Implant-retained Restorations Research Articles

What every dental practitioner should know about how to examine patients with dental implants

Dental implants are a common treatment modality provided in both primary and secondary care settings. It is increasingly common for a general dental practitioner to see patients with implant-retained restorations. This article suggests an implant safety checklist for general dental practitioners to help them examine an implant-retained prosthesis.

Evaluation of biofilm formation on acrylic resins used to fabricate dental temporary restorations with the use of 3D printing technology

BackgroundTemporary implant-retained restorations are required to support function and esthetics of the masticatory system until the final restoration is completed and delivered. Acrylic resins are commonly used in prosthetic dentistry and lately they have been used in three-dimensional (3D) printing technology. Since this technology it is fairly new, the number of studies on their susceptibility to microbial adhesion is low. Restorations placed even for a short period of time may become the reservoir for microorganisms that may affect the peri-implant tissues and trigger inflammation endangering further procedures. The aim of the study was to test the biofilm formation on acrylamide resins used to fabricate temporary restorations in 3D printing technology and to assess if the post-processing impacts microbial adhesion.MethodsDisk-shaped samples were manufactured using the 3D printing technique from three commercially available UV-curable resins consisting of acrylate and methacrylate oligomers with various time and inhibitors of polymerization (NextDent MFH bleach, NextDent 3D Plus, MazicD Temp). The tested samples were raw, polished and glazed. The ability to create biofilm by oral streptococci (S. mutans, S. sanguinis, S. oralis, S. mitis) was tested, as well as species with higher pathogenic potential: Staphylococcus aureus, Staphylococcus epidermidis and Candida albicans. The roughness of the materials was measured by an atomic force microscope. Biofilm formation was assessed after 72 h of incubation by crystal violet staining with absorbance measurement, quantification of viable microorganisms, and imaging with a scanning electron microscope (SEM).ResultsEach tested species formed the biofilm on the samples of all three resins. Post-production processing resulted in reduced roughness parameters and biofilm abundance. Polishing and glazing reduced roughness parameters significantly in the NextDent resin group, while glazing alone caused significant surface smoothing in Mazic Temp. A thin layer of microbial biofilm covered glazed resin surfaces with a small number of microorganisms for all tested strains except S. oralis and S. epidermidis, while raw and polished surfaces were covered with a dense biofilm, rich in microorganisms.ConclusionsUV-curing acrylic resins used for fabricating temporary restorations in the 3D technology are the interim solution, but are susceptible to adhesion and biofilm formation by oral streptococci, staphylococci and Candida. Post-processing and particularly glazing process significantly reduce bacterial biofilm formation and the risk of failure of final restoration.

Martens Hardness of CAD/CAM Resin-Based Composites

(1) Background: The properties of CAD/CAM resin-based composites differ due to differences in their composition. Instrumented indentation testing can help to analyze these differences with respect to hardness, as well as energy-converting capabilities due to viscoelastic behavior. (2) Methods: Eleven materials were investigated using instrumented indentation testing. Indentation depth (hr), Martens hardness (HM), indentation hardness (HIT), indentation modulus (EIT), the elastic part of indentation work (ηIT), and indentation creep (CIT) were investigated, and statistical analysis was performed using one-way ANOVA, Bonferroni post-hoc test, and Pearson correlation (α = 0.05). (3) Results: All of the investigated parameters revealed differences between the analyzed materials. Besides the differences in hardness-associated parameters (hr, HM, and HIT), instrumented indentation testing demonstrated differences in energy-converting properties. The subsequent one-way ANOVA revealed significant differences (p < 0.001). A significant (p < 0.01, Pearson correlation >0.576) correlation between the materials and HM, HIT, or EIT was identified. (4) Conclusions: Due to the differences found in the energy-converting properties of the investigated materials, certain CAD/CAM resin-based composites could show superior stress-breaking capabilities than others. The consequential reduction in stress build-up may prove to beneficial, especially for implant-retained restorations or patients suffering from parafunctions.

