Effects of dental implants on dietary and nutritional outcomes in older adults: a systematic review

Abstract

Background

Maintaining oral health has become a major concern in preserving overall well-being and nutritional quality of life among older adults. The tooth loss is highly prevalent in them and can result in diminished chewing as well as inadequate food consumption. Dental implants offer a viable solution to restore function and potentially improve nutrition. This review systematically examined the impact of dental implants on dietary patterns and nutritional outcomes within the demographic of older adults.

Methods

An extensive literature search was conducted across six major databases, encompassing studies published in English between January 2004 and January 2024. The databases searched included SCOPUS, Web of Science, PubMed, Dentistry and Oral Science Source, The Allied and Complementary Medicine Database (AMED) and the Psychology and Behavioural Sciences Collection. Studies which incorporated the focus on older individuals who received dental implants and reported on dietary or nutritional outcomes were included. All records and extracted data were managed using Excel and Rayyan software to streamline organization and ensure transparency in the review process. The main outcomes evaluated were chewing ability, nutrient intake, anthropometric measures, and oral health-related quality of life. The study quality was assessed using the Mixed Methods Appraisal Tool (MMAT).

Results

Following a comprehensive search of six databases that initially yielded 3,229 records, eighteen studies which met the inclusion criteria. After removing 751 duplicates, 2,478 unique records underwent title and abstract screening, with 54 full texts were reviewed and 38 were excluded and 2 studies were identified through manual searching. The review found that dental implants generally led to improvements in chewing efficiency, with one study reporting an increase in bite force, supporting better masticatory function. One study reported a significant increase in bite force from the baseline after 52 weeks, indicating improved masticatory function following implant-supported prostheses. However, changes in anthropometric indicators and nutritional biomarkers were inconsistent. A study reported a 79% mitigation of total protein intake decline and 71% for animal protein intake with prostheses, whereas another study found no significant differences in fibre, energy, or micronutrient intake. The quality of the included studies assessed using the MMAT, revealed moderate to high methodological quality.

Conclusions

Current evidence suggests improved mastication and patient satisfaction with implant-supported rehabilitation, while nutritional outcomes remain inconsistent. Patient satisfaction and oral health-related quality of life showed consistent improvement, but objective nutritional details showed variability. A multidisciplinary approach should be used to maximize treatment success with dietary counselling and long-term monitoring of nutritional status during prosthetic rehabilitation of edentulous/ partially dentate patients.

PROSPERO registration

This systematic review was pre-registered in the International Prospective Register of Systematic Reviews (PROSPERO) with the ID CRD42024593129 on October 01, 2024.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-026-07708-w.

Background

Older adults are defined as individuals aged 65 years and above, in accordance with the United Nations classification of older persons outlined in World Population Ageing 2019 [1]. The United Nations World Social Report 2023 further indicates that the global population aged 65 years and older is projected to double by 2050 compared with 2021, with a particularly rapid increase expected among those aged 80 years and above [2]. While increased life expectancy represents a major public health achievement, it also highlights the growing need to ensure that older adults maintain a healthy, functional, and comfortable quality of life. Without adequate attention to their specific health and well-being needs, longevity may be accompanied by functional limitations and diminished quality of life.

The ageing population, edentulism and partially dentate status

According to the Global Burden of Disease Study 2021, approximately 3.69 billion people worldwide are affected by oral conditions, including untreated dental caries, severe periodontal disease, and edentulism, underscoring their substantial impact on diet, nutrition, and overall health [3]. Edentulism continues to represent a major global public health challenge, with the number of affected individuals expected to increase further in the coming decades [4]. However, there is no specific data on partially dentate status in the world population. A recent global survey has identified that only 39% of the countries have the data related to partially dentate status of their populations [5]. According to the literature reports, one quarter (26%) of adults aged 65 or older in USA had 8 or fewer teeth, describing the requirement of attention by health authorities [6].

Tooth loss significantly impairs masticatory function, making chewing and digestion difficult and predisposing individuals to nutritional deficiencies. In particular, the inability to chew harder or fibre-rich foods such as fruits and vegetables may result in inadequate intake of essential vitamins and minerals [7]. A community-based cohort study among older adults in China demonstrated that individuals with fewer remaining natural teeth were more likely to be underweight [8]. Beyond dietary limitations and altered body weight, edentulism has also been associated with an increased risk of systemic conditions, including cardiovascular and respiratory diseases, diabetes, certain cancers, and higher mortality rates [8]. Therefore, addressing tooth loss in older adults is essential not only for maintaining nutritional well-being but also for reducing broader systemic health risks.

Functional benefits of dental implants

Advances in modern dentistry have provided effective treatment options for individuals experiencing tooth loss. For many older adults, dental implants have increasingly replaced conventional removable dentures due to their superior stability, improved function, enhanced aesthetics, and positive impact on quality of life. Implant-supported prostheses involve the surgical placement of titanium or titanium-alloy fixtures into the alveolar bone of the maxilla or mandible, creating a stable foundation for prosthetic rehabilitation. Evidence from the literature indicates high success rates of dental implants in older adult populations, with no clear increase in implant failure rates even among individuals with compromised medical conditions [9]. Furthermore, age alone has not been shown to adversely affect implant treatment outcomes, supporting the use of dental implants as a viable and effective option for improving oral function and quality of life in older adults [10].

