The effect of radiotherapy on survival of dental implants in head and neck cancer patients

Dental implant considerations in patients with systemic diseases: An updated comprehensive review

BACKGROUND

Various medical conditions and the drugs used to treat them have been shown to impede or complicate dental implant surgery. It is crucial to carefully monitor the medical status and potential post-operative complications of patients with systemic diseases, particularly elderly patients, to minimize the risk of health complications that may arise.

AIM

The purpose of this study was to review the existing evidence on the viability of dental implants in patients with systemic diseases and to provide practical recommendations to achieve the best possible results in the corresponding patient population.

METHODS

The information for our study was compiled using data from PubMed, Scopus, Web of Science and Google Scholar databases and searched separately for each systemic disease included in our work until October 2023. An additional manual search was also performed to increase the search sensitivity. Only English-language publications were included and assessed according to titles, abstracts and full texts.

RESULTS

In total, 6784 studies were found. After checking for duplicates and full-text availability, screening for the inclusion criteria and manually searching reference lists, 570 articles remained to be considered in this study.

CONCLUSION

In treating patients with systemic conditions, the cost-benefit analysis should consider the patient's quality of life and expected lifespan. The success of dental implants depends heavily on ensuring appropriate maintenance therapy, ideal oral hygiene standards, no smoking and avoiding other risk factors. Indications and contraindications for dental implants in cases of systemic diseases are yet to be more understood; broader and hardcore research needs to be done for a guideline foundation.

The dental implant survival rate in 18 patients with post-operation revolutionary jaw reconstruction using free fibular flap, dental implants, and overdentures

Background/purpose

This retrospective study assessed the risks and complications associated with dental implants after jaw surgery and radiotherapy for large defects, highlighting challenges for reconstructive surgeons and prosthetic dentists.

Materials and methods

From 2002 to 2008, National Taiwan University's Department of Maxillofacial Surgery used preoperative stereolithographic models and microvascular flaps for mandibular reconstruction in 18 patients with defects from ameloblastoma or advanced gingival cancer. They received free fibular flap grafts, followed by 46 osseointegrated dental implants. Patient outcomes, monitored for up to 60 months, were assessed through clinical and radiographic evaluations of implant success.

Results

The overall survival rate of dental implants following tumor surgery and radiotherapy was 84.8%. Seven implants failed due to peri-implantitis (3), tumor recurrence (2), and osteoradionecrosis (ORN) (2). The ameloblastoma group did not contribute to implant failure, with 4 implant failures in the stage III gingival cancer group, and 3 implant failures in the stage IV gingival cancer group.

Conclusion

Following segmental mandibulectomy for mandible lesions, free fibular bone graft reconstruction restored mandible continuity, while subsequent dental implantation and overdenture fabrication restored occlusion and aesthetics for patients. Besides considering treatment strategies for ameloblastoma groups, similar approaches can be extended to oral cancer patients undergoing post-operative reconstruction. However, additional considerations (peri-implant soft tissue condition, tumor recurrence, ORN, etc.) are necessary for oral cancer patients predisposed to dental implant failure post-surgery.

Survival of osseointegrated implants in head and neck cancer patients submitted to multimodal treatment: a systematic review and meta-analysis

PURPOSE

To investigate the survival rate in implants placement in irradiated and non-irradiated bone in patients undergoing head and neck cancer (HNC) treatment. We focused on the consequences of the main complications, such as osteoradionecrosis and peri-implantitis.

METHODS

An electronic search conducted by PRISMA protocol was performed. Full texts were carefully assessed, and data were assimilated into a tabular form for discussion and consensus among the expert panel. The quality assessment and the risk of bias are verified by Joanna Briggs Institute checklist (JBI) and The Newcastle-Ottawa Scale (NOS), and Risk of Bias in Non-Randomized Studies of Interventions (ROBINS-I) assessment tool.

