Alveolar Ridge Preservation with Autologous Platelet-Rich Fibrin (PRF): Case Reports and the Rationale.

In dental implantology, alveolar ridge preservation (ARP) has emerged as a standard technique to address dimensional changes that affect alveolar ridge morphology following tooth loss. Various alternative graft materials, including xenografts, alloplasts, and allografts, have been effectively employed in fresh extraction sites for ARP. Current evidence suggests that these materials primarily serve as bio-scaffolds, which are slowly incorporated, thus necessitating a waiting period of at least 4-6 months before implant placement. Consequently, the ARP technique extends the overall duration of implant treatment by several months. Recently, the incorporation of a form of autologous platelet concentrate, known as platelet-rich fibrin (PRF), has been advocated in conjunction with ARP as a method of bioenhancement of soft- and hard-tissue healing and regeneration. PRF contains platelet-derived growth factors, hormones, and bioactive components like cytokines that have demonstrated the ability to stimulate angiogenesis and tissue regeneration throughout all phases of wound healing. Additionally, the concentration of leukocytes present in the PRF matrix plays a vital role in tissue healing and regeneration as part of the osteoimmune response. The reported advantages of incorporating autogenous PRF platelet concentrates during ARP encompass reduced healing time, improved angiogenesis and bone regeneration, socket sealing through the fibrin matrix, antibacterial properties, and decreased post-extraction pain and infection risk. Therefore, the objective of this paper is to review the existing evidence regarding the application of PRF in alveolar ridge preservation (ARP) following tooth extraction. Two clinical case studies are presented, wherein ARP was enhanced with PRF, followed by implant placement within a relatively short period of 8 weeks. These cases serve as further proof of concept for supporting the adjuvant use of PRF to enhance healing and accelerate implant placement after ARP.

Success of Xenografts in Alveolar Ridge Preservation Based on Histomorphometric Outcomes.

Different xenograft approaches in alveolar ridge preservation (ARP) are essential to understand relative to their histomorphometric outcomes. Therefore, the aim of this study involved studying biomaterials of a xenograft nature that are used in ARP procedures, to compare the different approaches and evaluate their efficacy in relation to histomorphometric data. An electronic search was completed using the databases: Ovid (Medline), Google Scholar and Wiley Online Library, including a hand search for relevant articles and grey literature. Only randomised controlled trials, using xenograft biomaterials for alveolar ridge preservation procedures involving human studies, dated from 2010-2022 were included in the review. An initial search yielded 4918 articles, after application of the eligibility criteria, 18 studies were deemed eligible for inclusion in the systematic review. The two main xenograft groups found were of bovine origin and of porcine origin. The main histomorphometric outcomes evaluated included new bone percentage (N.B%) and residual graft percentage (R.G%). The mean N.B% for the bovine and porcine groups were 33.46% and 39.63% respectively and the mean R.G% for the bovine and porcine groups were 19.40% and 18.63% respectively. The current evidence suggests that the two main xenograft biomaterials used in ARP procedures after tooth extraction, which are of bovine and porcine origin, displayed effectiveness in producing new bone.

Differences in Dental Implant Survival between Immediate vs. Delayed Placement: A Systematic Review and Meta-Analysis.

OBJECTIVES: To compare the impact of immediate and delayed implant placement upon the survival of implants and to investigate the differences in implant survival between immediate and delayed placement in adults. METHODS: A search for the relevant literature was performed using the databases of CENTRAL, MEDLINE and Scopus. The studies found were limited to publications between 2014 and 2022, written in the English language, peer-reviewed, and were randomised trials or comparative studies. The quality of the evidence was assessed using the Cochrane Risk of Bias 2.0 and Risk of Bias in Non-randomised Studies-of Interventions appraisal tools and implant survival, and the primary outcome was meta-analysed using RevMan v.5.3. RESULTS: A total of 10 studies were eligible for inclusion, including six randomised controlled trials and four non-randomised comparative studies. Five of the six randomised trials observed a low risk of bias, while the comparative studies had a moderate-to-serious risk of bias. The search strategy resulted in 341 implants placed immediately into fresh extraction sites (332 survived, 97.4%) and 359 implants inserted into delayed sites (350 survived, 97.5%). CONCLUSION: The meta-analysis demonstrated that there was no significant difference in the implant survival rates between immediately placed implants and implants placed using a delayed timing protocol (risk ratio 0.99; 95% CI 0.96, 1.02, Z = 0.75, p = 0.45). However, the detailed analysis showed that slightly more implant failures happened in the immediate dental implant placement group, with survival rates in some studies ranging between 90 and 95%, while the delayed placement group had survival rates of more than 95%.

