Effect of hypothyrodism's medication (T4) on implant osstointegration: A case series and literature search

Abstract

Introduction: 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.

Case presentation: 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.

Discussion: 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.

Conclusion: After a 1-year follow-up, patients with T4-treated hypothyroidism who had received dental implants fulfilled the criteria for successful implants.

Keywords: Dental implants; Hypothyroid disease; Medically compromised patient; Osseointegration; T4.

Fig. 1

The illustration shows how the bone height and width were measured immediately (D0) and 1 year (D1) after implant insertion. Two reference lines are drawn: the blue, vertical, broken line denotes the center of the implant crossing the apical reference point, while the red, horizontal, broken line. Present the apical limit for measuring the crestal bone height. The mesial bone width (MBW) and distal bone width (DBW) are also shown.

Fig. 2

Case one showing (A) inserted upper implant, (B) inserted lower implants, (C) loading of the upper implant 12 months after insertion.

Fig. 3

(A) Two implants inserted in the premolar-molar area before loading. (B) Implants are loaded with a bridge, replacing the premolar area.

Fig. 4

Timeline for assessment of implant and radiographs.

Fig. 5

(A) Single implant inserted to replace molar tooth. (B) 12 months after loading of the implant.

Fig. 6

(A) Two implants after insertion, with healing cap. (B) 12 months after loading of the two implants.

Fig. 7

(A) Area after extraction. (B) Two implants replacing lower premolar and molar. (C) 12 month after implant loading.

Fig. 8

(A) Two implants inserted to replace missing lower anterior teeth. (B) 12 months after loading.