Comparing Single Tooth Implant Placement With and Without Allogenic Soft Tissue Augmentation. A Randomized Clinical Trial.

OBJECTIVE: To explore the effect of adding an allogenic soft tissue graft at time of single implant placement using a fully digital workflow for single implant placement and restoration without making either analog or digital impressions. MATERIALS AND METHODS: A prospective randomized clinical study was performed enrolling thirtynine participants requiring single tooth implant randomized into (+ graft) group which received an allogenic dermal graft at the time of implant placement (n=19), or (- graft) group (n=20). A fully digital surgical and restorative protocol was implemented. Intraoral scans were taken before implant placement (T0), at time of final crown delivery (T1) and at one-year post placement (T2). Intraoral scans were aligned using Geomagic Control X 2020 software), linear and volumetric changes in buccal tissues were measured at T0, T1 and T2. Implant survival, probing depths, and complications were recorded. Participants were asked to complete an OHIP-14 survey at T0 and T2. Marginal bone levels were measured at T0 and T2 on peri-apical x-rays. RESULTS: 39 participants completed surgery and restoration in incisor, canine, premolar and molar positions. Two early failures were recorded in central incisor positions (95% survival). Crown delivery without complication from the digital workflow (impressionless) was achieved for 36/39 of cases (92%) with implant depth control being implicated as the chief challenge. Thirtyseven participants attended the one-year follow-up visit. Both groups showed gain in buccal tissues thickness without significant differences between the two groups for both linear and volumetric measurements (P>0.05). Soft tissue grafting was associated with minimal added morbidity. The interproximal marginal bone changes recorded were -0.16mm mesial and - 0.12mm distal for the graft group and -0.01mm mesial and -0.11mm distal for the non-graft group (p=0.07 for mesial and 0.83 for distal). OHIP score was significantly reduced at T2 compared to T0 (P=0.003) for the entire cohort. CONCLUSIONS: The augmentation of alveolar mucosa on the buccal aspect of single tooth implants is associated with clinically favorable outcomes. A fully digital workflow has been validated to permit crown delivery on CAD/CAM abutments without implant impressions.

Comparative Osteogenesis of Three Clinical Bone Graft Materials: An In Vivo Study.

PURPOSE: To investigate bone regeneration among three different bone graft materials in a rat calvarum model. MATERIALS AND METHODS: A total of 24 rats had two 5-mm defects placed per calvarial. Rats were divided into four groups: bovine xenograft (XG), demineralized bone matrix (DBM), mineralized bone graft (MBG), and collagen membrane control (CC). Within each group, samples were collected at two time points: 4 weeks (T4) and 8 weeks (T8). Bone regeneration was assessed by microcomputed tomography (micro-CT) imaging and was analyzed using MATLAB software. Additionally, the fixed samples were subsequently demineralized for immunohistochemistry and histomorphometry. Slides were mounted and stained with hematoxylin and eosin (H&E) stain as well as bone morphogenetic protein 2 (BMP-2) and runt-related transcription factor 2 (RUNX2) markers. The numbers of positive cells/area were calculated for each group and analyzed. RESULTS: At 4 weeks, DBM showed low mineral density (7.7%) compared to the control (25.2%), but increased dramatically at 8 weeks (DBM, T8 = 27.6%; CC, T8 = 27.2%). Xenograft material showed an increase in mineral desnity between T4 and T8 (XG, T4 = 25.0%; XG, T8 = 32.3%). MBG remained consistent over the 8-week trial period (MBG, T4 = 30.4%; MBG, T8 = 30.4%). BMP-2 expression was present in cells adherent to all graft materials. RUNX2 expression was also observed in cells adherent to all graft materials, indicating that during the 4- to 8-week healing period, all materials supported osteogenesis. CONCLUSIONS: Compared to other materials, the DBM had high osteoinductive properties during the 4- to 8-week time period based on increased mineral content. All materials were associated with immunohistologic evidence of osteogenesis in the rat calvarial defect model.

Retrospective Cohort Evaluation of Full-Arch Zirconia Implant-Supported Fixed Prostheses.