Addressing the nutritional impact in older adults

Malnutrition is an increasingly prevalent concern among the rapidly growing older adult population. Difficulties related to chewing and swallowing, along with social and behavioural factors, can significantly influence food intake and dietary habits, leading to compromised nutritional status [11]. Implant-supported prostheses offer a more natural and efficient chewing experience, enabling older adults to eat more comfortably and maintain a varied diet. Nutritional status of the dental implants may vary with multiple factors including tooth baseline oral health status, type of implant-supported prosthesis, dietary behaviour, post-treatment nutritional counselling. The relationship between dental implants supported rehabilitation and the nutritional outcome are multifactorial dependent and remains incompletely understood, creates the need for the comprehensive evaluation of the interacting influences.

Rationale for the current review

This systematic review aims to address an important gap in the existing literature by critically evaluating the impact of dental implants on both dietary outcomes and nutritional health in older adults. Specifically, the review seeks to achieve two key objectives: first, to assess the effects of dental implants on dietary outcomes, with particular emphasis on masticatory function; and second, to evaluate their influence on nutritional status. Despite increasing interest in the relationship between oral rehabilitation and nutrition, recent systematically synthesized evidence focusing specifically on older adults remains limited. Therefore, the findings of this review are intended to support informed clinical decision-making and public health planning by clarifying the dietary and nutritional implications of implant-supported prostheses in older adult populations.

Methodology

Protocol and registration

This review followed the Cochrane Handbook’s methodological guidance for systematic reviews of interventions [12] and met the standards of the PRISMA statement [13]. The review protocol was registered in advance on PROSPERO (ID: CRD42024593129) as of October 1, 2024.

Search strategy

A thorough literature search was performed using six primary online databases: SCOPUS, Web of Science, PubMed, AMED, Psychology and Behavioural Sciences Collection, and Dentistry & Oral Sciences Source. Studies released between January 2004 and January 2024 were included in the search and were limited to publications in English. To ensure the inclusion of relevant literature, the search strategy incorporated Medical Subject Headings (MeSH) and a broad range of keywords related to dental implants, nutrition, and older adult population. The researchers used AND and OR Boolean operators to combine keywords representing key concepts, including “dental” and “oral”; “implant*,” “anchor*,” and “fixture*”; diet- and nutrition-related terms such as “chew*,” “diet,” “eating,” “food,” “nutri*,” “BMI,” and “weight”; as well as demographic descriptors like “aged,” “elder*,” and “senior citizen.” These terms were organized and combined according to the PEO (Population, Exposure, Outcome) model, as outlined in Tables S1–S4 in the Supplementary File. To further ensure completeness, a manual forward and backward citation of the reference lists of all selected studies was examined.

Eligibility criteria

Studies were identified following specific pre-set criteria for inclusion and exclusion. The following criteria were applied:

Inclusion Criteria:

• Studies including participants aged 65 years or older and mixed-age studies if they contained participants aged 65 years or older.

• Participants must have received prostheses on dental implants as part of their oral rehabilitation.

• Studies reporting dietary and/or nutritional outcomes such as food intake, chewing ability, nutritional status, BMI, or indicators of malnutrition.

• Case series with a minimum sample size of five or more participants.

• Articles published in peer-reviewed journals.

• Research employing quantitative or mixed-methods approaches.

Exclusion Criteria:

• Review articles, editorials, commentaries, and letters.

• Animal or in-vitro studies.

• Literature published in non-peer-reviewed sources (e.g., books, book chapters, webpages).

Screening and study selection

The initial database search was conducted by one of the reviewers (KKK). Screening of the retrieved records was managed using Rayyan software [14] and followed a three-step process: deduplication, screening of titles and abstracts, and the full-text review. Due to the large number of retrieved articles, the blind screening process was conducted by two independent pairs of reviewers, with a total of four reviewers (SI & DL and KS & RMJ). Each reviewer pair independently reviewed titles and abstracts to determine which studies satisfied the established inclusion criteria. The same paired approach was applied during full-text screening. Final inclusion decisions were made through discussion and consensus. In cases where disagreements arose, a third reviewer (RDJ) was consulted to reach a resolution.

Data extraction

Four reviewers independently carried out the data extraction (SI, CHK, MB, and PB) using a customized data extraction table. This table was initially piloted on a subset of studies to evaluate its usability and clarity. Based on feedback and team discussions, the table was refined prior to the commencement of full data extraction to ensure consistency and comprehensiveness across all reviewers.

For each included study, detailed information was collected regarding the general study, such as author(s), publication year, journal title, country of origin, and study type (e.g., randomized controlled trial, cohort, case-control, cross-sectional, or qualitative study). Information regarding the study population was also extracted, covering sample size, age range or mean age of participants, gender distribution, and the oral health status of participants at baseline.

