Diamond-Like Carbon Coating Reduces Connection Screw Head Stripping After Multiple Tightening Instances.

The stability of implant-abutment joint is fundamental for the long-term success of implant rehabilitation. The screw loosening, fracture, and head deformation are among the most common mechanical complications. Several surface treatments of titanium screws have been proposed to improve their resistance and stability. Diamond-like carbon (DLC) coating of the materials is widely used to increase their wear resistance and durability. The present study aimed to evaluate the effect of carbon fiber coating on the screw head on screw removal torque and screw head stripping. One hundred titanium implant screws were used, 50 without coating (Group 1) and 50 with DLC coating of the screw head (Group 2). Each screw was tightened with a torque of 25 Ncm and unscrewed 10 times. The removal torque was measured with a digital cap torque tester for each loosening. Optical 3d measurement of the screw head surface was performed by a fully automatic machine before and after multiple tightening to investigate surface modifications. The reverse torque values decreased with repeated tightening and loosening cycles in both groups without significant differences (P > .05). Optical measurements of surface dimensions revealed average changes of 0.0357 mm in Group 1 and 0.02312 mm in Group 2, which resulted to be statistically significant (P < .001). The DLC coating of the retention screw head can prevent its distortion and wear, especially after multiple tightening.

Implant survival rate and marginal bone loss of 174 implants with different variables associated over a minimum observational period of 20 years: A retrospective study.

PURPOSE: To investigate the long-term implant survival rate and marginal bone loss (MBL) of implants with different variables associated over an observational period of at least 20 years. MATERIALS AND METHODS: Patients with at least one implant placed prior to 2001 were recalled and visited. Data on implant macro-design, prosthetic aspects, site distribution, and patient-related factors were collected. MBL was evaluated on intraoral X-rays and peri-implant soft tissue parameters were recorded. The patients were asked to fill out a questionnaire to evaluate their satisfaction with the treatment received. Descriptive statistics indicators were estimated. Analysis of variance and analysis of covariance models were used to investigate any differences in the MBL and peri-implant probing depth (PPD) among the variables. A chi-square analysis was performed to investigate any association between different types of prosthetic implant-supported rehabilitations and survival/success outcomes. RESULTS: Forty-one (41) patients and 174 implants were included with a mean observational period of 23.3 ± 2.8 years. The implant survival and success rates were 96.5% and 83.3% respectively, while 3.5% of early failures were detected. The lowest success rates were observed for implants supporting fixed full-arch rehabilitations (71.05%) and overdenture rehabilitations (86.11%). A mean MBL of 1.81 ± 0.71 mm and a mean PPD of 3.38 ± 1.62 mm were recorded. The interaction between the collected data with MBL and PPD did not reveal any statistically significant differences between the variables (p > 0.05). A statistically significant difference was recorded when analyzing the association between the different types of prosthetic implant-supported rehabilitations and success rates (p = 0.014), with fixed and removable full-arch rehabilitations presenting with lower success rates. Answers to the questionnaire showed a generally high level of satisfaction. CONCLUSIONS: Within the limits of this retrospective study and based on the results, an implant survival rate higher than 96% was observed after a mean observational period of 23.3 ± 2.8 years. Both the implant survival rate and MBL seemed stable after a mean observational period of 23.3 ± 2.8 years. Implants supporting fixed and removable full-arch rehabilitations seemed to present lower success rates over time. Implant rehabilitation seemed to provide patients with optimal long-term outcomes in terms of functional and psychological aspects.

Oral Health-Related Quality of Life and Full-Arch Immediate Loading Rehabilitation: An Evaluation of Preoperative, Intermediate, and Posttreatment Assessments of Patients Using a Modification of the OHIP Questionnaire.

