Using Cone-Beam Computed Tomography to Assess Changes in Alveolar Bone Width around Dental Implants at Native and Reconstructed Bone Sites: A Retrospective Cohort Study

Changes in alveolar bone width around maxillary implants, as determined through cone beam computed tomography based on bony landmarks: A preliminary study

PURPOSE

This study aimed to investigate changes in alveolar bone width around dental implants and identify the anterior nasal spine (ANS), posterior nasal spine (PNS), and floor of the nasal cavity that can be used as reference landmarks for standardizing the orientation of different cone-beam computed tomography (CBCT) scans.

MATERIALS AND METHODS

We enrolled two groups that comprised 30 implants. Two CBCT scans from the same patient after implant surgery in the first group were obtained to determine differences in the relative distance and angle between the ANS and apex of the dental implant. Then we compared the second group of patients' presurgical and postsurgical CBCT images to evaluate changes in alveolar bone width after dental implant surgery by the aforementioned bony landmarks.

RESULTS

In the first group, no statistically significant differences were detected in the mean distance between the ANS, PNS and implant tip in different directions. In the second group, bone width increased at 1 mm (p = 0.020) and decreased at 4 mm (p < 0.001) and 7 mm (p < 0.001) below the alveolar bone crest after implant surgery.

CONCLUSIONS

Within the limitations of the present study, the ANS, PNS, and floor of the nasal cavity can be useful in standardizing the orientation of CBCT scans and alveolar bone remodeling after implant surgery varied depending on the height and direction from the alveolar bone crest based on the three landmarks.

Three-dimensional radiographic assessment of bone changes around posterior dental implants at native bone site in Gansu Province, Northwest of China: A retrospective cohort study

PURPOSE

The aim of this study was to assess bone density and thickness changed following dental implant placement in the maxillary and mandibular jaws. Also, observe the form of bone loss around the implant and the relationship between preoperative bone density and bone thickness with bone loss around dental implants.

METHODS

65 patients, including 102 dental implants, were assessed in this study. CBCT was utilized to determine the bone condition (bone thickness and density at three levels (sub-crestal bone at 3 mm (CB3), 6 mm (CB6), and 9 mm (CB9)) before implant placement, and 2 to 3 years after placement, also determine the bone loss pattern.

RESULTS

The difference in bone thickness was 0.32 ± 0.50 mm at CB3, 0.18 ± 0.40 mm at CB6, and 0.14 ± 0.07 mm at CB9. The change buccal bone density at CB3, CB6, and CB9 were 344.5 ± 278.9, 260.5 ± 276, and 138.9 ± 313.9 HU, respectively, and the change in lingual bone density was 252.7 ± 247, 179.9 ± 244.1, and 281 ± 4063 HU, respectively. Only the CB3 level showed a significant decrease in bone thickness (p < 0.001), and a change in bone density was observed at the three levels (p < 0.001). The means of vertical and horizontal bone loss were 0.19 ± 0.23 mm and 0.18 ± 0.22 mm, respectively. Splinted or adjacent dental implants have more horizontal bone loss, with statistically significant (p < 0.001). Age, gender, and implant position were not statistically related to the outcome variables. There was a negative correlation between the preoperative status of the bone condition and pattern bone loss, as indicated by Pearson's correlation coefficient.

CONCLUSION

CBCT detected a significant bone thickness decrease was found only at the crestal third. A significant bone density increase was found at three levels around dental implants. Implant areas with higher bone thickness and density had less bone loss.

Dimensional Changes in the Alveolus after a Combination of Immediate Postextraction Implant and Connective Grafting and/or Socket Shield Technique

Immediate implant placement protocols after dental extraction have enabled a reduction in surgical phases. This procedure has increased patient satisfaction and similar survival rates to late implant placement procedures. However, placing an implant immediately after dental extraction does not counteract the physiological remodeling of alveolar bone. For this reason, additional surgical techniques have been developed, such as the placement of a connective tissue graft (CTG) or the socket shield technique (SST). Dimensional changes in the peri-implant tissues were observed after placement of immediate implants following the extraction and CTG and/or SST. A total of 26 surgical interventions were carried out in which dimensional change variables of peri-implant tissues were analyzed. The preoperative state and immediate postoperative situation were compared with the situation after one year. Measurements were taken at 3, 5, and 7 mm from the gingival margin and analyzed in this CBCT radiological study (Planmeca Promax 3D). The implant platform was used as a reference point for the measurement of changes in alveolar crest height. One year after performing either of the two techniques (CTG and/or SST), a significant increase in the gingiva thickness and vestibular cortex occurred at 5 mm (0.65 ± 1.16 mm) and 7 mm (0.95 ± 1.45 mm) from the gingival margin. Additionally, an increase in thickness of palatal bone was registered at 3 mm (0.48 ± 0.90 mm). The graft placement group showed an increase in thickness of peri-implant tissue in the vestibular area after one year, although CTG and SST groups were clinically similar. The implementation of SST revealed promising results regarding the buccal thickness of hard and soft tissues after one year. A significant increase in vestibular cortical bone thickness, as well as the overall mucosa thickness and buccal bone at 3 mm from the gingival margin, was observed. A significant reduction in the distance from the bone crest to the platform was detected in both techniques. Both techniques (CTG and SST) are appropriate to provide sufficient volume to peri-implant tissues in the vestibular area of anterior maxillary implants. Some limitations were detected, such as the lack of an aesthetic analysis or small sample size, so results should be interpreted with caution. Future studies are necessary to further evaluate the long-term predictability of these techniques.