Fixed restorations supported by Morse-taper connection implants: a retrospective clinical study with 10-20 years of follow-up

Guided versus freehand single implant placement: A 3-year parallel randomized clinical trial

OBJECTIVES

The present parallel randomized clinical trial aimed to assess, after a 3-year follow-up period, whether the choice of surgical technique-either manual or guided-and of the operator - non-expert operator or skilled - can affect the stability of peri‑implant marginal bone levels in implants placed 1 mm sub-crestal.

MATERIALS AND METHODS

Patients received platform-switched implants (Anyridge, MegaGen Implant Co., Gyeongbuk, South Korea) featuring a 5-degree internal conical connection and supporting single screw-retained fixed crowns. The implants were randomly assigned to be placed through a digitally static guided surgery procedure (Test group - GS) or a freehand surgical technique (Control Group - FH). A non-expert operator (fewer than 20 implants placed in his professional activity) was selected to perform procedures for the GS Group, while a skilled operator (with over 1000 implants placed in his professional activity) was chosen for the FH Group. Marginal bone level (MBL) was measured at prosthesis installation (t0) and at 1 (t1), 2 (t2) and 3 years (t3) of follow-up. Changes in MBL from t0 to t3 were analyzed through periapical radiographs. Moreover, MBL changes at all time points were correlated to different supra-crestal soft tissue heights (STH): less than 3 and ≥ 3 mm, respectively.

RESULTS

60 implants in 18 patients were examined, with 30 implants allocated to the GS group and 30 to the FH group. The difference in MBL change between the two groups was 0.11 ± 0.22 mm, which was not statistically significant (p = 0.61). At the time of prosthetic loading, the mean MBL for implants with STH less than 3 mm was 0.33 mm higher than implants with STH ≥ 3 mm, though this difference was not statistically significant (P = 0.065).

CONCLUSIONS

Digitally static guided implant placement, performed by a non-expert operator, does not limit marginal bone remodeling, when compared to a freehand procedure performed by an experienced operator.

CLINICAL SIGNIFICANCE

After correct and careful planning, early marginal bone levels (MBL) around conical connection, platform-switched implants placed sub-crestally may be stable in time. Digital planning and surgery have the potential to assist non-expert clinicians in achieving implant placements with comparable outcomes to those performed by experts.

Accuracy analysis of robotic-assisted immediate implant placement: A retrospective case series

OBJECTIVES

This study aimed to investigate the accuracy of a robotic computer-assisted implant surgery (r-CAIS) for immediate implant placement.

METHODS

Patients requiring immediate implant placement in the maxillary anterior region were enrolled for r-CAIS. Before surgery, the patients underwent a cone beam computed tomography (CBCT) scan with a positioning marker. Virtual implant placement position and drilling sequences were planned. Following spatial registration and calibration, the implants were placed with the robotic system under supervision. A postoperative CBCT was taken to control the actual implant positions. The DICOM data of the virtually planned and the actually placed implant were superimposed and registered through the accuracy verification software of the robotic system. The accuracy was calculated automatically. The deviation at the mesial-distal, labial-palatal, and apico-coronal directions were recorded.

RESULTS

Fifteen patients with 20 implants were included. No adverse surgical events or postoperative complications were reported. The global platform, apex, and angular deviation were 0.75 ± 0.20 mm (95 % CI: 0.65 to 0.84 mm), 0.70 ± 0.27 mm (95 % CI: 0.57 to 0.82 mm), and 1.17 ± 0.73° (95 % CI: 0.83 to 1.51°), respectively. Moreover, the vertical platform and apex deviation were 0.50 ± 0.31 mm, (95 % CI: 0.35 to 0.64 mm) and 0.48 ± 0.32 mm, (95 % CI: 0.33 to 0.63 mm), respectively. All the placed implant positions were further labial and apical than the planned ones, respectively.

CONCLUSIONS

High accuracy of immediate implant placement was achieved with the robotic system.

CLINICAL SIGNIFICANCE

Our study provided evidence to support the potential of the robotic system in implant placement, even in challenging scenarios.

Application of artificial intelligence in dental implant prognosis: A scoping review

OBJECTIVES

The purpose of this scoping review was to evaluate the performance of artificial intelligence (AI) in the prognosis of dental implants.

DATA

Studies that analyzed the performance of AI models in the prediction of implant prognosis based on medical records or radiographic images. Quality assessment was conducted using the Joanna Briggs Institute (JBI) Critical Appraisal Checklist for Quasi-Experimental Studies.

SOURCES

This scoping review included studies published in English up to October 2023 in MEDLINE/PubMed, Embase, Cochrane Library, and Scopus. A manual search was also performed.

STUDY SELECTION

Of 892 studies, full-text analysis was conducted in 36 studies. Twelve studies met the inclusion criteria. Eight used deep learning models, 3 applied traditional machine learning algorithms, and 1 study combined both types. The performance was quantified using accuracy, sensitivity, specificity, precision, F1 score, and receiver operating characteristic area under curves (ROC AUC). The prognostic accuracy was analyzed and ranged from 70 % to 96.13 %.

CONCLUSIONS

AI is a promising tool in evaluating implant prognosis, but further enhancements are required. Additional radiographic and clinical data are needed to improve AI performance in implant prognosis.

CLINICAL SIGNIFICANCE

AI can predict the prognosis of dental implants based on radiographic images or medical records. As a result, clinicians can receive predicted implant prognosis with the assistance of AI before implant placement and make informed decisions.

Accuracy in static guided implant surgery: Results from a multicenter retrospective clinical study on 21 patients treated in three private practices

PURPOSE

To evaluate the accuracy of a static computer-assisted implant surgery (s-CAIS) system across different private practices.

METHODS

This retrospective clinical study was based on data retrieved from 21 patients who received 61 implants between 2018 and 2020 in 3 private practices run by surgeons with extensive experience with s-CAIS. All patients were treated using the same s-CAIS system, planning software, template manufacturing process, and surgical guides. The standard tessellation language (STL) file of the intraoral scan of the fixture taken immediately after implant placement was matched with that of the preoperative plan for comparisons of preoperative and planned implant positions with postoperative and actual implant positions. The study outcomes were linear and angular deviations between the planned and actual implant positions.

RESULTS

No surgical or postsurgical complications occurred. The overlap of the two STL files resulted in a mean angular deviation of 2.94° The mean linear deviation at the implant shoulder was 0.73 mm, and that at the apex was 1.06 mm. The mean vertical deviations at the implant shoulder and the apex were 0.29 mm and 0.01 mm, respectively.

CONCLUSION

All cases showed satisfactory accuracy within the limits of this study (small number of patients and retrospective design). These results might be related to the use of a standardized digital workflow by experienced operators.

STATEMENT OF CLINICAL RELEVANCE

The study shows that careful control of each step, from data acquisition to final execution, is key for the accuracy of stent-guided systems.

Full-arch restoration with the NEXUS IOS® system: A retrospective clinical evaluation of 37 restorations after a one year of follow-up

OBJECTIVES

Report the results with a novel workflow of digital restoration for completely edentulous patients with implant supported full arch fixed dental prostheses (ISFDP).

METHODS

This multicenter retrospective clinical study was based on the evaluation from a cohort of 29 patients restored with 37 ISFDP designed and manufactured from the data captured by a direct intraoral scan, using a novel full digital system (NEXUS IOS®, Osteon Medical, a Keystone Dental Group company, Melbourne, Australia). Data was collected over a 3-year period, in six different dental centers. This study reported on the clinical parameters including: precision of marginal fit, functional and aesthetic integration of Nexus ISFDP. All patients were followed for a period of one year post delivery. Implant survival, biologic and prosthetic complications were assessed, at one year. A statistical analysis was conducted.

RESULTS

All 37 ISFDP were deemed clinically acceptable on insertion. Implant survival at one year was 100 %. The biologic and prosthetic complications were minimal during the follow-up period.

CONCLUSIONS

ISFDP, designed and manufactured using the NEXUS IOS® system, are clinically acceptable, with a low incidence of complications at one year. Long-term clinical studies are needed.

STATEMENT OF CLINICAL RELEVANCE

Within the limitations of this study (retrospective design, small patient sample, limited follow-up) the NEXUS IOS® system seems to represent a viable solution for the restoration of completely edentulous patients with ISFDP, in a full digital workflow.

Deep learning-based segmentation of dental implants on cone-beam computed tomography images: A validation study

OBJECTIVES

To train and validate a cloud-based convolutional neural network (CNN) model for automated segmentation (AS) of dental implant and attached prosthetic crown on cone-beam computed tomography (CBCT) images.

METHODS

A total dataset of 280 maxillomandibular jawbone CBCT scans was acquired from patients who underwent implant placement with or without coronal restoration. The dataset was randomly divided into three subsets: training set (n = 225), validation set (n = 25) and testing set (n = 30). A CNN model was developed and trained using expert-based semi-automated segmentation (SS) of the implant and attached prosthetic crown as the ground truth. The performance of AS was assessed by comparing with SS and manually corrected automated segmentation referred to as refined-automated segmentation (R-AS). Evaluation metrics included timing, voxel-wise comparison based on confusion matrix and 3D surface differences.