The aim of this study was to assess oral health-related quality of life (OHRQoL) of patients before, during, and after completion of implant-supported full-arch immediate loading rehabilitation according to the Columbus Bridge Protocol. Twenty-five patients with compromised dentition were rehabilitated according to the Columbus Bridge Protocol and were assessed for OHRQoL using 4 questionnaires specifically designed for this study and inspired by the Oral Health Impact Profile questionnaire. Patients assessed themselves before surgery, during the healing period (1 week and 2 months after surgery), and after definitive prosthodontic treatment (4 months after surgery). The questionnaires specifically investigated patients' pain, comfort, home oral hygiene habits, satisfaction related to esthetics, masticatory ability, phonetics and general satisfaction with the treatment. Patients reported an improvement of OHRQoL after full-arch immediate-loading rehabilitation. A statistically significant improvement in esthetics and chewing ability was found. After 4 months 92% of the patients did not feel tense about their smile, 96% did not indicate problems relating to other people or smiling, and 92% did not have difficulty eating some foods. Phonetics were a critical issue, especially in the intermediate phase of healing. One week after surgery, the percentage of patients who were very satisfied with phonetics slightly decreased from 48% to 36%. The assessment of patients' OHRQoL related to full-arch immediate-loading implant therapy exhibited a significant improvement in quality of life. The questionnaires herein presented could be an effective tool to evaluate patients' reaction to oral rehabilitation.

Radiological and Histomorphometric Outcomes of Homologous Bone Graft in Postextractive Implant Sites: A 6-Year Retrospective Analysis.

OBJECTIVES: The aim was to investigate the in vivo efficacy of a cancellous particulate allograft bone in the regeneration of postextractive atrophic sites. MATERIAL AND METHODS: Ten patients were selected, and after a minimally invasive extraction of the teeth (T0), a cone beam computed tomography was performed (T1). Seven days after extraction, Puros cancellous particulate homologous graft was inserted into the elected sites together with a membrane (T2). After 4 months, a cone beam computed tomography of the sites was performed (T3). After 5 months, samples of the regenerated sites were taken contextually to implant insertion (T4). The samples were histologically and histomorphometrically analyzed. Intraoral periapical radiographs were accomplished at T4 and at the 6-year follow-up appointment (T5). RESULTS: The mean vertical bone augmentation was of 4.1 mm in the lower jaw and of 3.35 mm in the maxilla at T3 appointment. The mean horizontal bone augmentation in the lower jaw was 2.02 and 2.15 mm in the maxilla. At T4, the mean total bone was 60.01% and the mature bone was 98.41. At the 6-year follow-up visit, the mean periimplant bone resorption was 0.14 mm (range 0-0.5 mm). CONCLUSIONS: Cancellous particulate allograft bone demonstrated excellent bone regeneration behavior both in terms of quantity and quality, and stable results over a 6-year period. CLINICAL RELEVANCE: Cancellous allograft bone can be successfully used to regenerate atrophic sites.

Accuracy of multi-unit implant impression: traditional techniques versus a digital procedure.

OBJECTIVES: The objective of this study was to evaluate the accuracy of different impression techniques on multiple implants. MATERIAL AND METHODS: A master cast simulating a jaw with four implants was used. Eight impression techniques were tested: open tray-polyether#1, open tray plus splint of impression copings with acrylic resin-polyether#1, closed tray-polyether#1, open tray-polyether#2, open tray-splint-polyether#2, closed tray-polyether#2, open tray-impression plaster, and digital impression (DI). Five impressions of the master cast were taken with each traditional impression (TI) technique, pouring 35 sample casts. Three different clinicians took 5 DI each (n = 15). A three-dimensional coordinate measurement machine (CMM) was used to measure implant angulation and inter-implant distances on TI casts. TI data and DI Standard Tessellation Language datasets were compared with the master cast. The best and the worst impressions made with TI and DI were selected to fabricate four milled titanium frameworks. Passive fit was evaluated through Sheffield test, screwing each framework on the master cast. Gaps between framework-implant analogs were measured through a stereomicroscope (×40 magnification). RESULTS: Statistically significant differences in accuracy were found comparing the different impression techniques by CMM (p < 0.01). DI performed the best, while TI techniques revealed a greater variability in the results. Sheffield test revealed a mean gap of 0.022 ± 0.023 mm (the best TI), 0.063 ± 0.059 mm (the worst TI), 0.015 ± 0.011 mm (the best DI), and 0.019 ± 0.015 mm (the worst DI). CONCLUSIONS: Within the limits of this in vitro study, the digital impression showed better accuracy compared to conventional impressioning. CLINICAL RELEVANCE: The digital impression might offer a viable alternative to traditional impressions for fabrication of full-arch implant-supported prostheses with satisfactory passive fit.