Intervention and exposure details were systematically documented, including the type of dental intervention implemented, such as dental implant supported fixed prostheses, or implant-supported overdentures, the anatomical location of implant placement (e.g., maxillary or mandibular), the total implants placed, and the timing of placement or follow-up duration when reported. In terms of dietary and nutritional outcomes, data were extracted on the specific outcomes assessed, such as nutrient intake (including energy, protein, and micronutrients), food consistency or texture, masticatory ability, and nutritional biomarkers as well as the methods of assessment. The methods used to assess these outcomes were also recorded, including dietary assessment tools (e.g. Food Frequency Questionnaires, 24-hour dietary recall), clinical or biochemical tests, anthropometric measures (such as BMI), and direct observation where applicable. Reviewers also noted whether standardized and validated instruments, such as the Mini Nutritional Assessment (MNA), have been employed.

Key findings were summarized for each study, highlighting the specific outcome measures reported (e.g., changes in dietary intake, BMI, or biochemical indicators), along with statistical significance and effect sizes when available. This approach ensured a comprehensive synthesis of the interventions, outcomes, and methods used across studies, allowing for more meaningful comparisons and interpretations, such as dietary recall, food frequency questionnaires, biochemical testing, or direct observation. Reviewers also noted whether any validated assessment tool was used.

Quality assessment

Study quality was appraised independently by a pair of reviewers (KS and PB) using the Mixed Methods Appraisal Tool (MMAT 2018) [15]. The assessment process began with identifying the study design for each included article. Since all studies followed a quantitative research design, the relevant MMAT criteria for quantitative studies were applied accordingly.

The MMAT includes five core criteria tailored to different quantitative study designs covering randomized trials, non-randomized research, and descriptive studies. Each study was evaluated against these five criteria, and results were reported using a criterion-level judgement of “met” (✓) or “not met” (✗), in accordance with MMAT 2018 guidelines. A qualitative overall interpretation was provided for each study to summarize its methodological quality. This approach avoids numerical scoring and aligns with the recommended MMAT reporting standards. This structured and standardized approach ensured a consistent and transparent appraisal across all included studies [16].

Disagreements between reviewers were settled through discussion and, if needed, by involving a third reviewer (RDJ).

Data synthesis

As substantial methodological and clinical heterogeneity was identified across the included studies, a quantitative meta-analysis was not appropriate. The synthesis followed the Synthesis Without Meta-analysis (SWiM) guideline, addressing all nine SWiM items as detailed below.

Grouping studies for synthesis:

Studies were grouped by primary outcome domain - chewing and masticatory function, dietary intake and food selection, nutritional biomarkers and anthropometry, and oral health related quality of life (OHRQoL). Within each domain, studies were further classified by participants’ oral status (edentulous vs. partially dentate) and type of prosthesis (implant-supported overdenture, fixed implant prosthesis, or single-implant restoration).

Standardized metric and transformation:

As outcome measures varied (e.g., bite force in Newtons, dietary intake in kcal/day, nutrient concentrations, questionnaire scores), data were synthesized descriptively without statistical transformation. Reported values were summarized as presented in each study (mean, median, or frequency) to preserve original measurement integrity.

Synthesis method:

A structured narrative synthesis was used. Findings were tabulated and summarized by outcome domain, and the direction of effect (improvement, no change, or decline) was noted for each study. Vote counting by direction of effect was applied where comparable measures existed.

Criteria to prioritize results:

Greater weight was given to studies with higher methodological quality, larger sample sizes, and longitudinal or randomized designs. These studies were prioritized when discussing the consistency and strength of evidence.

Investigation of heterogeneity:

Heterogeneity was assessed qualitatively across study designs, populations, interventions, and outcomes. Variation in measurement tools and follow-up duration precluded calculation of I². Observed differences were explored narratively to identify potential sources of inconsistency (e.g., edentulous vs. partially dentate participants, fixed vs. removable prostheses).

Sensitivity analysis:

Owing to methodological heterogeneity and the limited number of studies per subgroup, formal sensitivity analysis was not feasible. However, interpretation of findings emphasized those from higher-quality and randomized studies to enhance robustness.

Reporting effect direction and certainty:

Effect direction for each study was recorded (positive, neutral, or negative). Certainty of evidence was inferred qualitatively based on MMAT scores and study design hierarchy, with randomized controlled trials and longitudinal studies providing greater confidence.

Summary of synthesis findings:

Across the 18 included studies, dental implants generally improved chewing efficiency, bite force, and self-perceived dietary satisfaction. Improvements in objective nutritional markers and anthropometric measures were inconsistent. Implant-supported overdentures and fixed prostheses yielded better functional outcomes than conventional dentures.

Limitations of the synthesis:

The synthesis was limited by heterogeneity in study design, outcome measurement, and reporting format, which prevented meta-analysis. Reliance on self-reported dietary data in several studies may have introduced recall bias. Consequently, findings should be interpreted with caution, emphasizing trends rather than precise effect magnitudes.