RESULTS

A total of 452 records were identified in the based on our PICOs strategy and after screening, 19 articles were included in the descriptive analysis of the review. Totaling 473 implants placed in irradiated and non-irradiated bone, and 31.6% of the patients were over 60 years of age. 57.9%) performed implant placement in a period of 12 months or more after the ending of radiotherapy. Only 5 studies had a follow-up period longer than 5 years after implant placement, of which three were used for the meta-analysis. In the meta-analysis of 5-year survival rate, analysis of implants in irradiated bone was assessed; a random effect model was used and a weighted proportion (PP) of 93.13% (95% CI: 87.20-99.06; p < 0.001), and in the 5-year survival rate, analysis of implants in non-irradiated bone was analysed; a fixed effect model was used and a weighted proportion (PP) of 98.52% survival (95% CI: 97.56-99.48, p < 0.001).

CONCLUSIONS

Survival rates of implants placed in irradiated bone are clinically satisfactory after a follow-up of 5 years, with a fewer percentage than in implants placed in non-irradiated bone after metanalyses performed.

Outcomes and influential factors in functional and dental rehabilitation following microvascular fibula flap reconstruction in the maxillomandibular region: a systematic review and meta-analysis

BACKGROUND

This systematic review and meta-analysis aimed to evaluate the factors influencing and success rates of dental implants for functional and dental rehabilitation following microvascular fibula flap reconstruction in the maxillomandibular region.

MAIN TEXT

We conducted a comprehensive search of electronic databases, including MEDLINE, Web of Science, Embase, Scopus, and Cochrane's CENTRAL, as well as gray literature sources and manual searches of notable journals. The search was performed from inception until February 2023. Studies were included if they examined functional and dental rehabilitation outcomes in patients receiving maxillofacial reconstruction using microvascular fibula flaps and were retrospective or prospective cohort studies involving human subjects. Case-control studies, research involving other reconstruction methods, and animal-based studies were excluded. Data was extracted and confirmed by two independent researchers, and risk of bias was assessed using the Newcastle-Ottawa Scale. Meta-analyses were conducted for dental implant and graft success rate, with separate analyses for different factors affecting the outcome. Heterogeneity was evaluated using Cochran's Q test and the I² test. The pooled success rate for implants was 92% and for grafts, 95%, with significant heterogeneity. Implants in fibular grafts had a 2.91 times higher failure rate than those in natural bones. Radiated bone and smoking were identified as factors influencing implant failure, with radiated bone having a 2.29 times higher risk and smokers having a 3.16 times higher risk compared to their respective counterparts. Patient-reported outcomes showed improvements in key areas such as dietary intake, mastication, speech, and esthetics. The success rates declined over time, emphasizing the importance of long-term follow-up.

CONCLUSIONS

Dental implants in free fibula grafts generally have favorable success rates, with minimal bone resorption, manageable probing depths, and limited bleeding on probing. Implant success is influenced by factors such as smoking and radiated bone.

Neural network system for analyzing statistical factors of patients for predicting the survival of dental implants

Implants are now the standard method of replacing missing or damaged teeth. Despite the improving technologies for the manufacture of implants and the introduction of new protocols for diagnosing, planning, and performing implant placement operations, the percentage of complications in the early postoperative period remains quite high. In this regard, there is a need to develop new methods for preliminary assessment of the patient's condition to predict the success of single implant survival. The intensive development of artificial intelligence technologies and the increase in the amount of digital information that is available for analysis make it relevant to develop systems based on neural networks for auxiliary diagnostics and forecasting. Systems based on artificial intelligence in the field of dental implantology can become one of the methods for forming a second opinion based on mathematical decision making and forecasting. The actual clinical evaluation of a particular case and further treatment are carried out by the dentist, and AI-based systems can become an integral part of additional diagnostics. The article proposes an artificial intelligence system for analyzing various patient statistics to predict the success of single implant survival. As the topology of the neural network, the most optimal linear neural network architectures were developed. The one-hot encoding method was used as a preprocessing method for statistical data. The novelty of the proposed system lies in the developed optimal neural network architecture designed to recognize the collected and digitized database of various patient factors based on the description of the case histories. The accuracy of recognition of statistical factors of patients for predicting the success of single implants in the proposed system was 94.48%. The proposed neural network system makes it possible to achieve higher recognition accuracy than similar neural network prediction systems due to the analysis of a large number of statistical factors of patients. The use of the proposed system based on artificial intelligence will allow the implantologist to pay attention to the insignificant factors affecting the quality of the installation and the further survival of the implant, and reduce the percentage of complications at all stages of treatment. However, the developed system is not a medical device and cannot independently diagnose patients. At this point, the neural network system for analyzing the statistical factors of patients can predict a positive or negative outcome of a single dental implant operation and cannot be used as a full-fledged tool for supporting medical decision-making.

