Impact of surface chemical treatment in surgical regenerative treatment of ligature-induced peri-implantitis: A canine study.

BACKGROUND: Implant surface decontamination is a critical step in peri-implantitis treatment. The aim of this study was to assess the effect chemotherapeutic agents have on reosseointegration after treatment on ligature-inducted peri-implantitis. METHODS: Six male canines had 36 implants placed and ligatures were placed around them for 28 weeks to establish peri-implantitis. The peri-implant defects were randomly treated by 1 of 3 methods: 0.12% chlorhexidine (CHX test group), 1.5% sodium hypochlorite (NaOCl test group), or saline (Control group). Sites treated with NaOCl and CHX were grafted with autogenous bone, and all sites then either received a collagen membrane or not. Histology sections were obtained at 6 months postsurgery to assess percentage of reosseointegration. RESULTS: Thirty-five implants were analyzed (CHX: 13; NaOCl: 14; Control:8). NaOCl-treated sites demonstrated reosseointegration with direct bone-to-implant-contact on the previously contaminated surfaces (42% mean reosseointegration), which was significantly higher than Controls (p < 0.05). Correspondingly, clinical improvement was noted with a significant reduction in probing depth from 5.50 ± 1.24 mm at baseline to 4.46 ± 1.70 mm at 6-months postsurgery (p = 0.006). CHX-treated sites demonstrated a nonsignificant reosseointegration of 26% (p > 0.05); however, in the majority of cases, the new bone growth was at a distance from the implant surface without contact. Probing depths did not improve in the CHX group. The use of membrane did not influence reosseointegration or probing depths (all p > 0.05). CONCLUSION: Titanium implants with peri-implantitis have the capacity to reosseointegrate following regenerative surgery. However, treatment response is contingent upon the chemotherapeutic agent selection. Additional chemical treatment with 1.5% NaOCl lead to the most favorable results in terms of changes in defect depth and percentage of reosseointegration as compared to CHX, which may hinder reosseointegration.

Accuracy of robotic surgery for dental implant placement: A systematic review and meta-analysis.

OBJECTIVES: To systematically analyze the accuracy of robotic surgery for dental implant placement. MATERIALS AND METHODS: PubMed, Embase, and Cochrane CENTRAL were searched on October 25, 2023. Model studies or clinical studies reporting the accuracy of robotic surgery for dental implant placement among patients with missing or hopeless teeth were included. Risks of bias in clinical studies were assessed. Meta-analyses were undertaken. RESULTS: Data from 8 clinical studies reporting on 109 patients and 242 implants and 13 preclinical studies were included. Positional accuracy was measured by comparing the implant plan in presurgery CBCT and the actual implant position in postsurgery CBCT. For clinical studies, the pooled (95% confidence interval) platform deviation, apex deviation, and angular deviation were 0.68 (0.57, 0.79) mm, 0.67 (0.58, 0.75) mm, and 1.69 (1.25, 2.12)°, respectively. There was no statistically significant difference between the accuracy of implants placed in partially or fully edentulous patients. For model studies, the pooled platform deviation, apex deviation, and angular deviation were 0.72 (0.58, 0.86) mm, 0.90 (0.74, 1.06) mm, and 1.46 (1.22, 1.70)°, respectively. No adverse event was reported. CONCLUSION: Within the limitation of the present systematic review, robotic surgery for dental implant placement showed suitable implant positional accuracy and had no reported obvious harm. Both robotic systems and clinical studies on robotic surgery for dental implant placement should be further developed.

Accuracy and safety of a haptic operated and machine vision controlled collaborative robot for dental implant placement: A translational study.