Revisiting the functionally generated path technique: is this an aid to predictable digital occlusal design? Part 2. The technique

The precision of the occlusal scheme is paramount to the production of a successful fixed restoration(s) and its long-term success. The provision of the correct occlusal scheme is one of the requirements when working conformatively, whether in analogue or digital format. Part 1 highlighted occlusal schemes that provide difficulties using established techniques in arriving at a predictable restoration requiring minimal occlusal adjustments chairside. Part 2 introduces the theory of the functionally generated path (FGP) technique. Two cases involving implant-retained restorations are used to highlight the benefit of adopting this technique into the digital workflow in the provision of occlusally precise restorations. CPD/Clinical Relevance: This article describes the value of the functionally generated path technique, when working digitally, for recording the occlusion for implant-retained restorations.

Occlusion on a Single Implant-Supported Crown: Any differences?

Dental implants react biomechanically to the occlusal forces placed on them, in a different fashion to teeth, which can make them prone to overloading. This can lead to a range of mechanical problems, including screw loosening, ceramic chipping, and fracture of components, but it can also be associated with biological complications such as later peri-implantitis. Appropriate occlusal loading is essential to maintain long-term stability of implant-retained restorations. Clinicians must be aware that, to varying extents, complications do occur with single implant-retained crowns. Dental implants are not a panacea; it is unwise to describe implants as being either perfect or permanent because they are neither. Patients need to understand, well in advance of having implant-based treatment, that the placement of titanium in their jaw(s) will not stop their parafunctional habits, such as clenching or bruxism. Insertion of titanium screws of various types and roughness will certainly not alter their susceptibility to their own plaque-induced inflammatory periodontal disease which is often manifested as peri-mucositis, or later as peri-implantitis in susceptible patients. Based on the available data, this paper provides recommendations to optimise clinical outcomes for single implant-supported crowns. When designing implants, the focus should be on achieving axial forces during chewing. It is wise to minimise horizontal and non-axial loads to avoid potential damage to ceramic or other prosthetic components, and to minimise the risks of bone resorption occurring around the implants themselves at a later stage. Occlusal relationships of implant-retained restorations should be carefully evaluated on a regular basis. Accurate occlusal records of the starting point are extremely helpful in assessing the ongoing status of any restorations.

Revisiting the Functionally Generated Path Technique: Is this an Aid to Predictable Digital Occlusal Design? Part 1: Introduction and Background

Registering a pre-existing occlusal scheme is paramount to the long-term success of a fixed restoration(s) and a requirement when working conformatively, whether in analogue or digital format. Part 1 of this two-part series highlights those occlusal schemes that provide difficulties using established techniques in arriving at a predictable restoration requiring minimal occlusal adjustments chairside. Part 2 introduces the theory of the functionally generated path (FGP) technique, and two cases involving implant-retained restorations will be used to highlight the benefit of adopting this technique into the digital workflow in the provision of occlusally precise restorations. CPD/Clinical Relevance: This article provides an overview of difficult occlusal schemes and identifies those that would benefit from using the functionally generated path technique in the provision of occlusally correct restorations.

Dental Implants for the General Dental Practitioner. Part 2: Complications, Management and Maintenance

With dental implants becoming a more common treatment option for the replacement of missing teeth, and with survival rates upwards of 90% after 10 years, it is likely that primary care dentists and dental care professionals will encounter patients presenting with problems. The second article in this two-article series outlines common biological and mechanical complications arising with dental implants and their component parts, and how to manage them.CPD/Clinical Relevance: This article highlights important aspects the primary care practitioner should consider when examining and maintaining dental implants, and provides an overview of common biological and mechanical complications associated with implant-retained restorations.

