-implant BoP, PD, and CBR were measured in all groups. Group comparisons were performed using 1-way analysis of variance, and for multiple comparisons, the Bonferroni post hoc adjustment test was performed. The level of significance was set at P < .05. Forty-eight patients (25 smokers and 23 nonsmokers) had cement-retained dental implants, and 48 (24 smokers and 24 nonsmokers) had screw-retained dental implants. Among patients with cement- and screw-retained dental implants, PD (P < .05) and CBR (P < .05) were significantly higher among smokers than nonsmokers. The peri-implant sites that demonstrated BoP were statistically significantly higher among nonsmokers (P < .05) than smokers among patients with cement- and screw-retained dental implants. There was no statistically significant difference in peri-implant PD and CBR among smokers with cement- and screw-retained dental implants. Among nonsmokers with cement and screw-retained dental implants, there was no statistically significant difference in BoP, PD, or CBR. Cigarette smoking is associated with an increased PD and CBR around cement- and screw-retained dental implants. Cigarette-smoking increases peri-implant soft-tissue inflammation as well as loss of crestal bone, and this relationship is independent of the type of implant retention protocol used. The author recommends that cement- and screw-retained dental implants are suitable for prosthesis restoration in nonsmokers. Further studies on dual smokers (individuals smoking cigarettes and other forms of tobacco products) are needed related to the clinicoradiographic inflammatory parameters around cement- and screw-retained dental implants

Purpose This study investigated the in-vitro performance of anterior implant-supported fixed dental prostheses (FDP). The effect of ceramics, fabrication, finalization and the presence of a screw-channel wa s investigated. Methods Identical anterior ceramic FDPs (tooth 11-13; n=80) were milled (Lithiumdisilicate (LiSiCAD, emaxCAD, Ivoclar-Vivadent), Lithiumaluminiumsilicate (LiAlSi, experimental material) or pressed (Lithiumdisilicate (LiSiPress, emaxPress, Ivoclar-Vivadent), Lithiumsilicate (ZLS, CeltraPress, Dentsply Sirona). FDP-groups (n=8 per material and group) simulated a cemented or screw-retained approach. After cementation or screwing on titanium abutments, thermal cycling and mechanical loading (TCML) was performed on all restorations to mimic 5-year clinical performance. Performance and fracture force were determined and failures were analyzed. Statistics (Kolmogorov-Smirnov-test, one-way-ANOVA; post-hoc-Bonferroni, multivariate-regression, α=0.05). Results All FDPs survived TCML without aging, cracks, fractures or chipping. For FDPs without screw channel fracture values varied between with 839.8±112.3N (LiAlSi glazed) and 1485.9±232.6N (LiSiCAD). With screw channel, fracture results varied between 701.4±220.1N (LiALSi glazed) and 1516.3±253.7N (LiSipress). The type of material had a significant influence on the fracture results (LiSi>ZLS>LiAlSi; p≤0.012). Fabrication and finalization had no influence on the results. A screw channel did not significantly (p≥0.135) reduce the fracture force of the FDPs. Type of failure was mostly characterized by a fracture of the connector (LiSi, LiAlSi) or the abutment (ZLS, LiAlSi). Conclusions FDPs survived TCML without failures indicating that the in vitro performance was not influenced by the tested parameters. Composition of ceramic material has significant influence on the fracture resistance of implant supported LiSi based FDPs. Screw channel, fabrication or finalization did not weaken the FDPs.

Marginal bone loss (MBL) is a key factor in long-term implant success rate. Among the different factors that influence MBL, it is the different implant shoulder designs, such as scalloped or non-scalloped, which have been widely studied on screw retained but not on cemented retained implants. Thus, the aim of the present study was to evaluate the MBL around scalloped and non-scalloped cemented retained dental implants after 4 years of loading, in humans. A total of 15 patients were enrolled in the present study. A radiographic and clinical examination was performed after implant placement (T0) and after 4 years from it (T1). The results demonstrated a differential MBL (T1-T0) of 2.436 &plusmn, 1.103 mm and 1.923 &plusmn, 1.021 mm, respectively for test (scalloped) and control (non-scalloped) groups with a statistically significant difference between them. On the other hand, no statistically significant differences were found between the groups in terms of prosthetic complication and abutment decementation, whilst ceramic crowns chipping was shown in both groups. In conclusion, the use of a scalloped platform did not provide better results on the maintenance of MBL after 4 years follow-up. In this study, this probably was determined by multiple factors, among which was the subcrestal insertion of scalloped implants.

