Osseointegrated Implant Rehabilitation of Irradiated Oral 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.

Optimal Treatment Order With Fibula-Free Flap Reconstruction, Oncologic Treatment, and Dental Implants: A Systematic Review and Meta-Analysis

Head and neck cancer (HNC) patients benefit from craniofacial reconstruction, but no clear guidance exists for rehabilitation timing. This meta-analysis aims to clarify the impact of oncologic treatment order on implant survival. An algorithm to guide placement sequence is also proposed in this paper. PubMed, Embase, and Web of Science were searched for studies on HNC patients with ablative and fibula-free flap (FFF) reconstruction surgeries and radiotherapy (RTX). Primary outcomes included treatment sequence, implant survival rates, and RTX dose. Of 661 studies, 20 studies (617 implants, 199 patients) were included. Pooled survival rates for implants receiving >60 Gy RTX were significantly lower than implants receiving < 60 Gy (82.8% versus 90.1%, P =0.035). Placement >1 year after RTX completion improved implant survival rates (96.8% versus 82.5%, P =0.001). Implants receiving pre-placement RTX had increased survival with RTX postablation versus before (91.2% versus 74.8%, P <0.001). One hundred seventy-seven implants were placed only in FFF with higher survival than implants placed in FFF or native bone (90.4% versus 83.5%, P =0.035). Radiotherapy is detrimental to implant survival rates when administered too soon, in high doses, and before tumor resection. A novel evidence-based clinical decision-making algorithm was presented for utilization when determining the optimal treatment order for HNC patients. The overall survival of dental prostheses is acceptable, reaffirming their role as a key component in rehabilitating HNC patients. Considerations must be made regarding RTX dosage, timing, and implant location to optimize survival rates and patient outcomes for improved functionality, aesthetics, and comfort.

Dental rehabilitation in irradiated oral cancer patients using patient-specific dental implants - Clinical outcome and oral health-related quality of life

INTRODUCTION

Dental rehabilitation in oral cancer patients is essential for good oral health-related quality of life (OHRQoL). Patient-specific dental implants are suitable for treating tumor-related bony defects, resulting in satisfactory OHRQoL. However, knowledge concerning the clinical outcome and OHRQoL following tumor irradiation is lacking.

MATERIAL AND METHODS

A retrospective analysis was carried out to evaluate clinical outcomes and OHRQoL in eight patients who received patient-specific dental implants and implant-supported dentures after surgical treatment for oral cancer with additional irradiation. OHRQoL assessment was performed using the German long version of the oral health impact profile (OHIP) questionnaire (OHIP-G53).

RESULTS

Clinical examination revealed successful dental rehabilitation in all the patients with only minor impairments. Restricted stability and function of implants were not observed. OHIP sum-scores of all the patients indicated acceptable OHRQoL, but this varied between patients treated in the upper or lower jaw. Single-item sum-scores concerning the adverse events "difficulty in chewing," "food catching," "sore jaw," "sore spots," and "unclear speech" were detected to be the worst, and pain-related OHIP dimensions demonstrated the highest scores (followed by functional limitation, physical disability, and psychosocial impact) with a worse OHRQoL following lower jaw treatment. Other dimension sum-scores were overall lower and nearly equally distributed in patients.

CONCLUSIONS

Dental rehabilitation of irradiated oral cancer patients using patient-specific dental implants may be suitable, leading to acceptable OHRQoL. However, implant insertion in the upper jaw seems to be more favorable. Further studies on patient-specific dental implants are warranted to validate the current results.

Reconstructive surgery and adjuvant radiotherapy for the multimodal approach in oral cancer: a single cancer centre experience

Introduction and importance

Ablative surgery for oral cancer, irrespective of the histological subtype, causes large tissue defects, functional and aesthetic damage. Microsurgical free flaps have been widely used in reconstruction after resection, with satisfactory success rates in conjunction with adjuvant radiotherapy (RT). This study aims to describe our clinical institutional experience based on the multimodal treatment performed in four cases diagnosed with oral squamous cell carcinoma with the use of different microvascular free flaps and RT.

Case series presentation

Four patients underwent reconstructive microsurgery after surgical resection of oral cancer, using three types of free flap: radial forearm fasciocutaneous, osteomyocutaneous fibular, and anterolateral thigh musculocutaneous flaps; RT was performed in Case 2 and Case 3. In the period of 3 years after microsurgical reconstruction and RT, flaps remain clinically stable without failure signs in full patients submitted to multimodal treatment.

Clinical discussion

After resection of oral carcinomas, extensive tissue defects can be successfully treated with reconstructive microsurgery using different types of microvascular free flaps. RT for locoregional control is a feasible option and did not seem to interfere with the survival of flaps.

Conclusion

An enhance long-term follow-up to assess overall and disease-free survival rates and quality of life must be carried out; however, cohort studies would be necessary for better understanding of the role of each treatment in the multimodal scheme.

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.