OBJECTIVES: Multiple generations of medical robots have revolutionized surgery. Their application to dental implants is still in its infancy. Co-operating robots (cobots) have great potential to improve the accuracy of implant placement, overcoming the limitations of static and dynamic navigation. This study reports the accuracy of robot-assisted dental implant placement in a preclinical model and further applies the robotic system in a clinical case series. MATERIALS AND METHODS: In model analyses, the use of a lock-on structure at robot arm-handpiece was tested in resin arch models. In a clinical case series, patients with single missing teeth or edentulous arch were included. Robot-assisted implant placement was performed. Surgery time was recorded. Implant platform deviation, apex deviation, and angular deviation were measured. Factors influencing implant accuracy were analyzed. RESULTS: The in vitro results showed that with a lock-on structure, the mean (SD) of platform deviation, apex deviation, and angular deviation were 0.37 (0.14) mm, 0.44 (0.17) mm, and 0.75 (0.29)°, respectively. Twenty-one patients (28 implants) were included in the clinical case series, 2 with arches and 19 with single missing teeth. The median surgery time for single missing teeth was 23 (IQ range 20-25) min. The surgery time for the two edentulous arches was 47 and 70 min. The mean (SD) of platform deviation, apex deviation, and angular deviation was 0.54 (0.17) mm, 0.54 (0.11) mm, and 0.79 (0.22)° for single missing teeth and for 0.53 (0.17) mm, 0.58 (0.17) mm, and 0.77 (0.26)° for an edentulous arch. Implants placed in the mandible had significantly larger apex deviation than those in the maxilla. CONCLUSION: Cobot-assisted dental implant placement showed excellent positional accuracy and safety in both the in vitro study and the clinical case series. More technological development and clinical research are needed to support the introduction of robotic surgery in oral implantology. Trial registered in ChiCTR2100050885.

Accuracy and primary stability of tapered or straight implants placed into fresh extraction socket using dynamic navigation: a randomized controlled clinical trial.

OBJECTIVES: To compare the accuracy and primary stability of tapered and straight implants undergoing immediate implant placement with dynamic navigation. MATERIALS AND METHODS: Patients with compromised anterior teeth in maxilla were recruited and allocated randomly into (1) tapered implant group (TI group) and (2) straight implant group (SI group). Implants were inserted into fresh sockets with dynamic navigation. Three-dimensional platform deviation, apex deviation, angular deviation, insertion torque value (ITV) and implant stability quotient (ISQ) were recorded. RESULTS: Twenty patients with 20 implants were included. The overall platform, apex, and angular deviation were 0.87 ± 0.35 mm, 0.81 ± 0.34 mm, and 2.40 ± 1.31°, respectively. The accuracy was 0.86 ± 0.26 mm, 0.76 ± 0.33 mm, and 2.49 ± 1.54° for TI, and 0.89 ± 0.44 mm, 0.88 ± 0.36 mm, and 2.31 ± 1.01° for SI, with no significant difference (p = 0.85, 0.45, 0.76). Sagittal root position classification (SRP) class I may obtain greater error in numerical values in straight implants (0.97 ± 0.47 mm vs. 0.6 ± 0.16 mm, 0.92 ± 0.36 mm vs. 0.73 ± 0.36 mm, 2.48 ± 1.19° vs. 1.71 ± 0.14°). The overall ISQ was 60.74. ISQ was 60.48 for TI and 60.96 for SI, with no significant difference. Acceptable ITV (> 15 Ncm) was achieved in most of the included patients (SI 7/10, TI 9/10). CONCLUSIONS: High accuracy and primary stability of immediate implant placement could be achieved both in tapered and straight implants with dynamic navigation systems. CLINICAL RELEVANCE: Tapered and straight implants did not reach a consensus on which was better in immediate implant regarding to accuracy and primary stability. Our study demonstrated implant macrodesign did not affect accuracy and primary stability in immediate implant using dynamic navigation.

Clinical, radiographic, and immunological evaluation of angulated screw-retained and cemented single-implant crowns in the esthetic region: A 1-year randomized controlled clinical trial.

BACKGROUND: Screw-retained implant crowns are considered more biologically compatible than cemented crowns due to the absence of excess cement. However, traditional screw-retained implant crowns are not viable when the access hole of the screw channel would need to be located in an esthetic area, which would compromise the esthetic outcome of the treatment. PURPOSE: To evaluate the clinical, radiographic, and immunological outcomes of angulated screw-retained and cemented single-implant crowns in the esthetic region. MATERIALS AND METHODS: The study was a single-center, open-label, randomized controlled clinical trial. Eligible patients were randomly placed in two groups: angulated screw-retained group (AG) and cemented group (CG). Implant survival rate, bleeding on probing rate (BOP%), probing depth (PD), modified plaque index (mPI), marginal bone loss (MBL), concentrations of pro-inflammatory cytokines (TNF-α, IL-6) in peri-implant crevicular fluid (PICF), mechanical complications, and pink esthetic score/white esthetic score (PES/WES) were evaluated. RESULTS: Fifty-six patients (AG: 29, CG: 27) attended the 1-year examination. The drop-out rate was 6.67%. No implant failure was found in both groups during the observation period. BOP% was significantly lower in the AG than that in the CG (mean, 21.84% ± 19.97% vs. 37.04% ± 26.28%, p = 0.018). The concentration of TNF-α in PICF was significantly higher in the AG than that in the CG (median, 13.54 vs. 4.62, p = 0.019). No significant difference of PD, mPI, MBL, IL-6, or mechanical complication rates was found between the two groups. Mean scores for PES/WES were 21.71 and 21.64 in the AG and CG, respectively. CONCLUSION: Based on the present results, both treatment options showed acceptable clinical outcomes in the short term. Angulated screw-retained crowns might benefit the peri-implant soft tissue. However, studies with long-term follow-up are needed to confirm whether the higher concentration of TNF-α will compromise the long-term outcomes of treatment.