Analysis of Different Impression Techniques and Materials on Multiple Implants Through 3-Dimensional Laser Scanner.

OBJECTIVE: The aim of this study was to evaluate the accuracy of 7 different implant impression techniques for full-arch prostheses. MATERIALS AND METHODS: A master cast simulating an edentulous arch with 4 implants was used. Seven impression techniques were tested: open tray with polyether Impregum (OTI); open tray with splint-polyether Impregum (OTSI); closed tray with polyether Impregum; open tray with polyether Ramitec; open tray with splint-polyether Ramitec; closed tray with polyether Ramitec (CTR); open tray with impression plaster (OTP). Five impressions of the master cast were taken for each technique using an impression simulator device. Casts were realized based on those impressions (n = 35). Median values of deviation from the master cast were recorded for each cast through a 3-dimensional laser scanner. RESULTS: Only OTI (P = 0.028) and OTSI (P < 0.001) presented a statistically significant difference compared to the master cast. OTP (P = 0.99) and CTR (P = 0.10) showed median values of deviation close to zero (-0.001 and -0.003 mm, respectively). CONCLUSION: Stiff impression materials (such as plaster or rigid polyether) guarantee greater accuracy in cases of multiple implant impressions of patients with full-arch rehabilitations. Splinting of impression copings with acrylic resin did not improve accuracy.

A Luting Technique for Passive Fit of Implant-Supported Fixed Dentures.

Several factors contribute to distortion of implant prostheses during fabrication and could prevent passive, accurate adaptation between implants and implant frameworks. The misfit between implants and restorative components may be significant and possibly lead to biologic or mechanical complications. The aim of this article is to describe a laboratory luting technique used to lute implant cylinders to metal frameworks in implant prostheses. This technique provides accurate, passive fits. According to this technique, titanium implant cylinders provided with corresponding external castable cylinders are used. Implant cylinders are screwed into the analogs in the master cast while the castable cylinders on top are splinted together using castable resin to realize a castable resin pattern. After casting, the framework is adjusted and cemented to the titanium cylinders on the master cast. Due to its ease and quickness of use and clinical efficiencies, this technique is deemed particularly useful in immediate loading rehabilitations.

Brånemark Novum® immediate loading rehabilitation of edentulous mandibles: 11-year retrospective study.

OBJECTIVES: Short-term results indicated that the Brånemark Novum® protocol (Nobel Biocare AB, Goteborg, Sweden) allowed successful rehabilitation of mandibular edentulism with immediately loaded implants. Yet, long-term studies are lacking. The aim of the present retrospective study was to report the 11-year outcomes for patients treated according to this protocol. MATERIAL AND METHODS: Four patients treated according to the Brånemark Novum protocol (Nobel Biocare AB) were followed-up to evaluate implant and prosthesis cumulative survival rate (CSR), implant stability (RFA), marginal bone loss by periapical radiographs, probing depth (PD), and possible complications. Clinical and radiographic parameters were evaluated immediately after completion of the treatment and 1, 5, and 11 years after loading. RESULTS: The 11-year implant and prosthesis CSRs were 100%. Implant stability (RFA values) remained stable over the 11-year follow-up. Small bone resorption was found next to distal implants (median 1 mm) after 11 years, while central implants showed greater bone resorption (median 4.5 mm). The PD (mean 3.75 mm at 11 years) grew together with marginal bone loss. One implant complication was detected on a central implant (crater-form bone destruction), and 10 prosthetic complications (fractures of resin or teeth), 80% of which registered on the same parafunctional patient. CONCLUSIONS: The 11-year results demonstrated that the Brånemark Novum protocol (Nobel Biocare AB) is a predictable technique with favorable long-term outcomes. This was a rigid protocol, which could be applied only in patients with specific anatomical characteristics of the lower jaw, but it had the merit of indicating the key factors for full-arch immediate loading rehabilitations.