RESULTS

The average time required for AS was 60 times faster (<30 s) than the SS approach. The CNN model was highly effective in segmenting dental implants both with and without coronal restoration, achieving a high dice similarity coefficient score of 0.92±0.02 and 0.91±0.03, respectively. Moreover, the root mean square deviation values were also found to be low (implant only: 0.08±0.09 mm, implant+restoration: 0.11±0.07 mm) when compared with R-AS, implying high AI segmentation accuracy.

CONCLUSIONS

The proposed cloud-based deep learning tool demonstrated high performance and time-efficient segmentation of implants on CBCT images.

CLINICAL SIGNIFICANCE

AI-based segmentation of implants and prosthetic crowns can minimize the negative impact of artifacts and enhance the generalizability of creating dental virtual models. Furthermore, incorporating the suggested tool into existing CNN models specialized for segmenting anatomical structures can improve pre-surgical planning for implants and post-operative assessment of peri‑implant bone levels.

Accuracy of freehand versus guided immediate implant placement: A randomized controlled trial

PURPOSE

This randomized controlled trial (RCT) aimed to compare the accuracy of immediate implant placement with freehand and static guided surgery.

METHODS

An RCT was conducted on 61 subjects who received a total of 80 dental implants. The enrolled patients were randomly allocated to two groups: freehand surgery (control group, n = 40 implants) and static guided surgery with R2Gate® (Megagen, Gyeongbuk, South Korea, test group, n = 40 implants). Crestal and apical deviations in both mesiodistal and buccolingual dimensions, as well as depth and angular deviations, were calculated by comparing the three-dimensional (3D) position of the implant in the planning software with the final implant position, revealed by an intraoral scan of the fixture after placement. The Mann-Whitney test was used for comparative assessment.

RESULTS

In the freehand group (control), crestal deviations of 1.13 ± 0.89 mm and 1.00 ± 0.76 mm were found in the mesiodistal and buccolingual directions, respectively, versus 0.34 ± 0.26 mm (p<0.001) and 0.37 ± 0.24 mm (p = 0.03) in the static guided surgery group (test). Apical deviation was also higher in the freehand group (control) than in the static guided surgery group (test) in the mesiodistal (4.04 ± 1.90 mm vs. 0.97 ± 0.55 mm, p = 0.04) and buccolingual directions (3.46 ± 1.82 mm vs. 0.94 ± 0.67 mm, p = 0.02). Freehand surgery had greater angular deviation (6.09° ± 3.23) compared to guided surgery (0.83° ± 0.53, p = 0.02). However, depth deviation was similar in the freehand surgery group (2.24 ± 1.58 mm) and static guided surgery group (0.66 ± 0.43, p = 0.09).

CONCLUSIONS

Immediate implant placement with static guided surgery demonstrated better accuracy than freehand surgery.

STATEMENT OF CLINICAL RELEVANCE

Guided implant surgery showed fewer deviations compared to freehand surgery in fresh extraction sockets; therefore, the use of static guides should be given preference over the freehand modality.

Custom-made computer-aided-design/ computer-assisted-manufacturing (CAD/CAM) synthetic bone grafts for alveolar ridge augmentation: A retrospective clinical study with 3 years of follow-up

PURPOSE

To report on the results obtained with computer-aided-design/ computer-assisted-manufacturing (CAD/CAM) custom-made synthetic hydroxyapatite/beta-tricalcium-phosphate (HA/beta-TCP) bone grafts in alveolar ridge augmentation for dental implant placement.

METHODS

The procedure included: (1) cone-beam computed tomography (CBCT) of the bone defect; (2) virtual design of the custom-made onlay bone grafts; (3) milling of grafts from a pre-formed block of synthetic HA/beta-TCP; and (4) bone reconstructive surgery. Implants were placed 8 months later. The patients were followed for 3 years. The study outcomes were: (1) intra- and immediate post-operative complications; (2) 8-month vertical and horizontal bone gain; (3) implant survival; (4) implant-crown success; and (5) peri-implant marginal bone loss (MBL).

RESULTS

Twenty-six patients underwent ridge augmentation with custom-made CAD/CAM HA/beta-TCP onlay grafts. Eight months later, these patients were rehabilitated with dental implants. During surgery, 25/26 (96.1%) of the grafts adapted well to the bone defect. Immediate post-operative complications were pain and swelling (2/26 patients: 7.6%), and bone graft exposure (3/26: 11.5%); one exposure led to infection, removal of the graft, and failure of the procedure. Excellent integration of the other grafts was observed 8 months after the regenerative procedure, with mean vertical and horizontal bone gains of 2.10 mm (± 0.35) and 2.96 mm (± 0.45), respectively. Twenty-five implants were placed and restored with single crowns. Three years later, all implants were in function. The 3-year implant crown success rate and peri-implant MBL were 92.0% and 0.7 mm (±0.19), respectively.

CONCLUSIONS

With custom-made CAD/CAM synthetic HA/beta-TCP onlay grafts reconstruction of small vertical and/or horizontal defects of the alveolar ridge was obtained; this enabled implant placement, with high implant-crown success rate after 3 years. Further studies are needed to validate this technique.

STATEMENT OF CLINICAL RELEVANCE

Custom-made CAD/CAM synthetic HA/beta-TCP onlay grafts may represent an option for regeneration of small bone defects prior to implant placement.

Guided implant surgery with R2Gate®: A multicenter retrospective clinical study with 1 year of follow-up

PURPOSE

To present the results obtained with a novel sleeveless and keyless guided implant surgery system.

METHODS

Inclusion criteria for this multicenter clinical retrospective study were fully or partially edentulous patients who had been treated with a sleeveless and keyless guided implant surgery system (R2Gate®, Megagen), and who had been rehabilitated with fixed restorations, with a minimum follow-up of 1 year. All surgeries and prosthetic procedures were conducted following the same protocol, and data were obtained from the patients' medical records. The outcomes were the fit and stability of the surgical guide, any intra-operative and immediate post-operative complications, any biologic and prosthetic complications that occurred during the 1-year follow-up period, implant survival, and prosthetic success.

RESULTS

Sixty patients were selected for the installation of 124 implants, through a guided procedure: 66 sleeveless, keyless surgical guides were manufactured. The incidence of immediate intra-operative (lack of space: 12.1%; lack of implant stability 2.6%) and immediate post-operative (pain and discomfort: 6.6%; mild swelling 3.3%) complications was low. In total, 112/124 implants (90.3%) were successfully placed with a guided procedure, in 52 patients; among them, 82 (73.2%) were placed with a flapless procedure. Thirty fixtures supported single crowns (SCs), 42 fixed partial dentures (FPDs) and 52 full-arch (FA) restorations. Sixty-two fixed prosthetic restorations (30 SCs, 22 FPDs and 10 FAs) were delivered; among these restorations, 15 (24.1%) were subjected to immediate functional loading. All implants (100%) survived. Two implants had peri‑implant mucositis (1.6%), two SCs had abutment screw loosenings (1.6%), two FAs and one FPD had ceramic chipping/fracture (2.4%), for an overall prosthetic success amounting to 88.7%.

CONCLUSIONS

Within the limits of this study, this novel guided surgery system appeared to be clinically reliable; further studies are needed to confirm these results.

STATEMENT OF CLINICAL RELEVANCE

The use of sleveless and keyless surgical guides can be clinically reliable and may be represent a valid option for the surgeon.

Implant-Abutment Connections: A Structured Review

The aim of the study was to carry out a structured review of studies that dealt with types of implant abutment connections, the concept of platform switching and its influence on hard and soft oral tissues. Electronic search was conducted over PubMed, Google Scholar, Medline, Embase to find articles dealing with Implant abutment connection and platform switching. We came across a total of 248 articles, which were filtered to a cumulative 19 articles after cross matching with predetermined inclusion and exclusion criteria. Most of the available literature gravitates in favor of an internal connection with the incorporation of platform switching to attain satisfactory hard and soft tissue outcomes.

Custom-Made Direct Metal Laser Sintering Titanium Subperiosteal Implants in Oral and Maxillofacial Surgery for Severe Bone-Deficient Patients—A Pilot Study

Background: Nowadays, a combination of classical subperiosteal implant designs with 3D imaging and printing allows one to reduce treatment time and provides support for fixed prostheses in cases where other techniques do not provide satisfactory results. This study aims to present a digital technique for the manufacturing of custom-made subperiosteal implants and what complications might appear after this type of surgery. Methods: Sixteen patients treated with a custom-made DMLS titanium subperiosteal implant during the period between October 2021 and February 2022 were enrolled in the study. Orthopantomography (OPT) and cone-beam computer tomography (CBCT) were recorded for all patients. The measurements taken into account in this study were the fit and stability of implants, duration of surgery, implant survival, and early and late complications. Results: The fit of the implants was extremely satisfactory, with a mean rating of 4 out of 5. The mean duration of the intervention was 86.18 min. At the end of the study, one implant was lost due to insufficient fit and recurrent, untreatable infections. Eleven implants (69%) were placed on the maxillary and five (31%) implants were placed on the mandible. Conclusions: Taking this into consideration, custom-made DMLS titanium subperiosteal implants could present satisfactory implant survival and low complication rates.

Evaluation of Correlation between Vitamin D Levels and Implant Stability in Indian Population: A Prospective Study in Bangalore

Purpose

Dental implants have become a definitive method for the esthetic and functional rehabilitation of both partially and completely edentulous arch. There is a significant role of vitamin D in bone metabolism and there are only few human studies that evaluate the effect of vitamin D deficiency on stability of dental implants. The study thus aims to evaluate the correlation of vitamin D deficiency and implant stability in delayed endosseous implant.