Circ_0008542 in osteoblast exosomes promotes osteoclast-induced bone resorption through m6A methylation.

With an increasing aging society, China is the world's fastest growing markets for oral implants. Compared with traditional oral implants, immediate implants cause marginal bone resorption and increase the failure rate of osseointegration, but the mechanism is still unknown. Therefore, it is important to further study mechanisms of tension stimulus on osteoblasts and osteoclasts at the early stage of osseointegration to promote rapid osseointegration around oral implants. The results showed that exosomes containing circ_0008542 from MC3T3-E1 cells with prolonged tensile stimulation promoted osteoclast differentiation and bone resorption. Circ_0008542 upregulated Tnfrsf11a (RANK) gene expression by acting as a miR-185-5p sponge. Meanwhile, the circ_0008542 1916-1992 bp segment exhibited increased m6A methylation levels. Inhibiting the RNA methyltransferase METTL3 or overexpressing the RNA demethylase ALKBH5 reversed osteoclast differentiation and bone resorption induced by circ_0008542. Injection of circ_0008542 + ALKBH5 into the tail vein of mice reversed the same effects in vivo. Site-directed mutagenesis study demonstrated that 1956 bp on circ_0008542 is the m6A functional site with the abovementioned biological functions. In conclusion, the RNA methylase METTL3 acts on the m6A functional site of 1956 bp in circ_0008542, promoting competitive binding of miRNA-185-5p by circ_0008542, and leading to an increase in the target gene RANK and the initiation of osteoclast bone absorption. In contrast, the RNA demethylase ALKBH5 inhibits the binding of circ_0008542 with miRNA-185-5p to correct the bone resorption process. The potential value of this study provides methods to enhance the resistance of immediate implants through use of exosomes releasing ALKBH5.

Influence of Different Factors on the Accuracy of Digital Impressions of Multiple Implants: An In Vitro Study.

PURPOSE: To investigate the effect of implant angulation, non-free-end partial edentulism, and number of scan bodies on the accuracy of digital impressions of multiple implants in partially edentulous arches. MATERIALS AND METHODS: Four reference models of partially edentulous mandibles with implants (RM1, RM2, RM3, and RM4) representing different intraoral situations were each scanned 10 times by an intraoral scanner. Reference scans were obtained by a laboratory scanner. Test scans were compared with reference scans to obtain the distance deviations (Δd) and angular deviations (Δθ) between scan bodies for trueness assessment. Differences among the repeated test scans of each model were measured and recorded as Δdp and Δθp for precision assessment. The Student t test (α = .05) was used to compare Δd, Δθ, Δdp, and Δθp of different reference models, including RM2 vs RM1 (effect of non-free-end partial edentulism), RM3 vs RM1 (effect of implant angulation), and RM4 vs RM1 (effect of number of scan bodies). RESULTS: The implant with 17-degree angulation in RM3 showed significantly lower Δd, Δθ, and Δθp compared with the parallel implant in RM1 (Δd: P = .0382, Δθ: P = .0267, Δθp: P = .0417). The RM2 of non-free-end partial edentulism had lower distance and angular deviations than RM1, but without a significant difference. The number of scan bodies had no significant effect on the Δd, Δθ, Δdp, and Δθp of RM4 and RM1. CONCLUSION: Angulated implants showed better accuracy of digital impressions in partially edentulous arches compared with parallel implants. Non-free-end partial edentulism was attributed to improved accuracy, while the number of scan bodies showed no effect.

Accuracy of full-arch digital implant impressions taken using intraoral scanners and related variables: A systematic review.