Objective: To determine the median event-free survival and relative complication rates of monolithic and minimally layered full-arch zirconia prostheses, as well as to identify risk factors for prosthesis complications. Materials and Methods: In this retrospective cohort study, a total of 129 subjects (173 prostheses) were included in the chart review and 56 subjects (75 prostheses) participated in a clinical follow-up visit. All subjects had either single- or dual-arch monolithic or minimally layered zirconia implant-supported prostheses. Data related to patient, implant, and prosthesis factors were extracted from charts. The subgroup that presented for a clinical visit were asked to complete a satisfaction questionnaire. For this subgroup, the following clinical measures were assessed: routine intraoral examination, number of occluding units, cantilever length on each side of the prosthesis (right and left), prosthesis height, occlusal scheme, and oral hygiene methods. Periapical radiographs were obtained when the last radiographs of the patient were taken more than 12 months prior. Results: The follow-up period ranged from 12 months to 7.1 years (mean: 1.9 years). Observed complications included implant loss, peri-implantitis, mucositis, purulence, sinus tract formation, oroantral communication, implant fracture, titanium base debonding, ceramic chipping, prosthetic screw fracture or loosening, damage to opposing teeth, and clicking sounds. There was an insufficient number of complications to evaluate the effect of covariates on the risk of specific complications, such as titanium base debonding (eight events), ceramic chipping (nine events), and peri-implantitis (eight events). The unadjusted event-free median survival time was 5.8 years. The proportion of all prostheses with at least one complication was 30%. There were no observed prosthesis losses during the follow-up period. Conclusion: Monolithic and minimally layered zirconia full-arch implant-supported prostheses demonstrate an acceptable median event-free survival time. Event-free survival times were increased and the number of complications was reduced in prostheses with five to eight implants and conventional (as opposed to zygomatic) implants. There was a reduced hazard of complications with a regular recall regimen. Patient satisfaction with these prostheses was high.

Macrogeometric Differentiation of Dental Implant Primary Stability: An In Vitro Study.

PURPOSE: To evaluate an alternative cutting, progressive thread design to increase primary stability in low-density bone. MATERIALS AND METHODS: Four different implants with different macrogeometries (Nobel Biocare Active [NA] Internal RP implants [4.3 × 11.5 mm], Straumann BLX Roxolid RB implants [4.5 × 10 mm], Astra Tech Implant EV implants [4.2 × 11 mm], and PrimeTaper [PT 4.2 × 11 mm]) were placed in simulated osteotomies and extraction sockets in synthetic bone (Sawbones) according to the manufacturers' protocol. Insertion torque and ISQ values were measured using Implantmed Plus motor and Ostell IDX, respectively. Insertion time was recorded. Average values were calculated and compared using ANOVA and Tukey test. RESULTS: Insertion torque (range: 5 to 44 Ncm) increased with increasing synthetic bone density for all implants. Different ISQ values in synthetic low-density bone were not observed in higher-density synthetic bone. Insertion torque of all implants was reduced when implants were placed in simulated sockets compared to simulated osteotomies. In both low-density and higher-density synthetic bone, the primary stability of PrimeTaper implants with cutting and progressive thread design was equivalent to that of the Nobel Biocare NobelActive implant with compressive thread design and greater than the BLX implant with compressive thread design. CONCLUSION: Different implant macrogeometries obtain relatively high primary stability in low-density bone when measured by ISQ. Doublethread implant designs reduce insertion times in higher-density bone. A cutting and progressive compressing thread design provides density-sensing performance compared to aggressive condensing thread designs. This macrogeometry can achieve high primary stability associated with modest insertion torque compared to aggressive threaded implant designs known to attain the highest insertion torque. The presence of multiple cutting threads may offer advantages in obtaining primary stability in low-density bone.

A Retrospective, Multicenter, Cross-Sectional Case Series Study Evaluating Outcomes of CAD/CAM Abutments on Implants from Four Manufacturers: 4-Year Mean Follow-up.

