Biological Complication Rates Research Articles

Partial Implant Rehabilitations in the Posterior Regions of the Jaws Supported by Short Dental Implants (7.0 mm): A 7-Year Clinical and 5-Year Radiographical Prospective Study.

Background: Short implants have been used in the restoration of edentulous jaws in the past several years. However, some studies have suggested that short implants are less successful than standard implants. The aim of this study is to investigate the outcome of short implants placed in the posterior maxilla or mandible following one-stage or immediate-function protocols with a follow-up of 7 years (clinically) and 5 years (radiographically). Methods: This study included 127 patients rehabilitated with 217 implants measuring 7 mm and supporting 157 fixed prostheses in the posterior segments of both jaws. Final abutments were delivered at the surgery stage and were loaded after 4 months in 116 patients (199 implants). The primary outcome measure was implant survival measured through life tables. Secondary outcome measures were marginal bone loss and the incidence of biological and mechanical complications at the patient level and implant level (evaluated through descriptive statistics). Results: Twenty-four patients (18.9%) with 45 implants (20.7%) were lost to the follow-up. In total, 32 implants failed (14.8%) in 22 patients (17.3%), resulting in a cumulative survival rate at 7 years of 81.2% for 7 mm implants in the rehabilitation of the posterior regions of the maxilla and mandible. The average (standard deviation) marginal bone loss was 1.47 mm (0.99 mm) at 5 years. The incidence rate of biological complications was 12.6% and 10.6% at the patient and implant levels, respectively. The incidence rate of mechanical complications was 21.3% for patients and 16.1% for implants. A higher failure rate was registered in smokers and in implant arrangements with a sequence of three fixtures in proximity. Conclusions: Within the limitations of this study, it can be concluded that the placement of 7 mm long implants for the partial implant-supported rehabilitation of atrophic posterior jaws is possible in the long term, judging by the survival rate and stable average marginal bone loss. Nevertheless, strict case selection should be performed, especially in smokers and with implant arrangements that provide a minimum of one unit in inter-implant distance.

Customized Subperiosteal Implants for the Rehabilitation of Atrophic Jaws: A Consensus Report and Literature Review.

(1) Background: The aim was to perform a literature review on customized subperiosteal implants (CSIs) and provide clinical guidelines based on the results of an expert consensus meeting held in 2023. (2) Methods: A literature search was performed in Pubmed (MEDLINE) in July 2023, including case series and cohort studies with a minimum follow-up of 6 months that analyzed totally or partially edentulous patients treated with CSIs. Previously, an expert consensus meeting had been held in May 2023 to establish the most relevant clinical guidelines. (3) Results: Six papers (four case series and two retrospective cohort studies) were finally included in the review. Biological and mechanical complication rates ranged from 5.7% to 43.8% and from 6.3% to 20%, respectively. Thorough digital planning to ensure the passive fit of the CSI is mandatory to avoid implant failure. (4) Conclusions: CSIs are a promising treatment option for rehabilitating edentulous patients with atrophic jaws; they seem to have an excellent short-term survival rate, a low incidence of major complications, and less morbidity in comparison with complex bone grafting procedures. As the available data on the use of CSIs are very scarce, it is not possible to establish clinical recommendations based on scientific evidence.

Prevention of peri-implant disease in edentulous patients with fixed implant rehabilitations.

To provide an overview about the current approaches to prevent peri-implant diseases in edentulous patients with complete-arch implant-supported prostheses, and to review the clinical applications of the latest digital technologies for implant prosthodontics. A review of the guidelines to prevent peri-implant diseases in patient's receiving complete-arch implant-supported prostheses including facially driven treatment planning procedures using either conventional or digital methods, computer-aided implant planning procedures, and prosthodontic design variables including the optimal number and distribution of dental implants, implant to abutment connection type, implant or abutment level design, screw- or cement-retained alternatives, prostheses contours, and material selection is provided. Furthermore, an outline of the current therapeutic management approaches to address peri-implant diseases is reviewed. Clinicians should understand and know different planning and design-related variables that can affect biological and mechanical complication rates of complete-arch implant-supported prostheses. Maintenance protocols are fundamental for minimizing biological and mechanical complications.