Cirurgia Guiada para Instalação de Implantes em Paciente Submetido à Radioterapia em Região de Cabeça e Pescoço

Introdução: O uso dos implantes osseointegrados para reabilitação de pacientes com dificuldade de adaptação de próteses convencionais mostra-se mais frequente a cada dia. Um grande grupo candidato à reabilitação com essa modalidade são os pacientes tratados para as neoplasias de cabeça e pescoço (CP). A irradiação na região de CP pode ser limitante para a instalação de implantes, porém a literatura apresenta evidências de técnicas e planejamentos favoráveis ao procedimento nesse grupo de pacientes. As técnicas menos traumáticas para intervenções na cavidade oral devem ser avaliadas, e os guias cirúrgicos para colocação de implantes podem ser aliados nesses procedimentos. Relato do caso: Paciente do sexo feminino, 64 anos, tratada com cirurgia, quimioterapia e radioterapia em cavidade oral para um carcinoma espinocelular (CEC) em língua e, em um segundo momento, diagnosticada e tratada com cirurgia para CEC em região de rebordo alveolar maxilar esquerdo por meio de hemipalatecmia, necessitava de reabilitação com implantes osseointegrados na região onde havia sido tratada com radiação primariamente. Realizou-se a cirurgia de colocação dos implantes com a tecnologia guiada para acarretar o mínimo trauma às estruturas bucais. Conclusão: O procedimento cirúrgico foi executado com sucesso. Atualmente, aguarda-se o período de osseointegração para a posterior reabilitação protética.

Dental implants in patients with head and neck cancer-A systematic review and meta-analysis of the influence of radiotherapy on implant survival

PURPOSE

The purpose of this meta-analysis was to compare implant survival in irradiated and non-irradiated bone and to investigate potential risk factors for implant therapy in oral cancer patients.

MATERIAL AND METHODS

An extensive search in the electronic databases of the National Library of Medicine was performed. Systematic review and meta-analysis were conducted according to PRISMA statement. The meta-analysis was performed for studies with a mean follow-up of at least three and five years, respectively.

RESULTS

The systematic review resulted in a mean overall implant survival of 87.8% (34%-100%). The meta-analysis revealed a significantly higher rate of implant failure in irradiated bone compared to non-irradiated bone (p < .00001, OR 1.97, CI [1.63, 2.37]). The studies also showed that implants placed into irradiated grafted bone were more likely to fail than those in irradiated native bone (p < .0001, OR 2.26, CI [1.50, 3.40]).

CONCLUSION

Even though overall implant survival was high, radiotherapy proves to be a significant risk factor for implant loss. Augmentation procedures may also increase the risk of an adverse outcome, especially in combination with radiotherapy.

CLINICAL RELEVANCE

The treatment of patients receiving radiotherapy of any form requires precise individual planning and a close aftercare. Implants should be placed in local bone rather than in bone grafts, if possible.

Survival of Dental Implants on Irradiated Jaws: A Systematic Review and Meta-analysis

Objectives

Dental implants play a significant role in functional rehabilitation of the oral cavity after debilitating jaw surgeries for oral cavity cancers followed by radiotherapy.

Design

The meta-analysis was done using Preferred Reporting Items for Systematic Review (PRISMA) guidelines published from January 1947 till August 2020. Twenty three articles consisting of 1246 participants with 4838 implants were included in our analysis.

Results

The mean age of the included participants was 51.4 years. 2186 and 1685 implants were placed on irradiated and non-irradiated jaws and showed a success rate of 82.47% and 89.37% respectively. Correspondingly, publication bias of p value = 0.2129 and p-value = 0.6525 was found by Egger's and Begg's test respectively for pooled data of 16 studies. The implant success rate of 70.4% on maxillary bone and 94.5% were observed on mandibular bone. Timing of implant placement and its influence on survival rate have resulted in a 75.5% survival rate of dental implants when placed primarily in comparison with 87.7% on delayed placement. The waiting interval of 14 months in delayed implant placement has shown better results.

Conclusion

Presence of radiotherapy does not play a significant role in the success rate of dental implants in oral cavity cancers. However, delayed implant placement may have a better chance of survival.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12663-022-01686-6.

Dental Implant Failure Risk in Post Oncological Patients, a Retrospective Study and Sapienza Head and Neck Unit Decisional Protocol- 7 Years of Follow-Up

(1) Background: Patients with head and neck cancer are treated by ablative surgery, radiotherapy, chemotherapy, or a combination of these. The side effects of cancer therapies can compromise conventional prosthesis rehabilitation; therefore, dental implants can result in a more effective solution. The aim of the study is to explain how to rehabilitate a patient that underwent head and neck cancer therapy. (2) Methods: This retrospective study conducted from 2015 to 2021 included 223 postoncological patients, aged between 32 and 80 years old. Eighteen patients did not proceed with any treatment, and two died. Therefore, 203 patients have been analyzed and rehabilitated following our decisional protocol, with a mean period of follow-up of 4 years. The implant placement was considered successful when a mean bone loss of 1.6 mm for the first year and a mean of 0.13 mm in subsequent years occurred (3) Results: A total of 161 patients were rehabilitated with a conventional prosthesis, 42 patients (F:M ratio 19:23) with an implant-supported prosthesis and a total of 200 implants were placed; 9 implants were lost (4.5% of 200 implants). Conclusions: The results confirmed that by following our protocol it is possible to obtain an acceptable rate of implant survival, considering the delicacy and complexity of post-oncological patients.

Survival rates of dental implants in patients with head and neck pathologies: 12-year single-operator study

OBJECTIVE

To evaluate the survival rates of dental implants placed in patients with head and neck pathologies treated with resective surgery with or without free flap reconstruction, radiotherapy alone, and/or chemotherapy.

STUDY DESIGN

In this study, we retrospectively analyzed the survival of intraoral dental implants placed by the same surgeon over a 12-year period from 2007 to 2019. These implants were followed up clinically and radiographically for a period of 36 months postoperatively and throughout the restorative phase.