PURPOSE: To evaluate the clinical, radiographic, and prosthetic outcomes of a single custom CAD/CAM abutment system on implants from four manufacturers, with a mean clinical service of 4 years in a retrospective, multicenter case series study. MATERIALS AND METHODS: Adult subjects (n = 142) previously restored with titanium or gold-shaded titanium nitride custom CAD/CAM abutments (Atlantis, Dentsply Sirona; n = 259) connected to implants from four different manufacturers (Dentsply Sirona Implants [AT], Biomet 3i [BM], Nobel Biocare [NB], Straumann [ST]), irrespective of implant-abutment interface, and replacing one or more teeth in any position were recalled for a single-visit examination by calibrated investigators at six university clinics. The primary outcomes evaluated included abutment success and survival; secondary outcomes included assessment of papillae fill, probing pocket depth (PD), bleeding on probing (BOP), marginal bone levels (MBLs), and patient-reported outcome measures (PROMs). RESULTS: Two-hundred fifty-five (98.5%) abutments supported cement-retained restorations, and four (1.5%) abutments supported screw-retained restorations. Forty-two patients had 64 AT implants (25%), 31 patients had 61 BM implants (24%), 26 patients had 50 NB implants (19%), and 43 patients had 84 ST implants (32%). The overall implant-CAD/CAM abutment success rate was 92.66% (95% CI: 88.78%, 95.53%) for all implants examined, and the survival rate was 98.84% (95% CI: 96.65%, 99.76%) for all implants evaluated. The Jemt papillae index demonstrated a minimum of at least 50% to complete fill of the interproximal papillae in 65.0% of sites. PDs had a median value of 3.0 mm, and BOP was present on 19% of abutment surfaces. Mean MBL changes from the time of placement to exam were -0.24 ± 0.99 mm (-4.9 to 2.3; P = .058) for mesial sites and -0.32 ± 0.96 mm (-4.9 to 2.1; P = .000) for distal sites. PROMs expressed 93% of patients reporting good to very good masticatory function, 97% of patients reporting being satisfied or very satisfied with their esthetic outcomes, and 94% of patients indicating that they were satisfied or very satisfied with their overall implant-restorative outcomes. CONCLUSION: This retrospective, multicenter clinical study of FDA 510k-approved titanium CAD/CAM abutments of a single manufacturer on multiple implant systems demonstrated high levels of success and survival as well as stable peri-implant tissue outcomes, reflected by overwhelmingly positive PROMs.

Full-arch implant-supported monolithic zirconia fixed dental prostheses: An updated systematic review.

PURPOSE: To update an existing systematic review assessing the clinical performance of full-arch implant-supported monolithic zirconia fixed dental prostheses. MATERIALS AND METHODS: The review was conducted according to the guidelines outlined in the Preferred Reporting Items of Systematic Reviews and Meta-analyses (PRISMA) statement. An electronic search was conducted using the PubMed, Science Direct and Cochrane Library databases to identify clinical studies on full-arch implant-supported monolithic and minimally layered zirconia fixed dental prostheses. Human studies with a mean follow-up of at least 1 year and published in an English-language peer-reviewed journal up to April 2020 were included. Two independent examiners conducted the search and the review process. RESULTS: The search generated 2110 articles. Thirty-three qualifying studies were retrieved for full-text evaluation and a total of 17 studies were included on the basis of preestablished criteria. All 17 studies reported satisfactory clinical and aesthetic outcomes. The technical complication rate related to this type of prosthesis is still minimal and survival rates are high. CONCLUSIONS: Full-arch dental implant restoration with monolithic zirconia is associated with high short-term success. Long-term data from studies with a strong level of evidence are still lacking.

A digital approach to robust and esthetic implant overdenture construction.