Double Crown-Retained Removable Prostheses Supported by Implants or Teeth and Implants: A Long-Term Clinical Retrospective Evaluation

Objectives: The objective of this retrospective clinical study was to investigate the survival rates and complications of implant (I)-retained or tooth-implant (TI)-retained prostheses and abutments (teeth, implants) over a mean observation period of 11.26 years. The study also aimed to analyze the differences and complication rates between implant-retained double crown removable dental prostheses (I-DC-RDPs) versus tooth-implant-retained double crown removable dental prostheses (TI-DC-RDPs). Material and Methods: We reviewed the clinical data of 110 nonsmokers (mean age = 53.9 years) who received DC-RDPs in maxillary or mandibular arches. 153 teeth and 508 implants were used to restore partially edentulous (PE; TI-DC-RDPs; n = 53) and completely edentulous (CE; TI-DC-RDPs; n = 57) arches. Two designs of the distal extension were used: cantilevers (CANs) and saddles (SADs). Restorations were examined for abutment survival, mechanical, or biological complications. Results: The 10-year survival rates were 99.3% (95% CI: 95.4–99.9%) for teeth and 99.3% (95% CI: 97.5–99.7%) for implants. The cumulative rates of TI- and I-RDPs free of technical complications were 77% and 86%, respectively. The risk of complications was not significantly different between the CAN and SAD subgroups of I-RDPs (p > 0.05). However, for TI-RDPs, technical complication risk was significantly higher in SAD type compared with CAN restorations (p = 0.02). Conclusions: I- and TI-DC-RDPs seem to be recommendable for restoration of CE or PE arches. The technical and biological complication rates were lower for I-DC-RDPs in the CE arches than for TI-DC-RDPs in the PE arches. Regarding the RDP design, CAN prostheses produced significantly fewer technical complications than did SAD prostheses.

Impact of local predisposing/precipitating factors and systemic drivers on peri-implant diseases.

Strong evidence suggests the infectious nature of peri-implant diseases occurring in susceptible hosts. Epidemiological reports, though, indicate that peri-implantitis is a site-specific entity. Hence, the significance of local factors that may predispose/precipitate plaque accumulation and the impact of systemic drivers that alter the immune response are relevant in the prevention and management of peri-implant disorders. The purpose of the present review is to shed light on the significance of local and systemic factors on peri-implant diseases, making special emphasis on the associations with peri-implantitis. The biologic plausibility and supporting evidence aiming at providing a concluding remark were explored in the recent scientific literature for local predisposing/precipitating factors and systemic drivers related to peri-implant diseases. Local predisposing factors such as soft tissue characteristics, implant position and prosthetic design proved being strongly associated with the occurrence of peri-implant diseases. Hard tissue characteristics, however, failed to demonstrate having a direct association with peri-implant diseases. Robust data points toward the strong link between residual sub-mucosal cement and peri-implant diseases, while limited data suggests the impact of residual sub-mucosal floss and peri-implantitis. Systemic drivers/habits such as hyperglycemia and smoking showed a strong negative impact on peri-implantitis. However, there is insufficient evidence to claim for any link between metabolic syndrome, atherosclerotic cardiovascular disease, and obesity and peri-implant diseases. Local predisposing/precipitating factors and systemic drivers may increase the risk of peri-implant diseases. Therefore, comprehensive anamnesis of the patients, educational/motivational programs and exhaustive prosthetically-driven treatment planning must be fostered aiming at reducing the rate of biological complications in implant dentistry.

A prospective, multicentre study of 6-mm short implants in posterior alveolar bone supporting splinted crowns: A 5-year follow-up study.