RESULTS

A total of 190 patients with a total of 739 dental implants, comprising both intraoral and zygomatic implants, were included in this study. Overall, the dental implant survival rate was 95%, with a similar rate for dental implants placed in irradiated and nonirradiated bone (90% vs 93%). A lower implant survival rate was noted in implants placed in transplanted bone (79%). In cases of implant failure (n = 17), 35% (n = 6) of protheses survived and remained functional.

CONCLUSIONS

Our findings support the placement of dental implants in patients with benign and malignant pathologies of the head and neck to improve their quality of life. However, we highlight the need for careful surgical planning and placement by experienced clinicians.

Dental management in head and neck cancers: from intensity-modulated radiotherapy with photons to proton therapy

INTRODUCTION

Despite reduction of xerostomia with intensity-modulated compared to conformal X-ray radiotherapy, radiation-induced dental complications continue to occur. Proton therapy is promising in head and neck cancers to further reduce radiation-induced side-effects, but the optimal dental management has not been defined.

MATERIAL AND METHODS

Dental management before proton therapy was assessed compared to intensity-modulated radiotherapy based on a bicentric experience, a literature review and illustrative cases.

RESULTS

Preserved teeth frequently contain metallic dental restorations (amalgams, crowns, implants). Metals blur CT images, introducing errors in tumour and organ contour during radiotherapy planning. Due to their physical interactions with matter, protons are more sensitive than photons to tissue composition. The composition of restorative materials is rarely documented during radiotherapy planning, introducing dose errors. Manual artefact recontouring, metal artefact-reduction CT algorithms, dual or multi-energy CT and appropriate dose calculation algorithms insufficiently compensate for contour and dose errors during proton therapy. Physical uncertainties may be associated with lower tumour control probability and more side-effects after proton therapy. Metal-induced errors should be quantified and removal of metal restorations discussed on a case by case basis between dental care specialists, radiation oncologists and physicists. Metallic amalgams can be replaced with water-equivalent materials and crowns temporarily removed depending on rehabilitation potential, dental condition and cost. Implants might contraindicate proton therapy if they are in the proton beam path.

CONCLUSION

Metallic restorations may more severely affect proton than photon radiotherapy quality. Personalized dental care prior to proton therapy requires multidisciplinary assessment of metal-induced errors before choice of conservation/removal of dental metals and optimal radiotherapy.

Significance of site-specific radiation dose and technique for success of implant-based prosthetic rehabilitation in irradiated head and neck cancer patients-A cohort study

BACKGROUND

Radiotherapy aggravates implant-based prosthetic rehabilitation in patients with head and neck cancer.

PURPOSE

To evaluate the impact of radiation dose at implant and parotid gland site for prosthetic rehabilitation.

MATERIAL AND METHODS

The retrospective study includes 121 irradiated head and neck cancer patients with 751 inserted implants. Radiation doses on implant bed and parotid gland site were recorded by 3-dimensional modulated radiation plans. Implant success was clinically and radiographically evaluated according to modified Albrektsson criteria and compared to treatment- and patient-specific data.

RESULTS

Implant overall survival after 5 years was 92.4% with an implant success rate of 74.9%. Main reasons for implant failure were marginal bone resorption (20.9%), implant not in situ or unloaded (9.6%) and peri-implantitis (7.5%). A mean radiation dose of 62.6 Gy was applied with a mean parotid dose of 35 Gy. Modulating radiation techniques went along with lower grades of xerostomia (p < 0.001). At implant site mean doses of 57.5, 42.0, and 32.3 Gy were recorded for oral, oropharyngeal, and hypopharyngeal/laryngeal carcinoma, respectively. Implant success inversely correlated to radiation dose at implant site. Strong predictors for implant failure in uni- and multivariate analysis were implant-specific dose >50 Gy (HR 7.9), parotid dose >30 Gy (HR 2.3), bone (HR 14.5) and soft tissue (HR 4.5) transplants, bad oral hygiene (HR 3.8), nonmodulated radiation treatment planning (HR 14.5), and nontelescopic prosthetics (HR 5.2).

CONCLUSION

Radiotherapy impedes implant success in a dose-dependent manner at implant site. Modern radiation techniques effectively reduce xerostomia favoring implant-based prosthetic rehabilitation. Implantation in bone grafts is more critical and telescopic-retained overdentures should be preferred.

BIOMECHANICAL EVALUATION OF RECONSTRUCTED EXTENSIVE MANDIBULAR DEFECTS BY DIFFERENT MODELS USING FINITE ELEMENT METHOD

Rehabilitation of major mandibular defects after tumor resection has become a serious challenge for surgeons. In this research, four various models were designed to repair a critical mandibular lateral defect. Biomechanical behavior of the models was assessed by Finite Element Method. These models are including Fibular-Free Flap (FFF), Customized Prosthesis (CP), Tray Implant without Bone Graft (TI-wo-BG), and Tray Implant with Bone Graft (TI-w-BG). FFF is a subset of microvascular free flap technique in which some segments of patient’s fibula bone are used to restore mandibular defects. CP is a hollow and light prosthesis which is fabricated using Additive Manufacturing technology from Ti alloy powder. TI-wo-BG is similar to a crib which is designed according to the geometry of the patient’s mandible. TI-w-BG, in fact, is a TI-wo-BG which is filled with small cortico-cancellous chips in order to benefit potential profit of bone grafting. The chewing operation and loading on the mandible was simulated considering the three mandibular muscular forces including masseter, medial pterygoid, and temporalis.