The aim of this study was to document the performance of a novel technique (OnlyOne), involving immediate restoration of postextraction implants supporting a partial or full-arch restoration. A retrospective analysis of patients with at least 3 years of follow-up was performed. Implants were tilted mesiodistally and vestibulopalatally according to the available bone. Prosthetically guided definitive abutments were connected at surgery and never disconnected. Anorganic bovine bone grafting was done to preserve the buccal bone and the ridge contour. Patients received a screw-retained provisional prosthesis within 24 hours of surgery and a final screw-retained prosthesis within 1 year. Prostheses emerged from natural soft tissue. Clinical and radiographic evaluation was routinely performed. A total of 70 patients received 153 implants in fresh extraction sockets. The mean follow-up was 38.0 ± 3.0 months (range 36 to 51 months). One implant failed at the 3-year follow-up. Implant survival was 99.3%. Marginal bone level change averaged -0.68 ± 1.2 mm at the last radiographic control. Immediate placement and restoration of implants designed for high primary stability with a definitive abutment placed at surgery and final screw-retained prosthesis with no artificial gingiva is a viable procedure with excellent medium-term outcomes.

Purpose: This systematic review aimed to evaluate retention failures in cement- and screw-retained fixed restorations on dental implants in partially edentulous arches. Methods: The relevant articles were retrieved from MEDLINE (PubMed), Cochrane Library, and EBSCO electronic databases for articles published from January 1995 to January 2016 and were restricted to randomized controlled trials and retrospective and prospective studies on human subjects that were reported in English. A further hand search was conducted on individual journals and reference list of the articles found. Reviewed studies which reported retention failures in fixed implant-supported prostheses using screw and cement retention mechanism. Information on the type and nature of restoration, as well as different luting cement, were also collected. Results: Thirty-three articles were finalized, 20 short-term clinical studies (up to 5 years) and 13 long-term studies (≥5 years). Out of 33 studies, 16 studies were included in meta-analysis, 8 in short-term and 8 in long-term studies. The results of the meta-analysis for short-term studies showed statistically significant difference between cement-retained and screw-retained prosthesis, with the forest plot favoring cement-retained prostheses (risk ratio [RR]: 0.26; confidence interval [CI]: 0.09–0.74; P < 0.0001; I2 = 79%). In long-term studies, the forest plot revealed statistically significant difference between both retention systems favoring cement-retained prostheses (RR: 0.31; CI: 0.13–0.76; P = 0.03; I2 = 56%). Conclusion: Analysis of the short- and long-term studies shows lesser retention failures with cement-retained prostheses when compared to screw-retained prostheses. Further, multicentric, high-quality randomized controlled studies with long-term observations and modified cementation protocols can yield higher grades of recommendation to avoid retention failures.

Introduction: The discovery of titanium osseointegrated implants enabled the development of screw or cement-retained dental prostheses. However, each retention method involves different aspects. Objective: this study aims at reviewing the literature of in vitro and in vivo studies of the last 7 years on the mechanical, biological, aesthetic and occlusal properties and the cost of screw and cementretained prostheses to identify what can promote greater longevity and economy by considering the patient’s clinical framework. Data sources: Our method was based on the collection of scientific articles published in English from 2012 to 2018 in the PubMed database. Summary of the findings: we noted that in some clinical cases, a retention method was more appropriate than the other, as seen in the access to the posterior region or the palatal face of the crowns, the position/angulation of implants in the anterior region, the patient’s health and economic conditions. Both protheses can suffer or not from mechanical and biological complications. Reversibility can also be associated to cement-retained protheses. There are alternatives to screwed prosthetics to achieve satisfactory aesthetics in the anterior region despite being more expensive. Ideal occlusion tends to be more easily achieved by cemented prosthesis as it avoids prosthetics screws and the formation of crown holes, despite the contributions of correct planning followed by the analysis of static and in motion occlusions. Conclusion: each retention method has its advantages and disadvantages. Therefore,the best method is the one that best fits the characteristics and needs of each patient.