OBJECTIVE: Overdenture therapy is an important option for implant rehabilitation. However, numerous reports suggest that mechanical/technical complications and failures can limit therapeutic success. The goal of this report is to illustrate a digital approach to design and construction of a robust overdenture with high-esthetic value. MATERIALS AND METHODS: Beginning with new denture design to establish esthetic parameters, 3D modeling of a metal framework and the denture teeth are completed in a connected manner. This enables connection of rapidly printed, prototype dentition that is attached directly to the framework without intervening wax or acrylic components. Following evaluation of the dentition and required adjustments, the final dentition is milled from resin and processed to the selective laser sintered framework. RESULTS: The advantages of the digital workflow include the control of dimensions and strength of the framework, the esthetic relationship of the framework to the dentition and the facilitation of esthetic try-in of the dentition. CONCLUSION: Enhancing a robust overdenture can be readily achieved using a digital workflow. CLINICAL SIGNIFICANCE: The use of digital technology enables the clinical team to plan and produce prostheses with dimensions and contours that support long-term function and esthetics. The clinical chair time can be potentially reduced by use of digital design that facilitates try-in and reduces major errors by improved communication between the patient, dentist, and technician.

Are Nongrafting Solutions Viable for Dental Implant Treatment in Limited Bone Volume?

Dental implant therapies must be planned and executed to meet both the immediate and longer-term expectations of patients. The early developmental success of dental implants was dependent on the quality and quantity of a patient's bone. Implants were commonly placed into the parasymphyseal mandibular and anterior maxillary bone. Building on this success, bone grafting allowed patients lacking sufficient bone to obtain implant-supported prosthetic solutions for treatment of partial or complete edentulism. More recently, several nongrafting solutions for implant therapy, including pterygoid implants, zygomatic implants, tilted implants, and short implants, have reported success. This article will consider the rationale for graftless solutions in implant therapy as well as the data supporting the use of various graftless protocols as alternatives to grafting and conventional dental implant therapy. It will discuss factors concerning graftless versus grafted approaches to treatment of patients with limited bone volume and will describe the use of short dental implants as a graftless solution in the edentulous maxilla.

Macrophage Control of Incipient Bone Formation in Diabetic Mice.

Both soft and hard tissue wound healing are impaired in diabetes. Diabetes negatively impacts fracture healing, bone regeneration and osseointegration of endosseous implants. The complex physiological changes associated with diabetes often manifest in immunological responses to wounding and repair where macrophages play a prominent role in determining outcomes. We hypothesized that macrophages in diabetes contribute toward impaired osseous wound healing. To test this hypothesis, we compared osseous wound healing in the mouse calvaria defect model using macrophages from C57BL/6J and db/db mice to direct osseous repair in both mouse strains. Initial analyses revealed that db/db mice macrophages showed an inflamed phenotype in its resting state. Incipient bone regeneration evaluated by µCT indicated that bone regeneration was relatively impaired in the db/db mouse calvaria and in the calvaria of C57BL/6J mice supplemented with db/db macrophages. Furthermore, osteogenic differentiation of mouse mesenchymal stem cells was negatively impacted by conditioned medium from db/db mice compared to C57BL/6J mice. Moreover, miR-Seq analysis revealed an altered miRNA composition in db/db macrophages with up regulated pro-inflammatory miRNAs and down regulated anti-inflammatory miRNAs. Overall, this study represents a direct step toward understanding macrophage-mediated regulation of osseous bone regeneration and its impairment in type 2 diabetes mellitus.

Prosthodontic Management of Implant Therapy: Esthetic Complications.

The essential promise of implant dentistry is the ability to imperceptibly replace missing teeth. To achieve this, careful planning, execution, and maintenance is required by the dentist and patient to maintain a long-term esthetic and functional result. Unfortunately, as a result of biological, prosthetic, and iatrogenic factors, unesthetic results can occur. This article explores the potential causes for the unesthetic dental implant and the possible solutions that may improve the clinical situation. Whereas relatively simple errors may be corrected through prosthetic means, greater complications may require surgical intervention to achieve the desired result.

Prosthodontic Management of a Patient with Moebius Syndrome: A Clinical Report.

