Ceramic Dental Implants: A Systematic Review and Meta-analysis.

Purpose: To evaluate the performance of one- and two-piece ceramic implants regarding implant survival and success and patient satisfaction. Materials and Methods: This review followed the PRISMA 2020 guidelines using PICO format and analyzed clinical studies of partially or completely edentulous patients. The electronic search was conducted in PubMed/MEDLINE using Medical Subject Headings (MeSH) keywords related to dental zirconia ceramic implants, and 1,029 records were received for detailed screening. The data obtained from the literature were analyzed by single-arm, weighted meta-analyses using a random-effects model. Forest plots were used to synthesize pooled means and 95% CI for the change in marginal bone level (MBL) for short-term (1 year), mid-term (2 to 5 years), and long-term (over 5 years) follow-up time intervals. Results: Among the 155 included studies, the case reports, review articles, and preclinical studies were analyzed for background information. A meta-analysis was performed for 11 studies for one-piece implants. The results indicated that the MBL change after 1 year was 0.94 ± 0.11 mm, with a lower bound of 0.72 and an upper bound of 1.16. For the mid term, the MBL was 1.2 ± 0.14 mm with a lower bound of 0.92 and an upper bound of 1.48. For the long term, the MBL change was 1.24 ± 0.16 mm with a lower bound of 0.92 and an upper bound of 1.56. Conclusion: Based on this literature review, one-piece ceramic implants achieve osseointegration similar to titanium implants, with a stable MBL or a slight bone gain after an individual initial design depending on crestal remodeling. The risk of implant fracture is low for current commercially available implants. Immediate loading or temporization of the implants does not interfere with the course of osseointegration. Scientific evidence for two-piece implants is rare.

Immediate loading of a fully tapered implant with deep apical threads placed in healed alveolar ridges vs. immediate extraction sockets.

OBJECTIVES: Immediate implant placement and loading is a practice that continues to gain traction in implant dentistry because it reduces treatment time and improves satisfaction. Novel implant designs that facilitate increased primary stability, while not compromising osseointegration and long-term survival are important to offer immediate solutions for missing teeth. Here, we hypothesize that fully tapered implants can obtain successful osseointegration with high survival rates after immediate loading in fresh extraction sockets and healed sites. MATERIALS AND METHODS: A total of 13 swine with 73 implants were evaluated. Fully tapered or apically tapered implants were placed in extraction sockets and healed sites. Insertion torque and resonance frequency analysis were determined at placement and euthanasia. Animals were evaluated at: placement, and 1-week and 12-weeks after placement. Bone to Implant Contact (BIC), Bone Area/Total Area (BA/TA), and first BIC (fBIC) analyses were conducted. RESULTS: The fully tapered implant achieved similar primary stability with lower insertion torque at placement. Apically and fully tapered implants had comparable BIC (50.1% vs 59.4%) and ISQ (82.5 vs 80.3) values by 12 weeks in healed sites. In extraction sockets, BIC and ISQ for the apically tapered implant was 35.8% and 73.2 and 37.8% and 79.2 for the fully tapered implants, respectively. CONCLUSIONS: In this short-term study, immediately loaded fully tapered implants obtained high survival with similar osseointegration ability as apically tapered implants when placed in healed sites and fresh extraction sockets. Fully tapered implants show promise for use in immediate loading and immediate placement.

Trb3 controls mesenchymal stem cell lineage fate and enhances bone regeneration by scaffold-mediated local gene delivery.

Aberrant lineage commitment of mesenchymal stem cells (MSCs) in marrow contributes to abnormal bone formation due to reduced osteogenic and increased adipogenic potency. While several major transcriptional factors associated with lineage differentiation have been found during the last few decades, the molecular switch for MSC fate determination and its role in skeletal regeneration remains largely unknown, limiting creation of effective therapeutic approaches. Tribbles homolog 3 (Trb3), a member of tribbles family pseudokinases, is known to exert diverse roles in cellular differentiation. Here, we investigated the reciprocal role of Trb3 in the regulation of osteogenic and adipogenic differentiation of MSCs in the context of bone formation, and examined the mechanisms by which Trb3 controls the adipo-osteogenic balance. Trb3 promoted osteoblastic commitment of MSCs at the expense of adipocyte differentiation. Mechanistically, Trb3 regulated cell-fate choice of MSCs through BMP/Smad and Wnt/ß-catenin signals. Importantly, in vivo local delivery of Trb3 using a novel gelatin-conjugated caffeic acid-coated apatite/PLGA (GelCA-PLGA) scaffold stimulated robust bone regeneration and inhibited fat-filled cyst formation in rodent non-healing mandibular defect models. These findings demonstrate Trb3-based therapeutic strategies that favor osteoblastogenesis over adipogenesis for improved skeletal regeneration and future treatment of bone-loss disease. The distinctive approach implementing a scaffold-mediated local gene transfer may further broaden the translational use of targeting specific therapeutic gene related to lineage commitment for clinical bone treatment.