Dental Implants with External Hex Inclined Shoulder in Full-Arch Immediate Loading Rehabilitations of the Maxilla.

Background: Coaxial implants with an inclined neck might overcome some problems related to angulation of the implant axis when using tilted implants. Therefore, the aim of the present work was to conduct a narrative review of the current literature and to present a case series comparing traditional and coaxial external hex implants in full-arch immediate loading rehabilitations of the maxilla. Methods: A total of 13 external hex tapered implants (Southern Implants) was inserted in the upper jaw of 3 patients. Each patient received two tilted implants in distal sites. In one randomly selected quadrant, the tilted implant was a standard implant, while a Co-Axis® implant with a 24° inclination of the implant shoulder was inserted on the other hemi-arch. Straight conical abutments were screwed on coaxial implants while multiunit abutments of appropriate inclination were screwed as needed on the other implants to correct their axes. Peri-implant bone level was recorded radiographically at T0 (delivery of the immediate loading prosthesis), and at 3, 6, 12, and 24 months of healing and then annually. Plaque index, probing depth, and bleeding on probing were also evaluated. Cumulative implant survival rate (CSR) was calculated, and biological or technical complications were recorded as well as the operator satisfaction towards the use of coaxial implants. Results: The preliminary data collected did not show significant differences in peri-implant tissues health and maintenance over time between the two implant types. No implants failed, and both implant types proved to be favorable for full-arch rehabilitation using tilted implants. Coaxial implants facilitated the prosthodontic procedures. However, a learning curve is required in order to optimize their insertion. Conclusions: Both implants proved to be reliable and suitable for achieving clinical success in full-arch immediate loading rehabilitations, but further research with longer follow-up and larger sample size is needed to confirm these preliminary outcomes.

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.

How often should implant-supported full-arch dental prostheses be removed for supportive peri-implant care to maintain peri-implant health? A systematic review.

PURPOSE: To systematically screen and summarise the available literature on when and how often it is advisable to perform supportive peri-implant care on implant-supported full-arch dental prostheses to maintain peri-implant health. MATERIALS AND METHODS: The authors employed the Preferred Reporting Items for Systematic reviews and Meta-Analyses statement and the Population, Intervention, Comparison and Outcomes tool. A literature search was conducted on PubMed for randomised controlled trials, controlled clinical trials and cohort studies, reporting results on supportive peri-implant care for full-arch dental prostheses with a follow-up period of at least 1 year. The studies were selected in a blind process with an agreement rate of 100%. For all the included studies, quality assessment was performed according to the Cochrane Handbook for Systematic Reviews of Interventions. RESULTS: The application of the search terms on PubMed led to the selection of 915 results. Only 11 studies were included in the review. Eight of these reported the frequency of supportive peri-implant care, and three detailed the procedures adopted. The number of patients included ranged from 15 to 85, with a mean age from 60.4 to 68.4 years. None of the included studies were judged to be at low risk of bias. CONCLUSIONS: Removal of implant-supported prostheses is a crucial aspect in the long-term care of patients rehabilitated with full-arch restorations. Although no specific indications can be drawn with respect to the frequency at which supportive peri-implant care should be delivered and the regime used to do so, practitioners should consider performing professional oral hygiene measures every 6 months and removing prostheses at least once per year. All interventions should be tailored to the patient's risk profile and characteristics.

Outcomes of Zygomatic Implants Combined with Anterior Regular Implants: A Retrospective Analysis with a Mean Follow-up Time of 36 Months.