PURPOSE: To evaluate the accuracy of full-arch digital implant impressions taken using intraoral scanners and analyse the related variables. MATERIALS AND METHODS: An electronic search of studies on the accuracy of digital implant impressions in fully edentulous arches from 1 January 2012 to 29 February 2020 was conducted in PubMed, EMBASE and the Cochrane Library. Only peer-reviewed experimental or clinical studies written in English were included. Studies assessing the accuracy of restorations, case reports, clinical reports, technical reports and reviews were excluded. The literature screening, article reading and assessment of risk of bias were carried out by two reviewers. The data on the study characteristics, accuracy outcomes and investigated variables were extracted. RESULTS: After removal of duplicates, a total of 166 studies were identified, of which 42 were initially selected for full-text reading and 30 were included in the final analysis (29 in vitro studies and one in vivo study). The trueness of digital implant impressions ranged from 7.6 to 731.7 µm, and the precision ranged from 15.2 to 204.2 µm. Angular deviations were between 0.13 and 10.01 degrees. Considering 100 µm and 0.4 degrees as clinically acceptable levels of deviation, 18 studies reported linear/distance/3D deviations larger than 100 µm and only two studies reported angular deviations below 0.4 degrees. The effect of interimplant distance/length of the arch scanned/scanning sequence/scanning range/implant position (nine studies), implant angulation (ten studies), implant depth (five studies), implant connection (two studies), operator experience (six studies), scan body type (three studies), intraoral scanner type (six studies), scanning strategy (two studies) and modification technique (three studies) was investigated. CONCLUSIONS: Based on the results of the included studies, full-arch digital implant impressions taken using intraoral scanners are not sufficiently accurate for clinical application. Accuracy varies greatly with interimplant distance, scan body type, intraoral scanner type and operator experience, whereas implant angulation, implant connections and implant depth have no effect. The effects of scanning strategy and modification technique need further investigation.

Bovine-Derived Xenografts Immobilized With Cryopreserved Stem Cells From Human Adipose and Dental Pulp Tissues Promote Bone Regeneration: A Radiographic and Histological Study.

Adipose tissue-derived stem cells (ADSCs) and dental pulp stem cells (DPSCs) have become promising sources for bone tissue engineering. Our study aimed at evaluating bone regeneration potential of cryopreserved ADSCs and DPSCs combined with bovine-derived xenografts with 10% porcine collagen. In vitro studies revealed that although DPSCs had higher proliferative abilities, ADSCs exhibited greater mineral depositions and higher osteogenic-related gene expression, indicating better osteogenic differentiation potential of ADSCs. After applying cryopreserved ADSCs and DPSCs in a critical-sized calvarial defect model, both cryopreserved mesenchymal stem cells significantly improved bone volume density and new bone area at 2, 4, and 8 weeks. Furthermore, the combined treatment with ADSCs and xenografts was more efficient in enhancing bone repair processes compared to combined treatment with DPCSs at all-time points. We also evaluated the sequential early bone healing process both histologically and radiographically, confirming a high agreement between these two methods. Based on these results, we propose grafting of the tissue-engineered construct seeded with cryopreserved ADSCs as a useful strategy in accelerating bone healing processes.

Clinical, radiographic and economic evaluation of short-6-mm implants and longer implants combined with osteotome sinus floor elevation in moderately atrophic maxillae: A 3-year randomized clinical trial.

AIM: To compare the 3-year clinical, radiographic and economic outcomes of short-6-mm implants and longer implants combined with osteotome sinus floor elevation (OSFE) in the posterior maxilla. MATERIAL AND METHODS: This study enrolled 225 patients (225 implants with diameter of 4.1 mm and 4.8 mm) with a posterior maxillary residual bone height (RBH) of 6-8 mm. Patients were randomly divided into three groups: Group 1 (6 mm implants alone), Group 2 (8 mm implants + OSFE) and Group 3 (10 mm implants + OSFE). The following outcomes were recorded at 1 and 3-year examinations: implant survival, probing pocket depth (PPD), bleeding on probing (BOP), modified plaque index (mPI), marginal bone loss (MBL), biological and technical complications, complication-free survival and treatment costs. RESULTS: At the 3-year follow-up, 199 patients (Group 1: 67; Group 2: 62; Group 3: 70) were re-examined. Implant survival rates were 91.80%, 97.08% and 100.00% in groups 1, 2 and 3. Implant survival rate in Group 1 was significantly lower than that in Group 3 (p = 0.029). A multivariate Cox model showed that the short-6-mm implants with wide diameter had a protective effect on implant survival (hazard ratio: 0.59, p = 0.001). No significant differences in BOP%, PPD, mPI, MBL and complication-free survival rate were found among the three groups. The average costs of retreatment were 8.31%, 1.96% and 0.56% of the total costs in groups 1, 2 and 3. The cost to avoid a 1% increase in implant loss associated with 6-mm implants over a 3-year period was 369 CNY (56 USD) using a 10-mm implant with OSFE and 484 CNY (74 USD) using an 8-mm implant with OSFE. CONCLUSION: In the moderately atrophic posterior maxillae, the three treatments showed acceptable clinical, radiographic and economic outcomes with up to 3-year follow-up. 10-mm implants combined with OSFE showed more favourable implant survival and fewer maintenance costs in comparison with short-6-mm implants, which were less expensive.

