Effect of Serum Vitamin D Levels on the Clinical and Radiographic Outcomes of Unsplinted Mandibular Implant Overdentures
Conditions: Vitamin D Deficiency, Implant Assesment, Radiography, Clinical and Radiographic Effect
Sponsor: Mansoura University

Effect of Serum Vitamin D Levels on the 
Clinical and Radiographic Outcomes of 
Unsplinted Mandibular Implant Overdentures 
 
 
 
Date of Document: 2 September 2025 
Ethics committee approval no.  R.25.07.10 
 
 
 
 
By 
Rahma El hussany Mohammed 
 
 
 
         
 
 
 
 
 
 
 

Introduction 
 
        Tooth loss, particularly in the edentulous mandible, remains a major oral 
health concern that can significantly impact a patient’s quality of life. The use of 
mandibular implant overdentures has become a reliable and widely accepted 
treatment option that improves prosthesis retention, stability, and masticatory 
efficiency compared to conventional complete dentures (1). Among the various 
approaches, unsplinted implant overdentures, using locator attachments or 
similar systems, offer the advantages of easier hygiene, reduced cost, and 
simplified prosthetic procedures (2,3). 
 
     The long-term success of implant-retained overdentures relies heavily on the 
health of peri-implant tissues and the maintenance of marginal bone levels. 
Multiple factors influence peri-implant outcomes, including biomechanical 
loading, oral hygiene, systemic health, and notably, the patient’s nutritional and 
metabolic status, especially vitamin D levels (4,5). 
 
        Vitamin D plays an important role in calcium-phosphate homeostasis, bone 
remodeling, and immune modulation. Recent studies have suggested that 
vitamin D deficiency may adversely affect osseointegration, increase the risk of 
early implant failure, and accelerate peri-implant bone loss. However, most of 
these findings are derived from studies on fixed implant restorations, while little 
is known about its effect in the context of implant overdentures, particularly the 
unsplinted type (6,7) 
 
 
 
       Despite the increasing use of unsplinted mandibular implant overdentures, 
there is limited clinical evidence regarding how serum vitamin D levels 
influence their clinical and radiographic outcomes. Understanding this 
relationship may help identify patients at risk, guide preoperative 
supplementation strategies, and ultimately improve long-term implant success (8). 
 

      Therefore, this study aims to evaluate the effect of serum vitamin D levels on 
clinical (e.g., implant stability, probing depth) and radiographic (e.g., marginal 
bone loss) outcomes in patients treated with unsplinted mandibular implant 
overdentures. 
 
Materials and Methods 
      This retrospective study are conducted at the Prosthodontic Department, 
Faculty of Dentistry, Mansoura University. Patient records from the department’s 
database were reviewed to identify individuals who had received unsplinted 
mandibular implant overdentures supported by three implants and retained by 
locator attachments. Only patients with complete clinical, radiographic, and 
laboratory documentation were included. This study included about 20 patients 
for each group. The sample size are limited due to retrospective nature and 
availability of complete records including serum vitamin D levels. 
The patients selected according to the following criteria: 
•  Patients' age ranged from 40 to 60 years. 
•  Patients 
rehablilitated with unsplinted 
three-implant mandibular 
overdentures retained by locator attachments. 
• Availability of serum vitamin D levels. 
• Complete records of follow up clinical and radiographic assessments. 
Assessment intervals are T0 at prothesis loading, T6 after 6 months and 
T12 after 12 months of loading. 
• All radiographic assessments are performed using standardized imaging 
protocols. Digital periapical radiographs were taken using the paralleling 
technique for all patients with an individualized film holder to ensure 
consistent angulation and image geometry across time points. Images 
were calibrated based on known implant lengths to allow for accurate 
bone level measurements 
 
Exclusion criteria: 
• Missing or incomplete patient records. 
• Patients on medications known to affect bone metabolism. 
• History of smoking or alcohol abuse. 
     This study is retrospective review that involves no direct with patients. All 
data will be anonymized and coded to ensure confidentiality. 

      The study is performed after being approved by The Ethics committee 
of Dental Research in Faculty of Dentistry, Mansoura University, number 
R250710 
 Patients will be categorized into two groups based on their recorded serum 
vitamin D levels (9): 
 
• 
Group A – Deficient: < 20 ng/mL 
 
• 
Group B – Sufficient: ≥ 30 ng/mL 
      Patients with borderline values (21-29 ng/mL) will be excluded to avoid 
classification bias. 
   The vitamin D level is retrieved from medical laboratory results recorded 
in the patients’ files. 
 Marginal bone loss (MBL) is measured from the implant platform to the 
first bone–implant contact (mesial and distal), using calibrated imaging 
software. Calibration is based on the actual implant length to ensure 
measurement consistency. 
 All measurements are performed in millimeters by the same examiner 
under identical settings. The examiner is blinded to patient's serum 
vitamin d levels during evaluation to minimize bias. 
 All data are extracted from patient records using a standardized data 
collection sheet designed for this study, to ensure consistency in clinical 
and laboratory parameters. 
 Once all data are collected, they will be statistically analyzed. 
 
Statistical analysis  
 Data are analyzed using statistical software (SPSS, version 22.0; SPSS 
Inc., Chicago, IL). The Shapiro-Wilk test is used to assess the normality of 
bone loss data. Descriptive statistics are expressed as mean ± standard 
deviation. Repeated measures analysis of variance (ANOVA) is used to 
evaluate changes in bone loss over time, followed by the Tukey Post hoc 
test for pairwise comparisons between time intervals. Intergroup 
differences are assessed using the independent samples t test. A P value 
<.05 was considered statistically significant at a 95% confidence level. 
 
 
 
 

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