Methods

The study included 20 subjects of either gender in the age group of 20-50 years, who required implant placement for rehabilitation of partially edentulous condition. Vitamin D status was evaluated for all subjects preoperatively. Implant stability was checked postoperatively at three months and six months using Electronic Technology Resonance Frequency Analysis.

Results

The study found that for every 1 ng/ml increase in Vitamin D levels, the implant stability Quotient value (ISQ) significantly increased by 0.48 at 3 months and 0.62 units at 6 months, which was statistically significant at P = 0.01 and P = 0.002, respectively. Statistical analysis was done using Student Paired t test, Pearson Correlation test and Simple Linear regression analysis.

Conclusion

Albeit the smaller sample size, the results of the study showed the positive influence of vitamin D on stability of implant. The study thus emphasizes on the significance of screening the vitamin D status of subjects prior to implant placement.

Model-free digital workflow and immediate functional loading of implant-supported monolithic glass-ceramic crowns: A case series

OBJECTIVES

The aim of this study is to evaluate surgical and prosthetic outcomes of immediate functional loading of implants with glass-ceramic screw-retained single crowns.

METHODS

A total of 22 implants were placed. Within 24 hours, functional full-contour glass ceramic crowns were delivered to patients. The amount of attached gingiva, Simplified Oral Hygiene Index Score, bleeding on probing, time after extraction, bone type, implant size, soft tissue thickness, primary stability, a general fit of the restoration, occlusal and proximal contacts were recorded. Restorations were followed-up at 1, 3, and 6 months tracking marginal bone loss (MBL), noting changes in occlusal and interproximal contacts, checking other possible complications.

RESULTS

One implant failed and was removed after 4 weeks (95.5 % survival rate). The rest of the implants and crowns functioned with no complications during the follow-up period of 6 months. Factors such as time after extraction, bone type, implant size, soft tissue thickness, and primary stability recorded in Ncm and implant stability quotient (ISQ) values, were not associated with MBL (p<0.05). Mean MBL was found to be 0.3 mm (standard deviation = 0.42) mesially and 0.4 mm (standard deviation = 0.66) distally. One distal and one mesial proximal contact were found to be missing at the 6-month check-up appointment.

CONCLUSIONS

Within the limits of this study, fully digital workflow without a 3D printed model could be successfully employed for immediate functional loading with single-unit implant-supported crowns. Further studies are needed to obtain long-term results with a larger sample of patients.

CLINICAL SIGNIFICANCE

Model-free digital workflow and immediate functional loading of implant-supported monolithic glass-ceramic crown might be viable option to restore a single tooth defect.

Influence of Serum Vitamin D Levels on Survival Rate and Marginal Bone Loss in Dental Implants: A Systematic Review

This systematic literature review set out to investigate the relationship between serum vitamin D levels and dental implants in terms of survival rates, marginal bone loss, and associated complications. The review was conducted according to PRISMA guidelines, performing an electronic search in four databases (Pubmed, Web of Science, Cochrane, and Scopus), complemented by a manual search up to April 2022. Four articles were selected for analysis. The Newcastle-Ottawa Quality Assessment Scale tool was used to assess the quality of evidence of cohort studies, and the Cochrane bias assessment tool was used to assess the quality of evidence of randomized clinical trials. The study included 1089 patients restored with 1984 dental implants, with follow-up periods ranging from 20-240 months. Cases presenting lower serum vitamin D levels obtained slightly worse results in terms of marginal bone loss. Longer follow-up periods are needed in order to determine whether serum vitamin D levels affect implant survival rates and osseointegration over time.

Effect of implant crestal position on primary stability before and after loading: an in vitro study

Abstract Introduction Primary stability is one of the goals of modern implant dentistry and if achieved, reduces treatment time for prosthetic rehabilitation and the number of interventions made in patients mouth. Several companies state as protocol for connical conection implants, a subcrestally positioning. Objective This in vitro study aimed to evaluate the effect of placing a conical connection implant equicrestally and subcrestally on static and loading condition in two types of bone density. Material and method A total of 200 bone cylinders were extracted from femur of pigs, standardized by means of x-rays and computerized microtomography scan (microCT) and separated in low and high density specimens. The implants were placed on the center of the bone cylinders and were evaluated before and after loading by means of microCT and histomorphometry. Result The results showed that placing the evaluated implant subcrestally provided better primary stability and performance on static and loading situations on low and high density bone. Conclusion Placing implant subcrestally improve primary stability outcomes under loading and static situations.

The Relationship Between Low Serum Vitamin D Level and Early Dental Implant Failure: A Systematic Review

The variety in shape and type of dental implants in the present time is considered one of the most successful evolutions in dentistry. This facilitates dental treatment options to restore patient function and appearance. However, numerous significant factors influence the predictability of survival or the success rates of dental implants, some of which, such as vitamin D levels, have not been included in many studies. The main purpose of this systematic review was to investigate whether there is a relationship between low serum levels of vitamin D and early dental implant failures (EDIFs). Our literature search involved international databases including PubMed, Directory of Open Access Journals (DOAJ), and Web of Science. Initially, according to our search criteria, 1200 studies were found. After excluding duplicates, incomplete studies, and studies not meeting our inclusion criteria, only six human studies were included in this research and analyzed. Finally, upon meticulous analysis of included studies, this systematic review revealed inconsistent results in articles with respect to the association between vitamin D deficiency and implant failures. Large-scale studies, especially clinically relevant studies, on this subject is recommended.

Prosthetic complications of fixed dental prostheses supported by locking-taper implants: a retrospective study with a mean follow-up of 5 years

BACKGROUND

Restoration with locking-taper implants is a widely used methodology. However, conical connection systems such as locking-taper implant systems have rarely been examined. This study provides a retrospective investigation of locking-taper fixed restorations, mainly focusing on prosthetic complications.

METHODS

Patients undergo treatment with conical connected implants from 2008 to 2010 were examined. Preparation of the implant sites was performed according to the standard procedures for the Bicon system. Bone healing took over 6 months, and the prosthetic procedure was initiated thereafter. Integrated abutment crowns or gold porcelain crowns were used, and the prosthesis type was a single crown or a fixed dental prosthesis. Once the crown was in place, its occlusion was thoroughly checked and adjusted, and then the crown was glazed or finely polished. The Kaplan-Meier method was used to calculate the cumulative complication-free rates for 5 and 10 years. Additionally, a Cox regression model was used to identify the factors that independently influenced the results. Implant survival and marginal bone loss were also investigated.

RESULTS

A total of 392 patients who underwent 541 implants and 434 locking taper implant-based restorations from 2008 to 2010 were examined. The overall 5-year cumulative complication-free rate was 83.34%. The most common prosthetic complication was veneer chipping, with a frequency of 67.53%. According to the Cox regression model, the complication-free rate of integrated abutment crowns was significantly higher than that of gold porcelain crowns, that of molar regions was significantly higher than that of premolar regions, and that of females was significantly higher than that of males. Only three implant failures happened, and the mean marginal bone loss values at 1- year, 5-years and 10- years were 0.25 mm (95% CI ± 0.12), 0.40 mm (95% CI ± 0.03) and 0.51 mm (95% CI ± 0.05), respectively.

CONCLUSION

Veneer chipping was the most common complication with locking-taper implant-supported fixed restorations. The incidence of complications for IACs is significantly higher than that for GPCs. Age, location, and prosthesis type are not determinants of prosthetic complications. Besides, the long-term clinical effect of locking-taper implant can meet the clinical needs. The bone tissue level around the implant can maintain long-term stability.

The Possible Role of Vitamin D Deficiency in Early Implant Failure

Background. Dental implants are one of the most successful treatments for restoring tooth function and beauty. Identifying the causes of dental implant failure is useful and vital. This review was aimed at studying the possible role of vitamin D in early implant failure. Method and Material. This review was designed based on the PRISMA guideline. Data was collected using keywords including implant, vitamin D, deficiency, failure, dental, OR tooth in international databases including PubMed, Scopus, Web of Science, Cochrane, and Embase, until 2020. Based on the inclusion and exclusion criteria, data were extracted and gathered in a checklist. Results. Finally, twelve studies were selected from five different countries. In 6 studies (2 animal studies and four human studies), there was no significant relationship between vitamin D deficiency and dental implant failure. In the other six studies (1 animal study and five human studies), there was a significant relationship in this regard. Conclusion. It is difficult to conclude the association between vitamin D and implant failure based on the literature’s researches. However, vitamin D appears to play an essential role in implant success through its effects on immune system modulation.

The Relationship Between Serum Level of Vitamin D3 and Osseointegration Around the Dental Implant

At present, dental implants are used more than before, and their high success rate is attributed to sufficient osseointegration, which depends on prosthetic-, implant-, and patient-related factors. The quality and quantity of bone and the host response are the main patient-related factors. Vitamin D3 affects bone metabolism by stimulating both osteoclasts and osteoblasts. This study aimed to review the human studies on the efficacy of vitamin D3 for dental implant osseointegration. Search of the literature yielded only 4 studies on human models, of which 2 showed the optimal efficacy of vitamin D3 for dental implant osseointegration, whereas the remaining 2 did not report any positive effect. However, this finding may be related to the small sample size of the vitamin D3-deficient group, which can compromise statistical analyses. In conclusion, vitamin D3 seems to be effective for dental implant osseointegration, although further research is required on human models.