Long-term outcomes of osteotome sinus floor elevation without grafting in severely atrophic maxilla: A 10-year prospective study.

OBJECTIVE: The aim of the present study was to report 10-year results of osteotome sinus floor elevation (OSFE) without grafting severely atrophic maxilla (residual bone height ≤4 mm). MATERIALS AND METHODS: Patients undergoing OSFE without grafting and implant placement were included for 10-year examinations. Implant survival, complication-free survival, modified bleeding index (mBI), modified plaque index (mPI), pocket probing depth (PPD), peri-implant marginal bone loss (MBL), endo-sinus bone gain (ESBG) and mean cost of recurrence were evaluated. RESULTS: Overall, 23 patients with 35 implants attended 10-year examination. Cemented implant crowns or implant-supported fixed dental prostheses were delivered to the patients. Kaplan-Meier implant survival was 89.2% at implant level and 84.1% at patient level. Complication-free survival was 26.0% at patient level and 37.0% at implant level. The average complication-free survival time was 74.6 months (95% CI: 63.2-86.0 months) at implant level and 69.1 months (95% CI: 54.8-83.4 months) at patient level. The mBI, mPI, PPD, MBL and ESBG at 10-year follow-up were 0.91 ± 0.58, 0.48 ± 0.51, 2.94 ± 0.79 mm, 1.63 ± 0.83 mm and 2.72 ± 0.51 mm, respectively. The cost of managing recurrence was 43.6% of the initial cost of treatment. CONCLUSION: The results of the present study indicate that OSFE without grafting is a reliable treatment option in severely atrophic maxilla. Acceptable survival rate, stable MBL and ESBG could be achieved within 10 years. Low complication-free survival and high costs of recurrence management need to be considered.

Long-term outcomes of osteotome sinus floor elevation with or without bone grafting: The 10-year results of a randomized controlled trial.

AIMS: To assess the long-term clinical and radiographic results of implants placed using osteotome sinus floor elevation (OSFE) with or without bone grafting. MATERIALS AND METHODS: Forty-five patients were randomly assigned into two groups: Group 1 (OSFE with deproteinized bovine bone mineral) and Group 2 (OSFE without grafting). The patients were recalled at 1, 3, 5 and 10 years after surgery. The implant survival, endo-sinus bone gain (ESBG), marginal bone loss (MBL), peri-implant bone height (PBH, distance from the most coronal level to the most apical level of bone-to-implant contact), prosthesis survival and hardware complications, and peri-implant soft tissue conditions were assessed. RESULTS: Forty patients attended the 10-year examination. Mean residual bone height was 4.58 ± 1.28 mm. The 10-year cumulative survival rate was 90.7% for Group 1 and 95.0% for Group 2. The PBH was 5.89 ± 1.24 mm for Group 1 and 5.74 ± 1.43 mm for Group 2 at 10 years. The ESBG of both groups remained stable after 3 years. Two-thirds of the implants were free of hardware complications. No significant differences in MBL and peri-implant tissue parameters were found. CONCLUSION: OSFE with or without grafting both yielded predictable clinical outcomes with similar PBH (ClinicalTrials.gov. NCT01619956).

The influence of initial defect morphology of alveolar ridge on volumetric change of grafted bone following guided bone regeneration in the anterior maxilla region: an exploratory retrospective study.