STRESS DISTRIBTUION ANALYSIS FOR THE MANDIBULAR SCREW-RETAINED FULL ARCH ACRYLIC PROSTHESIS WITH DIFFERENT CANTILEVER EXTENSION (3D FINITE ELEMENT ANALYSIS)

Background: Implant-retained restorations offer numerous advantages over regular removable dentures. Basically, efficient retention and stability is easily achieved by constructing a fixed restoration or at least by using overdenture attachments instead of depending on the weak physical means used with regular dentures. Methods: A geometrical model demonstrating screw retained acrylic fixed restoration, mucosa, implants, abutment, screw, alveolar bones were generated to accomplish the assessments. The parameters presented in the computer model were cantilever extent and stresses with 50 and 100 N performed to mimic the occlusal stresses. geometrics with the peripheries of stress were gained and the extreme stress at each site was designed in diagrams for analysis. Results: Stresses clustered at the elements closest to the loading point. implant deformation shows a reduction with the increase of cantilever length. Conclusion: Alveolar bone received less stresses and deformation under more rigid restoration that it distributes the applied load in a good manner than lower rigidity one.

Occlusal Schemes for Implant Restorations: Best Evidence Consensus Statement.

Numerous studies have focused on the various complications with implant-retained restorations and a common thread in these publications is the potential for occlusal overload. The purpose of this Best Evidence Consensus Statement on implant occlusal schemes was to review the literature to determine the level of scientific evidence upon which the articles are based. Limiting the search to Clinical trials, Randomized Controlled Trials, Systematic Reviews, Meta-analyses, the key words: dental implants, occlusion, found no citations. Expanding the search to Journal articles found 1,483 results, 20 of which pertained to the question. Doing a similar search including Journal Articles, the key words: dental implants and occlusal scheme found 47 citations, 17 of which were pertinent to the question. After eliminating duplicates and non-relevant articles, 15 were included in the review. Nineteen additional articles were culled by going through the reference lists in the aforementioned articles. There is a lack of scientific evidence regarding the occlusal scheme utilized with implant restorations that will minimize or eliminate complications. In light of this lack of scientific evidence, the style of occlusion a practitioner utilizes with tooth or mucosal supported prostheses may be used with implant-supported restorations until compelling evidence dictates otherwise.

Retrograde peri-implantitis associated with residual cysts: 3 Case reports

Background and OverviewThe authors describe 3 cases of retrograde peri-implantitis associated with residual cysts and their successful surgical and regenerative management. Implants were originally placed with both immediate and delayed protocols. Case DescriptionThree patients sought treatment at the authors’ specialist private practices with the chief symptoms of pain and swelling in association with implant-retained restorations. Clinical, radiographic, and histopathologic findings supported the diagnoses of infected residual cysts. The lesions were enucleated in toto, the implant surfaces were decontaminated, and bone regeneration procedures were carried out. Long-term recall visits, ranging from 3 through 10 years, confirmed successful retention of all implants treated accordingly. Conclusions and Practical ImplicationsThe authors describe an unusual clinical manifestation and emphasize the role of local procedures during implant placement in areas compromised with infection, cysts, or both and the importance of long-term recall visits.

Knowledge and Attitudes of Dental Interns and Dentists on Implants and Implant-Retained Restorations in Jeddah, Saudi Arabia

Objectives: This cross-sectional study aimed to assess the knowledge and attitudes of dental interns and dentists in Jeddah, Saudi Arabia, about Cement-Retained Restoration (CRR), Screw Retained Restoration (SRR), and implant restoration. Methods: A total of 530 dentists and students participated in the study. Data were collected using a self-administrated questionnaire modified from previous studies. The collected data were analyzed using SPSS software for t-test, linear regression, and ANOVA. Results: Participants had a mean score of 5.01 (SD = 1.50) for a total of nine implant-retained restoration (IRR)knowledge questions (lowest score = 0, highest score = 9), and general implant knowledge had a mean score of 3.12 (SD = 1.25) for five questions with scores of 0 to 5. The participants’ knowledge about implants significantly differed in relation to gender, place of work, and work status. Also, participant knowledge about IRR showed significant differences in relation to participants' knowledge, age, gender and place of work. The dental interns and dentists were in agreement in considering SRR to be better than CRR for six out of nine factors. Those factors were cost effectiveness, expertise required for provision, retrievability, retention, fracture resistance, and passivity of fit. Conclusion: The overall knowledge of dental interns and dentists regarding implants and IRR was fair and needs to be improved, given the tendency of general dentists to engage in implant dentistry. Both dentists and interns considered CRR to be aesthetically superior, easier to fabricate, and requiring comparatively less expertise in comparison to SRR.