Assessment of publication bias and subgroup analyses

As no quantitative meta-analysis was conducted, statistical assessments of publication bias (e.g., funnel plot visualization) and subgroup analyses could not be performed. Funnel plots require multiple comparable effect estimates with standard errors, which were unavailable due to the heterogeneity of outcome measures across studies. Subgroup analyses (e.g., by implant type or baseline oral status) were conducted narratively, as the included studies varied substantially in design, population characteristics, and measurement tools.

Results

A comprehensive search across six databases yielded a total of 3,229 records (SCOPUS- 2, 242, Web of Science- 630, PubMed- 205, Dentistry and Oral Science Source- 143, The Allied and Complementary Medicine Database AMED-7, Psychology and Behavioural Sciences Collection- 2). After removing 751 duplicate entries, 2,478 unique records remained for title and abstract screening. This screening process resulted in 54 articles selected for full-text review, of which 38 were excluded due to wrong population (n = 21), wrong publication type (n = 1) and wrong outcome (n = 16). Moreover, two pertinent articles were found by manually examining the reference lists of the selected studies. Consequently, a total of 18 articles satisfied the eligibility requirements and were included for data extraction (see Fig. 1, PRISMA flow diagram).

Fig. 1.

PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses). Flowchart diagram.

An overview of the study characteristics

The studies included were geographically diverse, originating from Brazil, Switzerland, Japan, Canada, Germany, Netherlands, Lebanon and USA. Specifically, eight studies (44.44%) were conducted in Brazil [17–24], two (11.11%) in Japan [25, 26], two (11.11%) in Switzerland [27, 28] two (11.11%) in Canada [29, 30], and one article each from Germany, Netherlands, Lebanon and USA [31–33]. These details are summarized in (Supplementary Table 1).

Quality assessment

Across the assessed studies, most met the criteria for clear research questions, appropriate design and relevant outcome measures while a few showed limitations in sample representation and controlling confounding factors. Overall, the methodological quality was interpreted qualitatively as moderate to high (Supplementary document2_Table 2).

Participant characteristics across studies

Age range and sex distribution

Completely edentulous adults

The completely edentulous participants generally represented older age spectrum, with mean or median ages ranging from 60 to 96 years. Several studies reported mean ages around 66–70 years [16–20], while research involving very old adults included participants with mean ages of 84–85 years [26]. Some studies encompassed even broader age ranges, such as 51–86 years [29] and 38–79 years [32]. Across these edentulous cohorts, female participants predominated, with most samples comprising between 55% and 75% women, consistent with demographic patterns observed in geriatric populations.

Partially dentate adults

A smaller subset of four studies involved partially dentate older adults, typically anterior teeth or a minimal number of teeth in one arch. These participants tended to be slightly younger within older adult category, with mean ages ranging from 62.6 to 81.1 years, and study-specific age ranges extending from 55 to 103 years [10, 15, 25, 30]. The sex distribution in partially dentate groups was more balanced compared with the edentulous cohorts, with female proportions ranging from 43% to 76%, depending on the study.

Oral health status before intervention

Among the included studies, participants’ baseline oral conditions varied between completely edentulous and partially dentate older adults. Fourteen studies recruited fully edentulous participants and most commonly individuals without teeth in the mandibular or both arches, whereas four studies involved partially dentate participants who retained some natural teeth often in the anterior region or opposing arch [27, 28]. Participants who had been wearing full dentures for over a year were reported in some of the studies [29, 31, 34]. Some studies provided more details about the type of tooth loss. The American College of Prosthodontists’ guidelines were used in some of the articles for classifying patients’ edentulous status [23].

The partially dentate patients were grouped by the number of remaining teeth and whether they used dental prostheses. A study focused on people who had only canines and incisors left in the lower arch [17]. A comprehensive overview of participant demographics, age range, gender distribution, and baseline oral health status is provided in (Supplementary Table 1).

Types of interventions with dental implants

Fixed and removable implant-supported prostheses

Completely edentulous participants

Most studies evaluated implant-supported prostheses in fully edentulous older adults, typically long-term complete denture wearers. Among these, the most common intervention was mandibular implant-supported overdentures, retained by either two implants [19, 20, 24, 29, 30] or a single midline implant [22, 31]. Several studies used varying numbers of implants, including 2–5 implants for overdentures [15] and five implants for immediately loaded fixed mandibular prostheses [22]. One multicentre study evaluated fixed mandibular screw-retained prostheses opposed by maxillary complete dentures [32], while another assessed both fixed and removable implant-supported prostheses in fully edentulous individuals [31]. All 14 studies involved interventions intended to replace complete loss of dentition, with removable overdentures being the dominant modality.

Partially dentate participants

Partially dentate older adults with remaining natural teeth, typically in the anterior region or one opposing arch. These interventions varied according to the extent of remaining dentition. One study evaluated implant-supported removable and fixed partial dentures (IRPDs and IFPDs) in participants retaining mandibular canines and incisors [9]. Two large population-based studies [25, 26] included mixed prosthetic users, bridges, dentures, and implant-supported restorations among participants with 1–19 remaining teeth. Another cross-sectional study [30] included partially dentate seniors using a combination of natural teeth, partial dentures, and implant-supported prostheses. In these partially dentate cohorts, fixed implant-supported partial prostheses were more common than overdentures, reflecting their preserved dentition and different prosthetic needs.