Purpose: To retrospectively evaluate the clinical outcomes of immediately loaded zygomatic implants combined with anterior regular implants (hybrid zygoma) for the fixed rehabilitation of atrophic maxillae. Materials and Methods: A total of 18 patients were enrolled in this study and treated with the hybrid zygoma concept by an experienced surgeon. Follow-up visits were planned after 1 week, 3 weeks, 4 months, 6 months, then annually. At the last follow-up appointment (mean: 36 months after surgery; range: 24 to 52 months), the prostheses were unscrewed and the implants and peri-implant tissues were examined. The primary outcome evaluated was implant success. Following the criteria proposed by Aparicio et al, implant success was classified in five grades, with grade I representing the best condition and grade V representing a failure. At the annual check-up, patients were asked to fill out a questionnaire to evaluate their satisfaction with their oral rehabilitation. Results: A total of 80 implants (34 zygomatic and 46 regular) were inserted. One zygomatic implant was lost in one patient, and two regular implants failed in two other patients. Of the zygomatic implants, 24 (70.6%) presented a success grade I, 9 (26.5%) a success grade II, and 1 (2.9%) a grade V. Sinusitis was the most common biologic complication, occurring in two patients (5.6%). Two patients showed unilateral upper lip paresthesia that was persistent at the last follow-up appointment. According to the annual follow-up visit questionnaire data, 72%, 89%, and 94% of patients declared that they were satisfied with their phonetic ability, chewing ability, and esthetics, respectively. Conclusion: Although zygomatic implants combined with anterior regular implants present a higher risk of complications than traditional implantology, they allow for immediately loaded full-arch fixed rehabilitation of patients with advanced atrophy of the posterior maxilla, which provides satisfactory chewing ability, esthetics, and phonetics.

Comparison of Milled Full-Arch Implant-Supported Frameworks Realised with a Full Digital Workflow or from Conventional Impression: A Clinical Study.

BACKGROUND: The aim of the present study was to investigate the accuracy of a new digital impression system, comparing it to the plaster impression technique in the realization of full-arch implant-supported metal frameworks. METHODS: We took 11 scans (8 of the upper maxilla and 3 of the lower jaw) on a sample of nine patients previously rehabilitated with fixed full-arch screw-retained prostheses following the Columbus Bridge Protocol (CBP) with four to six implants (total: 51) since at least 4 months. Two impressions were taken for each dental arch: one analogic plaster impression using pick-up copings and an open tray technique and a second one using an intra-oral scanner. Two milled metal substructures were realised. The precision and passivity of the substructures were clinically analysed through the Sheffield test and endo-oral radiographs. Laboratory scans of the plaster casts obtained from an intra-oral scanner (IOS) and of the plaster casts obtained from traditional impression were compared with the intraoral scans following Hausdorff's method and an industrial digital method of optical detection to measure discrepancies. A Mann-Whitney test was performed in order to investigate average distances between surfaces after the superposition. RESULTS: The Sheffield test demonstrated an excellent passivity of the frameworks obtained through both the digital and the analogic method. In 81.81% of cases (n = 9) both substructures were found to have a perfect fit with excellent passivity, while in 18.18% (n = 2) of cases the substructures were found to have a very slight discrepancy. From the radiographic examination, no gaps between the frameworks and the implant heads or multiunit abutments were observed, with 100% accuracy. By superimposing digital files of scans according to Hausdorff's method, a statistically significant discrepancy (p = 0.006) was found between the digital scans and the digital models obtained from plaster impressions. Three-dimensional optical detection found a mean discrepancy of 0.11 mm between the analogic cast and the cast derived from the digital impression. CONCLUSIONS: The present study clinically demonstrates that milled implant-supported full-arch frameworks obtained through a digital scan and the herein described technique have an accuracy comparable to those obtained with traditional plaster impression.

Immediate loading full-arch rehabilitation using transmucosal tissue-level implants with different variables associated: a one-year observational study.

