Long-term stable osseointegrated implants are the primary goal in dental implantology. Although dental implants have proven clinical reliable in the long term, the failure of implants at a very early stage of osseointegration has been described [1, 2]. The pursuit to identify the mechanisms leading to early implant failure is ongoing to date and include the following: tobacco usage, diabetes, wear particle release and foreign body reaction, local bone necrosis due to heat generation during bone preparation or implant placement [2–9]. Systematic reviews demonstrated that an antibiotic regimen before dental implant placement subtly reduces the early implant infection and consequently implant failure [10, 11]. In orthopedics, the risk to develop a periprosthetic joint infection has been associated with a low vitamin D level [12]. A relationship between bone metabolism, vitamin D, and early implant failure in human has not been proven to date. Vitamin D induces bone formation around implants in rodents [13–17]. Besides the classical function, findings of the last decades indicate vitamin D as an important immune regulator targeting both, the innate and adaptive immune response, since all cells of the immune system express vitamin d receptor (VDR) [18–20].

The definition of vitamin D serum level is discussed in the literature [21–25]. Currently, vitamin D insufficiency is defined as serum level ranges between 21 and 29 μg/l, a serum level below <20 μg/l as vitamin D deficiency (severe deficiency <10 μg/l) [22, 25, 26]. The prevalence of vitamin D deficiency in Europe varies widely with ranges between 2 to 30% in adults and up to 80% in elderly patients [27]. Malnutrition, insufficient sun exposure, premature and dysmature birth, pigmented skin, obesity and advanced age are known as factors for a vitamin D deficiency [28].

A current review article demands the investigation of vitamin D deficiency in the context of dental implant failures [16]. To address this demand, the present case reports raised the question if vitamin D deficiency influences implant survival in the early stages of healing. This article illustrates two apparently healthy patients with vitamin D deficiency and early implant failure and demonstrates that implant placement was successful after vitamin D supplementation.