Extraction Socket Augmentation with Autologous Platelet-Rich Fibrin (PRF): The Rationale for Socket Augmentation.

After tooth extraction, the alveolar ridge undergoes a physiological process of remodelling and disuse atrophy. Socket augmentation (SA) has been shown to preserve alveolar bone volume in order to facilitate implant placement and reduce the need for staged grafting at a later date. Although autogenic grafting has been shown to be the gold standard in bone regeneration, it has significant disadvantages. To prevent post-extraction volumetric alterations and alveolar bone resorption occurring, alternative grafting materials, including xenografts, alloplasts, and allografts, have been used successfully in fresh extraction sites. However, these materials act mostly as bio-scaffolds and require a slower integration period of 6-8 months prior to implant placement. Recently, the use of autologous platelet-rich fibrin (PRF) has been advocated alongside socket augmentation as a method of bio-enhancement of healing of soft and hard tissues. PRF contains platelet-derived growth factors, hormones, and bioactive components such as cytokines that have been shown to promote angiogenesis and tissue regeneration during wound healing. The aim of this article is to review the evidence base for the SA technique Clinical benefits of SA will be discussed with a reference to two cases. Therefore, this narrative review will discuss the post-extraction bone changes, the importance of SA, and the bio-enhancement role of PRF in the management of extraction site defects when the alternative technique of immediate implant placement is not possible or contraindicated.

Success Rates of Zygomatic Implants for the Rehabilitation of Severely Atrophic Maxilla: A Systematic Review.

Zygomatic implants are a treatment solution for patients with severe maxillary atrophy. This treatment option allows delivering immediate fixed teeth within 24 h. Numerous peer-reviewed publications have reported different success rates, resulting in a disagreement on the topic. Therefore, the overall efficacy and predictability of this rehabilitation is still a matter of discussion. With this study, we aimed to identify the published literature on the use of zygomatic implants for the reconstruction of the severely atrophic maxilla and report the cumulative success rate (CSR) as a function of follow-up time. A systematic review of the literature on zygomatic implant for the treatment of severe maxillary atrophy was performed and 196 publications were included in the study. The cumulative success rate of zygomatic implants for the treatment of severe maxillary atrophy was 98.5% at less than 1 year, 97.5% between 1 and 3 years, 96.8% between 3 and 5 years and 96.1% after more than 5 years. The most commonly reported complications were soft tissue dehiscence, rhinosinusitis and prosthetic failures. The treatment of severe lack of bone in the upper maxilla with zygomatic implants is a safe procedure, reaching a cumulative success rate of 96.1% after more than 5 years.

Current Undergraduate Dental Implantology Teaching in UK.

Dental Implants are a popular treatment option for tooth replacement, with documented long-term success and survival rates of more than 95% over a period of 10 years. However, incorporating dental implantology into an undergraduate dental curriculum has issues associated. Therefore, the aim of this research was to examine and evaluate current undergraduate dental implantology education in the UK, investigate the amount of time allocated to this subject and analyse the barriers that are currently impeding the development of the programmes. An online questionnaire hosted by Online Surveys was designed, piloted, and sent to 16 dental schools providing undergraduate education in the UK. Ethical approval was gained from The University of Salford to conduct the study. Out of the 16 dental schools contacted, eight questionnaire responses were received, hence a response rate of 50% was achieved. The hours dedicated to the implant teaching programme varied from 3 h to 25 h, with a mean average of 11 h. It was identified from the results that no teaching of dental implantology was conducted in year 2; 12% of the schools responded that the subject was taught in year 1, 37% in year 3, 75% in year 4 and 50% in year 5. The methods used to deliver the programme were mainly lecture-based teaching, with only one dental school allowing students to place implants on patients. The main barriers to progression of the programme were financial (75%), followed by time limitations imposed by the curriculum (37%) and liability insurance (37%). However, there appears to be a consensus that further training beyond bachelor's degree level is required to teach implantology effectively.

3D Guided Dental Implant Placement: Impact on Surgical Accuracy and Collateral Damage to the Inferior Alveolar Nerve.