BACKGROUND: The aim of the present observational study was to investigate the application of transmucosal tissue-level implants in immediate loading full-arch rehabilitation with different variables associated. METHODS: Patients needing a full-arch implant rehabilitation were recruited and rehabilitated with four transmucosal tissue level implants. Data related to implants' diameters and lengths, jaw distributions, and presence of angulated abutments were collected. The following outcomes were evaluated: survival rate, marginal bone loss (MBL), Plaque Index (PI), bleeding on probing (BoP), probing depth (PD). Descriptive statistical analysis was reported and univariate linear regression models were built to assess a significant correlation between MBL and the different implant related factors. RESULTS: Twenty patients were rehabilitated for a total implant number of 80; 11 rehabilitations were performed on the maxilla, while 9 were performed on the mandible; 48 implants presented a 3.8 mm diameter and 32 implants presented a 4.25 mm diameter. Implants length varied between 10 to 15 mm; 40 tilted implants were connected to angulated abutment, while 40 straight implants were connected directly to the prostheses (no abutments). At the one year follow-up visit no implants failed resulting in an implant survival rate of 100%. The overall MBL was 1.19±0.30 mm. No statistically significant difference (P>0.05) was highlighted among any of the subgroups analyzed. CONCLUSIONS: Despite different variables associated, tissue level implants seem to represent a valid option when applied in immediate loading full-arch rehabilitation. Further research and longer observational periods are encouraged to confirm the result.

Full-Arch Rehabilitation Using Trans-Mucosal Tissue-Level Implants with and without Implant-Abutment Units: A Case Report.

Recently, tissue-level implants with a convergent collar have been introduced. While different studies have investigated the outcomes of this implant design in the rehabilitation of single teeth, its use in full-arch rehabilitation has yet to be investigated. The present case report describes the clinical outcomes of a full-arch immediate loading rehabilitation using tissue-level implants, with and without using implant-abutment units, with 2 years of follow-up. A female patient with mandibular terminal dentition and a high level of bone resorption (distal areas with a few millimeters of residual bone in the vertical dimension and both distal and anterior areas with narrow crestal bone in the horizontal dimension) was seen at the C.I.R Dental School, Turin, Italy. The patient was seeking to be rehabilitated with fixed prosthodontics, and she was found eligible for an immediate loading implant full-arch rehabilitation. Four implants were inserted in the same appointment. The two anterior implants were inserted straight and connected directly to the prosthesis (no abutments); the two distal implants were tilted in order to avoid the alveolar nerve and connected to two 30° angulated abutments. Two years post-implant placement, all of the implants were successfully integrated, resulting in an implant survival rate of 100%. The peri-implant soft tissues were stable at all the implant sites. No differences were highlighted between those implants with and without abutments. Within the limitations of the present clinical report, implant full-arch rehabilitations with tissue-level implants both with and without implant-abutment units showed optimal outcomes after two years of follow-up. Further research is encouraged to confirm whether this implant design may be a valid alternative to traditional implants in this type of rehabilitation, with or without implant-abutment units.

One-stage versus two-stage technique using two splinted extra-short implants: A multicentric split-mouth study with a one-year follow-up.

OBJECTIVE: To compare the clinical outcomes of extra-short implants (≤6.5 mm) inserted with one-stage versus two-stage technique in adjacent sites of the upper or lower jaw. MATERIALS AND METHODS: In this split-mouth multicenter study, implants were randomly divided into two groups according to the healing phase: two-stage and one-stage technique. Primary outcome measures were implant survival, implant success, and prosthodontic complications. Secondary outcome measurements were: implant stability quotient (ISQ) collected at surgery time (T0), and after 3 (T3) and 12 (T12) months, marginal bone level (MBL) evaluated at T0, T3, T6, and T12, marginal bone loss evaluated at T6 and T12, plaque index (PI), probing depth (PD), bleeding on probing (BoP) evaluated at T3, T6, and T12. Significances of differences between groups were tested by linear mixed model with random intercept. RESULTS: Nineteen patients (8 males and 11 females) were included. A total of 38 implants were inserted. At T12 implant cumulative survival and implant success rate were 100% in both groups. No statistically significant differences were recorded for any of the analyzed parameters between the two groups at any time point. ISQ values were similar at T0 (two-stage: mean 67.53 ± SD 19.47; one-stage: mean 66.53 ± 19.07 p = 0.8738) and increased in both groups at the 12-month follow-up appointment (two-stage: 81.1 ± 7.04; one-stage: 81.39 ± 0.9266). MBL values were similar in the two groups at any time point. At T12 marginal bone loss was 0.46 ± 0.41 (two-stage) and 0.45 ± 0.38 (one-stage) mm (p = 0.9417), while mean PD was 2.7 ± 0.85 (two-stage) and 2.69 ± 0.89 (one-stage) mm. CONCLUSIONS: Within the limits of the present short-term report, extra-short implants demonstrated optimal clinical outcomes using the one-stage technique, without statistically significant differences compared with the traditional two-stage approach.