To evaluate the clinical and radiographic outcomes of 6-mm short implants, placed in the posterior jaws and supporting splinted crowns, at 5 years after early loading. Forty-five patients with 95 implants (diameter: 4 mm; length: 6 mm) were enrolled at three centres. Two to three implants were placed in either the maxillary or the mandibular posterior region in each patient and restored with screw-retained splinted crowns at 6 weeks later. Clinical and radiographic outcomes were evaluated at implant placement, at loading, and at 6, 12, 24, 36, and 60 months after loading. Biological and mechanical complications were recorded. Marginal changes in bone level in relation to clinical parameters were evaluated using a generalized linear mixed model. During the 5 years of follow-up, the mean change in the marginal bone level (MBL) was 0.04 ± 0.14 mm. Four implants in four patients were lost before loading, one implant in one patient was lost at the 5-year follow-up, and two patients were lost to follow-up. The survival and success rates were 88.4% (38/43) at the patient level. The incidence rates of peri-implant mucositis and peri-implantitis were 29.4% and 7.0%, respectively. The rate of technical complications was 14.0%. Over a 5-year period, 6-mm short implants supporting early loaded splinted crowns in maxillary or mandibular posterior regions showed stable MBLs and acceptable technical and biological complication rates.

The use of implant-level connection in screw-retained fixed partial dentures: A 3-year randomised clinical trial.

This randomised controlled trial compares the 3-year outcomes, that is, marginal bone-level (MBL) changes and clinical parameters, between an abutment-level (AL) and implant-level (IL) connection for implants with an internal conical connection (ICC) supporting a screw-retained fixed partial denture. Fifty patients with 119 implants were randomly allocated to either the AL or IL group. Radiographic and clinical examinations were performed after one, two, and 3years. A linear mixed model was used to evaluate the differences between groups. The MBL change was not significantly different between the groups at any point. The MBL was 0.12±0.31mm (AL) and 0.23±0.26mm (IL) after 1year; 0.15±0.34mm (AL) and 0.17±0.22mm (IL) after 2years; 0.18±0.39mm (AL) and 0.15±0.21mm (IL) after 3years. The bleeding on probing was 43.44±39.24% (AL) and 58.19±41.20% (IL) after 1year; 35.78±39.22% (AL) and 50.43±41.49% (IL) after 2years; 51.27±44.63% (AL) and 49.57±37.31% (IL) after 3years and was significantly different (p=.025) between 1 and 2years. The probing depth showed a significant difference at each time point while the plaque was not significant between the groups. The overall technical, biological and prosthetic complication rates were 5.04%, 3.36%, and 16.00%, respectively. The MBL change was similar in the groups. The slight differences in the soft tissue complications between the groups are likely not of clinical relevance. An IL connection is considered to be a valid alternative to an AL set-up in ICC implants.

Narrow-diameter implants versus regular-diameter implants for rehabilitation of the anterior region: a systematic review and meta-analysis

The aim of this systematic review and meta-analysis was to evaluate studies comparing implant survival rates, marginal bone loss (MBL), and mechanical and biological complication rates between narrow-diameter implants (NDIs) and regular-diameter implants (RDIs) used for oral rehabilitation in the anterior region. The review was conducted according to the PRISMA checklist. Two independent reviewers performed a comprehensive search of the PubMed/MEDLINE, Embase, Scopus, and Cochrane Library databases for studies published until May 2020. A total of 843 implants (484 NDIs and 359 RDIs) were included. No significant difference in implant survival rate (risk difference (RD) 0.01, 95% confidence interval (CI) −0.01 to 0.03; P=0.34), MBL (standardised mean difference −0.51mm, 95% CI −1.29 to 0.26mm; P=0.19), mechanical complications (RD 0.01, 95% CI −0.02 to 0.04; P=0.40), or biological complications (RD 0.01, 95% CI −0.09 to 0.11; P=0.85) was found between the implant groups. Within the limitations of this study, it is concluded that NDIs are an effective alternative to RDIs due to similar survival rates, MBL, and mechanical and biological complication rates. However, future studies are highly encouraged due to the small number of interventional studies on this topic.