Location of the dental implants

Completely edentulous participants

In many studies involving fully edentulous older adults, dental implants were placed predominantly in the mandibular arch, especially for supporting full dentures. Most interventions focused on the anterior or interforaminal region of the mandible, where two-implant overdentures were commonly used [18–20, 26]. Several studies utilized the mandibular midline [23] or mandibular symphysis region [31], particularly for single-implant overdentures. Narrow-diameter implants were also placed in the mandibular interforaminal region in edentulous patients [25]. These implant locations are consistent with standard protocols for full denture support, where stability and retention are optimized in the anterior mandible. A few studies compared mandibular implant overdentures with maxillary conventional dentures [18, 30].

Partially dentate participants

In contrast, studies involving partially dentate older adults used broader implant placement sites depending on the distribution of remaining teeth and prosthesis type. For example, participants with retained mandibular canines or incisors received implants in the posterior mandibular segments (premolar/molar regions) to support removable or fixed partial prostheses [10]. Large population-based studies [25, 26] that included partially dentate individuals incorporated a range of prosthetic types (partial dentures, bridges, implant restorations), although specific implant locations were not always reported. These partially dentate cases typically required implant placement in areas of localized tooth loss rather than sites used for full-arch overdentures.

Assessment of chewing function

Methods used to assess chewing function

Functional outcomes were interpreted with respect to the type of prosthesis, recognizing that fixed implant-supported prostheses typically yield higher bite force and chewing efficiency than removable overdentures. The studies used different methods to evaluate chewing function, which can be grouped into two main types, namely objective performance-based tests and subjective patient-reported measures. Under the objective performance-based tests, Colour-Mixing Ability Tests [25], Maximum Voluntary Bite Force (MVBF) tests [25, 26], Swallowing Threshold Tests [19], and Multiple Sieve Methods [20] were used across studies. Under the subjective patient-reported measures, Visual Analogue Scales (VAS) and versions of the Oral Health Impact Profile (OHIP), such as OHIP-EDENT and OHIP-G, were utilized in some articles [26, 31].

Changes in chewing efficiency and bite force

Several studies showed a statistically significant increase in maximum bite force (MBF). Across the studies, the effect of implants on chewing efficiency differed between edentulous and partially dentate older adults. Among edentulous patients, implant-supported overdentures consistently increased bite force, with studies reporting large, statistically significant gains, for example, maximum bite force increasing from 46.6 N to 103.9 N (p = 0.002) over one year [23] and similar improvements in very old adults (p < 0.0001) [22]. Subjective chewing ability, denture stability, and the ability to manage hard foods also improved significantly [22, 29]. However, objective chewing efficiency findings were mixed: some studies showed no significant improvements in colour-mixing tests (p = 0.256) [23], whereas others demonstrated significant reductions in median particle size (X₅₀) and improved homogenization indices (p < 0.05) after implant overdenture therapy [16, 18].

In contrast, partially dentate patients exhibited more consistent improvements in measurable chewing efficiency. Implant-supported fixed or removable partial dentures significantly reduced particle size (X₅₀; p = 0.002) and required fewer chewing cycles (p = 0.006), indicating more efficient mastication [10]. These participants also showed improved ability to chew tough foods and adopted healthier eating patterns [10]. Overall, while implants reliably enhanced bite force and perceived chewing ability in edentulous individuals, the strongest statistically supported gains in objective chewing efficiency were seen in partially dentate older adults. The assessment methods and key findings related to chewing efficiency and bite force are summarized in Supplementary document2_Table.

Changes in food selection or dietary consistency

An improvement in dietary habits and food selection patterns was reported in several studies after the dental implant’s treatment. Across the included studies, changes in food selection and dietary consistency after implant treatment differed between edentulous and partially dentate older adults. Among edentulous patients, implant-supported overdentures and fixed prostheses generally improved the ability to consume harder and more fibrous foods, leading to more varied food choices; for example, a mandibular implant-supported prosthesis was associated with an increase in vegetable intake from 2.5 to 3.3 servings (p < 0.05) and a marked reduction in difficulty chewing raw, hard, and fibrous foods (p < 0.001). Improvements in tolerance of foods such as bread, apples, carrots, meat, and fish and greater chewing confidence were also reported after implant rehabilitation [24, 29–31]. Nevertheless, several studies found no significant differences in total energy or nutrient intake between implant and conventional denture groups despite functional gains [29].

In contrast, partially dentate patients, those with remaining natural teeth rehabilitated with implant-supported partial or fixed prostheses showed more consistent quantitative dietary changes after implant treatment. Studies of implant-supported partial prostheses reported smaller particle sizes, fewer chewing cycles, and corresponding increases in intake of fibre, calcium, and iron [10]. Large cohort analyses likewise indicated that prosthesis use, including implant restorations, mitigated reductions in protein intake and reduced the risk of clinically significant weight loss among older adults with tooth loss [25–27]. Taken together, these findings suggest that while edentulous individuals most reliably gain improved food consistency and variety after implant rehabilitation, partially dentate older adults are more likely to demonstrate measurable improvements in nutrient and caloric intake following implant-supported treatment [10, 25, 26, 30]. Findings related to changes in food selection patterns and dietary consistency following implant treatment are detailed in Supplementary document2_Table 2.