An increase in the number of implants placed has led to a corresponding increase in the number of complications reported. The complications can vary from restorative complications due to poor placement to damage to collateral structures such as nerves and adjacent teeth. A large majority of these complications can be avoided if the implant has been placed accurately in the optimal position. Therefore, the aim of this in vitro pilot study was to investigate the effect of freehand (FH) and fully guided (FG) surgery on the accuracy of implants placed in close proximity to vital structures such as the inferior alveolar nerve (IAN). Cone-beam computed tomography (CBCT) and intraoral scans of six patients who have had previous dental implants in the posterior mandible were used in this study. The ideal implant position was planned. FG surgical guides were manufactured for each case. In this study, the three-dimensional 3D printed resin models of each of the cases were produced and the implants placed using FG and FH methods on the respective models. The outcome variables of the study, angular deviations were calculated and the distance to the IAN was measured. The mean deviations for the planned position observed were 1.10 mm coronally, 1.88 mm apically with up to 6.3 degrees' angular deviation for FH surgery. For FG surgical technique the mean deviation was found to be at 0.35 mm coronally, 0.43 mm apically with 0.78 degrees angularly respectively. The maximum deviation from the planned position for the apex of the implant to the IAN was 2.55 mm using FH and 0.63 mm FG. This bench study, within its limitations, demonstrated surgically acceptable accuracy for both FH and FG techniques that would allow safe placement of implants to vital structures such as the IAN when a safety zone of 3 mm is allowed. Nevertheless, a better margin of error was observed for FG surgery with respect to the angular deviation and controlling the distance of the implant to the IAN using R2 Gate® system.

Non-infectious status indicated by detectable IgG antibody to SARS-CoV-2.

A key tenet of protection from infection for dentists is to know who is not infectious. The evidence base regarding protection from respiratory pathogens in dentistry is poor. Those with a positive SARS-CoV-2 IgG antibody are non-infectious (>99% certainty) and can be safely treated with good universal precautions, even for aerosol generating procedures. Viral infectivity with SARS-CoV-2 lasts eight days, unlike viral polymerase chain reaction (PCR) swab tests which can persist for as long as seven weeks. SARS-CoV-2 IgG antibody becomes detectable from 11 days after infection. SARS-CoV-2 IgG antibodies are usually neutralising against the virus and their direct antiviral activity was partially demonstrated in 33,000 patients with COVID-19 treated with convalescent plasma in the USA. So, a positive SARS-CoV-2 IgG antibody is a much more accurate determination of infectiousness than a repeat PCR which is only 70% sensitive. It remains to be seen whether SARS-Cov-2 vaccine responses include protective IgG titres and, once vaccines become widespread, can be used to assist decision-making on appropriate personal protective equipment (PPE) in dentistry.

A Survey of the Opinion and Experience of UK Dentists Part 3: An Evidence-Based Protocol of Surgical Risk Management Strategies in the Mandible.

BACKGROUND: Implant surgery in the mandible can cause serious complications that can be life threatening. The incidence and cause of iatrogenic trigeminal nerve injury (TNI) related to dental implant surgery was investigated in a survey of the opinion and experience of the UK dentists and reported by the authors in part 1 of this series of articles. Part 2 reported on the risk assessment and management of implant-related inferior alveolar nerve (IAN), mental nerve (MN), and lingual nerve (LN) injuries. This article evaluates the significance of these findings and recommends an evidence-based protocol of risk management strategies to reduce the risk of TNI related to dental implant surgery. METHODS: A survey was distributed among 405 dentists attending an Association of Dental Implantology (ADI) congress, of which 187 completed the survey. RESULTS: In this study, the strategies to manage the risk of TNI included unilateral staging of implant placement (57%) and identification the MN when placing implants (43%). Twelve percent used drill stops when operating in the mandible. Nineteen dentists used steroids (eg, dexamethasone) routinely preoperatively and postoperatively. Twenty-six dentists used basic cone beam computed tomography minimally invasive techniques, and 70% encountered a large anterior loop of the IAN. Most dentists (76%) allowed a 2- to 4-mm safety zone radiologically above the IAN when placing implants, and over half of the responders (56%) used implants that were 10 mm in length. CONCLUSION: Given the elective nature of implant surgery, TNI should be fully avoidable. The evidence suggest that TNI can be minimized with meticulous attention to accurate assessment and surgical planning as well as carrying out the surgery with a high degree of precision. In part 3 of their series of articles, the authors presented an evidence-based protocol that comprises preoperative, intraoperative, and postoperative risk management strategies for dental implant surgical procedures in the mandible.