Evaluation of reliability of zirconia materials to be used in implant-retained restoration on the atrophic bone of the posterior maxilla: A finite element study.

PURPOSEZirconia materials have been used for implant-retained restorations, but the stress distribution of zirconia is not entirely clear. The aim of this study is to evaluate the stress distribution and risky areas caused by the different design of zirconia restorations on the atrophic bone of the posterior maxilla.MATERIALS AND METHODSAn edentulous D4-type bone model was prepared from radiography of an atrophic posterior maxilla. Monolithic zirconia and zirconia-fused porcelain implant-retained restorations were designed as splinted or non-splinted. 300-N occlusal forces were applied obliquely. Stress analyses were performed using a 3D FEA program.RESULTSAccording to stress analysis, the bone between the 1) molar implant and the 2) premolar in the non-splinted monolithic zirconia restoration model was stated as the riskiest area. Similarly, the maximum von Mises stress value was detected on the bone of the non-splinted monolithic zirconia models.CONCLUSIONSplinting of implant-retained restorations can be more critical for monolithic zirconia than zirconia fused to porcelain for the longevity of the bone.

Adhesion of microorganisms to various dental materials used to form a gum contour in implant-retained restorations

The article the literature review on dental materials for the manufacture of gum formers used in dental implantology. Adhesion of microorganisms to titanium, PMMA and PEEK resins is discussed. According to published studies PEEK polymer is characterized by a similar bacterial contamination compared to titanium but shows lower degree of contamination when compared to acrylic resins in equal conditions.

Dental implants: what have we learnt from long-term follow-up?

Abstract: At dental hospitals and general dental practices across the UK there are increasing numbers of patients attending with problems related to their dental implants. Many of the most challenging to deal with are those where implants were placed many years previously. With more evidence now available from long-term studies, this paper will look at the causes and incidence of implant and prosthesis complications, and suggest practical methods of management in these cases. The impact of obsolete implant systems on patient treatment will be considered, and how age-related patient factors can alter the management of these cases. CPD/Clinical Relevance: To explore the needs and treatment burden of patients with implant-retained restorations and consider important factors in the care and management of these patients over time.

Influence of Sealing of the Screw Access Hole on the Fracture Resistance of Implant-Supported Restorations.

The purpose of this study was to assess the influence of sealing of the screw access hole (SAH) on the fracture resistance of metal-ceramic implant-supported restorations. UCLA abutments were used to make 30 implant-retained mandibular molar restorations and divide equally into three groups: Group SRS: screw-retained restorations with SAH sealed; Group SRNS: screw-retained restorations with SAH not sealed; Group CR: cement-retained restorations. The following protocol was adopted to restore the SAH: the ceramic surface of the SAH was air-abraded with aluminum oxide; etched with 10% hydrofluoric acid; a silane coupling agent and a bonding agent were applied; cotton pellets were used as filling material and P-60 resin composite as restoring material. The cement-retained restorations were cemented with Rely-X U100. A metal rod with a spherical tip of 6.0 mm diameter was used to apply a vertical static load, simultaneously on the buccal and lingual incline cusps, at a crosshead speed of 0.5 mm/min until the fracture of the specimens. Data were analyzed using one-way ANOVA and Dunnet test (p<0.05) for multiples comparisons. The mode of failure was evaluated by a scanning electron microscopy (SEM). No significant difference between screw-retained restorations was found. The highest mean fracture resistance values were observed with CR group. Therefore, it was shown that SAH sealing did not influence the fracture resistance of the screw-retained restorations.