Cemented vs. screw‐retained single implant all‐ceramic crowns: 5‐year results of a clinical RCT

Background: In order to overcome esthetic limitations of metal-ceramic implant reconstructions, all-ceramic crowns were introduced. Zirconia abutments demonstrated particular esthetic advantages, predominantly in cases with thin facial mucosa. Custom-made zirconia abutments can be combined with a cemented crown or, as an alternative, be directly veneered and inserted as a screw-retained reconstruction. Up to date, in clinical studies, NOe of the retention types could show a clear advantage over the other. Aim/Hypothesis: To test whether or not screw-retained all-ceramic implant-supported single crowns present similar biological and technical outcomes to cemented all-ceramic crowns after a follow-up time of 5 years. Materials and Methods: Forty-four two-piece dental implants with non-matching implant–abutment junctions were placed in single tooth gaps in the esthetic zone. Patients randomly received a screw-retained (SR) or cemented (CR) all-ceramic single reconstruction. Follow-up visits were scheduled 1–3 weeks after crown insertion, as well as at 6 months, 1, 3 and 5 years. Biological and esthetic parameters were assessed at the implant and control sites (contralateral tooth). Technical outcomes of the reconstructions were evaluated according to modified USPHS (United States Public Health Service) criteria. In addition, profilometric measurements were performed with an image analysis software. Data were statistically analyzed with Wilcoxon-Mann-Whitney, Wilcoxon and Fisher exact tests. Results: Out of 44 included subjects, 3 patients (6.8%) were not available for the 5-year follow-up (2 SR, 1 CR group). Eight reconstructions (18.1%) were lost due to technical (13.6%; 2 CR, 4 SR group; implants still present) or biological complications (4.5%; 2 CR group; implant loss). A total of 33 subjects could be reexamined. No significant differences regarding technical, radiographic and profilometric outcomes could be shown between the groups (P > 0.05). Bleeding on probing (BOP) showed significant higher mean values at implant sites for the CR group (40.0 ± 47.1%) compared to the SR group (8.3 ± 19.2%; P = 0.034). The median marginal bone level was −0.4 mm (−0.5; −0.3) in the SR group and −0.4 mm (−0.8; −0.3) in the CR group (P = 0.582). Cemented reconstructions showed a statistically significantly higher biological complication rate (36.8%, SR 0.0%; P = 0.0022), as well as a significant higher overall complication rate (68.4%, SR 22.7%, P = 0.0049) compared to screw-retained reconstructions (SR). Conclusions and Clinical Implications: At 5-years, a high rate of technical and biological complications could be observed, in particular for cemented reconstructions. This retention type was associated with a higher rate of positive inflammatory parameters (BOP), as well as with a higher incidence of peri-implant diseases. On the long run, screw-retained reconstructions appear to be the preferred type of retention when using all-ceramic reconstructions in the esthetic zone. Acknowledgements: The investigators gratefully acknowledge Prof Dr. Jürg Hüsler for analyzing the data and Gisela Müller, study monitor at the Clinic of Reconstructive Dentistry, Center for Dental Medicine, University of Zurich, for the support. Keywords: biologic complications, technical complications, ceramic abutments, cemented, screw-retained.

Retrospective comparison of posterior fixed dental prostheses supported by two different titanium abutments on tissue level implants

Statement of problemClinical studies comparing compatible computer-aided design and computer-aided manufacturing (CAD-CAM) titanium abutments (CAs) and original prefabricated 1-piece titanium abutments (PAs) for posterior fixed dental prostheses (FDPs) on Straumann Tissue Level (STL) implants are sparse. PurposeThe purpose of this retrospective clinical study was to compare the performance of posterior FDPs supported by CAs and PAs on STL implants after a mean observation period of 7.2 years. Material and methodsPatients who received STL implants and posterior FDPs by using CAs or PAs between January 2002 and December 2012 and returned for follow-up between January 2017 and September 2018 were included in this study. Technical and biological complications of FDPs were examined and recorded. Radiographs were used for the measurement of marginal bone loss (MBL) of each implant. Variables, complication rates, and MBL of the 2 groups were analyzed by using a generalized estimating equation and multivariable linear mixed model. ResultsNinety-nine patients with 195 implants in the CA group and 75 patients with 143 implants in the PA group were included. The mean functional time of FDPs was 6.5 ±1.1 years for the CA group and 8.1 ±2.6 years for the PA group. No implant failure was noted in either group. The technical complication rate was 20.8% in the CA group and 26.3% in the PA group. Abutment screw loosening (ASL) was noted in the CA group (8.5%). The decementation rate was significantly higher in the PA group (14.1%) than that in the CA group (3.1%) (adjusted odds ratio=4.40, confidence interval=1.41 to 13.69, P=.011). No significant differences were found between the 2 groups in terms of the rates of ceramic chipping, peri-implantitis, peri-implant mucositis, or mean MBL. ConclusionsUsing CAs or PAs to support posterior FDPs on STL implants has no significant effect on the incidence rate of biological complications. However, a higher ASL rate and a lower decementation rate were noted with CAs than with PAs.