Nutrient intake and caloric intake

Mixed results were shown in terms of changes in nutrient and caloric intake after the interventions with dental implants. Across the included studies, changes in nutrient and caloric intake following implant treatment varied between edentulous and partially dentate older adults. Among edentulous patients, findings were generally mixed. Several studies showed that implant-supported overdentures did not consistently improve total calorie or macronutrient intake when compared with conventional dentures, despite functional gains. For example, no significant differences were observed in energy, protein, or micronutrient intake between implant overdenture users and complete denture users after one year [27]. Some studies even reported declines in total protein intake, accompanied by increases in plant-based proteins and micronutrients such as potassium and fibre [21]. Implant mandibular overdenture users demonstrated higher consumption of foods rich in vitamins B2 and B6, whereas conventional denture users had higher sodium intake [20]. Taken together, implant treatment in edentulous individuals tended to influence quality of food choices more than quantity of caloric or nutrient intake.

Partially dentate patients exhibited more consistent and measurable improvements in nutrient intake after implant rehabilitation. Individuals restored with implant-fixed partial dentures (IFPDs) showed significant increases in fibre, calcium, and iron intake, alongside reduced cholesterol consumption [10]. Large cohort studies involving older adults with partial tooth loss (1–19 teeth) also showed that prosthesis use, including implant-supported restorations, mitigated declines in total and animal protein intake by approximately 79% and 71%, respectively [25]. These prostheses also helped reduce the risk of clinically meaningful weight loss over time [26]. Overall, partially dentate patients benefited more from implant therapy in terms of actual nutrient and caloric improvements, likely because preserved natural teeth combined with implant support enable more efficient mastication and broader dietary choices. Detailed findings on nutrient and caloric intake variations across studies, including changes in protein, fibre, and micronutrient consumption, are outlined in Supplementary document2_Table 2.

Discussion

The present systematic review synthesized evidence from 18 research studies that examined the effects of dental implants on dietary patterns, nutritional status, and masticatory function in older adult populations. Owing to substantial heterogeneity among the included studies with respect to study design, implant interventions, outcome measures, and follow-up durations, quantitative synthesis through meta-analysis was not feasible.

The reviewed studies evaluated implant-based interventions using multiple outcome domains, including chewing efficiency, maximum bite force, dietary quality, and oral health-related quality of life (OHRQoL). Overall, the evidence indicates that dental implants improve masticatory function, thereby enabling older adults to consume a wider variety of fibrous and nutrient-dense foods, while also enhancing OHRQoL.

Evidence assessing the impact of dental implants on chewing ability consistently demonstrated superior outcomes compared with conventional dentures. Among completely edentulous older adults, implant-supported overdentures were associated with marked increases in maximum bite force and improved chewing comfort, facilitating the consumption of harder and more fibrous foods. Several studies reported that implant placement resulted in increases in maximum bite force ranging from 73% to 116% [35, 36]. Enkling et al. (2016) observed a significant increase in maximum bite force from a baseline value of 46.6 N to 103.9 N at 52 weeks post-implant placement (p = 0.002) [25].

In partially dentate older adults, particularly those rehabilitated with implant-supported fixed or removable partial dentures, improvements in masticatory performance were more consistently demonstrated through objective measurements. Chewing efficiency improved as patients required fewer chewing cycles and produced smaller food particles during mastication [35, 37]. Studies by Boven et al. (2014), Rismanchian et al. (2009), and Zembic and Wismeijer (2013) confirmed that implant-supported overdentures outperformed conventional dentures in terms of bite force, chewing efficiency, and patient satisfaction [26, 30, 36, 38, 39]. Similarly, Harder et al. (2011) reported enhanced ability to chew hard foods following implant rehabilitation [31].

Müller et al. (2013) provided statistically significant evidence of improvements in denture satisfaction, bite force, and OHRQoL after converting conventional dentures to implant-supported overdentures [26, 38, 40]. However, some studies reported conflicting findings, particularly in relation to objective chewing efficiency measurements. Enkling et al. (2016) and Müller et al. (2013) noted that improvements in subjective satisfaction were not always accompanied by statistically significant changes in objective masticatory performance tests, such as colour-mixing assessments [25, 26]. These inconsistencies were more frequently observed among completely edentulous participants, whereas partially dentate individuals rehabilitated with implant-supported partial dentures demonstrated more consistent functional gains. Variability in outcomes may be attributed to factors such as facial morphology, gender, prosthesis design, and duration of adaptation [26, 41].

