J Adv Prosthodont.  2024 Aug;16(4):212-220. 10.4047/jap.2024.16.4.212.

Restoration-oriented anatomical analysis of alveolar bone at mandibular first molars and implications for immediate implant placement surgery: a CBCT study

• Shi Q
• Huang Y
• Huo N
• Jiang Y
• Zhang T
• Wang J

• KMID: 2559037
• DOI: http://doi.org/10.4047/jap.2024.16.4.212

Abstract

PURPOSE
This cone-beam computed tomography (CBCT) study aimed to analyze the anatomical characteristics of alveolar bone at mandibular first molar (MFM) and their implications for immediate implant placement surgery.
MATERIALS AND METHODS
100 patients with 140 MFMs were reviewed retrospectively. We first performed a 3D reconstruction of the patient’s CBCT data to determine a reference plane with ideal implant placement and orientation. The following parameters of MFM region were analyzed: mesial-distal socket size (MDSS), buccal-lingual socket size (BL-SS), root furcation fornix to inferior alveolar nerve (IAN) distance (RF-I), interradicular bone thickness (IRB), mesial/distal root apex to the IAN distance (MRA-I/DRA-I), thickness of the buccal/lingual bone of the mesial root (MR-B/MR-L), thickness of the buccal/lingual bone of the distal root (DR-B/DR-L).
RESULTS
The MD-SS of MFM was 8.74 ± 0.76 mm, and the BLSS was 8.26 ± 0.72 mm. The MR-B, DR-B was 1.01 ± 0.40 mm and 1.14 ± 0.50 mm, and the difference was statistically significant (P = .001). The values of the MR-L, DR-L were 2.71 ± 0.78 mm and 3.09 ± 0.73 mm, and the difference was also statistically significant (P < .001). The mean distance of RF-I was 15.68 ± 2.13 mm, and the MRA-I was 7.06 ± 2.22 mm, which was greater than that of DRA-I (6.48 ± 2.30 mm, P < .001). The IRB at 2 mm, 4 mm apical from the furcation fornix, and at apex level was 2.81 ± 0.50 mm, 3.30 ± 0.62 mm, and 4.44 ± 1.02 mm, respectively.
CONCLUSION
There is relatively sufficient bone mass in interradicular bone in height, but an adequate width is lacking for the bone between the mesial and distal root after the extraction of the MFM for immediate implantation. The thickness of the MFM buccal bone is relative thin, especially for the mesial root.

Keyword

Mandibular first molar; Immediate implant placement; Cone-beam computed tomography; Anatomical analysis