Purpose: This review aimed to compile and enumerate all the factors described in the literature that may affect the decision to use either cemented or screw-retained restorations and to determine the relative weights of each factor by type of retention and prosthesis. Materials and Methods: The literature was reviewed, and the factors were classified as either determining (present in a clinical situation in which one of the retention mechanisms was clearly more suitable than the other) or conditioning (present in clinical situations in which one type of restoration was not clearly more advantageous than the other). Results: Three determining factors (esthetic outcome, retention, and biologic risk) and five conditioning factors (passive fit, fracture strength, occlusal area, complications, and retrievability) were identified. Conclusion: Although there is not a clearly better alternative for all clinical situations, determining factors in certain scenarios can render one of the two approaches more recommendable. For esthetic reasons, when the implant angle cannot be corrected to conceal the access hole, cementation is more suitable; however, screw retention is the better option when the occlusal space is under 6 mm or margins cannot be located supra- or equigingivally. In the absence of determining factors, the decision should be based on conditioning factors, which carry different weights depending on the type of prosthesis. Sin financiación 1.533 JCR (2018) Q3, 47/91 Dentistry, Oral Surgery & Medicine 0.914 SJR (2018) Q1, 657/2894 Medicine (miscellaneous) No data IDR 2018 UEM

Dental implants became a viable alternative involving the Odontology field developing the aesthetics function and the patient’s comfort. The choice of which type of prosthesis connection is based on their clinical situation of each case and also for own professional preferences. There are two types of prosthetic restorations commonly used in Implantology: the cemented one and the screw retained prosthesis; both have their own advantages and limitations. The decision of which prosthetic method to use starts during the planning stage and can imply the aesthetics, dental occlusion, retention, effect over the peri-implant tissue, among other complications, influencing the implant survival rate. The peri-implant marginal bone loss is one of the problems related to the late failure of the osseointegration of the implants, being a relevant cause of failure, because it may promote the implant removal due to the osseointegration loss. The goal of this study was to analyze and identify the relation of different types of prosthesis (cemented and screw retained) through a literary point, with the peri-implant marginal bone loss, as well as relate the used type of prosthesis with the implant survival rate. Therefore, it is concluded that the marginal peri-implant bone loss owns multifactorial etiology and there are other factors that influence the implant survival, which is not possible to obtain a straight bone loss comparison with the types of prosthesis installed. Nevertheless, the screw-retained prosthesis presented more biomechanical complications such as the screw loosening and the ceramic fracture; and the cemented prosthesis showed more biological complications involving the peri- implant tissues.

Key Clinical Message Treatment of atrophic edentulous jaws with implant‐supported fixed prostheses is one of the most complicated challenges in dentistry. This clinical report describes the prosthesis which consists of screw retained frameworks with individual cement retained crowns which combines the advantages of the screw retained restoration with the advantage of cement retained.

AIM: This study was established to evaluate the amount of bone height changes in the posterior mandibular area of edentulous patients receiving screw-retained prostheses versus removable telescopic implant overdentures.MATERIAL AND METHODS: Every patient received four inter-foraminal implants regarding the mandibular arch and four anterior implants for the maxillary arch, computer guided surgical guides were planned for the insertion of the implants accurately with a flapless technique. Panoramic radiographs were made immediately, six months and twelve months after the prostheses` use proportional area and vertical measurements were applied to determine changes in the bone height of the posterior mandibular edentulous area.RESULTS: After twelve months, a statistically non-significant amount of bone resorption was reported for both groups.CONCLUSION: Up to the limitations of this study both treatment options the screw retained and telescopic overdenture can be used for rehabilitation of completely edentulous patients. These cases must be followed for a longer period to have a definite answer regarding their efficiency in the long run.