The impact of dental implants on nutritional intake and nutritional health in older adults remains a subject of debate, as the included studies reported heterogeneous findings. Variations were observed in outcomes related to nutritional biomarkers and body mass index (BMI). Yamazaki et al. (2016) found no significant differences in BMI, serum albumin, or vitamin B12 levels between patients rehabilitated with implant-supported overdentures and those with conventional dentures during a six-month follow-up period [42]. Conversely, Amaral et al. (2019) and El Osta et al. (2017) reported improvements in nutritional status and associated biomarkers following implant therapy [23, 33]. In contrast, Hamdan et al. (2013) and Awad et al. (2012) observed no significant advantages in nutritional biomarkers when comparing implant-supported overdentures with conventional dentures [29, 30].

These mixed findings were predominantly observed among completely edentulous older adults, where implant overdentures improved chewing comfort and food consistency but did not consistently result in measurable improvements in nutrient intake or serum biomarkers. In contrast, partially dentate older adults demonstrated more consistent nutritional benefits following rehabilitation with implant-supported partial or fixed prostheses, including increased intake of fibre, calcium, and iron, as well as reduced cholesterol consumption, as reported in population-based studies and clinical trials [10, 25, 26].

The reliance on dietary assessment tools to estimate nutritional status highlights the need for objective analytical methods. Biomarkers are widely regarded as more reliable indicators of nutritional status than self-reported dietary intake alone [43].

Dental implant placement was associated with improved dietary diversity and nutritional intake through multiple mechanisms. Tajbakhsh et al. (2013) reported increased vegetable consumption among patients rehabilitated with mandibular implant-supported prostheses [34]. Implant users consistently reported improvements in perceived chewing ability, food selection, and satisfaction with eating [26, 30, 34]. Among edentulous patients, these improvements primarily reflected enhanced tolerance of harder and fibrous foods, greater vegetable intake, and increased dietary variety. In partially dentate individuals, implant-supported fixed or removable prostheses were associated with more clearly measurable nutritional benefits, including increased intake of plant-based proteins, fibre, and micronutrients, alongside a reduced risk of weight loss.

Although objective outcomes varied, several studies demonstrated favourable changes in BMI and nutrient consumption, particularly with respect to fibre, vegetable intake, and plant-based proteins [7, 23, 34]. Improved oral comfort and masticatory efficiency allowed individuals to consume a broader range of foods, potentially contributing to better overall health and quality of life [19, 20]. This relationship is well supported in the literature, as dietary fibre and micronutrient intake have been shown to correlate inversely with impaired masticatory function [44]. Individuals with compromised mastication often modify food consistency to accommodate oral limitations, which may lead to inadequate nutritional intake or increased reliance on digestive compensation, potentially increasing the risk of gastrointestinal disorders and reduced nutrient absorption [45].

Nutritional deprivation related to tooth loss and reduced masticatory function is further influenced by behavioural, cultural, and socioeconomic factors across populations. Differences in dietary practices, food availability, transportation systems, and socioeconomic status may contribute to inconsistent nutritional outcomes between countries. For example, older adults in Japan tend to consume higher amounts of raw vegetables compared with populations in Brazil, and socioeconomic disparities may further shape dietary habits and nutritional intake.

Evidence suggests that dietary counselling can enhance nutritional awareness and food selection; however, economic constraints and physical limitations often necessitate rapid assessment of older adults’ functional capabilities, which may vary widely across settings [46]. Importantly, replacement of missing teeth alone does not guarantee improved nutritional status in older adults [47]. These findings underscore the importance of integrating dietary counselling and long-term nutritional monitoring into prosthetic and implant rehabilitation protocols.

A multidisciplinary approach involving prosthodontists, nutritionists, and geriatric care providers is widely recommended to optimize treatment outcomes [48, 49]. Behaviour-based nutritional counselling has been shown to significantly improve nutritional knowledge and nutritional status among community-dwelling older adults [50]. Improvements in the intake of dairy products, fruits, meat, and eggs have been documented following counselling interventions, supporting the need for participant-centred nutritional programmes [50]. Additionally, a study with a six-month follow-up reported increased intake of protein, fibre, vitamin E, vitamin B12, folate, iron, and zinc following structured nutritional counselling [51]. Comprehensive geriatric assessment, including evaluation of frailty and nutritional status, is essential for preoperative planning and long-term treatment success [44]. Treatment success should therefore incorporate both patient-reported outcomes and validated OHRQoL measures.

According to Müller et al. (2011), the primary barriers to acceptance of dental implant therapy among older adults include financial constraints, limited perceived necessity, and inadequate knowledge regarding treatment options [26]. Psychological factors, including fear of surgical procedures, also influence patient preferences despite favourable clinical outcomes, as reported by Assunção et al. (2007) [18]. Furthermore, gender and baseline oral health status, particularly the extent of edentulism, may affect treatment outcomes, as demonstrated in studies involving predominantly female participants [19, 27].

Current evidence indicates that chronological age alone does not significantly influence implant success rates [7]. Moreover, systemic diseases do not appear to increase implant failure risk among older adults, as supported by French et al. (2021), who reported high implant survival rates over a 15-year follow-up period [9]. Overall, implant-supported prostheses provide substantial functional and psychological benefits; however, their superiority over conventional prostheses with respect to overall OHRQoL may depend on individual patient and treatment-related factors [26].