The biological width around implant

PURPOSE

The concept of biological width has been proposed and widely used in oral implantation. This review aimed to summarize the biological width around implant in detail.

STUDY SELECTION

An electronic search of the literature prior to March 2019 was performed to identify all articles related to biological width in periimplant soft tissue. The search was conducted in the MEDLINE (National Library of Medicine) database accessed through PubMed with no date restriction. The following main keywords were used: "implant", "biological width", "soft tissue", "junctional epithelium", "peri-implant epithelium", "connective tissue", "gingiva", "mucosa" (connecting multiple keywords with AND, OR).

RESULTS

The identified researches focused on several aspects related to biological width in oral implantation, namely the concept, formation, remodeling, dimension, structure and function.

CONCLUSIONS

Based on of the reviewed literature, the concept, formation, remodeling, structure, dimension, and functional significances of periimplant biological width are explored in this narrative review. The formation of biological width around implant is a complex process after several weeks of healing. The biological width around implant is a 3-4mm distance from the top of the peri-implant mucosa to the first bone-to-implant contact or the stabilized top of the adjacent bone, consisting of sulcular epithelium, junctional epithelium and fibrous connective tissue between the epithelium and the first bone-to-implant contact or the stabilized top of the adjacent bone. The biological width forms a biological barrier against the bacteria, influences the remodeling of soft and hard tissue around implant and has implications for clinical aspects of dental implantation.

Comparative evaluation of crestal bone level in patients having low level of Vitamin D treated with dental implant with or without Vitamin D3 supplements

INTRODUCTION

Vitamin D has been shown to play a vital role in bone mineral homeostasis by stimulating the intestinal absorption of calcium and phosphate. The critical role of Vitamin D in bone metabolism triggered the need to evaluate the effect of Vitamin D deficiency and hence replacement of the same on osseointegration of dental implants. This prospective study evaluated the crestal bone level in patients having low level of Vitamin D treated with dental implant with or without Vitamin D3 supplements.

MATERIALS AND METHODS

A prospective clinical study was conducted on 32 patients based on the inclusion and exclusion criteria. Patients were divided into two groups on the basis of Vitamin D level < 30 ng/ml (Group I: patients receiving Vitamin D3 supplements, i.e., cholecalciferol 1 g sachet 60,000 IU/month) or <30 ng/ml (Group II: not receiving Vitamin D3 supplements). The crestal bone level measurements were made with the help of Digimizer Image Analysis, MedCalc software.

RESULTS

All implants showed clinically acceptable crestal bone level at interval of 1 week (baseline), 3 months, and 6 months. There was a statistically nonsignificant difference seen for the values between the groups (P > 0.05) for all other values at various time intervals. However, there was a statistically significant/highly significant difference seen for the values between the groups (P < 0.01, 0.05) for 3 months distal with higher values for Group I as compared to Group II.

CONCLUSION

From the study, it can be concluded that cholecalciferol has systemic effects on accelerating bone formation around titanium implant.

Effect of Vitamin D Supplementation on Clinical and Radiographic Evaluation of Oral Rehabilitation with Osseointegrated Implants

Abstract   Vitamin D (VD) is important for the development and maintenance of bone tissue. This study used clinical and radiographic evaluations to analyze whether insufficient VD levels affect the periimplant health of patients with implant-supported prostheses. Data were collected for 33 patients with implant-supported prostheses: probing depth (PD); width of keratinized mucosa (wKM); bleeding index (mBI); periimplant plaque index (mPI); distance from implant to bone crest and VD level using chemiluminescence. After 1 year of implant-supported prosthesis installation, patients with levels under 30 ng/ml at baseline received 50000 IU of VD per week for 8 weeks (post treatment, PT), when clinical and radiographic evaluations were repeated for the control (n=19) and the VD (n=14) groups. Clinical and radiographic results were compared at baseline and at PT.  There were differences in PD (p=0.0247) and distance from implant to bone crest (p<0.0001), but there were not statistically different after supplementation.  wMK, mBI and mPI were not statistically different between groups.  VD levels were 24.95 ± 0.96 ng/mL in the VD group (42.42% of patients), whereas 57.57% of all participants had a mean VD value of 40.99 ± 1.23 ng/mL, a statistically significant difference (p = 0.0034). According to clinical and radiographic findings, VD serum levels do not seem to affect periimplant health. Keywords: Bone Density. Clinical Study. Dental Implantation.  ResumoA vitamina D (VD) é importante para o desenvolvimento e a manutenção do tecido ósseo. Este estudo clínico e radiográfico avaliou a reposição dos níveis de vitamina D na saúde periimplantar de pacientes com próteses implantossuportadas. Profundidade bolsa a sondagem (PS), largura da mucosa queratinizada (LMQ), sangramento a sondagem (mBI), presença de placa bacteriana (mPI), distância entre implante e cristas ósseas e dosagem de VD utilizando o teste de quimioluminescência, foram medidos em 33 pacientes. Pacientes com dosagens acima de 30 ng/ml foram classificados como suficientes de VD (grupo controle, n = 19). Pacientes com menos de 30ng/ml (grupo VD, n = 14) receberam, após 1 ano da instalação da prótese sobre implante, reposição de 50.000 UI por semana durante 8 semanas, quando os exames foram repetidos. Dados iniciais intragrupos, bem como dados iniciais e pós-tratamento (PT) intergrupos e intragrupos, foram comparados. Diferenças estatísticas foram encontradas em PS (p=0.0247) e distância entre crista óssea e implante (p<0.0001) entre os grupos, mas não após reposição. Não houve diferença em LMQ, mBI e mPI entre os grupos. O valor médio de VD do grupo VD foi 24,95±0.96 ng/ml para 42,42% dos pacientes, enquanto 57,57% da amostra apresentaram valor médio de 40,99±1.23 ng/ml, demonstrando diferença estatística (p=0.0034). A reposição de VD não parece influenciar os achados clínicos e radiográficos da saúde periimplantar. Palavras-chave: Densidade Óssea. Estudo Clínico. Implantação Dentária.

Impact of Different Titanium Implant Thread Designs on Bone Healing: A Biomechanical and Histometric Study with an Animal Model

Threads of dental implants with healing chamber configurations have become a target to improve osseointegration. This biomechanical and histometric study aimed to evaluate the influence of implant healing chamber configurations on the torque removal value (RTv), percentage of bone-to-implant contact (BIC%), bone fraction occupancy inside the thread area (BAFO%), and bone and osteocyte density (Ost) in the rabbit tibia after two months of healing. Titanium implants with three different thread configurations were evaluated: Group 1 (G1), with a conventional “v” thread-shaped implant design; Group 2 (G2), with square threads; and Group 3 (G3), the experimental group with longer threads (healing chamber). Ten rabbits (4.5 ± 0.5 kg) received three implants in each tibia (one per group), distributed in a randomized manner. After a period of two months, the tibia blocks (implants and the surrounding tissue) were removed and processed for ground sectioning to evaluate BIC%, BAFO%, and osteocyte density. The ANOVA one-way statistical test was used followed by the Bonferoni’s multiple comparison test to determine individual difference among groups, considering a statistical difference when p < 0.05. Histometric evaluation showed a higher BAFO% values and Ost density for G3 in comparison with the other two groups (G1 and G2), with p < 0.05. However, the RTv and BIC% parameters were not significantly different between groups (p > 0.05). The histological data suggest that the healing chambers in the implant macrogeometry can improve the bone reaction in comparison with the conventional thread design.

A systematic review of the survival and complication rates of zirconia-ceramic and metal-ceramic single crowns

OBJECTIVES

The aim of the present systematic review was to analyze the survival and complication rates of zirconia-based and metal-ceramic implant-supported single crowns (SCs).

MATERIALS AND METHODS

An electronic MEDLINE search complemented by manual searching was conducted to identify randomized controlled clinical trials, prospective cohort and retrospective case series on implant-supported SCs with a mean follow-up time of at least 3 years. Patients had to have been clinically examined at the follow-up visit. Assessment of the identified studies and data extraction was performed independently by two reviewers. Failure and complication rates were analyzed using robust Poisson's regression models to obtain summary estimates of 5-year proportions.

RESULTS

The search provided 5,263 titles and 455 abstracts, full-text analysis was performed for 240 articles, resulting in 35 included studies on implant-supported crowns. Meta-analysis revealed an estimated 5-year survival rate of 98.3% (95% CI: 96.8-99.1) for metal-ceramic implant supported SCs (n = 4,363) compared to 97.6% (95% CI: 94.3-99.0) for zirconia implant supported SCs (n = 912). About 86.7% (95% CI: 80.7-91.0) of the metal-ceramic SCs (n = 1,300) experienced no biological/technical complications over the entire observation period. The corresponding rate for zirconia SCs (n = 76) was 83.8% (95% CI: 61.6-93.8). The biologic outcomes of the two types of crowns were similar; yet, zirconia SCs exhibited less aesthetic complications than metal-ceramics. The 5-year incidence of chipping of the veneering ceramic was similar between the material groups (2.9% metal-ceramic, 2.8% zirconia-ceramic). Significantly (p = 0.001), more zirconia-ceramic implant SCs failed due to material fractures (2.1% vs. 0.2% metal-ceramic implant SCs). No studies on newer types of monolithic zirconia SCs fulfilled the simple inclusion criteria of 3 years follow-up time and clinical examination of the present systematic review.