Purpose: The aim of the paper is to present the designing and manufacturing process ofthe screw-retained superstructure of the dental arch in the maxilla based on six implants usingCAD/CAM technology.Design/methodology/approach: The methodology is presented on the example of theimplantoprosthetic treatment in a 55-year-old female patient with a significant deficit of the alveolarbone. 6 implants were placed to achieve a good anchorage for the ceramic suprastructure. Theprosthetic reconstruction was milled out of a zirconium dioxide block and covered with veneeringceramics to obtain good aesthetics of the restoration. Special copings were designed andmanufactured to achieve stabile connection between the implants and the suprastructure.Findings: To properly plan the prosthetic work rebuilding the alveolar ridge on dental implantsit is necessary to plan the final prosthetic work before implant placement planning the numberof implants and their location in the bones and the possibility of using a fixed or a mobilesuprastructure.Practical implications: Design of the suprastructure has to take into account the followingfactors: 1. The number of implants, copings and openings for the abutment screws, 2.Arrangement of teeth in the prosthesis, 3. The shape of the alveolar ridge, 4. The shape of thespace for the porcelain and for the individual crowns, which will be pasted on the suprastructure.Originality/value: For technological reasons it is not possible to make an extensivesuprastructure in a single piece. It is necessary to execute the foundation of the reconstructionof the alveolar ridge and the teeth in one piece and separately the individual crowns. Itis possible, however, to design and manufacture the complex screw-retained prostheticsuprastructures by means of CAD/CAM technology.

Background: The objective of this study was to compare conventional versus digital impressions for Full-Arch maxillary rehabilitations. Methods: Patients selected for this study were treated with full-arch screw-retained rehabilitations supported by six immediately loaded dental implants. Patients have been scheduled randomly into control (conventional impression group, CIG) and test (digital impression group, DIG) groups respectively for a fully conventional workflow and a fully digital workflow. In both groups, within 24 h, temporary prostheses were delivered. Four months after the implant positioning, the two groups dealt with the fabrication of definitive restorations: conventional pick-up was performed in the control group, and definitive digital impressions were carried out in the test group. The time involved following these two procedures was recorded. Patients underwent intraoral digital radiographs to evaluate the accuracy of the framework-implant connection, check for the presence of voids at the bar-implant connection and measure bone level. Criteria used to assess success at the prosthetic level were the occurrence of prosthetic maintenance, the absence of fractures of the acrylic resin superstructure and voids. Results: A total of 50 patients received immediately loaded prostheses supported by six implants (total 300 implants). A fixture and prosthetic survival rate of 100% was observed. All digital X-ray examinations revealed a bar-implant connection accuracy and no voids. Differences that were not statistically significant (p &gt, 0.05) in marginal bone loss were found between control and test groups. Significantly less time was spent to perform digital impression procedure (p &lt, 0.05). Conclusions: Clinical and radiological results of the test group advocate a satisfactory accuracy and predictability of the intraoral scanner (IOS) to be a reliable alternative in clinical practice for implant full-arch rehabilitations and suggest fabrication of definitive restorations with a successful marginal fit precision.

Background: Discordant opinions have emerged among clinicians and researchers regarding a digital impression for full-arch implant-supported fixed dental prostheses (FDPs). The purpose of this study was to assess the fit of screw-retained milled frameworks on six implants realized from digital impressions through the Sheffield test. Methods: One patient received a maxillary full-arch implant-supported FDP. Six months after the surgical procedure, ten intraoral full-arch digital impressions were performed to mill ten frameworks. To clinically assess the fit, the Sheffield test was applied for all frameworks. The gaps among the frameworks and the implant analogs were measured using a microscope on the master model realized with a traditional impression. The Wilcoxon sum-rank test was used to compare the misfit value among the different implant positions. Results: The Sheffield test did not show gaps in the framework–implant interfaces when the screw was completely tightened on the more distal implant for all the milled frameworks. The mean misfit value calculated after microscope examination was 38 ± 5 μm. Differences that were statistically significant emerged when the misfit values of central positions were compared with other values. Conclusions: The use of full-arch implant digital impressions represents a viable alternative to traditional impressions for the fabrication of implant-supported FDPs.