Dental Implant Healing Screws as Temporary Oral Drug Delivery Systems for Decrease of Infections in the Area of the Head and Neck

Background

Periimplantitis is continuously one of major threats for the uneventful functioning of dental implants. Current approaches of drug delivery systems are being more commonly implemented into oral- and maxillofacial biomaterials in order to decrease the risk of implant failure due to bacterial infection. Silver nanoparticles and their compounds have been proven in eradicating oral bacteria responsible for peri-implant infections. Nevertheless, their evaluation as coating for implant abutments has not been extensively evaluated so far. This article describes a novel coating consisting of zinc oxide (ZnO) and silver (Ag) nanoparticles (NPs). This coating was used to modify healing abutments that could be used as drug delivery systems in oral implantology.

Materials and Method

Nanoparticles with a ZnO + 0.1% Ag composition were produced by microwave solvothermal synthesis and then incorporated into the surface of titanium healing abutments by high-power ultrasonic deposition. Surface morphology, roughness, wettability were evaluated. Ability of biofilm formation inhibition was tested against S. mutans, S. oralis, S. aureus and E. coli.

Results

ZnO+0.1%Ag NPs were sufficiently deposed on the surface of the abutments creating nanostructured coating which increased surface roughness and decreased wettability. Modified abutments significantly decreased bacterial biofilm formation. Bacteria present in SEM studies were unlikely to settle and replicate on the experimental abutments as their cells were rounded, insufficiently spread on the surface and covered with released NPs.

Conclusion

Experimental nanostructured abutments were easily manufactured by high-power ultrasonic deposition and provided significant antibacterial properties. Such biomaterials could be used as temporary drug delivery abutments for prevention and treatment of intra- and extraoral peri-implant infections in the area of the head and neck.

Survival of dental implants and occurrence of osteoradionecrosis in irradiated head and neck cancer patients: a systematic review and meta-analysis

OBJECTIVES

This systematic review assesses dental implant survival, calculates the incidence rate of osteoradionecrosis, and evaluates risk factors in irradiated head and neck cancer patients.

MATERIALS AND METHODS

Various databases (e.g., Medline/Embase using Ovid) and gray literature platforms were searched using a combination of keywords and subject headings. When appropriate, meta-analysis was carried out using a random effects model. Otherwise, pooled analysis was applied.

RESULTS

A total of 425 of the 660 included patients received radiotherapy. In total, 2602 dental implants were placed, and 1637 were placed in irradiated patients. Implant survival after an average follow-up of 37.7 months was 97% (5% confidence interval, CI 95.2%, 95% CI 98.3%) in nonirradiated patients and 91.9% (5% CI 87.7%, 95% CI: 95.3%) after an average follow-up of 39.8 months in irradiated patients. Osteoradionecrosis occurred in 11 cases, leading to an incidence of 3% (5% CI 1.6%, 95% CI 4.9%). The main factors impacting implant survival were radiation and grafting status, while factors influencing osteoradionecrosis could not be determined using meta-analysis.

CONCLUSION

Our data show that implant survival in irradiated patients is lower than in nonirradiated patients, and osteoradionecrosis is-while rare-a serious complication that any OMF surgeon should be prepared for. The key to success could be a standardized patient selection and therapy to improve the standard of care, reduce risks and shorten treatment time.

CLINICAL RELEVANCE

Our analysis provides further evidence that implant placement is a feasible treatment option in irradiated head and neck cancer patients with diminished oral function and good long-term cancer prognosis.

Prosthetic Reconstruction of the Maxilla and Palate

Maxillary defects commonly present following surgical resection of oncologic processes. The use of rotational and free flaps has largely replaced the use of prosthetic options for hard palate and maxillary reconstruction, but prostheses remain a useful tool. Prosthetic devices may be invaluable in patients considered poor candidates for surgical reconstruction secondary to poor vascularity, need for postoperative radiation, or medical comorbidities that place them at high risk for healing following reconstruction. Obturators may also be considered over soft tissue options if oncologic surveillance via direct visualization of the surgical site is warranted.

