Clinical Paper
Dental Implants
Radiographic analysis of critical anatomical structures for pterygoid implant placement in Chinese patients with a severely atrophied maxilla

https://doi.org/10.1016/j.ijom.2023.01.005Get rights and content

Abstract

The pterygoid implant is a feasible alternative for posterior dental rehabilitation without grafting; however, the ideal pterygoid implant placement continues to be debated. The aim of this study was to identify effective landmarks and establish valid guidelines to determine the ideal pterygoid implant placement. Cone beam computed tomography (CBCT) data of 100 severely atrophied maxillae requiring implant rehabilitation, obtained between January 2015 and December 2018, were included. The CBCT data were obtained in DICOM format from the radiographic database and imported into Nobel Clinician software (Nobel Biocare) for radiographic analysis. Virtual pterygoid implant placement was successful in 67 maxillae: a 13-mm virtual implant in four maxillae (6.0%), 15-mm in 52 maxillae (77.6%), and 18-mm in 11 maxillae (16.4%). For the virtual pterygoid implant, the mean implant angulation± standard deviation in the anteroposterior axis (sagittal view) was 45.08 ± 2.56° relative to the Frankfort plane. In the buccopalatal axis (coronal view), the mean implant angulation was 64.30 ± 4.99° relative to the Frankfort plane and the mean value for the shortest linear distance between the palatine canal and apical tip of the virtual implant was 3.91 ± 0.62 mm. A 15-mm pterygoid implant placed at 45° in the anteroposterior axis and 60° in the buccopalatal axis (relative to the Frankfort plane), is generally recommended in this Chinese patient population.

Section snippets

Study protocol

The cone beam computed tomography (CBCT) data of consecutive patients requiring implant rehabilitation of the posterior atrophied maxilla between January 2015 and December 2018 were obtained from the tomography database of Shanghai Ninth People’s Hospital. An access approval was obtained from the Ethics Board of Shanghai Ninth People’s Hospital and the Institutional Review Board of Shanghai Jiao Tong University to check the tomography data and files. Each file retrieved was assigned a number to

Results

A total of 100 severely atrophied maxillary sides in 86 patients (left maxillary side in 43 patients, right side in 29 patients, and bilateral in 14 patients) were eligible for inclusion in this study (Fig. 3). Of the 86 patients, 48 were male and 38 were female; their mean age was 59.3 ± 8.9 years (range 31–77 years). Virtual pterygoid implant placement failed in 33 out of the 100 maxillary sides. Among the 67 successfully placed virtual implants, 13-mm virtual implants were placed in four

Discussion

The pterygoid implant is considered an alternative option for posterior dental rehabilitation obviating the need for grafting. This option can shorten the treatment duration, reduce the cost, and avoid the risk of graft failure.20 Additionally, pterygoid implant placement eliminates the distal cantilever design, therefore supporting the biomechanical stress distribution. However, until recently, there has been no universal consensus for guiding the ideal position of pterygoid implant placement,

Funding

None.

Ethical approval

The study protocol was approved by the Ethics Committee of Shanghai Jiao Tong University, School of Medicine (Shanghai, China). All participants were informed of the research procedure and signed the participation consent agreement.

Competing interests

None.

Patient consent

Not required.

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1

Qiaoyu Zhang and Ahmed Abdelrehem are co-first authors.

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