BACKGROUND: This study aimed to explore the influence of initial ridge defect morphology on the outcome of guided bone regeneration (GBR) in the anterior maxilla region. METHODS: Cone beam computed tomography (CBCT) examinations of patients who participated in a previous randomized controlled trial were used to assess linear and volumetric changes of bone grafts (LCB and VCB) from immediately (T0) to 6 months (T1) after surgery. The three-dimensional (3D) surface rendering of the initial defect was reconstructed, and morphological variables were defined in mesial-distal, buccal-lingual, and coronal-apical directions. The Spearman correlation, logistic regression model, and receiver operating characteristic (ROC) analyses were used to assess the possible association between initial defect morphological variables and VCB. RESULTS: A total of 62 eligible patients were included in this study. The median value of LCB was less than 20% at different levels, while the corresponding value of VCB was 52.0%. The Spearman correlation analysis showed that the standard deviation of buccal-lingual distance (BLSD) was negatively associated with VCB (r=-0.315, P=0.013), whereas the ratio of maximum coronal-apical/mesial-distal distance (RmCA/mMD) was positively related to VCB (r=0.607, P<0.001). The multivariate regression analysis revealed that the prognosis effect of BLSD (OR: 0.220, 95% CI: 0.074 to 0.655, P=0.0047) and RmCA/mMD (OR: 7.045, 95% CI: 2.361 to 21.024, P=0.0017) remained significant. ROC curve analysis showed that RmCA/mMD could be used to correctly classify VCB in 78.9% patients and BLSD in 71.0% of patients, as classified by the median of VCB. The discrimination value of BLSD and RmCA/mMD revealed the areas under curve (AUC) of 0.71 (95% CI: 0.545 to 0.883) and 0.74 (95% CI: 0.573 to 0.913), respectively. CONCLUSIONS: Within the limitations of this study, the present data confirmed the effect of initial ridge morphology on the GBR outcome in the anterior maxilla region. Specifically, a defect morphology with more BLSD and/or lower RmCA/mMD may significantly decrease the resorption amount of grafted bone.

The responses of human gingival fibroblasts to magnesium-doped titanium.

The titanium (Ti) implant is widely used in implant dentistry; yet peri-implantitis has always been one of the most common and serious complications. Here, we demonstrated that magnesium-doping would be an effective way of enhancing the integration between implant surfaces and gingival tissues, which is critical to peri-implant health. The magnesium (2.76-6.35 at %) was immobilized onto the titanium substrate by a magnesium plasma immersion ion implantation (Mg-PIII) technique. Mg-PIII treatments did not alter surface topographies of the original titanium substrate but improved its hydrophilicity. The in vitro study including cell viability, adhesion, proliferation, migration, and real-time polymerase chain reaction assays disclosed improved adhesion, proliferation, migration, and extracellular matrix remodeling abilities of human gingival fibroblasts (HGFs) on the magnesium-doped titanium. The results of western blot suggested that the Mg-modified titanium induced the phosphorylation of AKT through the activation of PI3K. Our results revealed that magnesium-doping would potentially enhance soft tissue sealings by promoting cellular functions of HGFs in a dose-dependent manner, boding well for its applications on surfaces of implant necks in early peri-implant soft tissue integrations.

Short versus longer implants with osteotome sinus floor elevation for moderately atrophic posterior maxillae: A 1-year randomized clinical trial.

PURPOSE: To compare the clinical, radiographic outcomes and patient satisfaction of short-6-mm implants and longer implants combined with osteotome sinus floor elevation (OSFE). MATERIALS AND METHODS: Two hundred and twenty-five patients with 225 implants were included and randomly assigned into three groups (each group: 75 implants) using randomizing table method: group 6 mm (6 mm implants alone), group 8 mm + O (8 mm implants + OSFE) and group 10 mm + O (10 mm implants + OSFE). Outcomes measures were as follows: implant survival, complication, resonance frequency analysis measurement, surgical time, bleeding on probing (BOP), pocket probing depth (PPD), modified plaque index (mPI), marginal bone loss (MBL) and patient satisfaction. RESULTS: The dropout rate was 3.6% at 1 year. Implant survival rates were 96%, 100% and 100% in group 6 mm, group 8 mm + O and group 10 mm + O, respectively. In group 6 mm, the survival rates of implants with diameter of 4.1 mm were 90% (27/30), while the survival rates of implants with diameter of 4.8 mm were 100% (42/42). The surgical time (min) in group 6 mm was significantly shorter than those in group 8 mm + O and group 10 mm + O (13.6 ± 2.2, 19.4 ± 3.7 and 18.3 ± 4.3, respectively, p = 0.03). No significant differences in ISQ values, BOP, PPD, mPI and MBL were found among three groups. Significant higher value of intra-operative discomfort was found in group 6 mm (p = 0.02). CONCLUSION: All treatment options provided acceptable clinical and radiographic results up to 1 year after loading. The current 1-year results must be confirmed by longer follow-ups of at least 5 years.