CONCLUSION

Zirconia-ceramic implant-supported SCs are a valid treatment alternative to metal-ceramic SCs, with similar incidence of biological complications and less aesthetic problems. The amount of ceramic chipping was similar between the material groups; yet, significantly more zirconia crowns failed due to material fractures.

A systematic review of the survival and complication rates of zirconia-ceramic and metal-ceramic multiple-unit fixed dental prostheses

OBJECTIVES

The aim of the present review was to compare the outcomes, that is, survival and complication rates of zirconia-ceramic and/or monolithic zirconia implant-supported fixed dental prostheses (FDPs) with metal-ceramic FDPs.

MATERIALS AND METHODS

An electronic MEDLINE search complemented by manual searching was conducted to identify randomized controlled clinical trials, prospective cohort studies and retrospective case series on implant-supported FDPs with a mean follow-up of at least 3 years. Patients had to have been examined clinically at the follow-up visit. Assessment of the identified studies and data extraction was performed independently by two reviewers. Failure and complication rates were analyzed using robust Poisson regression models to obtain summary estimates of 5-year proportions.

RESULTS

The search provided 5,263 titles and 455 abstracts. Full-text analysis was performed for 240 articles resulting in 19 studies on implant FDPs that met the inclusion criteria. The studies reported on 932 metal-ceramic and 175 zirconia-ceramic FDPs. Meta-analysis revealed an estimated 5-year survival rate of 98.7% (95% CI: 96.8%-99.5%) for metal-ceramic implant-supported FDPs, and of 93.0% (95% CI: 90.6%-94.8%) for zirconia-ceramic implant-supported FDPs (p < 0.001). Thirteen studies including 781 metal-ceramic implant-supported FDPs estimated a 5-year rate of ceramic fractures and chippings to be 11.6% compared with a significantly higher (p < 0.001) complication rate for zirconia implant-supported FDPs of 50%, reported in a small study with 13 zirconia implant-supported FDPs. Significantly (p = 0.001) more, that is, 4.1%, of the zirconia-ceramic implant-supported FDPs were lost due to ceramic fractures compared to only 0.2% of the metal-ceramic implant-supported FDPs. Detailed analysis of factors like number of units of the FDPs or location in the jaws was not possible due to heterogeneity of reporting. No studies on monolithic zirconia implant-supported FDPs fulfilled the inclusion criteria of the present review. Furthermore, no conclusive results were found for the aesthetic outcomes of both FDP-types.

CONCLUSION

For implant-supported FDPs, conventionally veneered zirconia should not be considered as material selection of first priority, as pronounced risk for framework fractures and chipping of the zirconia veneering ceramic was observed. Monolithic zirconia may be an interesting alternative, but its clinical medium- to long-term outcomes have not been evaluated yet. Hence, metal ceramics seems to stay the golden standard for implant-supported multiple-unit FDPs.

How do peri-implant biologic parameters correspond with implant survival and peri-implantitis? A critical review

Objectives

The aim of this critical review was to evaluate whether commonly used biologic diagnostic parameters correspond to implant survival and peri‐implantitis prevalence.

Materials and methods

Publications from 2011 to 2017 were selected by an electronic search using the Pubmed database of the US National Library of Medicine. Prospective and retrospective studies with a mean follow‐up time of at least 5 years and reporting prevalence of peri‐implantitis as well as mean bone loss and standard deviation were selected. The correlation between reported prevalence of peri‐implantitis and reported implant survival, mean follow‐up time, mean bone loss, mean probing depth, and mean bleeding on probing was calculated. Mean bone loss and standard deviation were used for estimation of proportion of implants with bone loss exceeding 1, 2, and 3 mm.

Results

Full‐text analysis was performed for 255 papers from 4,173 available ones, and 41 met all the inclusion criteria. The overall mean weighted survival rate was 96.9% (89.9%–100%) and the reported prevalence of peri‐implantitis ranged between 0% and 39.7%, based on 15 different case definitions. The overall weighted bone loss was 1.1 mm based on 8,182 implants and an average mean loading time ranging from 5 to 20 years. No correlation was found between mean bone loss and the reported prevalence of peri‐implantitis. The estimated prevalence of implants with bone loss above 2 mm was 23%. The overall weighted mean probing depth was 3.3 mm, and mean weighted bleeding was 52.2%. Only a weak correlation was found between survival and function time (r = −0.49). There was no relation between the probing depth or bleeding and the mean bone loss, mean follow‐up time, and reported prevalence of peri‐implantitis.

Conclusion

Biologic parameters mean probing depth and mean bleeding on probing do not correlate with mean bone loss and this irrespective of follow‐up. Case definition for peri‐implantitis varied significantly between studies indicating that an unambiguous definition based on a specified threshold for bone loss is not agreed upon in the literature.

A Novel Full-Digital Protocol (SCAN-PLAN-MAKE-DONE®) for the Design and Fabrication of Implant-Supported Monolithic Translucent Zirconia Crowns Cemented on Customized Hybrid Abutments: A Retrospective Clinical Study on 25 Patients

Purpose: To present a novel, full-digital protocol for the design and fabrication of implant-supported monolithic translucent zirconia crowns cemented on customized hybrid abutments. Methods: The present retrospective clinical study was based on data from patients who had been treated with single Morse-taper connection implants (Exacone^®, Leone Implants, Florence, Italy) and were prosthetically restored with monolithic translucent zirconia crowns, cemented on customized hybrid abutments. The full-digital protocol (SCAN-PLAN-MAKE-DONE^®) consisted of 8 phases: (1) intraoral scan of the implant position with scanbody; (2) computer-assisted design (CAD) of the individual abutment (saved as “supplementary abutment design” in external folder) and temporary crown; (3) milling of the individual zirconia abutment and of the temporary polymethyl-methacrylate (PMMA) crown, with extraoral cementation of the zirconia abutment on the relative titanium bonding base, to generate an individual hybrid abutment; (4) clinical application of the individual hybrid abutment and cementation of the temporary PMMA crown; (5) two months later, intraoral scan of the individual hybrid abutment in position; (6) CAD of the final crown with margin line design on the previously saved “supplementary abutment design”, superimposed on the second scan of the abutment in position; (7) milling of the final crown in monolithic translucent zirconia, sintering, and characterization; and (8) clinical application of the final crown. All patients were followed for a period of 1 year. The primary outcomes of this study were the marginal adaptation of the final crown (checked clinically and radiographically), the quality of occlusal and interproximal contact points at delivery, and the aesthetic integration; the secondary outcomes were the 1-year survival and success of the implant-supported restoration. An implant-supported restoration was considered successful in the absence of any biological or prosthetic complication, during the entire follow-up period. Results: In total, 25 patients (12 males, 13 females; 26–74 years of age; mean age 51.1 ± 13.3 years) who had been restored with 40 implant-supported monolithic translucent zirconia crowns were included in this study. At delivery, the marginal adaptation was perfect for all crowns. However, there were occlusal issues (2/40 crowns: 5%), interproximal issues (1/40 crowns: 2.5%), and aesthetic issues (1/40 crowns: 2.5%). The overall incidence of issues at delivery was therefore 10% (4/40 crowns). At 1 year, one implant failed; thus the survival of the restorations was 97.5% (39/40 crowns in function). Among the surviving implant-supported restorations, three experienced complications (one loss of connection between the hybrid abutment and the implant, one decementation of the zirconia abutment, and one decementation of the zirconia crown). The success of restorations amounted to 92.4%. Conclusions: The restoration of single Morse-taper connection implants with monolithic translucent zirconia crowns cemented on customized hybrid abutments via the novel SCAN-PLAN-MAKE-DONE^® full-digital protocol seems to represent a reliable treatment option. However, further studies on a larger number of patients and dealing with different prosthetic restorations (such as implant-supported fixed partial prostheses) are needed to confirm the validity of this protocol.

Prosthetic Complications Affecting Single-Tooth Morse-Taper Connection Implants

PURPOSE

To evaluate the long-term cumulative implant survival rate (CISR%) and cumulative implant-crown success rate (CICSR%) of single-tooth Morse-taper connection implants, with particular attention to documenting the incidence of prosthetic complications.

METHODS

The customized records of all patients who had been treated with single-tooth Morse-taper connection implants in 2 dental centers during the period between January 2002 and December 2012 were revisited. These records included patient-related (gender, age at surgery, smoking, bruxism), implant-related (date of insertion, site/location, and length/diameter of the implant, previous/concomitant bone regeneration), and restoration-related (date of delivery of the provisional and final crown) information. In addition, these records contained information about any implant failure and biologic and/or prosthetic complication that occurred during the follow-up period as well as the radiographic documentation. The follow-up period comprised between 5 and 15 years. The main outcomes were CISR% and CICSR%, with the latter being defined as the condition in which no complication had affected the surviving implant-supported crown during the entire follow-up. Life-table analysis was used for the analysis of CISR% and CICSR%. Peri-implant marginal bone resorption (PIMBR) at 5, 10, and 15 years was a secondary outcome of this study.