The result of FEM analysis of TI-wo-BG and TI-w-BG showed that in both models, screw number 6 endured a strain of 5684 and 2852[Formula: see text][Formula: see text]m/m which exceeded pathological and mild overload risk, respectively. This may increase the probability of screw loosening and system failure. The results proved the stability of the FFF and CP models. In addition, it can be concluded that stress and strain on the screw’s interfaces can decrease by improving the plate and increasing the friction at the interface of plate, bone and screw.

Hyperbaric oxygen therapy for the placement of dental implants in irradiated patients: systematic review and meta-analysis

This study was a systematic review with meta-analysis to evaluate the influence of hyperbaric oxygen therapy (HBOT) on the survival of dental implants placed in patients who had had radiotherapy for cancer of the head and neck. A systematic literature search was conducted using the PubMed/Medline, Science Direct, Embase and the Cochrane Library, between January 1985 and July 2018. The study observed the PRISMA (Preferred Reporting Items for Systematic review and Meta-Analysis) declaration and norms, and the systematic review was duly recorded in the PROSPERO (International prospective register of systematic reviews) database. Inclusion and exclusion criteria were applied, and all articles were selected on the basis of PICO questions. The process of eligibility and quality evaluation yielded three studies for statistical analysis. Based on the survival rates, there was no evidence that the risk of an implant failing was different between the patients who received HBOT and those who did not. Moreover, the risk of an implant failing did not depend on the anatomical site. HBOT exerted no beneficial influence on the survival rates of implants placed in irradiated patients, and the risk of an implant failing did not depend on its location.

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.

Postimplantation radiation therapy in head and neck cancer patients: Literature review

There is no recommendation regarding the timing for implant surgery in patients with head and neck cancer (HNC) who require postoperative radiation therapy (RT). This systematic review focused on the literature about the outcomes of implants placed during ablative surgery in patients with HNC who underwent postoperative RT. Implants placed after radiation therapy and implants placed in reconstructed jaws were excluded. Four comparative studies involving 755 native mandible primary implants were analyzed. The survival rate with postimplantation RT was 89.6% vs 98.6% in patients with no additional radiation. The overall success of implant-retained overdenture in patients with RT performed postimplantation was 67.4% vs 93.1% in patients with implant surgery that was carried out 1 year after the completion of radiation therapy. Only five cases of osteoradionecrosis (ORN) of the jaw were reported. The outcomes for implant survival rates appear to be positive for irradiated implants.

Maxillofacial Rehabilitation With Zygomatic Implants in an Oncologic Patient: A Case Report

Tumor ablation results in significant sequelae in the appearance, function, and esthetics of a patient with cancer, especially resection for head and neck cancer. Reconstruction with local and microvascular flaps is a workable option; however, the esthetic results will occasionally be unfulfilling and inadequate for the rehabilitation of lost structures. Prosthetic rehabilitation with conventional and zygomatic implants can provide favorable and predictable long-term results. We report the clinical case of a 53-year-old female patient with adenoid cystic carcinoma (ACC). The treatment protocol included radical surgery, radiotherapy, and maxillofacial rehabilitation with conventional and zygomatic implants. Management of an ACC case requires a timely, radical, and multidisciplinary approach. In our patient, rehabilitation of masticatory function was accomplished in the immediate postoperative period and before radiotherapy. The rehabilitation of masticatory function improved the patient's systemic and nutritional status and her speech, with coverage of the esthetic defect. These outcomes reduced the psychological and emotional effects of tumor ablation.

Ability to Propose Optimal Prosthetic Rehabilitation can be Improved by Discussion between the Dentist and Radiation Oncologist Regarding Upstream Dosimetry

Objective Improvement of dental rehabilitation for patients who have undergone radiation therapy requires knowledge of the dose in the maxillary and mandible bones.

Materials and Methods Forty-three patients with head and neck cancers underwent evaluation for dental rehabilitation before radiation treatment dosimetry. The delivered dose to the maxilla and mandible was determined. From the dose data in the literature, three levels of risk of implant failure were defined. According to the delivered doses, the authors calculated the percentage of patients who could be fully rehabilitated with an implant, as proposed by the dentist before radiation planning.

Results Before dosimetry calculation, all of the completely edentulous arches and 94 partially edentulous (PESs) sextants could be optimally rehabilitated. After dose calculation, among the 14 arches of 7 patients who were completely edentulous, according to the mean and maximal delivered doses, 11 arches (78.6%) and 7 arches (50%) could receive an optimal prosthesis, respectively. For the three patients, who were PESs but with one arch that was completely edentulous, according to the mean and maximal delivered doses, one arch for each dose condition could receive an optimal prosthesis. Among the 94 PESs sextants, according to the mean and maximal delivered doses, 41 (43.6%) and 24 (25.5%) sextants could receive an optimal prosthesis, respectively.

Conclusion By determining the sites of implantation before dosimetry, the radiation oncologist could shield specified areas, potentially improving the possibilities for dental rehabilitation. The dialogue between the dentist and the radiation oncologist can improve the possibilities for implants and decrease the risk of unsafe implantation.