Surgical extrusion with an atraumatic extraction system: A clinical study

Statement of problemClinical studies evaluating the feasibility of a novel technique for the surgical extrusion of nonrestorable teeth with subgingival caries are lacking. PurposeThe purpose of this clinical study was to investigate the success rate and incidence of biological and technical complications after tooth extrusion with an atraumatic extraction system (AES). Material and methodsParticipants were recruited from 61 consecutive patients initially referred to a specialist oral surgery practice. Fifty-one participants who underwent surgical extrusion with an AES followed by endodontic treatment and coronal restoration could be re-evaluated clinically and radiographically. ResultsThe mean observation period was 3.1 years (range: 0.8 to 6.5 years). The participants varied in age between 24.8 and 86.3 years. The amount of extrusion was between 2.5 and 5.0 mm (mean 3.2 mm). At recall, 92.2% (47 of 51) of the extruded teeth were considered successful. All extruded teeth were asymptomatic, without clinical signs of inflammation. Percussion appeared normal and did not differ from that of the adjacent teeth, indicating absence of ankylosis. Transient resorption with a slightly altered root contour was detected in 5 of the 51 teeth. Minor reduction of the bone level (less than 10%) was detected in 8 of the 51. In a further 2 teeth, bone loss amounted to 25% and 30%. Periapical periodontitis at recall was seen in 4 of the 51 teeth, and a preexisting periapical lesion healed in 10 of 13. Root perforation was identified in 3 of the 51, and a further 3 of 11 were not available for recall. Thus, the technical complication rate was 9.7% (6 of 62). ConclusionsThe AES may be successfully used for surgical extrusion to save apparently nonrestorable teeth, irrespective of patient age.

Surgical techniques used in the rehabilitation of partially edentulous patients with atrophic posterior mandibles: A systematic review and meta-analysis of randomized controlled clinical trials

PurposeGiven the lack of general consensus in the literature regarding the best method to rehabilitate partially edentulous patients with extended atrophic edentulous sites in the posterior zone of the mandible, and with a residual ridge height less than 8 mm (with or without bone augmentation procedures), the aim of this systematic review was to analyze all the relevant randomized clinical trials (RCT), and, by means of a meta-analysis of the collected data, draw some conclusions regarding the best available treatments for the rehabilitation of posterior edentulism in partially dentate mandible. Materials and methodsAn electronic search was conducted in the MEDLINE and Cochrane Oral Health Group databases for studies published between January 2000 and September 2015 with the use of relevant keywords and hand-searching. All identified publications were screened by the authors according to the Cochrane Data Collection Form for Intervention Reviews. Collected outcomes such as biological complications, vertical ridge changes, implant and prosthetic failure were studied by subgroups analyses. ResultsAn initial search yielded 81 potential articles, of which 12 studies were chosen for inclusion. Short implants seemed to be effective in limiting incidence of the biological complications (RR: 2.822; 95% CI: 1.809–4.403; p < 0.0001) and degree of ridge height reduction (difference in means of 0.052 mm; 95% CI: 0.026–0.079 mm; p < 0.0001) when compared with long implants placed in augmented bone. Implants placed in augmented areas with the use of onlay block grafts seemed to behave worse than implants placed in the augmented sites regardless of the augmentation procedures. However, this difference did not reach statistical significance. ConclusionFindings from subgroup analyses revealed that (1) short implants placed in the posterior atrophic areas of partially edentulous mandibles were associated with superior outcomes compared with long implants in augmented bone, such as lower rate of biological complications and of peri-implant bone loss; whereas (2), there was no evidence that onlay augmentation was inferior to any of the other augmentation techniques employed.