The Effects of Systemic Diseases and Medications on Implant Osseointegration: A Systematic Review.

Since their development, dental implants have become one of the most common procedures to rehabilitate patients with single missing teeth or fully edentulous jaws. As implants become more mainstream, determining the factors that affect osseointegration is extremely important. Medical risk factors identified to negatively affect osseointegration include diabetes and osteoporosis. However, other systemic conditions and medications that interfere with wound healing have not been as widely investigated. The aim of this systematic review was to evaluate the effect of systemic disorders including diabetes and osteoporosis on implant osseointegration. The aim was also to evaluate the effect of other diseases, such as neurocognitive diseases, cardiovascular disease, human immunodeficiency virus (HIV), hypothyroidism, rheumatoid arthritis, and medications, such as selective serotonin reuptake inhibitors (SSRIs), proton pump inhibitors (PPIs), and antihypertensives. Although the literature does not demonstrate that diabetes negatively affects implant osseointegration, most studies focus on well-controlled diabetics and the use of prophylactic antibiotics. In addition, studies have shown increased long-term bone and soft tissue complications. For osteoporosis, recent studies and reviews also fail to demonstrate a lower osseointegration rate. However, caution must be exercised in these patients due to the risk for osteonecrosis of the jaws (ONJ), especially in patients with bone malignancies. There is also no direct evidence that patients with HIV, cardiovascular disease, neurologic disorders, hypothyroidism, or rheumatoid arthritis have a decreased rate of implant osseointegration. However, some preliminary evidence suggests that medications such as SSRIs or PPIs may have a negative effect on implant osseointegration. These studies are fairly recent and must be validated with continuous research. Moreover, disease control, concomitant medications, and other comorbidities complicate implant osseointegration and must guide our treatment approaches and clinical guidelines.

Is Bone Morphogenetic Protein-2 as Effective as Alveolar Distraction Osteogenesis for Vertical Bone Regeneration?

PURPOSE: The aim of this study was to assess the clinical effectiveness of alveolar distraction osteogenesis (ADO) versus recombinant human bone morphogenetic protein-2 (rh-BMP-2) for vertical ridge augmentation. Few data have been published on vertical bone regeneration using rh-BMP-2. MATERIALS AND METHODS: The authors implemented a retrospective cohort study and enrolled a sample composed of patients with deficient alveolar vertical bone height. The primary predictor variable was vertical augmentation with BMP-2 and a titanium mesh or ADO. The primary outcome variable was gain in vertical bone height (millimeters) measured using computed tomography. The secondary outcome variable was postoperative complications, namely need for further grafting before or simultaneous with implant placement, soft tissue dehiscence, paresthesia, infection, implant failure, and pain. Other outcomes included implant stability at time of placement and follow-up (implant stability quotient by resonance frequency analysis), surgical time (minutes), and total treatment time until implant placement (weeks). Other study variables included location of reconstruction (maxilla or mandible). Appropriate bivariate statistics were computed and statistical significance was set a P value less than .05. RESULTS: The retrospective review yielded 21 patients in the BMP group and 19 in the ADO group. For the BMP-2 group, the average vertical bone gain was 2.96 ± 1.8 mm overall (maxilla, mean 3.6 ± 3.1 mm; mandible, mean 2.32 ± 1.8 mm). For the ADO group, this gain was 4 ± 1.69 mm overall (maxilla, mean 2.8 ± 1.94 mm; mandible, mean 5.2 ± 4.67 mm). For complications, group BMP showed a statistically minor tendency for more postoperative problems, such as wound dehiscence. For implant survival, group BMP showed a 92.2% survival rate versus 96.3% in group ADO at 3 to 45 months after delivery of the prosthesis (average, 22 months). CONCLUSION: The 2 techniques showed similar values in absolute vertical bone gain. Group ADO showed a slightly better outcome in outright vertical regenerative potential, albeit with a more frequent need for regrafting before and simultaneous with implant placement. Group BMP showed a lesser need for regrafting, despite having a higher postoperative complication rate.