Systemic and local effects of radiotherapy: an experimental study on implants placed in rats

OBJECTIVES

Evaluate the modulating effect of ionizing radiation, blood cytokine levels, and bone remodeling of the interface around the implant to understand the radiation mechanisms which can impair the implants receptor site.

MATERIAL AND METHODS

Sixty rats were submitted to grade V titanium implants in the femurs and were divided into the following groups: no-irradiation (N-Ir): control group with implant only; early-irradiation (E-Ir): implant + irradiation after 24 h; late-irradiation (L-Ir): implant + irradiation after 4 weeks; and previous-irradiation (P-Ir): irradiation + implant after 4 weeks. The animals in the E-Ir, L-Ir, and P-Ir groups were irradiated in two fractional stages of 15 Gy. At 3 days, 2 weeks, and 7 weeks after the final procedure, five animals were randomly euthanized per group. Serum levels of TNF-ɑ, IL-1β, TGF-β, IL-6, M-CSF, and IL-10 were measured from blood collected prior to euthanasia using the ELISA test. The pieces containing the implants were subjected to immunohistochemical labeling using the tartrate acid resistant to phosphatase, osteocalcin, and caspase-3 markers and mCT. The ANOVA test was used for statistical analysis, and the Tukey multiple comparison test (p < 0.05) was applied.

RESULTS

The results indicated that ionizing radiation modifies the production of pro- and anti-inflammatory serum cytokines, the expression of proteins involved in bone remodeling and cellular apoptosis, as well as changes in bone formation.

CONCLUSIONS

The results suggests that a longer period between radiotherapy and implant placement surgery when irradiation occurs prior to implant installation would allow the recovery and renewal of bone cells and avoid future failures in osseointegration.

CLINICAL RELEVANCE

The search for modifications caused by ionizing irradiation in bone tissue can indicate the ideal period for implant placement without affecting the osseointegration process.

The influence of Cisplatin-based chemotherapy on the osseointegration of dental implants: An in vivo mechanical and histometrical study

OBJECTIVES

To evaluate the effect of Cisplatin on bone repair and mineralization around implants and on the mechanical properties of bone tissue.

MATERIALS AND METHODS

Forty-three Wistar rats were randomly divided into two groups: Cisplatin (CIS, medication) and control (CTL, placebo solution), administered once a week for 4 weeks. After 4 weeks, implants were installed in both tibiae metaphysis. After 30 and 60 days, the animals were sacrificed and their femurs and tibiae were removed. Femurs were subjected to mechanical tests and tibiae for removal torque, arrangement and distribution of collagen fibers, morphometrical analyses (bone tissue in contact with the implant surface [BIC] and areal fraction between implant threads occupied by bone tissue [BAFO]) and scanning electron microscopy to calcium and calcium/phosphorus analysis. Data were analyzed by ANOVA or MANOVA, and Tukey or Games-Howell post hoc tests, respectively (α = 0.05).

RESULTS

The CTL specimens had significantly higher values (0.0001 ≤ p≤0.036) of strength (N), removal torque (N/cm² ), %BIC, and %BAFO than CIS specimens, being their best results at day 60. No significant differences were found among the groups regarding the values of deformation, percentage of calcium, and calcium/phosphorus ratio. In CIS groups, there was a reduction in the organization of collagen at the bone/implant interface, resulting in a trabecular bone with thin trabeculae and birefringent collagen and irregular arrangement.

CONCLUSIONS AND CLINICAL IMPLICATIONS

Cisplatin interfered negatively in the repair and mineralization around dental implants, as well as on the quality of the bone tissue, mainly in the period of 30 days after the implant placement.

Are There Contraindications for Placing Dental Implants?

There are few absolute contraindications to dental implant placement. Relative contraindications include cognitive decline, American Society of Anesthesiology patient status IV or higher categories, or medical conditions that may jeopardize the life or lifespan of the patient. Precautions for placing dental implants should be viewed with respect to the evidence-based exposures that can contribute to risk of failure, including but not limited to local, behavioral, and medical factors. Risk for dental implant failure increases in association with (1) past history of periodontal disease, (2) bruxism, (3) smoking, and (4) radiation therapy.

Long-term implant failure in patients treated for oral cancer by external radiotherapy: a retrospective monocentric study

Introduction: The placement of dental implants in irradiated bone has allowed functional rehabilitation for many oral cancer patients. Nonetheless, there is only few data about implant failure in irradiated tissues and their consequences. This retrospective study aims to highlight the rate and circumstances of implant failure. Material and method: Patients treated with external radiotherapy for oral carcinoma and who received dental implants were included. Patients reconstructed with free bone flaps were excluded. Results: Eighteen patients were included. Forty implants were placed between 2004 and 2007, 8 failed, of whom one osteoradionecrosis was observed. Time interval between radiotherapy and implantation was 44.6 (6–182) months. Mean dose was 51.8 (50–66) Gy. Discussion: In the series, the implant failure rate is 20%, which corroborates the literature's data. Failures occur more often for doses over 50 Gy. The placement of dental implant in irradiated bone leads to soft tissue complications but also increases the risk of osteoradionecrosis. The recent reimbursement of dental implants in oral cancer patients by the National Social Health system will probably increase the indications. Multidisciplinary staffs should be aware of benefit/risk ratio for each patient.

Can gamma irradiation during radiotherapy influence the metal release process for biomedical CoCrMo and 316L alloys?