Retrospective Analysis of Biological and Technical Complications Using Individual CAD/CAM Abutments

Purpose: The aim of the present study was to assess the biological and technical complication and survival rates of implants and prosthetic superstructures using custom-milled CAD/CAM abutments made of titanium or zirconia. Material and Methods: A total of 109 patients were treated with 225 AstraTech OsseoSpeed implants (Dentsply IH) between July 2008 and November 2012 in the same private dental practice. Following submerged healing, the implants were uncovered and restored with Atlantis custom CAD/CAM abutments made of zirconia or titanium. Single crowns, fixed bridges, or telescope crowns as attachments for removable prostheses were connected to the abutments with zinc oxide phosphate cement. Patients were clinically and radiologically followed at the abutment level for a mean 20.85 months. The clinical assessment included biological and technical complications a well as the survival of the implants, abutments, and prosthetic superstructures. Mean crestal bone loss was assessed on standardized radiographs. Patient satisfaction was surveyed with a self-developed questionnaire. Results: The records of 69 patients (49 female, 20 male: mean age: 53.51 years) treated with 124 implants/custom abutments were included in the final analysis. Most abutments were made of titanium (n=90), followed by zirconia (n=34). The survival rates of implants and abutments were 100.00%. Eight restorations (6.50%) had to be replaced during follow-up, for an implant/abutment-related cumulative prosthetic success rate of 93.50%. The patient-related cumulative prosthetic survival rate was 92.75%. A mean bone gain of 0.06 mm (SD: 0.28 mm) on the mesial side and 0.11 mm (SD: 0.37 mm) at the distal side of the implants (n=122) was recorded. Only a few cases of soft-tissue complications such as mucositis, loss of papilla height, or bleeding on probing were observed. Therapy was rated as very good by 92.65% of patients. The esthetic result was assessed as very good as well by the majority of patients (88.41%). Due to the small sample size, no tests for statistical significance could be performed for any of the examination parameters, except for radiological crestal bone loss. No statistical significance was found for crestal bone loss as a function of the abutment material (p ≥ 0.05). Conclusions: Individual CAD/CAM -abutments are a good and predictable treatment option and deliver high patient satisfaction concerning the therapeutic and esthetic results.

The effect of rigid and non-rigid connections between implants and teeth on biological and technical complications: a systematic review and a meta-analysis.

To assess survival, as well as technical and biological complication rates of partial fixed dental prostheses (FDPs) supported by implants and teeth. An electronic Medline search was conducted to identify articles, published in dental journals from January 1980 to August 2015, reporting on partial FDPs supported by implants and teeth. The search terms were categorized into four groups comprising the PICO question. Manual searches of published full-text articles and related reviews were also performed. The initial database search produced 3587 relevant titles. Three hundred and eighty-six articles were retrieved for abstract review, while 39 articles were selected for full-text review. A total of 10 studies were selected for inclusion. Overall survival rate for implants ranged between 90% and 100%, after follow-up periods with a mean range of 18-120months. The survival of the abutment teeth was 94.1-100%, while the prostheses survival was 85-100% for the same time period. The most frequent complications were "periapical lesions" (11.53%). The most frequent technical complication was "porcelain occlusal fracture" (16.6%), followed by "screw loosening" (15%). According to the meta-analysis, no intrusion was noted on the rigid connection group, while five teeth (8.19%) were intruded in the non-rigid connection group [95% CI (0.013-0.151)]. The tooth-implant FDP seems to be a possible alternative to an implant-supported FDP. There is limited evidence that rigid connection between teeth and implants presents better results when compared with the non-rigid one. The major drawback of non-rigidly connected FDPs is tooth intrusion.