Moebius/MÓ§bius Syndrome (MS) is an extremely rare congenital disorder characterized by uni- or bilateral palsy of the abducens (VI) and the facial (VII) nerves, causing facial paralysis. Dysfunction of cranial nerves III through XII is common, most often the glossopharyngeal (IX) and hypoglossus (XII). Afflicted individuals seeking prosthodontic care, particularly removable prosthetics, present multiple challenges related to inherent facial and tongue muscle weakness and microstomia. Other extraoral anomalies may include congenital multiple arthrogryposis and malformations of the upper and lower limbs. This clinical report describes the rehabilitation of a patient with Moebius Syndrome using a maxillary 2-implant retained overdenture and mandibular partial removable denture prosthesis.

Maxillary Complete Denture Outcomes: A Systematic Review of Patient-Based Outcomes.

PURPOSE: The aim of this systematic review is to report on the current knowledge regarding patient satisfaction as a primary outcome for maxillary complete denture therapy. We asked, "For the maxillary edentulous patient treated using maxillary dentures, what are the patient-based outcomes regarding quality of life and treatment satisfaction." MATERIALS AND METHODS: An electronic search of publications up to March 2014 was established using four databases: PubMed, Web of Science, Scopus, and Embase. To meet the ultimate goal of establishing clinical guidelines based on available information, prospective comparative studies, cohort prospective studies, and retrospective studies on more than 10 subjects were included. The electronic search identified 4,530 articles that were evaluated at the title, abstract, and article level to include 31 articles of interest. The patient-based outcomes and satisfaction data included were examined and reported. RESULTS: The studies included 5,485 participants. Of these, 2,685 were identified as wearing maxillary complete dentures. Reported mean ages ranged from 59.7 to 73.6 years. A systematic review indicated that the provision of new maxillary complete dentures for edentulous patients results in improved self-reported satisfaction and oral health-related quality of life. The included reports, while providing evidence that complete denture satisfaction of participants and new dentures improve self-reported outcomes, did not include variables that influence these positive outcomes. CONCLUSION: A broad range of evidence supports the use of complete dentures for rehabilitation of the edentulous maxilla. When considering treatment of the edentulous maxilla, the expectations of patients for esthetic and phonetic (social) rehabilitation are high and can be met using maxillary complete dentures as the mode of prosthetic rehabilitation. Patients dissatisfied with new complete dentures may be referred for dental implant therapies involving fixed or removable prostheses.

Maxillary Implant-Supported Fixed Prosthesis: A Survey of Reviews and Key Variables for Treatment Planning.

PURPOSE: This review was conducted to provide information to support the establishment of clinical guidelines for the treatment of maxillary edentulism using implant-supported fixed dental prostheses. MATERIALS AND METHODS: Initial efforts were directed toward a systematic review with a defined PICO question: "For maxillary edentulous patients with dental implants treated using a fixed prosthesis, what is the impact of prosthesis design on prosthesis survival and complications?" Following a title search of more than 3,000 titles identified by electronic search of PubMed, 180 articles were identified that addressed the clinical evaluation of maxillary dental implant prostheses. The broad methodologic heterogeneity and clinical variation among reports precluded this approach for a systematic review. The information was extracted using a standardized extraction table by two pairs of investigators, and the reported outcomes were then summarized according to reported outcomes for implant prostheses supported by four, six, or eight implants using unitary or segmented prostheses. RESULTS: This review indicated that high prosthetic survival is observed using all approaches. The advantages of using fewer implants and a unitary prosthesis are revealed in the surgical phases, and complications commonly involve the fracture or detachment of acrylic teeth and reduced access for proper oral hygiene and related biologic complications. Using six implants typically involved grafting of posterior regions with advantages of reduced cantilevers and redundancy of implant support. Reduced prosthesis survival in these cases was associated with poor implant distribution. Segmented prostheses supported by six or more implants offered greater prosthetic survival, perhaps due to posterior implant placement. Advantages of a segmented prosthesis included pragmatic issues of accommodating divergent implants, attaining passive fit, combining prosthetic materials, and relative simplicity of repair. CONCLUSION: The existing literature demonstrated that maxillary edentulism may be treated successfully using alternative approaches involving four, six, or more implants. The procedural diagnostics, treatment, and maintenance for these different approaches all require advanced knowledge and careful communication among the therapeutic team. The prosthetic therapeutic success requires maintenance, repair, and possible multiple replacements within the patient's lifetime.

