Table of Contents
- Key Points
- Background: Why This Research Matters
- How the Research Was Conducted
- How Studies Were Selected
- Characteristics of the Included Reviews
- Key Finding: Implant Survival in Irradiated vs. Non-Irradiated Patients
- Key Finding: Upper Jaw vs. Lower Jaw in Irradiated Patients
- Key Finding: Grafted Bone vs. Native Bone, Radiation Dose, and Timing
- Methodological Quality of the Included Reviews
- Clinical Implications: What This Means for Patients
- Limitations: What the Study Could Not Prove
- Recommendations
- Frequently Asked Questions
- Source Information
Key Points
- Across 48,563 implants, survival was 81.52% in irradiated bone versus 94.64% in non-irradiated bone, a difference supported by 11 meta-analyses.
- In irradiated patients, upper-jaw implants survived at 79.04% versus 93.55% for lower-jaw implants, based on 3,378 implants.
- Irradiated native bone showed 87.06% implant survival versus 82.21% in irradiated grafted bone, though one meta-analysis found no significant difference.
- One meta-analysis found a non-significant tendency toward higher survival with lower radiation dose: 90.01% versus 82.05% for higher dose.
- All 11 included systematic reviews had critically low methodological quality, so the authors urge caution and call for further well-designed clinical studies.
Background: Why This Research Matters
Dental implants that fuse with the jawbone (osseointegrated dental implants) are widely used. They can be a safe treatment option for patients who have lost all their teeth (edentulous patients). These implants show promising survival rates within a 5-year to 10-year follow-up period.
However, researchers have studied the risks of implant failure extensively over the years. Several factors can raise the risk that an implant will fail:
- Low insertion torque in implants planned for immediate or early loading
- Inexperienced surgeons placing the implants
- Placement of the implant into the upper jaw (maxilla)
- Patient history, including radiotherapy, teeth grinding (bruxism), gum disease (periodontitis), and previous early implant loss
The number of head and neck cancer cases is rising worldwide. According to the Global Cancer Observatory (GLOBOCAN), the incidence of head and neck cancer in 2022 was approximately 1.5 million new cases, with around 500,000 deaths from the disease.
More and more patients who receive radiation therapy (radiotherapy) for head and neck cancer want oral rehabilitation. The number of dental implants placed in these patients has also increased. However, radiotherapy appears to harm implant-based oral rehabilitation.
Radiation causes a process called radiation-induced fibroatrophic change. This process leads to low oxygen levels in tissue (hypoxia), fewer cells (hypocellularity), fewer blood vessels (hypovascularity), and a reduced ability of bone to regenerate.
Earlier umbrella reviews recognized implant-based oral rehabilitation as a feasible treatment option for patients who had undergone radiotherapy. Yet many systematic reviews on implant survival in head and neck cancer patients receiving radiotherapy have produced inconclusive findings. These reviews used various clinical analyses and reached conflicting results.
Study results are also hard to compare because the studies differ from one another (heterogeneity), and most included reports lacked a comparison group. For these reasons, the authors recommend interpreting earlier results with caution.
To address inconsistent study methods and to make research more objective, Cochrane introduced the umbrella review. An umbrella review is a study design that combines evidence from multiple systematic reviews into a single comprehensive analysis. This approach supports more reliable decision-making by systematically comparing scientific data.
Because results have been conflicting, this umbrella review aimed to analyze the available relevant systematic reviews. The review compared irradiated patients with non-irradiated patients. The goal was to determine whether head and neck radiotherapy influences dental implant survival in patients with head and neck cancer.
How the Research Was Conducted
This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. The research protocol was registered on the International Prospective Register of Systematic Reviews (PROSPERO) database under the number CRD42023406059.
The authors used the PICO strategy to build their research question. PICO stands for Population, Intervention, Comparison, and Outcome. The research question was: "What is the survival of dental implants installed before and/or after radiotherapy in patients (male and female) with head and neck cancer? How does this survival compare to patients not exposed to radiation?"