Fixed Rehabilitation of Edentulous Mandibles Using 2 to 4 Implants: A Systematic Review.

This systematic review evaluated survival rates, marginal bone loss (MBL), and complications of using 2 to 4 implants to support full-arch fixed prostheses in the mandible. An electronic search was performed in PubMed, Web of Science, and the Cochrane Central Register of Controlled Trials to identify relevant articles published until March 2015. Articles were critically reviewed to determine the level of quality. The initial search resulted in 910 articles from PubMed/MEDLINE, 162 titles from the Cochrane Central Register of Controlled Trials, and 363 from the Web of Science. After an initial assessment and careful reading, 19 studies published between 1999 and 2014 were included in this review. The results of this review suggest that full-arch fixed dental prosthesis in mandible supported by 2 to 4 implants exhibited a low rate of failures for implants and prostheses, a low rate of MBL, and a low rate of biomechanical and biological complications.

The prognosis of splinted restoration of the most-distal implants in the posterior region.

PURPOSEThe aim of this study was to compare the efficacies of two-implant splinting (2-IS) and single-implant restoration (1-IR) in the first and second molar regions over a mean functional loading period (FLP) of 40 months, and to propose the appropriate clinical considerations for the splinting technique.MATERIALS AND METHODSThe following clinical factors were examined in the 1-IR and 2-IS groups based on the total hospital records of the patients: sex, mean age, implant location, FLP, bone grafting, clinical crown-implant ratio, crown height space, and horizontal distance. The mechanical complications [i.e., screw loosening (SL), screw fracture, crown fracture, and repeated SL] and biological complications [i.e., peri-implant mucositis (PM) and peri-implantitis (PI)] were also evaluated for each patient. In analysis of two groups, the chi-square test and Student's t-test were used to identify the relationship between clinical factors and complication rates. The optimal cutoff value for the FLP based on complications was evaluated using receiver operating characteristics analysis.RESULTSIn total, 234 patients with 408 implants that had been placed during 2005 - 2014 were investigated. The incident rates of SL (P<.001), PM (P=.002), and PI (P=.046) differed significantly between the 1-IR and 2-IS groups. The FLP was the only meaningful clinical factor for mechanical and biological complication rates in 2-IS.CONCLUSIONThe mechanical complication rates were lower for 2-IS than for 1-IR, while the biological complication rates were higher for 2-IS. FLP of 39.80 and 46.57 months were the reference follow-up periods for preventing biological and mechanical complications, respectively.

Mechanical and biological complication rates of the modified lateral-screw-retained implant prosthesis in the posterior region: an alternative to the conventional Implant prosthetic system.

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 METHODSMechanical 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.RESULTSMechanical 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.CONCLUSIONWithin 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.

Spinal Cord Stimulation Failures in Refractory Chronic Pain

Background: Spinal cord stimulation (SCS) is a well-established modality for the treatment of refractory chronic pain and may utilize percutaneous or paddle leads. Methods: The study is conducted at the Unit of Functional Neurosurgery of University “Magna Graecia” of Catanzaro. We perform a retrospective review of our prospective database of 523 SCS patients undergoing surgery for routine indications between January 1993 and December 2013 to evaluate failures rates during trial period and during chronic stimulation. Results: SCS trial was less effective for patients with differentiation neuropathic pain and post herpetic pain. Patients with allodynic dominant pain can feel unpleasant or painful parenthesis during trial stimulation. SCS trial has presented a very low hardware-associated complication rate (lead migration 1.3%) and absence of biological complications. During chronic SCS 29% of cases had equipment failures. In particular mechanical failures occurred in 18% of cases with 8.5% of lead displacements or migrations and 9.5% of lead breakages; biological failures occurred in 11% of cases with 6% of skin erosions and 5% of infections. Conclusion: SCS is a minimally invasive procedure effective in managing medically intractable pain of various origins. Despite advances in the design and production of SCS systems, these devices remain prone to failure from various causes. A careful analysis of mechanical complications coupled to a clinical strategy to minimize the tensile loads on the components of the system should lead to an improvement of the performance of the SCS implanted system and the effectiveness of the stimulation and the long-term reduction in the rate of complications that currently it remains quite significant.