Small molecule-mediated tribbles homolog 3 promotes bone formation induced by bone morphogenetic protein-2.

Although bone morphogenetic protein-2 (BMP2) has demonstrated extraordinary potential in bone formation, its clinical applications require supraphysiological milligram-level doses that increase postoperative inflammation and inappropriate adipogenesis, resulting in well-documented life-threatening cervical swelling and cyst-like bone formation. Recent promising alternative biomolecular strategies are toward promoting pro-osteogenic activity of BMP2 while simultaneously suppressing its adverse effects. Here, we demonstrated that small molecular phenamil synergized osteogenesis and bone formation with BMP2 in a rat critical size mandibular defect model. Moreover, we successfully elicited the BMP2 adverse outcomes (i.e. adipogenesis and inflammation) in the mandibular defect by applying high dose BMP2. Phenamil treatment significantly improves the quality of newly formed bone by inhibiting BMP2 induced fatty cyst-like structure and inflammatory soft-tissue swelling. The observed positive phenamil effects were associated with upregulation of tribbles homolog 3 (Trib3) that suppressed adipogenic differentiation and inflammatory responses by negatively regulating PPARγ and NF-κB transcriptional activities. Thus, use of BMP2 along with phenamil stimulation or Trib3 augmentation may be a promising strategy to improve clinical efficacy and safety of current BMP therapeutics.

Enhanced Mandibular Bone Repair by Combined Treatment of Bone Morphogenetic Protein 2 and Small-Molecule Phenamil.

Growth factor-based therapeutics using bone morphogenetic protein 2 (BMP-2) presents a promising strategy to reconstruct craniofacial bone defects such as mandible. However, clinical applications require supraphysiological BMP doses that often increase inappropriate adipogenesis, resulting in well-documented, cyst-like bone formation. Here we reported a novel complementary strategy to enhance osteogenesis and mandibular bone repair by using small-molecule phenamil that has been shown to be a strong activator of BMP signaling. Phenamil synergistically induced osteogenic differentiation of human bone marrow mesenchymal stem cells with BMP-2 while suppressing their adipogenic differentiation induced by BMP-2 in vitro. The observed pro-osteogenic and antiadipogenic activity of phenamil was mediated by expression of tribbles homolog 3 (Trb3) that enhanced BMP-smad signaling and inhibited expression of peroxisome proliferator-activated receptor gamma (PPARγ), a master regulator of adipogenesis. The synergistic effect of BMP-2+phenamil on bone regeneration was further confirmed in a critical-sized rat mandibular bone defect by implanting polymer scaffolds designed to slowly release the therapeutic molecules. These findings indicate a new complementary osteoinductive strategy to improve clinical efficacy and safety of current BMP-based therapeutics.

Effect of length, diameter, intraoral location on implant stability.

OBJECTIVES: To quantitatively compare stability of dental implants with varying lengths, diameters, and intraoral locations. STUDY DESIGN: Retrospectively, 200 consecutive NobelReplace Tapered Groovy implants of varying lengths and diameters were evaluated via implant stability quotient readings at placement (T1) and follow-up (T2). Data were analyzed by analysis of variance and simple linear regression tests. RESULTS: Intraoral location was statistically significant at T1 and T2. Although implant diameter was not statistically significant, implant length resulted in T1 (P = .08) and T2 (P = .09), which may have a clinically relevant effect on implant stability. An overall implant survival rate of 98% was achieved. Gender and age did not seem to affect implant stability quotient values at placement, follow-up, or implant survival. CONCLUSIONS: Intraoral location is an important factor in implant stability, with implants placed in the mandible being more stable than implants placed in the maxilla both at T1 and T2. Length may have a clinically relevant effect on implant stability.

The Predictive Value of Resonance Frequency Analysis Measurements in the Surgical Placement and Loading of Endosseous Implants.

