Benefits of dental implants installed during ablative tumour surgery in oral cancer patients: a prospective 5-year clinical trial

Oral Surgery and Osteoradionecrosis in Patients Undergoing Head and Neck Radiation Therapy: An Update of the Current Literature

Osteoradionecrosis (ORN) is a serious long-term complication of head and neck radiotherapy (RT), which is often triggered by dental extractions. It results from avascular aseptic necrosis due to irradiated bone damage. ORN is challenging to treat and can lead to severe complications. Furthermore, ORN causes pain and distress, significantly reducing the patient's quality of life. There is currently no established preventive strategy. This narrative review aims to provide an update for the clinicians on the risk of ORN associated with oral surgery in head and neck RT patients, with a focus on the timing suitable for the oral surgery and possible ORN preventive treatments. An electronic search of articles was performed by consulting the PubMed database. Intervention and observational studies were included. A multidisciplinary approach to the patient is highly recommended to mitigate the risk of RT complications. A dental visit before commencing RT is highly advised to minimize the need for future dental extractions after irradiation, and thus the risk of ORN. Post-RT preventive strategies, in case of dento-alveolar surgery, have been proposed and include antibiotics, hyperbaric oxygen (HBO), and the combined use of pentoxifylline and tocopherol ("PENTO protocol"), but currently there is a lack of established standards of care. Some limitations in the use of HBO involve the low availability of HBO facilities, its high costs, and specific clinical contraindications; the PENTO protocol, on the other hand, although promising, lacks clinical trials to support its efficacy. Due to the enduring risk of ORN, removable prostheses are preferable to dental implants in these patients, as there is no consensus on the appropriate timing for their safe placement. Overall, established standards of care and high-quality evidence are lacking concerning both preventive strategies for ORN as well as the timing of the dental surgery. There is an urgent need to improve research for more efficacious clinical decision making.

Site-specific radiation dosage and implant survival in oral cancer patients: A cohort study

OBJECTIVES

We assessed the radiation dosages (Dmean ) on implant regions to identify the threshold for implant loss in patients with an intraoral malignancy treated with dental implants to support a mandibular denture during ablative surgery before volumetric-modulated arc therapy (VMAT).

MATERIALS AND METHODS

Data was collected prospectively from 28 patients treated surgically for an intraoral malignancy, followed by postoperative radiotherapy (VMAT) and analyzed retrospectively. Patients received 2 implants in the native mandible during ablative surgery. Implant-specific Dmean values were retrieved from the patients' files. Radiographic bone loss was measured 1 year after implant placement and during the last follow-up appointment. Implant survival was analyzed with the Kaplan-Meier method. Univariate logistic regression and Cox-regression analyses were performed to investigate the effect of increasing implant-specific radiation dosages on implant loss.

RESULTS

Five out of 56 placed implants were lost during follow-up (median 36.0 months, IQR 39.0). Radiographically, peri-implant bone loss occurred in implants with a Dmean  > 40 Gy. Implant loss occurred only in implants with a Dmean  > 50 Gy.

CONCLUSION

An implant-specific Dmean higher than 50 Gy is related to more peri-implant bone loss and, eventually, implant loss.

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.

Clinical performance of different types of dental prosthesis in patients with head and neck tumors-a retrospective cohort study

OBJECTIVES

To investigate how different types of dental prosthesis perform in patients with head and neck tumors.

MATERIALS AND METHODS

In this retrospective clinical cohort study, the impact of different patient-related factors was analyzed as influencing factors on the survival probability of dental prosthesis using Kaplan-Meier estimate. For analysis, the dental prosthesis was divided into groups: group 1 (fixed dental prosthesis), group 2 (removable dental prosthesis), group 3 (implant-supported dental prosthesis), and group 4 (prostheses anchored using wrought wire clasps and obturators). The incidental aftercare measures were also evaluated.

RESULTS

Two hundred seventy-nine restorations were observed (mean observation: 2.7 ± 3.0 years, max.14.8 years) out of which 49 (17.6%) had to be replaced during the observation. After 5 years, 100% of group 1 restorations, 79.9% of group 2 restorations, 91.4% of group 3 restorations, and 30% of group 4 restorations were still functional. Four hundred eighty-eight dental implants were observed, of which 77 (15.8%) failed.

CONCLUSIONS

Groups 1, 2, and 3 restorations showed good survival times after 5 years in function, whereas group 4 presented the worst survival times. Group 2 restorations showed the highest amount of necessary aftercare measures.

CLINICAL RELEVANCE

The current investigation shows that groups 1, 2, and 3 restorations should be preferred in the prosthetic treatment planning of patients with head and neck tumors. A treatment with group 4 restorations should only be considered if no other prosthetic treatment is possible or as temporary treatment.