A study on the prevalence of dental anxiety, pain perception, and their interrelationship in Chinese patients with oral implant surgery.

BACKGROUND: Accumulating evidence has revealed that dental anxiety (DA) is associated with pain and patient satisfaction related to dental procedures. However, relevant reports are limited and inconsistent in oral implant patients. PURPOSE: The purpose of this study was to investigate the prevalence of dental anxiety, pain perception, and analyze their interrelationship in Chinese patients with oral implant surgery. MATERIALS AND METHODS: A cross-sectional study was performed according to the strengthening the reporting of observational studies in epidemiology (STROBE) guideline. Consecutive patients who received oral implant surgeries during February-March of 2018 in Shanghai Ninth People's Hospital were recruited. The modified dental anxiety scale and visual analog scale were used to evaluate the level of the patient's DA and pain perception. Multivariate logistic regression was applied to analyze the influence of DA on pain perception of patients during oral implant surgery. RESULTS: The prevalences of moderate and high preoperative DA were 66.6% and 11.9% in Chinese patients with oral implant surgery, respectively. Seven points eight percent of patients experienced pain perception during surgery. The result of multiple logistic regression showed that there was no significant influence of moderate preoperative DA (OR = 2.0, 95%CI: 0.5-8.2) on pain perception. However, a significant influence of high preoperative DA (OR = 6.4, 95%CI: 1.3-30.8) was found on pain perception of patients with oral implant surgery. Significant influences of moderate perioperative DA (OR = 5.0, 95%CI: 1.1-22.9) and high perioperative DA (OR = 8.7, 95%CI: 1.1-69.9) were also found on pain perception of patients during oral implant surgery. CONCLUSIONS: The results of the study indicated that DA was very common in Chinese patients with oral implant surgery. DA may increase pain perception of patients during oral implant surgery.

A novel semiautomatic segmentation protocol to evaluate guided bone regeneration outcomes: A pilot randomized, controlled clinical trial.

OBJECTIVES: The aims of this study were to (a) present a novel morphological contour interpolation (MCI) algorithm based method to evaluate grafted bone alterations following guided bone regeneration (GBR), (b) compare clinical and radiological outcomes of GBR with two different collagen membranes. MATERIALS AND METHODS: The data were retrieved from an ongoing randomized controlled trial. Patients were randomly allocated into two groups: (a) control group (CG): Bio-Gide (b) test group (TG): bovine dermis-derived collagen membrane. Cone beam computed tomography examinations were performed 1 week (T0) and 6 months after surgery (T1). PES/WES at T1, grafted bone volume and density changes from T0 to T1 were recorded. RESULTS: Thirty-six patients (16/20 in test/control group, respectively) were enrolled in the present study. Excellent inter-observer reliability (ICC ≥ 0.97) was revealed for repeated measurements using this method. Significant volumetric reduction of grafted bone were found in both groups (test group: from 0.60 to 0.39 cm3 , p < 0.01; control group: from 0.54 to 0.31 cm3 , p < 0.01). Mean bone density (gray-scale values) significantly increased from 305.12 to 456.69 in CG (p < 0.01). In TG, it slightly increased from 304.75 to 393.27 (p = 0.25). The mean PES/WES values were 13.84 (6.62/7.22) and 13.90 (6.70/7.20) for TG and CG, respectively. As for inter-group comparison, no significant differences of grafted bone volume change, density change and PES/WES were found between two groups. CONCLUSION: Within the limitations of this study, the novel MCI-based method is a reproducible tool to segment and visualize changes of grafted bone in 3D. Furthermore, both collagen membranes could be used as a barrier membrane for GBR in humans.

Long-term outcomes of narrow diameter implants in posterior jaws: A retrospective study with at least 8-year follow-up.