What is the optimal timing for implant placement in oral cancer patients? A scoping literature review

BACKGROUND

Oral cancer patients can benefit from dental implant placement. Traditionally, implants are placed after completing oncologic treatment (secondary implant placement). Implant placement during ablative surgery (primary placement) in oral cancer patients seems beneficial in terms of early start of oral rehabilitation and limiting additional surgical interventions. Guidelines on the ideal timing of implant placement in oral cancer patients are missing.

OBJECTIVE

To perform a scoping literature review on studies examining the timing of dental implant placement in oral cancer patients and propose a clinical practice recommendations guideline.

METHODS

A literature search for studies dealing with primary and/or secondary implant placement in MEDLINE was conducted (last search December 27, 2019). The primary outcome was 5-year implant survival.

RESULTS

Sixteen out of 808 studies were considered eligible. Both primary and secondary implant placement showed acceptable overall implant survival ratios with a higher pooled 5-year implant survival rate for primary implant placement 92.8% (95% CI: 87.1%-98.5%) than secondary placed implants (86.4%, 95% CI: 77.0%-95.8%). Primary implant placement is accompanied by earlier prosthetic rehabilitation after tumor surgery.

CONCLUSION

Patients with oral cancer greatly benefit from, preferably primary placed, dental implants in their prosthetic rehabilitation. The combination of tumor surgery with implant placement in native mandibular bone should be provided as standard care.

Masticatory performance and oral health-related quality of life in edentulous maxillectomy patients: A cross-sectional study to compare implant-supported obturators and conventional obturators

OBJECTIVE

The aim of this cross-sectional study was to compare the masticatory performance and oral health-related quality of life (OHRQoL) of edentulous maxillectomy patients with and without implant-supported obturator prostheses.

MATERIAL AND METHODS

Nineteen edentulous maxillectomy patients with completed prosthetic obturator treatment in the upper jaw participated in this study. In nine patients, the obturator prosthesis was supported by implants in the remaining bone of the midface and/or skull base to improve retention. Masticatory performance was measured objectively by the mixing ability test (MAT) and subjectively by three OHRQoL questionnaires: (a) the Oral Health Impact Profile for EDENTulous people (OHIP-EDENT), (b) the Obturator Function Scale (OFS), and (c) the Dutch Liverpool Oral Rehabilitation Questionnaire version 3 (LORQv3-NL). The independent t test and the Mann-Whitney U test were used to test for differences in outcomes of patients with and without implant-retention of their obturator prostheses.

RESULTS

Patients with implant-supported obturator prostheses had significantly better masticatory and oral function, reported fewer chewing difficulties, and had less discomfort during food intake than did patients with a conventional obturator.

CONCLUSION

Supporting prosthetic obturators after maxillectomy with implants improve oral functioning, chewing, and eating comfort. This treatment modality is a viable technique to improve the functionality of prosthetic rehabilitation in patients who have undergone maxillectomy.

Amifostine Suppresses the Side Effects of Radiation on BMSCs by Promoting Cell Proliferation and Reducing ROS Production

This study is aimed at investigating the effect of amifostine (AMI) on rat bone marrow stromal stem cells (BMSCs) exposed to 2 Gy radiation. The BMSCs were divided into four groups, namely, group A that received 0 Gy radiation, group B that received 0 Gy radiation and AMI, group C that received 2 Gy radiation, and group D that received 2 Gy radiation and AMI. The proliferation, apoptosis, and distribution of BMSCs in the cell cycle, along with their osteogenesis ability, adipogenesis ability, and ROS production, were subsequently examined. The levels of ALP, PPARγ, P53, and TNFα were determined by Western blotting. The results demonstrated that the proliferation of BMSCs and the levels of ALP in group C were much lower than those in group A. The production of ROS and levels of PPARγ, P53, and TNFα in the group that received 2 Gy radiation were much higher than those in group A. Furthermore, the production of ROS and the levels of PPARγ, P53, and TNFα were much lower in group D than in group C. Additionally, the levels of ALP and extent of cell proliferation were much higher in group D than in group C. The results demonstrated the potential of AMI in reducing the side effects of radiation in BMSCs and in treatment of bone diseases caused by radiation.