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.

Clinical long-term and patient-reported outcomes of dental implants in oral cancer patients

BACKGROUND AND PURPOSE

The aim of this clinical study was to investigate the clinical long-term and patient-reported outcome of dental implants in patients with oral cancer. In addition, analysis of the influence of radiation therapy, timing of implant insertion, and augmentation procedures on implant survival was performed.

MATERIAL AND METHODS

This retrospective study investigated the clinical outcome of 711 dental implants in 164 oral cancer patients, inserted by experienced surgeons of the Department of Oral and Maxillofacial Surgery, University Medical Center Mainz, Germany. Oral health-related quality of life (OHRQoL) was evaluated.

RESULTS

Cumulative 5-year and 10-year implant survival rates for all included implants were 87.3% and 80.0%. Implants placed straight after ablative surgery (primary implant placement) and implants placed after completing the oncologic treatment (secondary implant placement) showed a comparable implant survival (92.5% vs. 89.5%; p = 0.635). Irradiation therapy had no significant influence on implant survival of secondary placed implants (p = 0.929). However, regarding implant site (native bone vs. augmented bone) and radiation therapy (non-irradiated bone vs. irradiated bone), implants inserted in irradiated bone that received augmentation procedures showed a statistically significant lower implant survival (p < 0.001). Patients reported a distinct improvement in OHRQoL.

CONCLUSIONS

Promising long-term survival rates of dental implants in patients after treatment of oral cancer were seen. In addition, patients benefit in form of an improved OHRQoL. However, bone augmentation procedures in irradiated bone may result in an impaired implants' prognosis.

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.

Influence of implant-specific radiation doses on peri-implant hard and soft tissue: An observational pilot study

OBJECTIVES

The aim of this study was to investigate the influence of real implant-bed-specific radiation doses on peri-implant tissue health in head and neck cancer (HNC) patients after radiotherapy.

MATERIAL AND METHODS

Specific radiation doses in the area of 81 implants, in 15 irradiated HNC patients, were analyzed by matching data from the radiotherapy planning system with those of three-dimensional follow-up scans after implantation. Peri-implant bone resorption was measured radiographically after 1 and 3 years, and peri-implant tissue health was evaluated clinically. Individual parameters, such as age, gender, and localization, regarding the implant-specific radiation dose distribution were analyzed statistically.

RESULTS

The mean implant-bed-specific radiation dose was high, with 45.95 Gy to the mandible and 29.02 Gy to the maxilla, but significantly lower than the mean total dose to the tumor bed. Peri-implant bone resorption correlated with local inflammation and plaque. After 1 year, women temporarily showed significantly more bone loss than men and implant-specific radiation dose had a significant impact on peri-implant bone loss after 3 years.

CONCLUSIONS

The presented method is a feasible option to define precise implant-bed-specific radiation doses for research or treatment planning purposes. Implant-based dental restoration after radiotherapy is a relatively safe procedure, but a negative radiation dose-dependent long-term effect on peri-implant bone resorption calls for interdisciplinary cooperation between surgeons and radio-oncologists to define high-risk areas.

European white paper: oropharyngeal dysphagia in head and neck cancer

Purpose

To develop a European White Paper document on oropharyngeal dysphagia (OD) in head and neck cancer (HNC). There are wide variations in the management of OD associated with HNC across Europe.

Methods

Experts in the management of specific aspects of OD in HNC across Europe were delegated by their professional medical and multidisciplinary societies to contribute to this document. Evidence is based on systematic reviews, consensus-based position statements, and expert opinion.

Results

Twenty-four sections on HNC-specific OD topics.

Conclusion

This European White Paper summarizes current best practice on management of OD in HNC, providing recommendations to support patients and health professionals. The body of literature and its level of evidence on diagnostics and treatment for OD in HNC remain poor. This is in the context of an expected increase in the prevalence of OD due to HNC in the near future. Contributing factors to increased prevalence include aging of our European population (including HNC patients) and an increase in human papillomavirus (HPV) related cancer, despite the introduction of HPV vaccination in various countries. We recommend timely implementation of OD screening in HNC patients while emphasizing the need for robust scientific research on the treatment of OD in HNC. Meanwhile, its management remains a challenge for European professional associations and policymakers.

Biomechanical and morphological changes produced by ionizing radiation on bone tissue surrounding dental implant

Objective:

This study analyzed the effect of ionizing radiation on bone microarchitecture and biomechanical properties in the bone tissue surrounding a dental implant.