The PICO elements were defined as follows:
- Population: Patients undergoing radiotherapy for head and neck cancer
- Intervention: Installation of dental implants before and/or after radiotherapy
- Comparison: Patients with head and neck cancer (non-irradiated)
- Outcome: Survival of dental implants
The inclusion criteria were systematic reviews, with or without meta-analysis. These reviews had to assess the survival of dental implants installed before and/or after radiotherapy in patients with head and neck cancer. The comparison had to be patients with head and neck cancer whose implants were installed in non-irradiated bone.
The authors excluded several types of studies:
- Systematic reviews of animal studies
- Other types of reviews that were not systematic reviews
- Studies for which the full text was unavailable
Two independent reviewers (MCDP and LCA) conducted the electronic search. They searched PubMed, the Cochrane Library, Embase, and Web of Science from each database's inception until February 23, 2024. They also searched the Google Scholar database for grey literature. The reviewers developed search strategies for each database using indexed terms and synonyms. They also performed a manual search of references in all included studies. A third reviewer (DVC) was consulted when there was doubt. Team members are experts in study translation, so there were no restrictions on language or year of publication.
The two reviewers selected studies independently in a two-stage process. They used the Rayyan QCRI website (Rayyan, Qatar Computing Research Institute, Al-Rayyan, Qatar). Duplicate studies were removed using reference management software (EndNote® X9; Clarivate, Philadelphia, PA, USA). In the first stage, the reviewers assessed titles and abstracts. In the next stage, they read the full text of the selected articles and excluded those that did not meet the eligibility criteria. A third reviewer (DVC) resolved disagreements. The reviewers did not need to contact authors to clarify doubts. Agreement between the reviewers was almost perfect, with a Cohen's Kappa value of 0.90.
Two reviewers (MCDP and LCA) collected data independently in April 2024. They used a customized Excel form that captured the main characteristics of the studies:
- Study and publication year
- Number of participants and age range
- Country of publication
- Number of included studies and study design
- Presence of meta-analysis
- Variation in radiation dose (Gy) and implant installation time
- Number of failed and installed implants
- Implantation site
- Time interval between radiotherapy and implant installation
- Follow-up period
- Implant characteristics
- Cancer characteristics
- Adjuvant therapy
- Bone crest stability
- Postoperative complications
- Prosthetic rehabilitation
A third author (DVC) reviewed the data. In cases of missing data, the authors planned to contact the original authors by email twice.
Two reviewers (MCDP and LCA) independently appraised the quality of the included systematic reviews. They used the A Measurement Tool to Assess Systematic Reviews (AMSTAR 2) tool. A third reviewer (DVC) resolved disagreements. The AMSTAR 2 tool consists of 16 items. Items 2, 4, 7, 9, 11, 13, and 15 are considered critical. Questions are answered with the options: yes, partial yes, no, or meta-analysis not conducted.
The overall confidence rating of a review's results is categorized as follows:
- High: no weakness or one non-critical weakness
- Moderate: more than one non-critical weakness
- Low: one critical flaw, with or without non-critical weaknesses
- Critically low: more than one critical flaw, with or without non-critical weaknesses
The authors performed a descriptive synthesis of the results of the included studies. They calculated the percentage of implant survival using the arithmetic mean.
How Studies Were Selected
The literature search identified 1,811 articles. After removing 670 duplicates, the reviewers evaluated the remaining 1,141 publications by reading titles and abstracts. A manual search identified five additional reports. This process resulted in 45 records selected for full-text reading.
The reviewers excluded 34 references for the following reasons:
- Eleven did not investigate a non-irradiated control group
- Eight were not systematic reviews
- Seven had no full text available
- Three did not focus on oral rehabilitation with implants in irradiated patients
- Two included non-specific data for head and neck cancer
- Two were editorials
- One did not investigate implant survival
Finally, the authors included 11 systematic reviews for qualitative synthesis.
Characteristics of the Included Reviews
The 11 included systematic reviews covered a total of 16,193 patients who received 73,674 dental implants. Of these implants, approximately 31,137 were installed in irradiated sites.