PURPOSE: The purpose of this study was to investigate the predictive value of resonance frequency analysis in assessing implant survival. This was accomplished by determining the correlation between implant stability quotients (ISQs) and implant survival following different placement staging (1-stage vs 2-stage) and loading (early vs traditional) protocols. MATERIALS AND METHODS: A retrospective study was performed on implant patient data collected over a 5-year period. Patients ranged in age from 16 to 91 years. We analyzed 703 implants during placement and 1,254 implants before loading. All implants were placed with respective ISQs recorded by 1 oral and maxillofacial surgeon. Receiver operating characteristic (ROC) statistical analysis was used to calculate sensitivity and specificity values corresponding to various ISQ cutoff points for different placement staging and loading protocols; χ(2) tests were used to identify significant differences. RESULTS: In predicting implant failure, sensitivity progressively increased and specificity decreased as ISQ cutoff values increased. All failures occurred at an ISQ less than 66 for the placement staging protocol and an ISQ less than 67 for the loading protocol. When ISQ values were below 60, higher survival rates were observed when implants were placed using a 2-stage rather than a 1-stage placement staging protocol (P < .05). The area under the ROC curve for placement staging was 0.80, and the area under the ROC curve for loading was 0.89. An implant survival rate of over 98% was achieved. CONCLUSIONS: Resonance frequency analysis is a noninvasive technique used to measure the stability of implants and to help guide placement staging and loading protocols. This study showed that increasing ISQ values correlated with increased sensitivity in detecting implant failure. Given the high survival rates of dental implants, additional studies can further elucidate the relationship between ISQ values and survival rates.

Resonance Frequency Analysis of Sinus Augmentation by Osteotome Sinus Floor Elevation and Lateral Window Technique.

PURPOSE: To evaluate the use of resonance frequency analysis (RFA) to quantitatively compare the stability of implants placed in the atrophic posterior maxilla using 3 sinus augmentation techniques: osteotome sinus floor elevation (OSFE) and 1- and 2-step lateral window techniques (LWTs). MATERIALS AND METHODS: Data were retrospectively collected from 50 patients, 29 to 85 years old. One hundred twenty-eight implants were subdivided based on sinus augmentation technique as determined by available native bone height. Thirty-three implants were placed using OSFE in at least 8.0 mm of bone. Forty-four implants were synchronously placed using 1-step LWT in 3.0 to 7.9 mm of bone. In cases with less than 3.0 mm of bone, the 2-step LWT was performed and the remaining 51 implants were placed after a period of healing. Implant stability quotient (ISQ) was recorded from RFA at stage 1 and subsequently at stage 2 (follow-up) 3 to 12 months later. Statistical analysis was completed using t test and analysis of variance to assess differences in implant stability over time and among techniques, respectively. RESULTS: ISQ values at placement averaged 70.9, 68.9, and 72.2 for OSFE, LWT, and LWT with delayed placement, respectively. These differences were not statistically significant (P = .2). At stage 2 (follow-up), average ISQ values were 76.7, 77.7, and 78.7 for OSFE, LWT, and LWT with delayed placement, respectively. These differences were not statistically significant (P = .3). In contrast, differences in ISQ at stage 2 (follow-up) versus stage 1 were statistically significant for all 3 techniques (P < .01). OSFE, 1-step LWT, and 2-step LWT yielded average increases in ISQ of 5.8, 8.8, and 6.5, respectively. CONCLUSIONS: The results support the use of OSFE, 1-step LWT, and 2-step LWT to augment bone in the atrophic edentulous posterior maxilla. All 3 methods provide predictable osseointegration and yield statistical increases in ISQ at stage 2 (follow-up) compared with time of placement. With appropriate case selection according to native vertical bone height, there are no statistical differences in ISQ among these 3 techniques at either stage.

Sinus membrane perforations and the incidence of complications: a retrospective study from a residency program.

OBJECTIVE: The purpose of this study is to evaluate sinus membrane perforations and the incidence of complications in a residency program. STUDY DESIGN: Data from 107 consecutive direct sinus augmentation procedures were reviewed retrospectively from 2008 to 2012. DISCUSSION: All perforations were repaired intraoperatively with the use of a collagen tape. Intraoperative membrane perforations were observed in 64 of 107 cases (59.8%). Of the perforations, 58 were less than 5 mm in diameter and 6 were 5 mm or greater in diameter. It was found that there were 6 cases (5.6%) that experienced postoperative complications. Of those, 3 occurred in cases with no perforations, 2 with perforations less than 5 mm in diameter, and 1 with a perforation 5 mm or more in diameter. These differences were not statistically significant (P > .05). All observed post-operative complications were related to symptoms of acute infection. CONCLUSIONS: Although membrane perforation was a frequent intraoperative finding, there was no evidence that the presence and size of membrane perforation influences the likelihood of postoperative complications.

Mechanical versus biological stability of immediate and delayed implant placement using resonance frequency analysis.