Double Full‐Arch Versus Single Full‐Arch, Four Implant‐Supported Rehabilitations: A Retrospective, 5‐Year Cohort Study

To report the 5-year outcome of the All-on-4 treatment concept comparing double full-arch (G1) and single-arch (G2) groups. This retrospective cohort study included 110 patients (68 women and 42 men, average age of 55.5 years) with 440 NobelSpeedy groovy implants. One hundred sixty-five full-arch, fixed, immediately loaded prostheses in both jaws were followed for 5 years. G1 consisted of 55 patients with double-arch rehabilitations occluded with implant-supported fixed prostheses, and G2 consisted of 55 patients with maxillary single-arch rehabilitations or mandibular single-arch rehabilitations occluded with natural teeth or removable prostheses. The groups were matched for age (±6 years) and gender. Primary outcome measures were cumulative prosthetic (both interim and definitive) and implant survival (Kaplan-Meier product limit estimator). Secondary outcome measures were marginal bone levels at 5 years (through periapical radiographs and using the patient as unit of analysis) and the incidence of mechanical and biological complications. Differences in survival curves (log-rank test), marginal bone level (Mann-Whitney U test), and complications (chi-square test) were compared inferentially between the two groups using the patient as unit of analysis with significance level set at p ≤ 0.05. No dropouts occurred. Prosthetic survival was 100%. Five patients lost 5 implants (G1: n = 3; G2: n = 2) before 1 year, rendering an estimated cumulative survival rate of 95.5% (G1: 94.5%; G2: 96.4%; Kaplan-Meier, p = 0.645, nonsignificant). The average (SD) marginal bone level was 1.56 mm (0.89) at 5 years [G1: 1.45 mm (0.77); G2: 1.67 mm (0.99); p = 0.414]. The incidence rate of mechanical complications (in both interim and definitive prostheses) was 0.16 and 0.13 for G1 and G2, respectively (p = 0.032). The incidence rate of biological complications was 0.06 and 0.05 for G1 and G2, respectively (p = 0.669). Based on the results, rehabilitating double- or single-arch edentulous patients did not yield significant differences on survival curves. The incidence of mechanical complications was significantly higher for double-arch rehabilitated patients but nevertheless, these mechanical complications did not affect the long-term survival of either the prostheses or the implants.

The impact of cantilevers on biological and technical success outcomes of implant‐supported fixed partial dentures. A retrospective cohort study

To investigate the biological and technical success outcomes of implant-supported fixed dental prostheses with and without cantilevers, after a minimum of one year loading. One hundred and seven subjects with 128 cantilever FDPs (cFDP) supported by 132 implants were compared with 99 individuals with 144 non-cantilever FPDs (ncFDPs) supported by 203 implants. Outcomes such as marginal bone loss from FDP insertion to final follow-up as well as frequency and extent of biological and technical complications were investigated and correlated with patient, site, implant and FDP design characteristics. The cFDPs were followed for average of 51 months (1551 days, SD ± 977), and ncFPDs for 49 months (1483 days, SD ± 809 days). Implant survival and success rates were 96.7% and 87.9% for implant supporting cFDPs, and 99.5% and 92.6% for ncFDPs. There was no significant difference in overall bone loss between cFDPs and ncFDPs (cantilever side: 0.58, SD ± 1.16 - non-cantilever side: 0.59, SD ± 0.99), but implants in the cantilever group lost significantly more bone in the posterior mandible (0.50 SD ± 1.3 mm for cFDPs and 0.24 SD ± 0.80 mm for ncFDPs). Within the cantilever group, cantilever arm length and implant location had an influence on bone loss. Regardless of the presence of cantilever, implants associated with technical complications had a higher rate of biological complications as well. Furthermore, the length of the cantilever arm was positively correlated with implant failure, technical complications and bone loss ≥1.5 mm (P = 0.011, <0.001, and 0.007). Overall implants can be successfully used to support cantilever FDPs. However, there are technical and biological implications which appear inter-related.