الفهرس 
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Abstract
Implant success and osseointegration depend on multiple factors: surgical and prosthetic factors, the implant design, and patient-related factors. It can be difficult to define which of them might be determining the success or failure of the treatment. The different quantity and quality of bone at the implant receiving sites and the patient response are unavoidable factors. Some patients are more prone to implant failure, in particular those with systemic conditions that might increase the risk of implant failure. It is worthy to mention that several micronutrients are hypothesized to have an influence on the skeletal system, particularly on alveolar bone and on dental implant osseointegration. Which in turn affects dental implant stability and can be a cause of dental implant early failure, particularly.
This study’s main aim is to investigate the impact of vitamin D deficiency in relation to early dental implant failure. As a result of the worldwide increasing incidence of vitamin D deficiency and the huge impact of it reflected in dental implant dentistry. Available data suggest that vitamin D deficiency leads to a higher implant failure rate.
However, several critical issues persist regarding the effect of vitamin D in enhancing osseointegration, particularly concerning its mechanism of action and the influence of different serum 25(OH)D levels required to avoid and minimize the possible
incidence of early implant failure and significantly improve the dental implant success rate.
The present observational cross-sectional study on 53 patients confirms the evidence established by other studies, which reported a high incidence of failure of 46.2% in the group with serious vitamin D deficiency (<10 ng/mL) compared to 4.5% in patients with optimum serum levels of vitamin D (>30 ng/mL) and 2.3% in the group of patients with insufficient serum levels of vitamin D (10–30 ng/mL). The difference between the three groups ( P = 0.001 ) was statistically significant. This result is particularly interesting and could suggest that the operator should prescribe patients vitamin D supplements in the weeks before implant procedures.
This study has the following pros: restricted to early implant failures within 3 to 4 months. Only one implant system was used, installed by operators of the same level of experience, and all surgeries were performed in the same clinic under the same surgical protocol. All the vitamin D assessments were held at the same laboratory using the same test. All the assessments of implant stability, primary and secondary, were done using the Osstell device, and both clinical and radiographic evaluations were done by the same investigator. Moreover, patients with systemic pathologies (such as uncontrolled diabetes mellitus,
immunodeficient states, bleeding disorders, etc.) or those who underwent radiotherapy and chemotherapy treatments were excluded from that study.
The drawbacks of this study include the following: It is an observational cross-sectional study in which the number of patients with a severe deficiency of vitamin D in the blood was low only six patients. Thus, the presence of even just one less failure in this group would have led to quite different results. It is possible that some residual confounding factors may have biassed the association between vitamin D and implant failures that we observed. For instance, this study did not investigate the influence of other patient-related factors such as bone quality, which can affect implant survival in the period immediately following implant placement, nor the effects of other micronutrients that may affect vitamin D levels, such as magnesium. In addition, the presence of diabetes in some patients, especially in failure cases, may be regarded as a confounding factor, though all diabetic patients in this study had controlled HbA1c below 7, which proved statistically to have impact on vitamin D serum levels.
To the best of our knowledge, this is the first study to investigate the role of vitamin D deficiency in the implant stability of dental implants using resonance frequency analysis (Osstell) both primary at the time of placement and secondary 12 weeks
later, correlated to early implant failures. However, we found that in relation to serum vitamin D the mean values of primary stability and secondary stability were statistically very significant, with a P value of 0.001. Moreover, we found that mean secondary stability in sufficient and insufficient groups was higher than deficient groups. Statistically significant difference between sufficient and deficient groups with P value ˂0.01 and between sufficient and insufficient groups with P value ˂0.001 while there was no significant difference between deficient and insufficient groups. Finally, we found that there was no significant relationship between the implant failure in ISQ 1and ISQ 2, nor between the implant failure and the implant location.
Our findings support the role of vitamin D as a risk factor for early implant failure in patients with vitamin D deficiency we concluded that:
• The incidence of early implant failures was higher in patients with serum levels of vitamin D below 15 ng/ml.
• The incidence of failure was very high in patients with both vitamin D level below 15ng/ml and type 2 diabetes mellitus.
• Incidence of failure was high in posterior maxilla (molar region) followed by posterior mandible.
Therefore, we recommended that:
• Further well-designed randomized clinical trials investigate the influence of vitamin D serum levels below 15 ng/ml on implant failure.
• Further investigation on role of vitamin D supplementation on early implant failure in patients with vitamin D levels below 15 ng/ml
• We recommend further investigation on roles of other micronutrients that modulate bone metabolism on dental implant osseointegration.