RESULTS

In total, 578 patients who had received 612 implants were included in this study. The overall CISR% at 15 years was 94.8% (94.2% maxilla, 95.3% mandible). Among the surviving crowns, the overall CICSR% at 15 years was 94.5% (93.1% and 94.9% for anterior and posterior crowns, respectively), and the incidence of prosthetic complications was low (1.5%). The PIMBL amounted to 0.38 ± 0.29 mm, 0.49 ± 0.35 mm, and 0.94 ± 0.58 mm at the 5-, 10-, and 15-year follow-ups, respectively.

CONCLUSION

Morse-taper connection implants represent a reliable treatment procedure for the restoration of single-tooth gaps in the long term, with high CISR% (94.8%) at 15 years, a very low incidence of complications, and a high CICSR% (94.5%).

Morse taper implant macrodesign, loading protocol and site of installation – retrospective study of 5,601 implants

Abstract Introduction The long-term implant-supported prosthetic rehabilitation monitoring is extremely important in evaluating parameters that could interfere in the success of the treatment. Objective To evaluate the influence of macrodesign (shape of the body and apex), length and diameter, insertion torque, site of installation as well as the loading protocol, on long-term survival rates. Material and method The data obtained was from the medical records of rehabilitated patients who had had at least one Morse taper implant surgery done at ILAPEO School between 2006 -2012. Incomplete medical records, from which it would have been impossible to extract all data essential to complete the study, were excluded. Result A total of 1,142 patient’s medical records comprised the sample; documenting the progress of 5,601 implants, done in both jaws and mandibles. The final survival rate was 98.31%, over an average time of 37.54 months. The type of implant most used was cylindrical (70.33%). The mean installation torque most evidenced in the study was between 41 and 50 Ncm. A logistical regression analysis showed that none of the following variables, site of installation, body and apex shape designs and length, had any significant statistical influence on implant loss. Torque increase and diameter influenced implant loss while immediate loading favored implant maintenance. Conclusion It can be concluded that Morse taper implants present a long-term survival rate that can be lowered by excessive torque, as well as by the diameter of the implant.

Bacterial leakage and bending moments of screw-retained, composite-veneered PEEK implant crowns

Due to its elastic modulus close to bone, the high-performance material PEEK (polyetheretherketone) represents an interesting material for implant-supported dental prostheses. Besides a damping effect of masticatory forces, it might have a sealing effect against bacterial leakage of the implant-abutment interface (IAI). So far, PEEK has only been used for provisional implant crowns. Therefore, the aim of the study was the evaluation of the bacterial tightness of screw-retained PEEK crowns on titanium implants with conical IAI during masticatory simulation and subsequent bending moment testing. Ten screw-retained implant crowns in the shape of an upper central incisor consisting of a PEEK crown framework veneered with composite were connected to NobelActive RP titanium implants (4.3 × 11.5 mm, Nobel Biocare AB, Göteborg, Sweden) with a tightening torque of 15 Ncm. Prior to tightening, the interior of the implant was inoculated with a bacterial suspension of Enterococcus faecium. The specimens were overmolded with indicating agar (Kanamycin-Aesculin-Azid-Agar (KAAA), Oxoid Limited, Basingstoke United Kingdom), that turns black in contact with E. faecium. The specimens were subjected to a cyclic masticatory simulation whereby a force of 50 N cm was applied at an angle of 30° to the implant axis for 1.2 million cycles. Afterwards, the specimens were subjected to a static loading test according to ISO 14801:2007 to determine the bending moment. During masticatory simulation neither a loosening of the implant screws nor any damage to the veneer or the PEEK framework occurred. Furthermore, no bacterial leakage could be observed in any of the specimens. The average maximum bending moment was measured at 352.13 ± 48.96 N cm. Regarding masticatory forces, PEEK implant crowns seem to be applicable as definitive implant-supported restorations. Furthermore, the bacterial tightness of the IAI of screw-retained one-piece PEEK implant crowns is advantageous compared to superstructures of conventional materials. Further studies are necessary to substantiate the clinical significance of these findings.

Full in-Office Guided Surgery with Open Selective Tooth-Supported Templates: A Prospective Clinical Study on 20 Patients

Background: Guided implant surgery appears to have several benefits, such as the possibility of inserting flapless implants in a prosthetically driven manner, avoiding dangerous anatomical structures. However, to date, only a few surgeons routinely use guided surgery in partially edentulous patients. Aim: To present the results obtained with tooth-supported surgical templates characterized by an innovative open design with selective support, and manufactured via a full in-office procedure with a low-cost desktop 3D printer. Methods: Over a two-year period (2016–2018), all partially edentulous patients with one to three missing teeth (in maxilla and/or mandible), referred to a private dental practice for restoration with dental implants, were considered for inclusion in this prospective clinical study. An intraoral scanner (CS 3600^®, Carestream Dental) and cone beam computed tomography (CS 9300^®, Carestream Dental) were used to acquire the 3D information on the patients. Guided surgery software (SMOP^®, Swissmeda) was used to plan the surgeries and to design open, selective, tooth-supported templates that were fabricated with a stereolithographic (SLA) desktop 3D printer (XFAB2000^®, DWS). Guided implant surgeries were performed and patients were followed for a period of one year. The study outcomes were fit and stability of surgical templates, duration (time) of surgery, intra and post-operative complications, and implant stability and survival. Results: Twenty (20) partially edentulous patients (9 males, 11 females; mean age 54.4 ± 9.4 years) were included in the study; 28 open, selective, tooth-supported templates were designed with the aim of inserting 38 implants. Among the surgical templates, 24 had optimal fit and stability, three had optimal fit and sufficient stability, and only one had inadequate fit and unsatisfactory stability and was therefore not suitable for clinical use. The average time of the intervention was 15.7 ± 5.2 min per template. No intra-operative complications were reported, but one implant was not stable at placement and had to be removed. In total, 36 implants were restored with 10 two-unit fixed partial prostheses and 16 single crowns. All implants were successfully functioning at one year, even if, in two single crowns, minor prosthetic complications (abutment screw loosening) occurred. Conclusions: Full in-office guided surgery with open, selective, tooth-supported templates seem to represent a clinically predictable surgical procedure to restore partially edentulous patients. Further studies are needed to confirm these positive outcomes.

Low serum vitamin D and early dental implant failure: Is there a connection? A retrospective clinical study on 1740 implants placed in 885 patients

Background. Since osseointegration depends on bone metabolism, low levels of vitamin D in the blood may negatively affect bone formation around dental implants. To date, only a few studies have investigated the possible connection between serum levels of vitamin D and early dental implant failure (EDIF), i.e. failure that occurs within 4 months after placement, before the connection of the prosthetic abutment. The aim of this study was to investigate whether there is a relationship between low serum levels of vitamin D and EDIF.

Methods. Data used for this retrospective study were derived from the records of a private dental clinic. Inclusion criteria were patients who had been treated with dental implants, inserted with a submerged technique from January 2003 to December 2017. EDIF was the outcome of this study. Chi-squared test was used to investigate the effect of patient-related variables (age, gender, smoking habit, history of periodontal disease and serum levels of vitamin D) on EDIF.

Results. Originally, 885 patients treated with 1,740 fixtures were enrolled in this study. Overall, 35 EDIFs (3.9%) were reported. No correlation was found between EDIF and the patients' gender (P=0.998), age (P=0.832), smoking habit (P=0.473) or history of periodontal disease (P=0.386). Three EDIFs (11.1%) were reported in 27 patients with serum levels of vitamin D <10 ng/mL, 20 EDIFs (4.4%) in 448 patients with levels between 10 and 30 ng/mL, and 12 EDIFs (2.9%) in 410 patients with levels >30 ng/mL. Although there was a clear trend toward an increased incidence of EDIF with lowering of serum vitamin D levels, no statistically significant difference (P=0.105) was found among these three groups.

Conclusion. Within its limitations (retrospective design, low number of patients with severe blood levels of vitamin D enrolled), this study failed to demonstrate a significant relationship between low serum levels of vitamin D and increased risk of EDIF. However, since a dramatic increase in EDIFs with lowering of vitamin D levels in the blood has been reported, further clinical studies with appropriate design (prospective or randomized controlled studies on a larger sample of severely deficient patients) are needed to better investigate this topic

Splinted and Nonsplinted Crowns with Different Implant Lengths in the Posterior Maxilla by Three-Dimensional Finite Element Analysis

The aim of this study was to evaluate stress distribution in the implants/components and bone tissue for splinted and nonsplinted prostheses with different lengths of implants using three-dimensional finite element analysis. Six models from the posterior maxillary area were used in simulations. Each model simulated three Morse taper implants of 4.0 mm diameter with different lengths, which supported metal-ceramic crowns. An axial load of 400 N and an oblique load of 200 N were used as loading conditions. Splinted prostheses exhibited better stress distribution for the implants/components, whereas nonsplinted prostheses exhibited higher stress in the first molar under axial/oblique loading. Implant length did not influence stress distribution in the implants/components. In cortical bone tissue, splinted prostheses decreased the tensile stress in the first molar, whereas nonsplinted prostheses were subjected to higher tensile stress in the first molar; implant length had no influence on stress distribution. Within the limitations of this study, we conclude that splinted prostheses contributed to better stress distribution in the implant/abutment and cortical bone tissue; however, the reduction in the implant length did not influence the stress distribution.