PURPOSE: The purpose was to objectively measure the stability of immediately placed implants compared with implants placed at healed sites using implant stability quotient (ISQ) values obtained by resonance frequency analysis. MATERIALS AND METHODS: Data were collected from 137 Nobel Replace Tapered Groovy Implants placed in 85 patients 19 to 93 years old. All implants were placed by the same surgeon from May 2007 to October 2011. Forty-one implants were placed immediately after extraction with MasterGraft bone grafting material and 96 were placed in healed sites with no grafting material. ISQ values obtained by the Osstell ISQ System were recorded at the time of implant placement and at a subsequent follow-up appointment (T2). T2 was split into 2- to 3-month and 4- to 6-month groups depending on when their follow-up ISQ values were obtained. Data were analyzed using simple linear regression. RESULTS: Implants placed in healed sites had higher average ISQ values at implant placement compared with immediately placed implants; however, mean ISQ values in the 2 immediate implant groups exceeded the ISQ threshold of 65. Immediately placed implants in the 2- to 3-month and 4- to 6-month groups had average ISQ values of 65.60 and 68.65, respectively, whereas implants placed in healed sites had averages of 76.73 (2- to 3-month group) and 71.23 (4- to 6-month group). These differences were statistically significant (P < .05). At subsequent follow-up appointments, implants placed in healed sites had higher mean ISQ values. Implants in healed sites had ISQ averages of 79.58 (2- to 3-month group) and 77.31 (4- to 6-month group), whereas immediately placed implants had averages of 73.88 and 70.14. These differences were statistically significant (P < .05). Moreover, these mean ISQ values in immediate implants exceeded the ISQ threshold of 65. CONCLUSION: Although mean ISQ values of immediately placed implants are lower than those of delayed implants at implant placement and follow-up appointments, immediate implant mean ISQ values consistently remain higher than the clinically successful ISQ threshold of 65 throughout the osseointegration process. These results support the immediate placement of implants in extraction sockets under favorable conditions.

Complications in implant dentistry.

The mainstream use of dental implants has allowed millions of patients to benefit from the predictability of dental implant therapy and, in many instances, dental implants have become the standard of care. Even though success rates in implant dentistry are well above 90 percent, complications do occur. Most complications are preventable with proper planning and execution. Others are inherent to the risks of surgery and may require intervention. The purpose of this paper is to classify the possible complications that may occur and to discuss their prevention and management.

Nasal floor augmentation for the reconstruction of the atrophic maxilla: a case series.

PURPOSE: The severely atrophic edentulous maxilla imposes a challenge for dental implant rehabilitation. Nasal floor augmentation (NFA) is a method of augmenting bone height in the anterior maxilla. Autogenous bone has been commonly used as a graft material. Because of variations in results and lack of insufficient studies reporting the use of bone substitutes to graft the nasal floor, this study aims to evaluate the survival and success of dental implants placed in nasally grafted maxillae with osteoconductive bone substitutes. MATERIALS AND METHODS: Six patients with completely edentulous maxillae and inadequate height in the anterior to support implants underwent NFA. The nasal floor was exposed through an intraoral approach and grafted with osteoconductive bone graft substitutes. Twenty-four dental implants were placed, restored with a bar-retained implant-supported overdenture after a traditional healing period, and followed up after prosthetic loading. Patient satisfaction was evaluated with a questionnaire, and responses were expressed on a visual analog scale from 1 to 10. Bone levels were quantified radiographically based on a score ranging from 1 to 3, where 3 represented the highest bone support. Implants were evaluated for thread exposure and soft tissue health and were considered successful if the following criteria were met: absence of mobility; lack of symptoms; bone score of 3; and healthy peri-implant soft tissue without thread exposure. RESULTS: The age of patients ranged from 48 to 84 years, with a mean of 71.2 years. Three patients underwent NFA and simultaneous implant placement, whereas the other 3 had a mean healing period of 6.5 months before implant placement. Post-loading follow-up ranged from 4 to 29 months, with a mean of 14.2 months. The implant survival rate was 100%, with no complications. Ninety-three percent of the responses to the treatment satisfaction questionnaire had a score of 7 or greater. Bone scores ranged from 2 to 3, with 87.5% of implants having a score of 3 and 12.5% having a score of 2. None of the implants had a bone score of 1. CONCLUSIONS: The use of osteoconductive bone substitutes for NFA, as shown in this small case series, is a reliable method for reconstruction of the anterior atrophic maxilla for implant-supported overdentures.