Can Abutment with Novel Superlattice CrN/NbN Coatings Influence Peri-Implant Tissue Health and Implant Survival Rate Compared to Machined Abutment? 6-Month Results from a Multi-Center Split-Mouth Randomized Control Trial.

Background: The aim of the present multi-center split-mouth randomized control trial was to investigate the effect on peri-implant tissue of abutment with chromium nitride/ niobium nitride (CrN/NbN) coatings (superlattice) compared to traditional machined surface. Methods: Two adjacent posterior implants were inserted in 20 patients. A machined abutment was randomly screwed on either the mesial or distal implant, while a superlattice abutment was screwed on the other one. Implant survival rate, peri-implant probing depth (PPD), plaque index (PI), and bleeding index (BI) were collected 6 months after surgery, while marginal bone loss (MBL) was evaluated at T0 and T6.; Results: Implant survival rate was 97.7%. A total MBL of 0.77 ± 0.50 mm was recorded for superlattice abutments, while a mean MBL of 0.79 ± 0.40 mm was recorded for the abutment with machined surface. A mean PPD of 1.3 ± 0.23 mm was recorded for the superlattice Group, and a mean PPD of 1.31 ± 0.3 was recorded for the machined surface Group. PI was of 0.55 ± 0.51 for superlattice Group and 0.57 ± 0.50 for machined Group, while BI was of 0.47 ± 0.49 for superlattice Group and of 0.46 ± 0.40 for the machined one. No statistically significant difference was highlighted between the two Groups (p > 0.05). Conclusions: After a 6-month observational period, no statistically significant differences were highlighted between superlattice abutment and traditional machined abutment. Further in vitro studies as well as clinical research with longer follow-ups are required to better investigate the surface properties of the novel abutments' superlattice coating and its effect on the oral tissues.

The effect of the post length and cusp coverage on the cycling and static load of endodontically treated maxillary premolars.

In endodontically treated teeth, cuspal coverage plays a fundamental role in reducing the risk of fracture. However, the adhesive techniques with or without fiber post increased the possibilities in restoring root-filled teeth. The aim of this study was to determine the effect of the fiber post and/or post length and/or cuspal coverage on the fracture resistance of endodontically treated maxillary premolars. Seventy intact single-rooted maxillary premolars were selected and divided in seven groups of ten each: "intact teeth" (control), "inlay without fiber post" (G1), "inlay with long fiber post" (G2), "inlay with short fiber post" (G3), "onlay without fiber post" (G4), "onlay with long fiber post" (G5), and "onlay with short fiber post" (G6). Except for intact teeth, all specimens were prepared with a mesio-occluso-distal (MOD) cavity, endodontically treated and restored with or without long or short post, with or without cusp coverage. All specimens were thermal-cycled, exposed to a cyclic loading, and then submitted to the static fracture resistance test. Fracture loads and mode of failure were evaluated. A statistically significant difference in fracture resistance was found between group 1 and the other groups (p < 0.001). χ2 test showed statistically significant differences in the patterns of fractures between the groups (p < 0.001). The highest number of favorable fractures was observed in groups 3 and 4. Similar fracture resistance was detected in maxillary premolars endodontically treated with MOD cavity preparations, restored with either direct resin composite with fiber post or cusp capping. The "short post" direct restoration may be a valid alternative in the restoration of root-filled premolars.

