Hypothyroidism reduces the recruitment, maturation, and activity of bone cells, decreasing bone resorption and formation. Several investigations have reported that T4 replacement therapy is associated with a significant decrease in bone mineral density in various skeletal parts, while others have failed to corroborate these results. The present study describes both a literature review and our own experience with dental implants in patients with hypothyroidism undergoing T4 replacement therapy.
The study included two parts: a literature review and case series. The literature review included 12 articles documenting the success rate of osseointegrated dental implants in patients with hypothyroidism. The clinical cases were chosen from King Saud University Dental College, Riyadh. The patients’ identity was only available to the main researcher. The inclusion criteria for the clinical cases were: T4-treated hypothyroidism, age 20-60 years, and use of dental implants with a follow-up period of 6-12 months after loading. The exclusion criteria were: any other medical condition alongside hypothyroidism, syndromic hypothyroidism, pregnancy, current smoking, bruxism, and hypothyroidism caused by surgical excision combined with radiotherapy. The following parameters were assessed: insertion torque (IT), crestal bone height (CBH), mesial bone width (MBW), and distal bone width (DBW) at different time points, probing depth, and signs of infection.
Seventeen dental implants placed in patients with T4-treated hypothyroidism showed median IT success (42.4 N⋅cm; range: 35-45 N⋅cm). The median crestal bone loss was measured at 6-12 months after loading was 0.6 mm (range: 0.5-0.7. mm). Conversely, the median bone loss differences in MBW and DBW at 6-12 months after loading were 0.3 mm and 0.2 mm, respectively.
After a 1-year follow-up, patients with T4-treated hypothyroidism who had received dental implants fulfilled the criteria for successful implants.