All selected studies assessed the survival of dental implants installed after the diagnosis of head and neck cancer. One systematic review was an update of a previous study by the same research team. The age range of participants varied from 6 to 94 years, and one study did not report the sample age. Most of the included reviews evaluated data from retrospective studies. All included studies conducted a meta-analysis.
The minimum radiation dose among the studies ranged from 10 Gy to 40 Gy. The maximum dose ranged from 72 Gy to 145 Gy. Two studies did not mention the radiation dose.
The timing of implant installation varied across the reviews:
- Five articles described implants installed before and after radiotherapy
- Four reported implants installed after radiotherapy
- One study evaluated implant installation during panendoscopy or ablative surgery, which is before radiotherapy
All selected studies evaluated the survival of implants installed in the upper jaw (maxilla) and the lower jaw (mandible). Seven studies investigated implants installed in both native bone and grafted bone. Two studies analyzed implants installed only in native bone. One study did not mention the bone type.
Only one study investigated the time interval between radiotherapy and implantation. The follow-up time among the studies varied from one month to 23 years. One study did not mention the follow-up period.
Key Finding: Implant Survival in Irradiated vs. Non-Irradiated Patients
The survival rate of implants was higher among non-irradiated patients, according to data from 11 meta-analyses. In contrast, three meta-analyses showed no significant difference between the irradiated and non-irradiated groups. Data were reported across four time periods (1990–2021, 1990–2006, 2007–2013, and 2013–2021) and two follow-up periods (at least 3 years of follow-up and at least 5 years of follow-up).
Overall, the analysis evaluated 48,563 implants:
- Irradiated group: 14,471 implants, with 2,674 failures, giving a survival rate of 81.52%
- Non-irradiated group: 34,092 implants, with 1,825 failures, giving a survival rate of 94.64%
Individual meta-analyses reported the following results:
- Camolesi et al. (2023), 5 years of follow-up: weighted proportion in the irradiated group was 93.13% (95% confidence interval [CI]: 87.20–99.6; p<0.001; I²=85%); weighted proportion in the control group was 98.52% (95% CI: 97.56–99.48; p<0.001; I²=0%). Survival rate: 93.13% irradiated vs. 98.56% non-irradiated.
- Shahi et al. (2023), follow-up not mentioned: 136 failures out of 1,226 implants in the irradiated group and 41 failures out of 932 in the control group. Odds ratio (OR): 1.79; 95% CI: 1.35–2.23; p<0.01; I²=62.89%. Survival rate: 81.35% irradiated vs. 87.45% non-irradiated.
- Kende et al. (2022), mean 52.5 months of follow-up: 364 failures out of 2,186 implants in the irradiated group and 179 failures out of 1,685 in the control group. OR: 0.24; 95% CI: 0.14–0.40; p<0.01; I²=73%. Survival rate: 82.47% irradiated vs. 89.37% non-irradiated.
- Schiegnitz et al. (2022), 2013–2021, at least 3 years of follow-up: OR: 2.07; 95% CI: 1.54–2.97; p<0.00001.
- Schiegnitz et al. (2022), 2013–2021, at least 5 years of follow-up: OR: 1.8; 95% CI: 1.21–2.67; p=0.003.
- Schiegnitz et al. (2022), 1990–2021, 3 years of follow-up: 500 failures out of 3,269 implants in the irradiated group and 339 failures out of 3,348 in the control group. OR: 2.06; 95% CI: 1.75–2.42; p<0.00001; I²=33%. Survival rate: 79.56% irradiated vs. 86.61% non-irradiated.
- Schiegnitz et al. (2022), 1990–2021, 5 years of follow-up: 373 failures out of 1,825 implants in the irradiated group and 278 failures out of 2,077 in the control group. OR: 1.97; 95% CI: 1.63–2.37; p<0.00001; I²=47%. Survival rate: 84.70% irradiated vs. 89.87% non-irradiated.
- Shokouhi and Cerajewska (2022), 1–3.8 years of follow-up: 62 failures out of 508 implants in the irradiated group and 13 failures out of 452 in the control group. OR: 4.77; 95% CI: 2.57–8.89; p<0.00001; I²=0%. Survival rate: 87.79% irradiated vs. 97.12% non-irradiated.