The extent of metal release from implant materials that are irradiated during radiotherapy may be influenced by irradiation-formed radicals. The influence of gamma irradiation, with a total dose of relevance for radiotherapy (e.g., for cancer treatments) on the extent of metal release from biomedical stainless steel AISI 316L and a cobalt-chromium alloy (CoCrMo) was investigated in physiological relevant solutions (phosphate buffered saline with and without 10 g/L bovine serum albumin) at pH 7.3. Directly after irradiation, the released amounts of metals were significantly higher for irradiated CoCrMo as compared to nonirradiated CoCrMo, resulting in an increased surface passivation (enhanced passive conditions) that hindered further release. A similar effect was observed for 316L showing lower nickel release after 1 h of initially irradiated samples as compared to nonirradiated samples. However, the effect of irradiation (total dose of 16.5 Gy) on metal release and surface oxide composition and thickness was generally small. Most metals were released initially (within seconds) upon immersion from CoCrMo but not from 316L. Albumin induced an increased amount of released metals from AISI 316L but not from CoCrMo. Albumin was not found to aggregate to any greater extent either upon gamma irradiation or in the presence of trace metal ions, as determined using different light scattering techniques. Further studies should elucidate the effect of repeated friction and fractionated low irradiation doses on the short- and long term metal release process of biomedical materials. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2673-2680, 2018.

Three-year Prospective Evaluation of Immediately Loaded Mandibular Implant Overdentures retained with Locator Attachments

INTRODUCTION

Immediate implant-loading protocol has progressed because of various clinical advantages offered by this treatment approach. However, available studies on edentulous patients are still few compared to those in which delayed implant-loading protocol was applied.

AIM

This prospective study was to evaluate the implant survival rate and the peri-implant tissue response in a group of patients who received two unsplinted immediately loaded dental implants in the mandibular anterior region to retain a complete overdenture using locator attachments.

MATERIALS AND METHODS

A total of 24 edentulous patients with a mean age of 63.4 years were involved in this study following certain inclusion criteria. All patients received a new set of complete dentures before implant positioning. Two Prima Connex tapered implants were put in the interforaminal area of the mandible with a flapless surgical procedure, and the prefabricated dentures were immediately retained with a zest locator attachment. Clinical and radiographic records of the patients were reviewed immediately after placement of the implant, at 3 months, and at 1, 2, and 3 years following fixture installation. The obtained data were analyzed using paired samples t-test and the Wilcoxon signed-rank test at 0.05 significance level.

RESULTS

At 3 years, all implants had osseointegrated with a 100% survival rate. In addition, the total mean marginal bone change was -0.89 ± 0.14 mm, and the mean periotest value was -7.631 ± 0.921.

CONCLUSION

Results of this study propose that immediate loading of mandibular implant overdentures that are retained with locator attachments was a feasible treatment alternative for this particular group of patients.

CLINICAL SIGNIFICANCE

Immediate implant- loading of mandibular implant overdentures that are retained with locator attachments is a reliable treatment option Keywords: Immediate implant loading, Implant survival rate, Locator attachments, Overdenture.

Survival/Success of Dental Implants with Acid-Etched Surfaces: A Retrospective Evaluation After 8 to 10 Years

Abstract The aim of this study was to conduct a retrospective evaluation of the survival and success rates of dental implants with acid-etched surfaces after 8-10 years of function. Forty-four patients who received 183 implants 8-10 years ago were evaluated. Clinical examinations were performed around the implants and natural teeth. The following parameters were measured: visible plaque index (VPI), marginal bleeding index (MBI), probing depth (PD), bleeding on probing (BOP) and clinical attachment level (CAL). To considerer an implant as a success case, the following criteria were considered: absence of peri-implant infection and suppuration, absence of implant mobility, absence of persistent pain and dysesthesia and absence of radiolucency around the implant. Overall, 178 implants were categorized as surviving (97.3%), 155 were categorized as successful (84.7%), 5 implants (2.7%) were lost (1 in the maxilla and 4 in the mandible), and 3 implants were not under functional load (2.0 %). 20 implants were diagnosed with peri-implantitis. Thus, the survival rate was 97% and the success rate was 85%. In conclusion, implants with acid-etched surfaces showed high survival and success rates after a period of 8 to 10 years of function.

Evaluation of Highly Porous Dental Implants in Postablative Oral and Maxillofacial Cancer Patients: A Prospective Pilot Clinical Case Series Report

PURPOSE

The aim of this study was to evaluate the clinical efficacy of new porous tantalum trabecular metal (PTTM)-enhanced titanium dental implants used for the prosthodontic rehabilitation of postablative cancer patients. First-year interim results of a prospective clinical case series are presented.

MATERIALS AND METHODS

A total of 25 PTTM-enhanced titanium implants were placed in both maxillas and mandibles of 6 patients, who met specific inclusion criteria. Resonance frequency analysis was conducted, and implant stability was recorded in Implant Stability Quotient (ISQ) values at implant placement and after 2, 4, 6, and 12 months of functional loading. Bone levels were calculated by digitally measuring the distance from the implant shoulder to the first bone-to-implant on periapical radiographs taken at surgery and after 2, 4, 6, and 12 months of functioning.

RESULTS

Cumulative implant survival was 100% (n = 25/25). At implant placement and the 2-, 4-, 6- and 12-month monitoring appointments, mean ISQ values were 72.14 ± 5.61 (range = 50-81), 64.39 ± 8.12 (range = 44-74), 74.26 ± 7.14 (range = 44-74), 76.84 ± 7.65 (range = 60-83), and 78.13 ± 4.14 (range = 64-84), respectively, and mean crestal marginal bone loss was 0.19 ± 0.25, 0.22 ± 0.4, 0.3 ± 0.46, and 0.57 ± 0.62 mm, respectively.