Methodology:

Twenty rabbits received three dental morse taper junction implants: one in the left tibia and two in the right tibia. The animals were randomized into two groups: the nonirradiated group (control group) and the irradiated group, which received 30 Gy in a single dose 2 weeks after the implant procedure. Four weeks after the implant procedure, the animals were sacrificed, and the implant/bone specimens were used for each experiment. The specimens (n=10) of the right tibia were examined by microcomputed tomography to measure the cortical volume (CtV, mm³), cortical thickness (CtTh, mm) and porosity (CtPo, %). The other specimens (n=10) were examined by dynamic indentation to measure the elastic modulus (E, GPa) and Vickers hardness (VHN, N/mm²) in the bone. The specimens of the left tibia (n=10) were subjected to pull-out tests to calculate the failure load (N), displacement (mm) up to the failure point and interface stiffness (N/mm). In the irradiated group, two measurements were performed: close, at 1 mm surrounding the implant surface, and distant, at 2.5 mm from the external limit of the first measurement. Data were analyzed using one-way ANOVA, Tukey’s test and Student’s t-test (α=0.05).

Results:

The irradiated bone closer to the implant surface had lower elastic modulus (E), Vickers hardness (VHN), Ct.Th, and Ct.V values and a higher Ct.Po value than the bone distant to the implant (P<0.04). The irradiated bone that was distant from the implant surface had lower E, VHN, and Ct.Th values and a higher Ct.Po value than the nonirradiated bone (P<0.04). The nonirradiated bone had higher failure loads, displacements and stiffness values than the irradiated bone (P<0.02).

Conclusion:

Ionizing radiation in dental implants resulted in negative effects on the microarchitecture and biomechanical properties of bone tissue, mainly near the surface of the implant.

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.

Mandibular dental implant placement immediately after teeth removal in head and neck cancer patients

BACKGROUND

Little is known about immediate implant placement in head and neck cancer patients. We studied implant survival and functional outcomes of overdentures fabricated on implants placed immediately after removal of the lower dentition during ablative surgery or preceding primary radiotherapy (RT).

METHODS

Inclusion criteria were primary head and neck cancer, dentate lower jaw, and indication for removal of remaining teeth. Two implants to support a mandibular overdenture were placed immediately after extraction of the dentition during ablative surgery, or prior to starting primary radiotherapy. Standardized questionnaires and clinical assessments were conducted (median follow-up 18.5 months, IQR 13.3).

RESULTS

Fifty-eight implants were placed in 29 patients. Four implants were lost (implant survival rate 93.1%). In 9 patients, no functional overdenture could be made. All patients were satisfied with their dentures.

CONCLUSIONS

Combining dental implant placement with removal of remaining teeth preceding head neck oncology treatment results in a favorable treatment outcome.

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.

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.

Effects of ionizing irradiation and interface backscatter on human mesenchymal stem cells cultured on titanium surfaces

Radiotherapy to the head and neck region negatively influences the osseointegration and survival of dental implants. The effects of cobalt 60 (⁶⁰ Co) ionizing radiation and the impact of backscatter rays were investigated on human mesenchymal stem cells cultured on titanium surfaces. Bone marrow-derived human mesenchymal stem cells were seeded on titanium (Ti), fluoride-modified titanium (TiF), and tissue culture plastic. Cells were exposed to ionizing γ-radiation in single doses of 2, 6, or 10 Gy using a ⁶⁰ Co source. Density and distribution of cells were evaluated using confocal laser-scanning microscopy, 21 d post-irradiation. Lactate dehydrogenase concentration and the levels of total protein and cytokines/chemokines were measured in the cell-culture medium on days 1, 3, 7, 14, and 21 post-irradiation. Unirradiated cells were used as the control. Irradiation had no effect on cell viability, collagen and actin expression, or cell distribution, but induced an initial increase in the secretion of interleukin (IL)-6, IL-8, monocyte chemotactic protein 1 (MCP-1), and vascular endothelial growth factor (VEGF), followed by a decrease in secretion after 3 or 7 d. Irradiation resulted in secretion of a lower amount of all analytes examined compared with controls on day 21, irrespective of radiation dose and growth surface. Backscattering from titanium did not influence the cell response significantly, suggesting a clinical potential for achieving successful osseointegration of dental implants placed before radiotherapy.

Masticatory function and related factors after oral oncological treatment: A 5-year prospective study

BACKGROUND

Chewing ability is often compromised in patients with oral cancer. The aim of this study was to identify which factors affect masticatory performance in these patients.

METHODS

Patients with primary oral cancer were assessed for up to 5 years after primary treatment. Healthy controls were assessed once. A mixed-model analysis was performed, with masticatory performance as outcome measure.