Single tooth implant restorations in the aesthetic area are a demanding challenge. If a complete osseointegration is mandatory, the final result has to result in a higher standard of biomimetic and soft tissue health among natural teeth. This outcome is traditionally pursued by cementing crowns over individualized abutments. However, in recent years, the need for controlling peri-implant health and the preference towards a retrievable solution has led to an increase in screw-retained crowns, which is not always applicable when the implant axis is not ideal. In the aesthetic area, the use of a novel technical solution represented by the angled screw channel (ASC) of the abutment has been proposed in order to match the advantages of the screwed solution with the aesthetic demands. The aim of this study was to compare ASC crowns to cemented crowns (CC) in single implant restorations using the white esthetic score (WES) and pink esthetic score (PES) at the crown delivery and at a follow-up of a minimum of 2 years. Peri-implant health and marginal bone loss (MBL) were also evaluated. The mean follow-up was 44.3 months, with a mean MBL of 0.22 mm in the ASC group and 0.29 mm in the CC group. The total WES/PES score was 16.6 for ASC, compared with 17.3 for CC at baseline, and 16.2 and 17.1, respectively, at follow-up. Both of the groups reached a high WES/PES, and this was maintained over time, without signs of peri-implant diseases or bone loss, regardless of the choice of connection. In conclusion, ASC can be adopted in cases where the implant axis is not ideal, with aesthetic and functional results that are comparable to implants restored by cemented crowns.

A technique is described where an interim abutment and crown are fabricated in the laboratory by utilizing computer-aided design/computer-aided manufacturing (CAD/CAM) technology and placed the day of dental implant surgery. The design and contours of the interim crown are designed by the computer software to be identical to the contours of the tentatively designed definitive prosthesis. The interim crown satisfies esthetics immediately after dental implant surgery while allowing the tissue to heal and obtain contours similar to the contours of the definitive prosthesis. The interim crown can be either cement retained or screw retained. The presented technique describes fabrication of a screw-retentive interim crown. After osseointegration is confirmed, a definitive impression is made with a CAD/CAM impression coping. The definitive prosthesis is then fabricated.

PURPOSE The modified lateral-screw-retained implant prosthesis (LSP) is designed to combine the advantages of screw- and cement-retained implant prostheses. This retrospective study evaluated the mechanical and biological complication rates of implant-supported single crowns (ISSCs) inserted with the modified LSP in the posterior region, and determined how these complication rates are affected by clinical factors. MATERIALS AND METHODS Mechanical complications (i.e., lateral screw loosening [LSL], abutment screw loosening, lateral screw fracture, and ceramic fracture) and biological complications (i.e., peri-implant mucositis [PM] and peri-implantitis) were identified from the patients' treatment records, clinical photographs, periapical radiographs, panoramic radiographs, and clinical indices. The correlations between complication rates and the following clinical factors were determined: gender, age, position in the jaw, placement location, functional duration, clinical crown-to-implant length ratio, crown height space, and the use of a submerged or nonsubmerged placement procedure. RESULTS Mechanical and biological complications were present in 25 of 73 ISSCs with the modified LSP. LSL (n=11) and PM (n=11) were the most common complications. The incidence of mechanical complications was significantly related to gender (P=.018). The other clinical factors were not significantly associated with mechanical and biological complication rates. CONCLUSION Within the limitations of this study, the incidence of mechanical and biological complications in the posterior region was similar for both modified LSP and conventional implant prosthetic systems. In addition, the modified LSP is amenable to maintenance care, which facilitates the prevention and treatment of mechanical and biological complications.

Objectives The aim of this controlled in vitro study was to identify and quantify up to 38 microbial species penetrating through the screw-retained implant prostheses with different sealing materials. Material and methods Sixty morse cone implants were restored with single-unit screw-retained prostheses. All the components were randomly divided into five groups (n = 12) according to the proposed materials: (1) polytetrafluoroethylene tape+composite resin; (2) polytetrafluoroethylene tape+gutta-percha; (3) polytetrafluoroethylene tape+light-polymerized provisional composite; (4) cotton pellet+gutta-percha; and (5) cotton pellet+light-polymerized provisional composite. Human saliva was used as contaminant media, and DNA checkerboard hybridization was used to identify and quantify microbial species. Results Microbial leakage was observed in all groups: M. salivarium, S. pasteuri, P. nigrescens, and P. melaninogenica were the species presenting the highest values of genome count, prevalence, and proportion within the groups. The total microbial mean counts (×105, ±SD) were as follows: Group 1 (2.81 ± 0.38), Group 2 (3.41 ± 0.38), Group 3 (6.02 ± 1.48), Group 4 (6.40 ± 1.42), and Group 5 (17.45 ± 1.67). Group 5 showed the higher microbial counts (P