- Gupta et al. (2021), 6–12 months of follow-up: 323 failures out of 2,203 implants in the irradiated group and 141 failures out of 2,349 in the control group. OR: 2.95; 95% CI: 1.93–4.50; p<0.00001; I²=50%. Survival rate: 85.80% irradiated vs. 93.90% non-irradiated.
- In't Veld et al. (2021), follow-up not mentioned: 37 failures out of 473 implants in the irradiated group and 5 failures out of 372 in the control group. Risk ratio (RR): 5.02; 95% CI: 0.92–27.38; p=0.06; I²=56%. Survival rate: 92.17% irradiated vs. 98.65% non-irradiated.
- Smith Nobrega et al. (2016), 16 years of follow-up: 629 failures out of 3,773 implants in the irradiated group and 191 failures out of 3,328 in the control group. RR: 2.63; 95% CI: 1.93–3.58; p<0.001; I²=56%. Survival rate: 84.30% irradiated vs. 94.26% non-irradiated.
- Chrcanovic et al. (2016), follow-up not mentioned: 640 failures out of 3,914 implants in the irradiated group and 684 failures out of 14,514 in the control group. RR: 2.18; 95% CI: 1.71–2.79; p<0.00001; I²=52%. Survival rate: 83.64% non-irradiated vs. 95.29% irradiated (as reported in the source table).
- Schiegnitz et al. (2014), 2007–2013, at least 5 years of follow-up: 19 failures out of 263 implants in the irradiated group and 13 failures out of 241 in the control group. OR: 1.44; 95% CI: 0.67–3.10; p=0.35; I²=75%. Survival rate: 92.77% irradiated vs. 94.60% non-irradiated.
- Schiegnitz et al. (2014), 1990–2006, at least 5 years of follow-up: 281 failures out of 983 implants in the irradiated group and 203 failures out of 1,040 in the control group. OR: 2.11; 95% CI: 1.69–2.65; p<0.00001; I²=72%. Survival rate: 71.41% irradiated vs. 80.48% non-irradiated.
- Chambrone et al. (2013), follow-up not mentioned: 110 failures out of 549 implants in the irradiated group and 293 failures out of 8,383 in the control group. RR: 2.74; 95% CI: 1.86–4.05; p<0.00001; I²=0%. Survival rate: 83.30% irradiated vs. 93.81% non-irradiated.
Key Finding: Upper Jaw vs. Lower Jaw in Irradiated Patients
Two meta-analyses showed higher implant survival when implants were installed in the irradiated lower jaw (mandible) compared with the irradiated upper jaw (maxilla).
The first meta-analysis reported a risk ratio (RR) of 3.16 (95% CI: 1.76–5.68; p=0.0001; I²=70%). The second meta-analysis reported an RR of 5.96 (95% CI: 2.71–13.12; p<0.00001; I²=33%).
A total of 3,378 implants were evaluated:
- Irradiated maxilla group: 897 implants, with 188 failures, giving a survival rate of 79.04%
- Irradiated mandible group: 2,481 implants, with 160 failures, giving a survival rate of 93.55%
In the study by Shokouhi and Cerajewska (2022), implants installed in the maxilla were significantly more likely to fail than those installed in the mandible. The odds ratio was 5.03 (95% CI: 1.07–23.58; p=0.04; I²=87%).
Key Finding: Grafted Bone vs. Native Bone, Radiation Dose, and Timing
Two meta-analyses covering literature from 1990 to 2021 showed higher implant survival in irradiated native bone compared with irradiated grafted bone.
- For follow-up of at least 36 months: OR 2.06; 95% CI: 1.44–2.94; p<0.0001; I²=0%
- For follow-up of at least 60 months: OR 2.26; 95% CI: 1.50–3.40; p<0.0001; I²=12%
In contrast, one meta-analysis showed no significant difference between irradiated grafted bone and irradiated native bone (RR: 1.35; 95% CI: 0.93–1.94; p=0.11; I²=48%).