Retrospective cohort study of a tapered implant with high primary stability in patients with local and systemic risk factors-7-year data

Objectives

This retrospective study examined the mid- to long-term clinical and radiographic performance of a tapered implant in various treatment protocols in patients with local and systemic risk factors (RFs).

Material and methods

Two hundred seven NobelActive implants were inserted in 98 patients in the period from 10/2008 to 02/2015. The subdivision of the cohort was defined by local (n = 40), systemic (n = 6), local and systemic (n = 8), or without any RFs (n = 44) to analyze implant survival and marginal bone levels.

Results

Fifteen implants failed within the follow-up period. The mean follow-up period of the remaining implants was 34 months (range 12 to 77 months). The cumulative survival rate according to Kaplan-Meier was 91.5%. The survival rate for 93 implants in 45 patients with no RFs was 94.8% whereas it was 94% for 83 implants in 48 patients with local RFs (p = 0.618), 81.3% for 14 implants in 6 patients with systemic RFs (p = 0.173), and 76.5% for 17 implants in 6 patients with local and systemic risk factors (p = 0.006). The interproximal marginal bone level was − 0.49 ± 0.83 mm at the mesial aspect and − 0.51 ± 0.82 mm at the distal aspect in relation to implant shoulder level and showed no relevant difference in the various risk factor groups.

Conclusions

It can be assumed that the negative effects of the local or/and systemic risk factors were partially compensated by the primary stability and grade of osseointegration of the NobelActive implant.

Clinical relevance

The use of this system in patients with risk factors and immediate loading procedures.

Combination Use of BMP2 and VEGF165 Promotes Osseointegration and Stability of Titanium Implants in Irradiated Bone

Background

Clinical data demonstrated that failure rate of titanium implant in irradiated bone was 2-3 times higher than that in nonirradiated bone and it is difficult to get the ideal results in irradiated bone.

Purpose

The aim of the study was to investigate the effects of HBO, BMP2, VEGF165, and combined use of BMP2/VEGF165 on osseointegration and stability of titanium implant in irradiated bone.

Materials and Methods

Sixty rabbits were randomly assigned to 5 groups (control group, HBO group, VEGF165 group, BMP2 group, and BMP2/VEGF165 group) after receiving 15 Gy radiation. Implant surgery was performed on tibias eight weeks later. They were sacrificed at two or eight weeks after operation. Implant stability, calcium, and ALP activity in serum, the ratio of bone volume to total volume, the rate of bone growth, and gene expression were assessed.

Result

There was no mortality and no implants failed during the experiment. Implant stability was significantly compromised in the control group compared to the other four experimental groups, and the BMP2/VEGF165 group had the highest implant stability. HBO, BMP2, and VEGF165 significantly increased BV/TV and the rate of bone growth, while the BMP2/VEGF165 showed the best effect among groups. The expression of RUNX2 in HBO, BMP2, and VEGF165/BMP2 group was higher than that in the VEGF165 and control groups at two weeks. The expression of OCN in HBO, BMP2, VEGF165, and VEGF165/BMP2 groups was higher than that in the control group, and the gene expression of CD31 was higher in HBO, VEGF165, and BMP2/VEGF165 groups than that in control and BMP2 groups.

Conclusion

HBO, BMP2, and VEGF165 could increase bone formation around the implant and improved the implant stability in irradiated bone. The combination use of BMP2 and VEGF165 may be promising in the treatment of implant patients with radiotherapy.

Increasing the Stability of Dental Implants: the Concept of Osseodensification

One of the most important factors that affect osseointegration is the primary stability of the implant. Dental implants inserted at the posterior region of the maxilla exhibit the lowest success rates as the low density bone in this area often jeopardize rigid fixation of the implant. Many surgical techniques have been developed to increase the primary stability of an implant placed in low density bone, such as bicortical fixation of the implant, undersized preparation of the implant bed and bone condensation by the use of osteotomes. A new promising technique, named osseodensification, has been recently developed that creates an autograft layer of condensed bone at the periphery of the implant bed by the aid of specially designed burs rotating in a clockwise and anti-clockwise direction. The purpose of this review is to emphasize that implant primary stability is strongly influenced by the surgical technique, to quote and briefly analyse the various surgical procedures laying weight to osseodensification procedure.