CONCLUSIONS

PTTM-enhanced dental implants were clinically effective in the prosthetic rehabilitation of postoncological patients. Larger long-term follow-up studies will help to evaluate clinical efficacy of PTTM dental implants.

Implant osseointegration in irradiated bone: an experimental study

BACKGROUND AND OBJECTIVES

The aim of this study was to evaluate the effect of radiotherapy on the osseointegration of dental implants in the tibia and the action of platelet-rich plasma (PRP) as an adjuvant therapy.

MATERIAL AND METHODS

A total of 18 rabbits received two implants in each tibial epiphysis, totalizing 72 implants. The control group (group I) was composed by six rabbits and did not receive radiotherapy. The test groups (II and III) received a single dose of 1727 cGy. Group II was composed by six irradiated animals and group III by six animals that received irradiation and PRP during implant placement. The implant success rate, the bone-implant contact (BIC), and the bone volume were analyzed.

RESULTS

There was no osseointegration in four of the implants, three in group II and one in group III. Total BIC was significantly higher in group I, when compared to the other groups. There was a significant difference of osteoid BIC only between irradiated animals (group II, 8.5%; group III, 4.7%; p = 0.001). On the other hand, the mineralized BIC was significantly higher in group I. Furthermore, group II had a lower mineralized BIC than group III (p = 0.002). Bone volume was higher in the control group (41.3%), followed by group III (33.4%) and II (25.1%), with differences between groups I and II (p = 0.001) and groups II and III (p = 0.022).

CONCLUSIONS

The present study showed that both the bone volume and BIC were higher in the control group. However, the failure rates of the implants were low in both irradiated groups. The PRP was a positive adjuvant in the osseointegration process.

Postradiotherapy Dental Implant Insertion Into Bone Grafts Harvested From Nonirradiated Tissue: Case Reports

BACKGROUND

Prostheses and dental implants are often used to aid oral rehabilitation after surgery (with/without radiotherapy) for oral cancer. However, some studies have reported that the insertion of dental implants into irradiated bone results in a higher frequency of implant failure than the insertion of such implants in nonirradiated bone.

MATERIALS AND METHODS

This report describes the cases of 4 patients with oral cancer who underwent surgery and radiotherapy (total dose: 50-86 Gy) and then had dental implants inserted within the irradiated area. In each case, an ilium bone graft or a latissimus dorsi myocutaneous flap containing scapular bone was transferred to the dental implant site before the insertion of the implants.

RESULTS

Twenty-three implants were inserted. After loading, 2 implants were lost, and 21 remained stable.

CONCLUSION

In patients who have undergone radiotherapy for oral cancer, transferring bone grafts harvested from nonirradiated tissue to the irradiated site before implant insertion might help to improve dental implant survival rates.

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

Objectives

To explore the current literature of the survival of dental implants in irradiated head and neck cancer patients considering the role of implant location, bone augmentation, dose of radiation and timing of implant placement.

Study Design

Pubmed search was conducted to identify articles published between January 2000 and December 2014 and presenting data of dental implant survival with radiotherapy in head and neck cancer patients. Studies on animal subjects and craniofacial implants were excluded.

Results

18 articles out of 27 were eligible for inclusion in this systematic review. 12 out of 18 studies reported favorable outcome of dental implants and radiotherapy with survival rates between 74.4% and 97%. Seven out of ten studies comparing the survival rates according to site of implant placement reported that implants were found to osseointegrate with greater success in the irradiated mandible than irradiated maxilla. 5 studies which compared implant survival in irradiated native bone versus irradiated grafted bone reported that irradiated grafted bone showed a significantly reduced dental implant survival rate in comparison to irradiated native bone. 6 out of 18studies in which radiation doses exceeded 70 Gy reported lower survival rates of dental implants in comparison to the studies in which radiation doses were ≤70Gy. Higher survival rates were reported in 2 studies in which implants placement was before radiotherapy in comparison to the remaining 16 studies in which implants placement was after radiotherapy.

Conclusions

Dental implants may be affected by radiotherapy especially when they are placed in maxilla, in grafted bone, or after radiation, however, they remain a functional option for rehabilitation of head and cancer patients. More Prospective cohort studies and randomized controlled trails are still needed to draw more evidence based conclusions.

Key words:Dental implants, implant survival, radiotherapy, head and neck cancer.

Assessment of the Survival of Dental Implants in Irradiated Jaws Following Treatment of Oral Cancer: A Retrospective Study

BACKGROUND

In patients undergoing head and neck surgery for various pathologic conditions, implants are one of the best restorative options and are increasing widely used. Therefore, we evaluated the success of dental implants in the irradiated jaws of patients following treatment of oral cancer oral cancer treated patients.

MATERIALS AND METHODS

Data of oral cancer treated patients was collected retrospectively from 2002 to 2008. We took 46 oral cancer treated patients in which implants were placed in irradiated jaws for rehabilitation.

RESULTS

It was found that out of 162 dental implants placed, 52 failed. Furthermore, there was no variation in the implant survival rate in between both the jaws. Radiation dose of <50 Gy units also showed significantly increased amount of implant survival rate.