A Survey of the Opinion and Experience of UK Dentists: Part 2: Risk Assessment Strategies and the Management of Iatrogenic Trigeminal Nerve Injuries Related to Dental Implant Surgery.

BACKGROUND: Dental implant-related iatrogenic injuries are proportionally increasing with dental implant surgery. This study assessed the experience of implant-related trigeminal nerve (TG) injuries among UK dentists. Risk management strategies and management of implant-related inferior alveolar nerve (IAN), mental nerve (MN), and lingual nerve injuries were investigated. METHODS: A survey was distributed among 405 dentists attending an Association of Dental Implantology (ADI) congress, of which 187 completed the survey. RESULTS: Most dentists (76% of 134 responses) allowed a 2 to 4 mm safety zone radiologically above the IAN when placing implants, and over half of the responders (56%) used implants that were 10 mm in length. The most frequent precautionary measure used by 73 (80%) responders was antibiotic coverage routinely to reduce the risk of infection when placing grafts in the posterior mandible. Other precautionary measures included unilateral staging of implant placement (57%), and 43% always identified the MN when placing implants. Nineteen dentists used steroids (eg, dexamethasone) routinely preoperatively and postoperatively. Twenty-six dentists used basic cone-beam CT (CBCT) minimally invasive techniques, and drill stops during implant placement were used by 14 responders. Although it is not highly recommended, steroids were used to manage the neuropathic pain and discomfort experienced by patients with IAN injuries in 40% of cases. CONCLUSION: Further training of dentists undertaking implant surgery is required so that they acquire up-to-date and evidence-based knowledge and skills in the prevention, diagnosis, and management of dental implant-related TG injuries. This training should also involve the justification and interpretation of CBCTs.

A Survey of the Opinion and Experience of UK Dentists: Part 1: The Incidence and Cause of Iatrogenic Trigeminal Nerve Injuries Related to Dental Implant Surgery.

BACKGROUND: Dental implant-related iatrogenic trigeminal nerve (TG) injuries are proportionally increasing with dental implant surgery. This study, which is presented in greater detail over a series of articles, assessed the experience of implant-related TG nerve injuries among UK dentists. Incidence and cause of inferior alveolar nerve (IAN), mental nerve (MN), and lingual nerve (LN) injuries, together with preoperative assessment and the consent process, are presented in this article. METHODS: A survey was distributed among 405 dentists attending an Association of Dental Implantology congress in the United Kingdom, of which 187 completed the survey. RESULTS: Most responding dentists were full-time general practitioners. Implant dentistry training was predominately through industry-organized courses. Eighty dentists encountered implant-related IAN injuries, whereas 8 encountered LN injuries. Inaccurate radiological identification of the IAN/MN and their anatomical variations (48%) were seen to be the most frequent cause of TG injuries. Disclosure of the relative risk and benefits of alternative implant treatment strategies as part of the informed consent process was not deemed to be essential by 47 (25%) of the participants. CONCLUSION: Inadequate radiological assessment was the most common cause of TG nerve injury. The use of small field of view cone beam computer tomography (CBCT) is therefore recommended when placing implants in the posterior mandible. Implant surgeons should acquire evidence-based skills in the prevention, diagnosis, and management of TG nerve injury as well as specific training on justification and interpretation of CBCT scans.

Immediate placement of tapered effect (TE) implants: 5-year results of a prospective, multicenter study.

PURPOSE: To evaluate the success and survival of immediately placed tapered implants to support fixed restorations in the maxilla and mandible. MATERIALS AND METHODS: The study was a prospective, multicenter, non-interventional study of patients requiring tooth extraction who requested an implant-supported restoration in the maxilla or mandible. Patients received at least one tapered implant (either immediately after tooth extraction or at a later time point). Abutments were placed 42 to 56 days after surgery, and prostheses were placed after a further 14 days. Treatment and implant success were the primary effectiveness criteria, and secondary parameters included radiographic bone loss, patient satisfaction, and gingival health. RESULTS: A total of 436 patients were enrolled, of whom 376 were included in the safety analysis. Single implants were placed in 77% of patients, two implants in 16%, and three or more implants in the remainder. The cumulative implant survival rates for immediately placed implants were 98.3% after 1 year and 97.7% from 2 to 5 years. Patient satisfaction was good or excellent in most patients and the majority of implants showed no or < 1-mm change in bone level for up to 5 years. CONCLUSIONS: The survival rate of immediately placed tapered implants was comparable to that found in other studies. Immediate implant placement with tapered implants can allow rapid rehabilitation with no adverse impact on implant survival.