Digital versus Analog Procedures for the Prosthetic Restoration of Single Implants: A Randomized Controlled Trial with 1 Year of Follow-Up

Aim

To compare the outcome of digital versus analog procedures for the restoration of single implants.

Methods

Over a two-year period (2014-2016), all patients who had been treated in a dental center with a single implant were randomly assigned to receive either a monolithic zirconia crown, fabricated with digital workflow (test group), or a metal-ceramic crown, fabricated with analog workflow (control group). All patients were followed for 1 year after the delivery of the final crown. The outcomes were success, complications, peri-implant marginal bone loss (PIMBL), patient satisfaction, and time and cost of the treatment.

Results

50 patients (22 males, 28 females; mean age 52.6±13.4 years) were randomly assigned to one of the groups (25 per group). Both workflows showed high success (92%) and low complication rate (8%). No significant differences were found in the mean PIMBL between test (0.39±0.29mm) and control (0.54±0.32mm) groups. Patients preferred digital impressions. Taking the impression took half the time in the test group (20±5min) than in the control (50±7min) group. When calculating active working time, workflow in the test group was more time-efficient than in the control group, for provisional (70±15min versus 340±37min) and final crowns (29±9min versus 260±26min). The digital procedure presented lower costs than the analog (€277.3 versus €392.2).

Conclusions

No significant clinical or radiographic differences were found between digital and analog procedures; however, the digital workflow was preferred by patients; it reduced active treatment time and costs. The present study is registered in the ISRCTN (http://www.isrctn.com/ISRCTN36259164) with number 36259164.

Custom-Made Direct Metal Laser Sintering Titanium Subperiosteal Implants: A Retrospective Clinical Study on 70 Patients

Purpose

To present a digital technique for the fabrication of custom-made subperiosteal implants and to report on the survival and complication rates encountered when using these fixtures.

Methods

The data used for this retrospective clinical study were derived from the medical records of five different private dental practices. Inclusion criteria were patients over the age of 60, treated with custom-made direct metal laser sintering (DMLS) titanium subperiosteal implants (Eagle-Grid®, BTK, Dueville, Vicenza) during a two-year period (2014-2015) and restored with fixed restorations; all enrolled patients needed to have complete pre- and postoperative clinical and radiographic documentation, with at least 2 years of follow-up. Exclusion criteria were smoking and bruxism. The main outcomes looked at were implant survival and complications.

Results

Seventy patients (39 males and 31 females, aged 62-79 years) who had been treated with custom-made DMLS titanium subperiosteal implants were enrolled in this study. After 2 years of follow-up, three implants were lost due to recurrent, untreatable infections; the survival rate was therefore 95.8% (67/70 implants). Four patients reported pain/discomfort/swelling after implant placement; the incidence of immediate postoperative complications was therefore 5.7% (4/70 implants). During the follow-up period, one patient suffered from recurrent infections classified as a biologic complication; the incidence of biologic complications was therefore 1.4% (1/67 surviving implants). Finally, four patients experienced prosthetic problems with their implant-supported restorations during the provisional phase (fracture of the acrylic restoration) and two patients had ceramic chipping of the definitive restoration; the incidence of prosthetic complications was therefore 8.9% (6/67 surviving implants).

Conclusions

Within the limits of the present study (limited follow-up time and low number of patients treated, retrospective design), the application of custom-made DMLS titanium subperiosteal implants showed satisfactory implant survival (95.8%) and low complication rates. Further studies are needed to confirm the positive outcomes found in this research.

Biomechanical analysis of different implant-abutments interfaces in different bone types: An in silico analysis

The purpose of this study was to analyze the stress distribution of bone tissue around implants with different implant-abutment interfaces: platform switching (PSW); external hexagon (EH) and Morse taper (MT) with different diameters (regular: Ø 4 mm and wide: Ø 5 mm), bone types (I-IV) and subjected to axial and oblique load conditions using three-dimensional finite element analysis (3D-FEA). Sixteen 3D models of various configurations were simulated using InVesalius, Rhinoceros 3D 4.0, and SolidWorks 2011 software, and processed using Femap 11.2 and NeiNastran 11.0 programs. Axial and oblique forces of 200 N and 100 N, respectively, applied at the occlusal surface of prostheses. Maximum principal stress values were obtained from the peri-implant cortical bone of each model. Statistical analyses were performed using ANOVA and Tukey's test for maximum principal stress values. Oblique loading showed higher tensile stress than axial loading (P < 0.001). Wide-diameter implants showed lower stress concentration rather than regular-diameter implants, regardless of both connection and bone type (P < 0.001). Under axial loading, wide-diameter EH implants with regular platforms showed more favorable stress distribution than PSW implants for axial loading (P < 0.001); however, under oblique loading, PSW implants exhibited lower stress concentrations (P < 0.001). Regular-diameter MT implants showed lower stress than EH implants (P < 0.001). Bone type IV showed higher stress in the cortical region than bone types I and II (P < 0.001), but no significant difference when compared with bone type III (P > 0.05). The conclusion drawn from this in silico is that MT implants should be considered for use in situations that preclude the placement of wide-diameter implants, particularly where bone types III and IV are concerned.

Retention System and Splinting on Morse Taper Implants in the Posterior Maxilla by 3D Finite Element Analysis

Abstract The purpose of this study was to evaluate different retention systems (cement- or screw-retained) and crown designs (non-splinted or splinted) of fixed implant-supported restorations, in terms of stress distributions in implants/components and bone tissue, by 3-dimensional (3D) finite element analysis. Four 3D models were simulated with the InVesalius, Rhinoceros 3D, and SolidWorks programs. Models were made of type III bone from the posterior maxillary area. Models included three 4.0-mm-diameter Morse taper (MT) implants with different lengths, which supported metal-ceramic crowns. Models were processed by the Femap and NeiNastran programs, using an axial force of 400 N and oblique force of 200 N. Results were visualized as the von Mises stress and maximum principal stress (σmax). Under axial loading, there was no difference in the distribution of stress in implants/components between retention systems and splinted crowns; however, in oblique loading, cemented prostheses showed better stress distribution than screwed prostheses, whereas splinted crowns tended to reduce stress in the implant of the first molar. In the bone tissue cemented prostheses showed better stress distribution in bone tissue than screwed prostheses under axial and oblique loading. The splinted design only had an effect in the screwed prosthesis, with no influence in the cemented prosthesis. Cemented prostheses on MT implants showed more favorable stress distributions in implants/components and bone tissue. Splinting was favorable for stress distribution only for screwed prostheses under oblique loading.

Scanning Electron Microscope (SEM) Evaluation of the Interface between a Nanostructured Calcium-Incorporated Dental Implant Surface and the Human Bone

Purpose. The aim of this scanning electron microscope (SEM) study was to investigate the interface between the bone and a novel nanostructured calcium-incorporated dental implant surface in humans. Methods. A dental implant (Anyridge^®, Megagen Implant Co., Gyeongbuk, South Korea) with a nanostructured calcium-incorporated surface (Xpeed^®, Megagen Implant Co., Gyeongbuk, South Korea), which had been placed a month earlier in a fully healed site of the posterior maxilla (#14) of a 48-year-old female patient, and which had been subjected to immediate functional loading, was removed after a traumatic injury. Despite the violent trauma that caused mobilization of the fixture, its surface appeared to be covered by a firmly attached, intact tissue; therefore, it was subjected to SEM examination. The implant surface of an unused nanostructured calcium-incorporated implant was also observed under SEM, as control. Results. The surface of the unused implant showed a highly-structured texture, carved by irregular, multi-scale hollows reminiscent of a fractal structure. It appeared perfectly clean and devoid of any contamination. The human specimen showed trabecular bone firmly anchored to the implant surface, bridging the screw threads and filling the spaces among them. Conclusions. Within the limits of this human histological report, the sample analyzed showed that the nanostructured calcium-incorporated surface was covered by new bone, one month after placement in the posterior maxilla, under an immediate functional loading protocol.

Tapered, Double-Lead Threads Single Implants Placed in Fresh Extraction Sockets and Healed Sites of the Posterior Jaws: A Multicenter Randomized Controlled Trial with 1 to 3 Years of Follow-Up

PURPOSE

To evaluate the survival, success, and complication rates of tapered double-lead threads single implants, placed in fresh extraction sockets and healed sites of the posterior jaws.

METHODS

The enrolled patients were randomly divided into 2 groups: in the test group (TG), all implants were inserted at the time of tooth extraction; in the control group (CG), all implants were placed 3 months after extraction. The implants were followed for a period of 1 to 3 years after loading. The main outcomes were implant survival, complications, and implant-crown success.

RESULTS

Ninety-two patients had 97 installed implants (49 in the TG, 48 in the CG). Only two implants failed, in the TG; the survival rates were therefore 95.9% (47/49) and 100% (48/48) for TG and CG, respectively. In the surviving implants, no complications were reported, for an implant-crown success of 100%.

CONCLUSIONS

Although a significant difference was found in the levels of primary stability between TG and CG, single implants placed in fresh extraction sockets and healed sites of the posterior jaws had similar survival and complication rates. Crestal bone levels and peri-implant bone resorption showed similar values. A longer follow-up period is however required, to confirm these positive outcomes.

