The Anatomical Conditions of the Alveolar Process of the Anterior Maxilla in Terms of Immediate Implantation-Radiological Retrospective Case Series Study

Abstract

The feasibility and the level of difficulty of immediate flapless implantation depend largely on the residual alveolar bone. The purpose of the study was to determine how often immediate flapless implantation in the anterior maxilla is feasible and assess the difficulty level using cone-beam computed tomography (CBCT) scans. A radiological retrospective case series study was conducted. In total, 1200 CBCT scans from 300 consecutive patients were analyzed with dedicated planning software. Immediate flapless implants were possible in 78.33% of cases. Drilling direction was either through the apex or the palatal slope. Bimodal was conducted in 9% of the cases; only through the apex in 13.08% of the cases and in 56.25% only in the slope. In 21.67%, immediate flapless implants were excluded. The feasibility and degree of difficulty differed statistically to the disadvantage of the lateral incisors compared to the central incisors. Drilling direction caused that BASE classification reflects the difficulty level of immediate implantation. CBCT is a helpful diagnostic tool for assessing the feasibility of immediate flapless implants due to the residual bone shape and volume. BASE classification helps to determine a challenge level that may also facilitate communication and result in comparison. The alveolar bone condition allows for immediate flapless implants in most cases in the aesthetic region of the maxilla, but they should be performed by an experienced specialist with regard to the bone and soft tissue quality.

Keywords: aesthetic region of maxilla; alveolar bone shape; bone anatomy; classification; cone-beam computer tomography (CBCT); dental implants; flapless implants; immediate implantation; predictable implantation.

Figure 1

Measurements of the alveolar bone on cross-section cone-beam computed tomography (CBCT) scans in the anterior maxilla. (A). Schematic drawing; (B). Radiological measurements (H—Total height of the alveolar process; H1—The height of the bone from the apical part of the alveoli to the bottom of the nose or the maxillary sinus; H2—The height of the palatal plate of the alveoli; H3—The height of the buccal plate of the alveoli; R—The root length of the tooth; W1—The width of the bone at the level of the alveoli aperture; W2—The width of the bone at the basis).

Figure 2

Measurements of the planned implant relationship to the alveolar process on cross-sectional CBCT scans in the anterior maxilla. (A). Scheme; (B). Radiological example of the taken measurements (L—Total implant length; L1- Implant length submerged in the bone on the buccal side; L2—Implant length protruding from the bone on the buccal side; L3—Implant length submerged in the bone on the palatal side; L4—Implant length protruding from the bone on the palatal side; G—Gap between the buccal surface of the implant and the bone buccal plate).

Figure 3

BASE—drilling guidelines for immediate flapless implants in the maxillary aesthetic region.

Figure 4

The most often alveolar bone modalities of the anterior maxilla depending on the tooth type. BASE classification: (A). The frequency of all modalities; (B). The feasibility of immediate implantation versus cases excluded; (C). The difficulty level of immediate implantation (1—all central incisors, 2—all lateral incisors).

Figure 5

The dental arch side dependent on bone condition comparison. BASE Classification: (A). Central incisors; (B). Lateral incisors (1 R—right central incisors; 1 L—left central incisors; 2 R—right lateral incisors, 2 L—left lateral incisors).