The influence of cantilever length and implant inclination on stress distribution in maxillary implant-supported fixed dentures.

STATEMENT OF PROBLEM: The benefits and limitations of jaw treatments with tilted versus vertical implants, as well as prosthesis design with and without posterior cantilevers, have been extensively discussed. However, biomechanical advantages associated with cantilevers in fixed dentures (FDs) and tilted implants in the maxillae are less well documented. PURPOSE: The purpose of this study was to compare and analyze, via 3-dimensional (3-D) finite element analysis, stresses transmitted to tilted versus vertical implants and the surrounding periimplant bone in the maxillae. MATERIAL AND METHODS: A 3-D edentulous maxillary model was created using customized computer software (FEMAP 8.3). Four implants were virtually placed in the premaxilla and splinted with an FD. Keeping the prosthesis length constant, 4 different configurations were evaluated with the distal implants inclined 0, 15, 30, and 45 degrees; cantilever extensions were 13, 9, 5, and 0 mm, respectively. A vertical load (150 N) was applied to the distal portion of the posterior cantilevers. Von Mises' stress values transmitted to periimplant bone and at the metal framework of FDs on implants were evaluated in cancellous and cortical bone. RESULTS: The maximum stresses recorded in periimplant bone for the vertical implants were 75.0 MPa (distal implants), 35.0 MPa (mesial implants), and 95.0 MPa for the metal frameworks. Tilted distal implants, with consequent reduction of the posterior cantilevers, resulted in decreased stress values for all of the variables: -12.9%, -18.3%, and -11.5% for the 15-degree configuration; -47.5%, -52.6%, and -31.3% for the 30-degree configuration; and -73.5%, -77.7%, and -85.6% for the 45-degree configuration CONCLUSIONS: Finite element analysis data regarding rehabilitation of atrophic maxillae revealed that tilted distal implants, rigidly splinted with an FD, decrease stress in the periimplant bone and frameworks. This treatment modality seems to be a valid therapeutic alternative to conventional maxillary fixed complete prostheses supported by vertical dental implants with posterior cantilevers.

Efficacy of air-polishing devices without removal of implant-supported full-arch prostheses.

PURPOSE: Long-term success of titanium dental implants is influenced by various factors, including the maintenance of good oral hygiene. The present study aimed to evaluate cleaning effectiveness and patient satisfaction with glycine powder air polishing and traditional professional oral hygiene treatments when applied to implant-supported full-arch restorations without removal of the fixed prosthesis. MATERIALS AND METHODS: A total of 85 patients with 357 implants supporting full-arch fixed restorations were included. After removal of the prosthesis (T0), the following parameters were recorded: Plaque Index, peri-implant spontaneous bleeding, probing depth and bleeding on probing. The prosthesis was then reinserted. The patients were divided into three groups, each of which received two hygiene therapies randomly administered in each hemiarch using a split-mouth design. The possible treatments were glycine powder air polishing and use of sponge floss vs sponge floss only in group 1; glycine powder air polishing vs use of an ultrasonic device with a polyetheretherketone fibre tip coating in group 2; and glycine powder air polishing vs use of carbon fibre curettes and sponge floss in group 3. After instrumentation, the prostheses were removed to assess the Plaque Index and peri-implant spontaneous bleeding. Questionnaires were used to record patients' levels of comfort and satisfaction in relation to the various treatments. RESULTS: Glycine powder air polishing resulted in a significantly higher reduction in plaque around implants compared to control treatments (sponge floss only, ultrasonic device with polyetheretherketone fibre tip coating, and manual scaling with carbon fibre curettes and use of sponge floss) (P = 0.020). Glycine powder air polishing followed by application of sponge floss provided the greatest reduction of plaque deposits on the prosthetic surfaces. On average, 80% of patients rated glycine powder air polishing highest with regard to satisfaction. CONCLUSIONS: Glycine powder air polishing is a highly effective and comfortable treatment to maintain good oral hygiene in clinical practice, and could be used as an alternative to manual and mechanical instrumentation when dealing with implant-supported restorations.