RESULTS

A total of 123 patients were included in the study. Factors positively associated with masticatory performance were number of occlusal units (OU), having functional dentures, and maximum mouth opening (MMO). The impact of tumor location and maximum bite force (MBF) differed per assessment moment. Masticatory performance declined for up to 1 year but recovered at 5 years after treatment.

CONCLUSION

Masticatory performance in patients treated for oral cancer is affected by MBF, MMO, number of OU, and dental status. These should be the focus of posttreatment therapy.

The use of dental implants, cast bars and sleeve overdentures in oral cancer patients

Surgical resection of an oral tumour (and the associated free flap reconstruction) can significantly alter the oral anatomy. The lack of sulcus depth, alveolar ridge, presence of a mobile flap and limited tongue movement can make it impossible for patients to control a removable prosthesis. To help this cohort of patients, dental implants can be invaluable. The Oral Rehabilitation Team at Central Manchester University Dental Hospital have used dental implants to rehabilitate oral cancer patients for over thirty years. After their resective surgery, a number of patients were dentally rehabilitated with a laboratory-made, precious metal-alloy bar supported by at least four dental implants. A metal-alloy under-sleeve retained overdenture was then provided to fit over the milled bar. The majority of the 50 patients in this case series had tumours in the anterior floor of the mouth. It was noted that 76% of the patients received a rim resection and were reconstructed with a fasciocutaneous, soft tissue free flap. Six percent of patients received a segmental resection and were reconstructed with either a fibular or deep circumflex iliac artery free flap. The dental implants and sleeve overdentures had a survival rate of 100%. None of the dentures lost retention, implying that the frictional grip between the overcasting and the milled bar was sufficient to appease the retention demands of this cohort. However, 10% of patients encountered complications. This would suggest a success (or complication free) rate of 90% for this cohort of 50 oncology patients. This would still imply that milled bars/sleeve overdentures carry a relatively low maintenance burden and may be a useful treatment option for oral cancer patients.

Using PROMs to guide patients and practitioners through the head and neck cancer journey

The measurement of patient-reported outcome measures (PROMs) following head and neck cancer (HNC) has the capacity to substantially enhance the care of patients and their care-givers following the diagnosis and treatment of HNC. Literature concerning PROMs has increased exponentially in the past 2 decades, producing a vast array of data upon which the multidisciplinary team can reflect. For this review, “Handle On QOL” has been used as a source of references to illustrate the points raised. PROMs are contextualized by considering the clinically-distinct key stages that cancer patients endure: diagnosis, treatment, acute toxicity, early recovery, late effects, recurrence, and palliation. The PROMs are considered in six main categories: 1) those addressing cornucopia of issues not specific to cancer; 2) those addressing issues common to all cancers; 3) questionnaires with items specific to HNC; 4) questionnaires that focus on a particular aspect of head and neck function; 5) those measuring psychological concerns, such as depression, anxiety, or self-esteem; and 6) item prompt lists. Potential benefits of PROMs in clinical practice are discussed, as are barriers to use. The way forward in integrating PROMs into routine HNC care is discussed with an emphasis on information technology.

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.

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.

Smoking, radiotherapy, diabetes and osteoporosis as risk factors for dental implant failure: a meta-analysis

BACKGROUND

There are conflicting reports as to the association between smoking, radiotherapy, diabetes and osteoporosis and the risk of dental implant failure. We undertook a meta-analysis to evaluate the association between smoking, radiotherapy, diabetes and osteoporosis and the risk of dental implant failure.

METHODS

A comprehensive research on MEDLINE and EMBASE, up to January 2013, was conducted to identify potential studies. References of relevant studies were also searched. Screening, data extraction and quality assessment were conducted independently and in duplicate. A random-effects meta-analysis was used to pool estimates of relative risks (RRs) with 95% confidence intervals (CIs).

RESULTS

A total of 51 studies were identified in this meta-analysis, with more than 40,000 dental implants placed under risk-threatening conditions. The pooled RRs showed a direct association between smoking (n = 33; RR = 1.92; 95% CI, 1.67-2.21) and radiotherapy (n = 16; RR = 2.28; 95% CI, 1.49-3.51) and the risk of dental implant failure, whereas no inverse impact of diabetes (n = 5; RR = 0.90; 95% CI, 0.62-1.32) on the risk of dental implant failure was found. The influence of osteoporosis on the risk of dental implant failure was direct but not significant (n = 4; RR = 1.09; 95% CI, 0.79-1.52). The subgroup analysis indicated no influence of study design, geographical location, length of follow-up, sample size, or mean age of recruited patients.

CONCLUSIONS

Smoking and radiotherapy were associated with an increased risk of dental implant failure. The relationship between diabetes and osteoporosis and the risk of implant failure warrant further study.