A total of 1,740 implants were evaluated:
- Irradiated grafted bone group: 596 implants, with 106 failures, giving a survival rate of 82.21%
- Irradiated native bone group: 1,144 implants, with 148 failures, giving a survival rate of 87.06%
One meta-analysis examined radiation dose. It showed a tendency for implants exposed to lower doses of radiotherapy to have higher implant survival (RR: 1.59; 95% CI: 0.98–2.59; p=0.06; I²=47%). However, no statistically significant difference was observed between the groups evaluated.
A total of 1,057 implants were evaluated in this dose analysis:
- Higher dose group: 546 implants, with 98 failures, giving a survival rate of 82.05%
- Lower dose group: 511 implants, with 51 failures, giving a survival rate of 90.01%
Another meta-analysis found no statistically significant difference when implants were installed before or after 12 months following radiotherapy (RR: 1.37; 95% CI: 0.76–2.45; p=0.29; I²=64%).
For the 445 implants installed up to 12 months after radiotherapy, 79 failures occurred, giving a survival rate of 84.26%. In the group of implants installed more than 12 months after radiotherapy, 58 failures occurred among 505 implants, giving a survival rate of 88.51%.
Methodological Quality of the Included Reviews
Overall, the eligible reviews showed critically low quality according to the AMSTAR 2 tool domains. This means the included systematic reviews had more than one critical flaw, with or without non-critical weaknesses. The authors detail the reasons for downgrading these studies in the supporting information of the original article.
Clinical Implications: What This Means for Patients
This umbrella review included 11 systematic reviews published between 2013 and 2023. The reviews assessed the survival of 14,471 dental implants installed before and/or after radiotherapy in head and neck cancer patients. These were compared with 34,092 implants in non-irradiated patients.
Overall, the survival rate of implants installed in irradiated patients was lower than that of implants installed in non-irradiated patients. This finding matters for patients who are considering dental implants after radiation treatment for head and neck cancer.
The location of the implant appears to matter. Implants placed in the irradiated upper jaw (maxilla) failed more often than implants placed in the irradiated lower jaw (mandible). The survival rate was 79.04% in the irradiated maxilla compared with 93.55% in the irradiated mandible.
The type of bone also appears to matter. Implants placed in irradiated native bone survived better than implants placed in irradiated grafted bone. The survival rate was 87.06% in irradiated native bone compared with 82.21% in irradiated grafted bone.
Radiation dose may also play a role. Implants exposed to lower doses of radiotherapy showed a tendency toward higher survival (90.01%) compared with implants exposed to higher doses (82.05%). However, this difference did not reach statistical significance.
The timing of implant placement after radiotherapy did not show a statistically significant effect. Implants placed up to 12 months after radiotherapy had a survival rate of 84.26%, and implants placed more than 12 months after radiotherapy had a survival rate of 88.51%.
Limitations: What the Study Could Not Prove
The authors identified several important limitations. The most significant limitation is the quality of the evidence. All included systematic reviews had critically low methodological quality according to the AMSTAR 2 tool.
The included studies also differed from one another (heterogeneity). Most included reports lacked a comparison group. For these reasons, the authors recommend interpreting the presented results with caution.
Three meta-analyses showed no significant difference between the irradiated and non-irradiated groups. This means the evidence is not entirely consistent, even though most meta-analyses favored non-irradiated bone.
Two studies did not mention the radiation dose. One study did not report the sample age. One study did not mention the follow-up period. Only one study investigated the time interval between radiotherapy and implantation. These gaps limit how completely the authors could analyze all relevant factors.
The authors conclude that further well-designed clinical studies are warranted.
Recommendations
Based on this umbrella review, the authors make the following points for patients and clinicians to consider:
- Discuss the lower implant survival rate in irradiated bone with your dental and cancer care team. The review found a survival rate of 81.52% in irradiated bone compared with 94.64% in non-irradiated bone.
- Ask about the planned implant location. Implants in the irradiated upper jaw (maxilla) had a lower survival rate (79.04%) than implants in the irradiated lower jaw (mandible, 93.55%).