The included studies demonstrated moderate to high methodological quality based on MMAT assessments, with most studies presenting clear research questions, appropriate designs, and reliable outcome measures. Nevertheless, several limitations were identified, including small sample sizes, short follow-up durations, lack of blinding, and reliance on self-reported dietary assessments, all of which may have compromised internal validity.

Methodological challenges remain prevalent in research examining dental implants and nutrition in older adults. Sample sizes ranged from 11 to 255 participants, limiting generalizability. Evidence suggests that improvements in oral function following implant placement may continue for 5–10 years post-treatment [25, 52], yet most studies employed follow-up periods of only 6–12 months. Tajbakhsh et al. (2013) demonstrated continued improvements in masticatory function and dietary intake over a five-year period [34], highlighting the need for longer follow-up durations. The lack of randomized controlled trials and standardized outcome measures further restricts causal inference. Additionally, most studies focused on relatively healthy, independent older adults, with limited representation of frail or institutionalized populations.

Future research should address these limitations by incorporating larger, more diverse participant cohorts, longer follow-up periods extending beyond five years, and standardized outcome measures. Randomized controlled trials with comprehensive nutritional assessments, including biochemical markers and detailed dietary analysis, are essential to better elucidate the long-term relationship between implant-based oral rehabilitation and nutritional health in older adults.

Limitations

No quantitative pooling of results was performed; standard meta-analytic procedures such as funnel plots and subgroup analyses were not applicable. The methodological diversity and lack of standardized effect estimates prevented formal testing for publication bias or subgroup differences. Instead, variability was explored qualitatively using the SWiM framework. Assessment of biomarkers as a more valid measure is required for objective and accurate evaluation of nutritional status of the individuals. Further, dietary counselling for the patients in the included studies could have confounded the observed nutritional improvements and can be considered as a limitation of the review.

Conclusion

Current evidence suggests improved mastication and patient satisfaction with implant-supported rehabilitation, while nutritional outcomes remain inconsistent. The outcomes of dental implant treatment depend on several factors such as type of prosthesis, facial structure, gender, initial oral health condition of the individual, and time needed for adaptation. Patient satisfaction and oral health-related quality of life showed consistent improvement, but objective nutritional details showed variability.

As recommendations, extensive randomized controlled trials with standardized outcome measures involving diverse participant groups are required to evaluate the long-term nutritional impact of dental implant therapy. A multidisciplinary approach should be used to maximize treatment success with dietary counselling and long-term monitoring of nutritional status during prosthetic rehabilitation of edentulous/ partially dentate old adult populations.

Abbreviations

ADL

Activities of Daily Living

AMED

Allied and Complementary Medicine Database

BMI

Body Mass Index

BDHQ

Brief Diet History Questionnaire

CD

Conventional Denture

CI

Confidence Interval

CRP

C-reactive Protein

DIDL

Dental Impact on Daily Living

eGFR

Estimated Glomerular Filtration Rate

FFQ

Food Frequency Questionnaire

GOHAI

Geriatric Oral Health Assessment Index

HRQoL

Health-Related Quality of Life

IFPD

Implant-Supported Fixed Partial Denture

IM-E-SA

INTERMED for the Elderly Self-Assessment

IMO

Implant-Retained Mandibular Overdenture

IOD

Implant Overdenture

IRPD

Implant-Supported Removable Partial Denture

MNA

Mini Nutritional Assessment

MMAT

Mixed Methods Appraisal Tool

MP

Masticatory Performance

MVBF

Maximum Voluntary Bite Force

MUAC

Mid Upper Arm Circumference

NDIs

Narrow Diameter Implants

OHRQoL

Oral Health-Related Quality of Life

OHIP

Oral Health Impact Profile

OHIP-EDENT

Oral Health Impact Profile – Edentulous

OHIP-G

Oral Health Impact Profile – German version

OR

Odds Ratio

PEO

Population, Exposure, Outcome

PRISMA

Preferred Reporting Items for Systematic Reviews and Meta-Analyses

PROSPERO

International Prospective Register of Systematic Reviews

QoL

Quality of Life

RCT

Randomized Controlled Trial

SIO

Single Implant Overdenture

ST

Swallowing Threshold

TDF

Total Dietary Fiber

tHcy

Total Homocysteine

VAS

Visual Analogue Scale

VOH

ViewGum Output Histogram (chewing efficiency measure)

Authors’ contributions

Conceptualization and designed the study: SI and KS. Screening: SI, KS, DL and RMJ. Analyzing and interpretation of the data: SI, KS, DL, MR, CHK, MB and PB. Writing the original draft: SI, CHK, and MB: Project Administration, Resources, Software, Supervision, Writing- Review, and Editing the final draft: DL, KKK, RMJ, and RDJ. All the authors have read and consented to the published version of this manuscript.

Funding

This study received no financial support from public, commercial, or nonprofit funding agencies.

Data availability

The corresponding author will provide the data upon reasonable request.

Declarations

Ethics approval and consent to participate

Not applicable for this study.

Consent for publication

Not applicable for this study.

Competing interests

The authors declare no competing interests.