Knowledge and attitude of dentists toward implant retained restorations in Saudi Arabia.

The aim was to assess the knowledge and attitudes of specialists (SP) and general dental practitioners (GDP) toward cement-retained restoration (CRR), screw-retained restoration (SRR) and implant restorations in Saudi Arabia. Self-designed-structured questionnaires were distributed between SP and GDP by hand and through E-mails. Opinion of dentists regarding factors vital in selection of CRR and SRR was enquired. Factors included esthetics, retrievability, retention, passive fit, fracture resistance, tissue health, cost-effectiveness, fabrication ease, and required expertise. Participants also graded significance of treatment-planning factors for implant-retained prosthesis. Analysis of comparative response frequencies and significance grades was done using the Chi-square and independent t-test. Of 552 respondents, 64% were SP and 36% were GDP with overall response rate of 67%. About 75% of SP and 80% of GDP used SRR in <50% and <25% of their implant practice respectively. The opinion of GDP and SP was significantly different with regards to esthetics, fabrication ease, retrievability, retention and cost-effectiveness between CRR and SRR ( P < 0.05). Overall, CRR were considered better in terms of esthetics, passive fit, fabrication ease, required expertise and fracture resistance. However, SRR were regarded as having better retention, retrievability, soft tissue health and cost-effectiveness. The average significance scores were significantly higher for SP as compared to GDP for six out of nine factors. Knowledge of SP and GDP for selection of implant-retained restorations was broadly in line with standard evidence. The clinical use of CRR was greater in comparison to SRR.

A simple technique to minimize excess luting agent in cement-retained implant restorations

The common complication of cement-retained implant restorations is the extrusion of the excess cement into the peri-implant sulcus, which may initiate a local inflammatory response leading to peri-implant disease and ultimate implant failure. This article presents a simple and time-saving method of controlling cement flow around implant abutments, minimizing the excess cement around implant-retained restorations.

Use of diagnostic templates at stages of prosthetics treatment with implant-retained restorations

The comparative analysis of efficiency of various types of diagnostic templates for planning orthopedic treatment of 50 patients with partial or complete absence of teeth was performed. The patients were divided in 3 groups according to template manufacturing technique. All diagnostic templates made in accordance with clinical conditions allowed transfering digital data of the scheduled prosthetic construction for virtual implantation planning. Advantages and pitfalls of each template type are discussed.

All-ceramic resin-bonded fixed dental prostheses: treatment planning, clinical procedures, and outcome.

Single-retainer resin-bonded fixed dental prostheses (RBFDPs) present a minimally invasive treatment option as an alternative to implant-retained restorations in the esthetic zone. Advantages such as applicability to juvenile patients who do not come into consideration for implant therapy, and highly predictable and esthetic results make them a valuable treatment modality. This article outlines the treatment procedures with an all-ceramic RBFDP and reviews the existing data on the clinical outcome of this prosthetic therapy. The materials used for fabrication and insertion of the RBFDPs as well as the current scientific data are discussed.

Rehabilitation of a Patient With Gunshot Injury Through the Iliac Graft and Implant-Retained Restorations With a 3-Year Follow-up

Trauma is one of the most common causes of teeth loss. Assault with a gunshot and bullet shot is life threatening, and for patients who survive the injury, it results in hard and soft tissue loss in the tissues and organs crossed by the bullet. The tissue loss results in the loss of structure and function. Rehabilitation of these patients to function and aesthetics requires surgical and prosthodontic procedures over time. This report is of a 24-year-old male patient who had a bullet injury resulting in hard and soft tissue deficiency. The ridge deficiency was augmented with iliac bone graft, and 3 months later, implants were placed. Five months later, hybrid prosthesis was delivered. At 3-year follow-up visit, the hybrid prosthesis was replaced with porcelain fused to a metal bridge. The bone levels on all the implants were stable.