CONCLUSIONS

Implant survival is multifactorial and depends upon a number of factors like level of radiation exposure in that area, time gap between last radiation doses etc., Further research is required in this field to improve the esthetics and quality of life of cancer treated patients.

Pathological mandibular fracture: A severe complication of periimplantitis

Nowadays, dental implant treatment is a very common option for patients even in medical compromised conditons. Some complications related to them have been described. Periimplantitis (PI) is one of the biggest concerns complications of these kind of treatments, probably has a multifactorial aethiology. Usually the consequences of PI are the loss of the implants and prostheses, expenses of money and time for dentists and patients. Very often PI implies the necesity of repeating the treatment . Pathological mandibular fracture due to PI is a severe but infrequent complication after dental implant treatment, especially after PI. In this study we present three cases of mandibular pathologic fractures among patients with different medical and dental records but similar management: two of them had been treated years ago of oral squamous cell carcinoma with surgery and radiotherapy, the other patient received oral bisphosphonates for osteoporosis some years after implantation. We analized the causes, consequences and posible prevention of these fractures as well as the special features of this kind of mandibular fractures and the different existing treatments. Key words:Periimplantitis, pathological mandibular fracture, mandibular atrophy, bicortical implants.

Dental implants in irradiated versus nonirradiated patients: A meta-analysis

The purpose of the present meta-analysis was to test the null hypothesis of no difference in dental implant failure rates, postoperative infection, and marginal bone loss for patients being rehabilitated by dental implants and being previously irradiated in the head and neck region versus nonirradiated patients against the alternative hypothesis of a difference. The study suggests that irradiation negatively affects the survival of implants, as well as the difference in implant location (maxilla vs mandible), but there is no statistically significant difference in survival when implants are inserted before or after 12 months after radiotherapy. The study failed to support the effectiveness of hyperbaric oxygen therapy in irradiated patients. It was observed that there was a tendency of lower survival rates of implants inserted in the patients submitted to higher irradiation doses. The results should be interpreted with caution because of the presence of uncontrolled confounding factors in the included studies.

[Dental state in patients with head and neck cancers]

In France, in 2005, there were approximately 16,000 new cases of head and neck cancer. These cancers have an unfavourable prognosis: the survival rates at 3 and 10 years are 50% and 10% respectively. The consumption of alcohol and tobacco is the most important risk factor; in some countries HPV infection was identified as a risk factor of head and neck tumours. Furthermore, a poor oral hygiene seems to raise this risk. We found many decay and periodontium problems in patients with an upper aerodigestive tract cancer. An evaluation of dental state is necessary before any cancer treatment. Treatments by radiotherapy engender noxious effects: hypocellular, hypovascularization, hypoxie of the irradiated tissues, which lead to immediate and chronically oral complications such as mucositis, fibrosis, xerostomia, decay, or osteoradionecrosis. An oral follow-up of these patients can prevent these complications, or reduce the severity of oral complications, and promote a good oral state.

Survival of dental implants in patients with oral cancer treated by surgery and radiotherapy: a retrospective study

Background

The aim of this retrospective study was to evaluate the survival of dental implants placed after ablative surgery, in patients affected by oral cancer treated with or without radiotherapy.

Methods

We collected data for 34 subjects (22 females, 12 males; mean age: 51 ± 19) with malignant oral tumors who had been treated with ablative surgery and received dental implant rehabilitation between 2007 and 2012. Postoperative radiation therapy (less than 50 Gy) was delivered before implant placement in 12 patients. A total of 144 titanium implants were placed, at a minimum interval of 12 months, in irradiated and non-irradiated residual bone.

Results

Implant loss was dependent on the position and location of the implants (P = 0.05–0.1). Moreover, implant survival was dependent on whether the patient had received radiotherapy. This result was highly statistically significant (P < 0.01). Whether the implant was loaded is another highly significant (P < 0.01) factor determining survival. We observed significantly better outcomes when the implant was not loaded until at least 6 months after placement.

Conclusions

Although the retrospective design of this study could be affected by selection and information biases, we conclude that a delayed loading protocol will give the best chance of implant osseointegration, stability and, ultimately, effective dental rehabilitation.

Key systemic and environmental risk factors for implant failure

Dental implants are an important treatment option for patients interested in replacing lost or missing teeth. Although a robust body of literature has reviewed risk factors for tooth loss, the evidence for risk factors associated with dental implants is less well defined. This article focuses on key systemic risk factors relating to dental implant failure, as well as on perimucositis and peri-implantitis.

Intra- and extraoral prostheses retained by zygoma implants following resection of the upper lip and nose

Upper lip cancers are infrequent lesions, being aggressive unless diagnosed and treated early. After the surgical resection, maxillofacial defects require special care in rehabilitation. This article describes the maxillofacial rehabilitation of an edentulous patient diagnosed with upper lip squamous cell carcinoma. The treatment consisted of a large amount of upper lip and nose tissue resection, followed by chemoradiotherapy. After the first surgical healing, zygoma implants were inserted in a two-step procedure. The maxillary and nasal prostheses were installed and fixed by a titanium framework. After 6 years follow-up, no recurrences were observed, and the patient did not develop metastases. Tissues around implants were in good health, and the prostheses remained well-fitted. The use of implant-retained prostheses improved the quality of life, and the patient was extremely satisfied with the final result. The implant-retained prostheses are well accepted by the patient, improving comfort and safety during function while recovering her esthetic apperance.