Maximum insertion torque of a novel implant-abutment-interface design for PEEK dental implants

Frequent reports attest to the various advantages of tapered implant/abutment interfaces (IAIs) compared to other types of interfaces. For this reason, a conical IAI was designed as part of the development of a PEEK (polyetheretherketone)-based dental implant. This IAI is equipped with an apically displaced anti-rotation lock with minimal space requirements in the form of an internal spline. The objective of this study was the determination of the average insertion torque (IT) at failure of this design, so as to determine its suitability for immediate loading, which requires a minimum IT of 32Ncm. 10 implants each made of unfilled PEEK, carbon fiber reinforced ("CFR") PEEK (> 50vol% continuous axially parallel fibers) as well as of titanium were produced and tested in a torque test bench. The average IT values at failure of the unfilled PEEK implants were measured at 22.6 ± 0.5Ncm and were significantly higher than those of the CFR-Implants (20.2 ± 2.5Ncm). The average IT values at failure of the titanium specimens were significantly higher (92.6 ± 2.3Ncm) than those of the two PEEK variants. PEEK- and CFR-PEEK-implants in the present form cannot adequately withstand the insertion force needed to achieve primary stability for immediate loading. Nevertheless, the achievable torque resilience of the two PEEK-variants may be sufficient for a two-stage implantation procedure. To improve the torque resistance of the PEEK implant material the development of a new manufacturing procedure is necessary which reinforces the PEEK base with continuous multi-directional carbon fibers as opposed to the axially parallel fibers of the tested PEEK compound.

The Ball Welding Bar: A New Solution for the Immediate Loading of Screw-Retained, Mandibular Fixed Full Arch Prostheses

Purpose

To present a new intraoral welding technique, which can be used to manufacture screw-retained, mandibular fixed full-arch prostheses.

Methods

Over a 4-year period, all patients with complete mandibular edentulism or irreparably compromised mandibular dentition, who will restore the masticatory function with a fixed mandibular prosthesis, were considered for inclusion in this study. The “Ball Welding Bar” (BWB) technique is characterised by smooth prosthetic cylinders, interconnected by means of titanium bars which are adjustable in terms of distance from ball terminals and are inserted in the rotating rings of the cylinders. All the components are welded and self-posing.

Results

Forty-two patients (18 males; 24 females; mean age 64.2 ± 6.7 years) were enrolled and 210 fixtures were inserted to support 42 mandibular screw-retained, fixed full-arch prostheses. After two years of loading, 2 fixtures were lost, for an implant survival rate of 97.7%. Five implants suffered from peri-implant mucositis and 3 implants for peri-implantitis. Three of the prostheses (3/42) required repair for fracture (7.1%): the prosthetic success was 92.9%.

Conclusions

The BWB technique seems to represent a reliable technique for the fabrication of screw-retained mandibular fixed full-arch prostheses. This study was registered in the ISRCTN register with number ISRCTN71229338.

Morse Taper Connection Implants Placed in Grafted Sinuses in 65 Patients: A Retrospective Clinical Study with 10 Years of Follow-Up

PURPOSE

To investigate the 10-year survival and complication rates of Morse taper connection implants (MTCIs) placed in grafted sinuses.

METHODS

This study reports on patients treated with maxillary sinus augmentation (with the lateral window technique (LWT) or the transalveolar osteotomy technique (TOT)) and installed with MTCIs supporting fixed restorations (single crowns (SCs) and fixed partial dentures (FPDs)), in two dental clinics. The outcomes of the study were the 10-year implant survival and complication rates.

RESULTS

Sixty-five patients (30 males and 35 females) with a mean age of 62.7 (±10.2) years were installed with 142 MTCIs: 79 fixtures were inserted with the LWT and 63 were placed with the TOT. After ten years, five implants failed, for an overall survival rate of 96.5%. Three implants failed in the LWT group, for a survival rate of 96.3%; two implants failed in the TOT group, for a survival rate of 96.9%. The 10-year incidence of biologic complications was 11.9%. Prosthetic complications were all technical in nature and amounted to 7.6%.

CONCLUSIONS

MTCIs seem to represent a successful procedure for the prosthetic restoration of the grafted posterior maxilla, in the long term. This study was registered in the ISRCTN registry with number ISRCTN30772506.

Early Bone Response to Dual Acid-Etched and Machined Dental Implants Placed in the Posterior Maxilla: A Histologic and Histomorphometric Human Study

PURPOSE

To compare the early bone response to implants with dual acid-etched (DAE) and machined (MA) surface, when placed in the posterior human maxilla.

MATERIALS AND METHODS

Fourteen patients received 2 implants in the posterior maxilla: 1 DAE and 1 MA. After 2 months, the implants were retrieved for histologic/histomorphometric evaluation. The bone-to-implant contact (BIC%), bone density in the threaded area (BDTA%), and the bone density (BD%) were calculated. The Wilcoxon matched-pairs signed rank test was used to evaluate differences (BIC%, BDTA%, and BD%) between the surfaces.

RESULTS

In the MA implants, a mean (±SD) BIC%, BDTA%, and BD% of 21.76 (±12.79), 28.58 (±16.91), and 21.54 (±11.67), respectively, was reported. In the DAE implants, a mean (±SD) BIC%, BDTA%, and BD% of 37.49 (±29.51), 30.59 (±21.78), and 31.60 (±18.06), respectively, was reported. Although the mean BIC% of DAE implants value was almost double than that of MA implants, no significant differences were found between the 2 groups with regard to BIC% (P = 0.198) and with regard to BDTA% (P = 0.778) and BD% (P = 0.124).

CONCLUSIONS

The DAE surface increased the periimplant endosseous healing properties in the native bone of the posterior maxilla.

Cumulative Success Rate of Short and Ultrashort Implants Supporting Single Crowns in the Posterior Maxilla: A 3-Year Retrospective Study

AIM

To determine cumulative success rate (CSR) of short and ultrashort implants in the posterior maxilla restored with single crowns.

PATIENTS AND METHODS

We performed a retrospective study in 65 patients with 139 implants. 46 were ultrashort and 93 short. Implants were placed with a staged approach and restored with single crowns. Success rate, clinical and radiographic outcomes, and crown-to-implant ratio (CIR) were assessed after three years. Statistical analysis was performed by descriptive and inferential statistics. A log-binomial regression model where the main outcome was implant success was achieved. Coefficients and 95% confidence intervals were reported. Analyses were performed with Stata 13.2 for Windows.

RESULTS

61.54% of patients were female and mean overall age was 51.9 ± 11.08 years old. Overall CSR was 97.1% (95% CI: 92.4-98.9): 97.9 and 95.1% for short and ultrashort, respectively (P value: 0.33). Four implants failed. Covariates were not associated with CSR (P value > 0.05). Regression model showed coefficients correlated with implant success for ultrashort implants (0.87) and most of covariates but none were statistically significant (P values > 0.05).

CONCLUSIONS

Our results suggest that short and ultrashort implants may be successfully placed and restored with single crowns in the resorbed maxillary molar region.

Implant Stability in the Posterior Maxilla: A Controlled Clinical Trial

Aim

To evaluate the primary and secondary stability of implants in the posterior maxilla.

Methods

Patients were allocated into three groups: (A) native bone, (B) partially regenerated bone, and (C) nearly totally regenerated bone. Insertion torque (IT) and implant stability quotient (ISQ) were measured at placement, to evaluate whether satisfactory high primary stability (IT ≥ 45 N/cm; ISQ ≥ 60) was achieved; ISQ was measured 15, 30, 45, and 60 days after placement, to investigate the evolution to secondary stability.

Results

133 implants (Anyridge®, Megagen) were installed in 59 patients: 55 fixtures were placed in Group A, 57 in Group B, and 21 in Group C. Fifty-two implants had satisfactory high primary stability (IT ≥ 45 N/cm; ISQ ≥ 60). A positive correlation was found between all variables (IT, ISQ at t = 0, t = 60), and statistically higher IT and ISQ values were found for implants with satisfactory high primary stability. Significant differences were found for IT and ISQ between the groups (A, B, and C); however, no drops were reported in the median ISQ values during the healing period.

Conclusions

The evaluation of the primary and secondary implant stability may contribute to higher implant survival/success rates in critical areas, such as the regenerated posterior maxilla. The present study is registered in the ISRCTN registry with ID ISRCTN33469250.

Histological and Histomorphometrical Analysis on a Loaded Implant With Platform-Switching and Conical Connection: A Case Report

The association of Morse taper implant-abutment design with the use of a smaller abutment diameter (platform switching) may improve dental implant success rate and prevent peri-implant bone loss. The aim of the present study was to histologically and histomorphometrically evaluate the behavior of peri-implant tissues around an implant with a conical connection associated with platform switching. A platform-switched Morse-cone connection implant was inserted in the left posterior mandible of a 61-year-old patient. The implant was inserted at the level of the alveolar crest. After 11 months from placement and 6 months of loading, the implant was retrieved for psychological reasons and processed for histological evaluation. The retrieved implant was wholly surrounded by bone tissue, except for a small area in the apical portion. At higher magnification, in the coronal portion of the implant, it was possible to observe bone directly at the implant platform level. No resorption of the coronal bone was present, except for 0.2 mm on the vestibular aspect. Crestally, bone remodeling with areas of newly formed bone was detected; the bone-implant contact was 73.9%. Apposition of bone was detected even upon the platform. Peri-implant crestal bone preservation can be achieved with the combination of Morse taper conical internal implant-abutment connection with the use of a smaller abutment diameter (platform-switching).