Nasal suction technique for maxillary sinus floor elevation: a report of 24 consecutive patients.

PURPOSE: Inadvertent perforation of the sinus membrane is a frequent complication encountered during sinus floor elevation (SFE). Different strategies have been described for the prevention or treatment of perforations, with varying results. This paper reports the findings of a preliminary study into the application of a novel nasal suction technique in which negative antral air pressure was used to facilitate the raising of the sinus lining and to reduce the risk of perforations occurring during SFE. MATERIALS AND METHODS: In 24 consecutive patients, nasal suction was applied through the ipsilateral nostril during SFE. The suction device was attached to a high-flow vacuum regulator that incorporated a suction canister connected to a -10-kPA medical vacuum (-75 mm Hg). Fifteen subjects received unilateral SFE, and six subjects had bilateral staged lateral wall sinus elevation; the remaining three subjects had osteotome sinus floor elevation (three unilateral and one bilateral) with simultaneous implant placement. RESULTS: During SFE, the use of nasal suction facilitated the inversion of the sinus lining around the edges of the lateral access window. This made the sinus lifting easier, as the need for extensive instrumentation was significantly reduced. In three subjects, elevation of the sinus lining occurred spontaneously from the lateral, medial, and inferior surfaces of the antrum when nasal suction was applied. CONCLUSION: Sinus lifting was facilitated by nasal suction. No perforation of the sinus lining occurred in this series. Controlled clinical trials are being designed to further demonstrate the clinical efficacy of the nasal suction technique in SFE.

A mathematical model for simulating the bone remodeling process under mechanical stimulus.

OBJECTIVES: Among the current mathematical models for bone remodeling, few can consider bone resorption due to overload. The objective of this paper is to develop a new bone remodeling model which can simulate both underload and overload resorptions that often occur in dental implant treatments. METHODS: Based on the traditional model, a new mathematical equation relating the density change rate with mechanical stimulus has been developed. The new equation contains an additional quadratic term which can produce reduction in bone density at high load levels. In addition, to fully exploit the characteristics of this model, a range of different bone remodeling behaviors were studied under the load cases with both constant and varying stress magnitudes. Finally, the model was applied in conjunction with the finite element method to a practical case of dental implant treatment. RESULTS: The FE analysis results showed that bone resorption at the neck of the implant occurred due to occlusal overload but then resorption stopped after some time before reaching the coarse threads. Meanwhile, the density of the bone deeper into the mandible increased slightly due to the additional mechanical stimulus provided by the occlusal load. This phenomenon is observable in some clinical situations. SIGNIFICANCE: The new model can describe the bone overload resorption, a feature which is absent in most of the current models. And by simulating the dental implant treatment using FE method, the ability of the new mathematical model to simulate overload bone resorption has been clearly demonstrated.

Shape optimization of dental implants.

PURPOSE: The purpose of this study was to derive alternative implant shapes which could minimize the stress concentration at the shoulder level of the implant. MATERIALS AND METHODS: A topological shape optimization technique (soft kill option), which mimics biological growth, was used in conjunction with the finite element (FE) method to optimize the shape of a dental implant under loads. Shape optimization of the implant was carried out using a 2-dimensional (2D) FE model of the mandible. Three-dimensional (3D) FE analyses were then performed to verify the reduction of peak stresses in the optimized design. RESULTS: Some of the designs formulated using optimization resembled the shape of a natural tooth. Guided by the results of the optimization, alternative implant designs with a taper and a larger crestal radius at the shoulder were derived. Subsequent FE analyses indicated that the peak stresses of these optimized implants under both axial and oblique loads were significantly lower than those observed around a model of commercially available dental implant. CONCLUSION: The new implant shapes obtained using FE-based shape optimization techniques can potentially increase the success of dental implants due to the reduced stress concentration at the bone-implant interface.