Gene Expression Profiles of Early Implant Adherent Cells in Smokers and Nonsmokers.

The objective of this study was to evaluate the impact of smoking on the early molecular events involved in peri-implant healing at either a micro-roughened or a micro-roughened with superimposed nanofeatures surface implant in humans. Twenty-one subjects, 10 smokers and 11 nonsmokers received 4 mini-implants (2.2 × 5.0 mm; 2 of each surface). After 3 and 7 days, paired mini-implants were retrieved by reverse threading and RNA isolated from implant adherent cells. Whole genome microarrays were used interrogate the gene expression profiles. The study failed to identify differences in the gene expression profiles of implant adherent cells at this early stage of osseointegration (up to day 7) comparing smoker and nonsmoker individuals.

Molecular assessment of osseointegration in vitro: a review of current literature.

This paper presents the results of a structured review of the literature concerning in vitro molecular assessment of osseointegration at the level of cell-surface topography interactions. A search of the electronic databases was performed up to and including November 2010, with 320 articles meeting the inclusion criteria. Characteristics of the included in vitro reports were model systems used, genes examined, techniques used for molecular assessment of the osseointegration process, and wide gene expression profiling studies. There exists a growing body of in vitro evidence to support a role for surface topography in the direct influence of cellular phenotypes as related to the process of osseointegration. Most recently, functional or mechanistic studies have provided evidence that particular topographic cues can be specifically integrated among the many extracellular signals received by the cell in its signal transduction network. Such investigations begin to define linkages between the character of the implant surface and adherent cellular responses, including cells from extravasated blood (eg, platelets) and of the immune system (eg, monocytes). In vitro studies involving cell culture on endosseous implant-related biomaterials offer important and beneficial insight into the clinical control of the implant-bone interface.

Implant-supported fixed dental rehabilitation with monolithic zirconia: a clinical case report.

OBJECTIVE: Veneer chipping in bilayered ceramic restorations is a current problem reported with significant frequency. CLINICAL CONSIDERATIONS: This clinical report describes the use of a monolithic, implant-supported restoration with gingiva-colored ceramics. Good esthetic and functional results were achieved with no complications reported after 3 years. CONCLUSIONS: Prosthetic rehabilitation using monolithic zirconia may help to prevent complications associated with bilayered ceramics systems. Further studies are essential to provide long-term data about the performance of this type of prostheses.

Radiographic stents: integrating treatment planning and implant placement.

The pivotal point in treatment planning for dental implants occurs when the location of bone is viewed radiographically in the context of the planned prosthesis. Radiographic planning for dental implant therapy should be used only after a review of the patient's systemic health, imaging history, oral health, and local oral conditions. The radiological diagnostic and planning procedure for dental implants can only be fully achieved with the use of a well-designed and -constructed radiographic guide. This article reviews several methods for construction of radiographic guides and how they may be utilized for improving implant surgery planning and performance.

Patient selection and treatment planning for implant restorations.

Dental implants are an indispensible tool for the restoration of missing teeth. Their use has elevated the practice of dentistry by improving both our technical ability to rehabilitate patients and general quality of life. To routinely achieve the associated high expectations, diligent attention to details must be observed and addressed from the outset. Of central concern is the attainment of osseointegration and the location of implants to ideally support the intended restoration. The pivotal point in treatment planning for dental implants occurs when the location of bone is viewed radiographically in the context of the planned prosthesis. This most often requires diagnostic waxing or tooth arrangement using mounted diagnostic casts.

Prosthodontic management of implant therapy.

Implant-supported dental restorations can be screw-retained, cement-retained, or a combination of both, whereby a metal superstructure is screwed to the implants and crowns are individually cemented to the metal frame. Each treatment modality has advantages and disadvantages. The use of computer-aided design/computer-assisted manufacture technologies for the manufacture of implant superstructures has proved to be advantageous in the quality of materials, precision of the milled superstructures, and passive fit. Maintenance and recall evaluations are an essential component of implant therapy. The longevity of implant restorations is limited by their biological and prosthetic maintenance requirements.