- Ask whether the implant will be placed in native bone or grafted bone. Irradiated native bone showed a higher survival rate (87.06%) than irradiated grafted bone (82.21%).
- Understand that the quality of the available evidence is critically low. The authors state that further well-designed clinical studies are needed before firm conclusions can be drawn.
- Interpret all results with caution, because the included studies differed from one another and most lacked a comparison group.
Frequently Asked Questions
If I had radiation for head and neck cancer, how well do dental implants survive?
An umbrella review of 11 systematic reviews found that across 48,563 implants, those in irradiated bone had a survival rate of 81.52%, compared with 94.64% in non-irradiated bone. Most meta-analyses favored non-irradiated bone, but three showed no significant difference, and all included reviews had critically low methodological quality.
Does it matter whether the implant goes in my upper or lower jaw after radiation?
Yes. In irradiated patients, implants in the upper jaw (maxilla) had a survival rate of 79.04%, while implants in the lower jaw (mandible) had a survival rate of 93.55%. Two meta-analyses showed higher survival in the irradiated lower jaw, and one study found upper-jaw implants were significantly more likely to fail.
Is an implant in grafted bone riskier than one in my own bone after radiation?
In irradiated patients, implants placed in native bone had a survival rate of 87.06%, compared with 82.21% in grafted bone. Two meta-analyses found higher survival in irradiated native bone, though one meta-analysis found no significant difference. Ask your clinician whether your implant will be placed in native or grafted bone.
Should I wait a certain amount of time after radiation before getting implants?
One meta-analysis compared implants placed up to 12 months after radiotherapy with those placed more than 12 months after. Survival was 84.26% and 88.51% respectively, with no statistically significant difference. Only one included study investigated this time interval, so the evidence on timing is limited.
How reliable is this information about implant survival after radiation?
All 11 included systematic reviews had critically low methodological quality according to the AMSTAR 2 tool, meaning more than one critical flaw. The studies also differed from one another, and most lacked a comparison group. The authors recommend interpreting the results with caution and say further well-designed clinical studies are needed.
What should I discuss with my dental and cancer care team about implants after radiation?
The authors recommend discussing the lower survival rate in irradiated bone (81.52% versus 94.64% in non-irradiated bone), asking about the planned implant location because the irradiated upper jaw had lower survival (79.04%) than the lower jaw (93.55%), and asking whether native or grafted bone will be used.
I had radiation for head and neck cancer and my dentist is recommending dental implants — when should I get a second opinion?
A second opinion is worth considering before implants are placed in irradiated bone, because survival is lower there (81.52%) than in non-irradiated bone (94.64%). Ask about the planned location: implants in the irradiated upper jaw survived less often (79.04%) than in the lower jaw (93.55%). Ask whether native or grafted bone is planned, since irradiated native bone survived better (87.06%) than grafted bone (82.21%). The available evidence is of critically low quality, so an independent review of your records can help. Diagnostic Detectives Network provides independent expert second opinions.
Source Information
Original article title: Survival of dental implants in irradiated head and neck cancer patients compared to non-irradiated patients: An umbrella review.
Authors: Maria Cândida Dourado Pacheco, Alexandre Henrique dos Reis Prado, Danilo Viegas da Costa, Lara Cancella de Arantes, Caio Fernando Teixeira Portela, Tarcísio Passos Ribeiro Campos, and Arno Heeren de Oliveira.
Author affiliations: Department of Nuclear Engineering, Federal University of Minas Gerais, School of Engineering, Belo Horizonte, Minas Gerais, Brazil; Restorative Dentistry, Federal University of Minas Gerais, School of Dentistry, Belo Horizonte, Minas Gerais, Brazil; Dental Clinics with an Emphasis on Periodontics at the Pontifical Catholic University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
Publication details: PLOS ONE, 20(9): e0324388. Published September 3, 2025. DOI: https://doi.org/10.1371/journal.pone.0324388
Review registration: PROSPERO number CRD42023406059.
Funding: The authors received no specific funding for this work.
Competing interests: The authors declared that no competing interests exist.
This patient-friendly article is based on peer-reviewed research.