OBJECTIVE: The aim of this study was to evaluate the long-term survival, complications, peri-implant conditions, marginal bone loss, and patient satisfaction of fixed dental prostheses supported by narrow diameter implants (NDIs) in the posterior jaws. MATERIALS AND METHODS: This study was designed as a retrospective cohort study with a mean follow-up time of 10.1 years (SD: 2.5 years). Patients receiving NDIs in posterior jaw were reviewed. Implant survival, hardware complication, modified plaque index (mPI), peri-implant probing depth (PPD), percentage of bleeding on probing (BOP%), marginal bone loss (MBL), and patient satisfaction were evaluated. Log-rank test and t test were used to detect the influence of implant location and restoration type. RESULTS: Sixty-seven patients with 98 NDIs (Premolar site: 81, Molar site: 17, Single crowns: 33, Splinted restorations: 65) were included. The overall implant survival rates were 96.9% at implant level and 97.0% at patient level. Veneer chipping was the most common hardware complication. The veneer chipping rates were 19.4% at patient level and 18.4% at implant level. All patients showed acceptable oral hygiene. Thus, the average MBL was 1.19 mm at implant level and 1.15 mm at patient level. Eight implants (8.5%) and six patients (9.2%) were diagnosed with peri-implantitis. Fifty-eight patients (89.2%) were satisfied with the esthetics of the restorations, while 55 patients (84.6%) were satisfied with the function of the restorations. CONCLUSION: Narrow diameter implants could be a predictable treatment option in the long term. High survival rates, high patient satisfaction, acceptable complication rates and marginal bone loss could be achieved. Further long-term studies are needed to evaluate the predictability of NDIs in molar sites.

Hardware complications and failure of three-unit zirconia-based and porcelain-fused-metal implant-supported fixed dental prostheses: a retrospective cohort study with up to 8 years.

OBJECTIVE: The aim of the present study was to assess the hardware complications and survival of three-unit implant-supported zirconia-based fixed dental prostheses (IZ) and implant-supported porcelain-fused-metal fixed dental prostheses (IP). MATERIAL AND METHODS: The study is a retrospective cohort study with up to 8 years (mean 4.8 years) follow-up. Patients with conventional three-unit implant-supported fixed dental prostheses (without cantilever) in posterior area were reviewed. Hardware complications and survival rate were evaluated. Chi-Square test was used to test the difference between IZ and IP groups. RESULTS: Two hundred and thirty-seven patents (IZ : 112, IP : 125) with 279 three-unit restorations (IZ : 127, IP : 152) participated in the study. The overall survival rate was 95.3% in IZ group and 94.7% in IP group at implant-level and 94.6% in IZ group and 94.4% in IP group at subject-level. Veneer chipping was the most frequently seen complication (20.1%). Significant higher minor veneer chipping rate (Grade 1) was found in IZ group (P = 0.04). No significant difference of veneer chipping rate (Grade 2 and Grade 3) was found between the two groups. The overall hardware complication rates of IZ were significantly higher than IP (33.07% and 18.42%, P = 0.01). CONCLUSION: High survival rate of zirconia-base and Porcelain-fused-to-metal (PFM) restorations can be achieved with up to 8 years follow-up. The zirconia-based restorations need more polishing procedures, maintenance, and professional care than PFM restorations. The number of implants supporting a fixed dental prosthesis did not influence the implant survival and hardware complications. Well-designed studies with high evidence level are still needed to further explore the hardware complications and clinical survival of IZ and IP.

Clinical Investigation and Patient Satisfaction of Short Implants Versus Longer Implants with Osteotome Sinus Floor Elevation in Atrophic Posterior Maxillae: A Pilot Randomized Trial.

PURPOSE: The aim of the study was to evaluate the clinical parameters and patient satisfaction of the treatments with short implants compared to longer implants with osteotome sinus floor elevation (OSFE) in atrophic posterior maxillae. MATERIALS AND METHOD: The patient data were retrieved from an ongoing randomized controlled trial (NCT02350075). Patients were randomly allocated into three groups: (group1: short-6 mm implant, group 2: short-8-mm implant with OSFE, group 3: standard-10 mm implant with OSFE). Early implant failure, complications, implant stability quotient (ISQ) and patient satisfaction by means of visual analogue scale (VAS) were evaluated. ANOVA analysis was performed for the data comparison. RESULTS: Fifty-six patients were enrolled in the present study. No implant loss was found by the end of the restoration placement. No significant difference of ISQ values was found among three groups at the time of implant surgery and impression taking (p = .67 and.54, respectively). VAS values regarding intraoperative vibratory sense in group 1 were significantly higher than those in group 3 (p = .01). CONCLUSION: All three treatments were safe in atrophic posterior maxilla (6 mm ≤ residual bone height < 8 mm). Patients were satisfied with all three treatments, while the malleting during the osteotome procedure could make patients feel uncomfortable.