2021, Number 1
Assessment of the posterior superior alveolar artery and its relationship with the maxillary sinus using the computed axial tomography
Language: English/Spanish [Versión en español]
References: 27
Page: 59-64
PDF size: 157.90 Kb.
ABSTRACT
Introduction: The location of the anatomical features is important for maxillary sinus elevation surgery and cone-beam computed tomography is a very useful technique to find them. Aim: To identify the prevalence and location of the posterior superior alveolar artery (PSAA) relative to the alveolar crest, using Ella's international classification in the Peruvian adult population who attend a diagnostic imaging center, recognized for medical care in the central Peruvian region. Material and methods: For the placement of dental implants, 240 computed tomography scans of patients with unilateral superior partial edentulism were studied. To locate the posterior superior alveolar artery, 0.5 mm thickness cross-sections in the edentulous sector were used. It was ranked in three degrees considering the distance from the alveolar crest. Results: Grade 3 had a higher prevalence in the location of the posterior superior alveolar artery and had grade 4 subantral maxillary segment height, registering 99.2% of the total. Conclusions: The highest degree of localization of the artery was found according to Ella's international classification when there was a greater height of the subantral maxillary segment -according to Misch's classification- in the partial edentulous space.INTRODUCTION
Partial edentulism is a problem that generally affects the Peruvian adult population. A missing tooth modifies the location of the adjacent anatomical landmarks such as arteries, nerves, and soft and hard tissues. Patients opt for fixed and long-lasting treatments –dental implants–. They are previously subjected to diagnostic examinations using computed axial tomography to evaluate the condition, differentiation, and quantification in three dimensions of all the surrounding structures.1,2
The posterior superior alveolar artery (PSAA) is responsible for providing vascularity to the mucous membrane of the maxillary sinus, the anterolateral wall of the sinus, and the underlying periosteal tissue.
Knowledge about the location and anatomy of the maxillary region is vitally important to prevent complications when surgically approaching maxillary sinus elevation when planning dental implant placement.3,4 The classification of the different maxillary sinus floor elevation techniques depends on the residual bone height between the alveolar ridge and the sinus floor (substantial maxillary segment height) described by Misch.5,6
That is why the study of this anatomical structure is proposed to treat partial edentulism in a Peruvian adult population. This study aims to evaluate the prevalence and location of the posterior superior alveolar artery (PSAA) relative to the alveolar crest, using Ella's7 international classification in the Peruvian adult population who attend a diagnostic imaging center in Huancayo, Peru.
MATERIAL AND METHODS
Two hundred and forty computed tomography scans of patients with unilateral upper partial edentulism were collected as samples from the Radiología y Tomografía Cero Huancayo diagnostic center. Inclusion criteria: well-preserved computed axial tomography scans with adequate resolution, belonging to patients with unilateral upper partial edentulism of both genders, aged 35 to 75 years, who were referred for tomographic study for dental implant placement. The exclusion criteria were computed axial tomography of patients with sinusitis and periodontal and systemic diseases.
To locate the PSAA 0.5 mm thickness cross-sections of the edentulous sector were used. It was grouped according to the distance to the alveolar crest in thirds, according to Ella's classification: as a minor middle third when located on the alveolar crest without involving the maxillary sinus, major middle third: when it was located from 3 mm to 13 mm involving the lower wall of the maxillary sinus and the upper-middle third when it exceeded 13 mm to the upper wall of the maxillary sinus. The computed tomography scans were also grouped according to Misch's residual alveolar ridge classification into four levels: grade 1: subantral maxillary segment height was equal to or greater than 10 mm; grade 2: subantral maxillary segment height was between 8 and 10 mm; grade 3: subantral maxillary segment height was found between 4 and 8 mm; and grade 4: subantral maxillary segment height was less than 4 mm. All these data were recorded in a form, in addition to patient identifier number, gender, age, and time of edentulism. The data were evaluated in the statistical program SPSS version 3.0. Tables and graphics were obtained to related variables and obtain results.
RESULTS
The samples were analyzed in their entirety, validating 240 elements for this research. In addition, they were grouped according to gender, finding that the number of computed axial tomography scans of females was higher (58.3%) than males (Table 1).
Table 2 shows that the most frequent time of edentulism is 10 to 13 years in females (140 cases out of 240 in total).
Table 3 shows that the highest frequency corresponds to grade 3 in the location of the PSAA and that they have 10 to 13 years of edentulism (82% of the total).
Table 4 shows that the cases with the highest frequency are grade 3 in locating the PSAA and a grade 4 subantral maxillary segment height, registering 99.2% of the total.
DISCUSSION
Partial edentulism is a problem that generally affects the Peruvian adult population. A missing tooth modifies adjacent anatomical landmarks such as arteries, nerves, and soft and hard tissues. Patients opt for fixed and long-lasting treatments -dental implants- and undergo diagnostic examinations to assess hard and soft tissues,5 preferably CT images. The PSAA can hinder the complete preservation of the sinus membrane as it can hamper the preparation and elevation of the maxillary sinus for implant placement through surgical procedures. Its correct location can prevent many complications in surgery and reduce the morbidity of dental implants placed where the maxillary sinus membrane has changed its location.7-10
Several authors have studied this important artery, prioritizing its correct location utilizing the first-choice auxiliary examination, computed axial tomography.11-13 Elian mentions that the PSAA is a collateral branch of the maxillary artery and is located approximately 16.4 mm from the alveolar crest. Therefore, it is present in 100% of patients, but it is only visible by computed axial tomography in 53% of cases.14
Wallace points out that computed axial tomography is an excellent tool in evaluating the presence of sinus, septa, and artery pathology prior to maxillary sinus surgery. These data can help surgeons estimate the risk of bleeding in a sinus elevation using a crestal or lateral entry route under local or general anesthesia.15 Ella7 establishes that the larger the diameter of the artery, the greater the risk of bleeding; techniques such as crestal access and lateral window for an elevation of the maxillary sinus membrane should be taken into account in the surgical treatment plan, evaluating the anatomical structures present by CT scan. Greenstein states that the preoperative image is clinically relevant to evaluate the presence of the septum in the maxillary sinus, location of the PSAA, and the existence of pathologies corresponding to the maxillary sinus. In addition, these data can be used so that the surgical access plan produces a successful implant treatment.16
It is suggested that computed axial tomography exploration be a valuable tool in evaluating a maxillary sinus pathology, presence of septum and arteries prior to maxillary sinus surgery.17 In addition, Cruz recommends that the location of the PSAA should be considered according to the ridge, the subantral maxillary segment height, and the maxillary sinus to guide the surgeon, allowing a less bleeding procedure and fewer complications.18
Garcia19 pointed out that the loss of teeth affects the maxillary sinus's pneumatization and that the maxillary sinus's highest degree of pneumatization occurred when there were at least two teeth adjacent to the edentulous side.20
Knowledge of the anatomy of the maxillary region must be essential for the surgeon before performing a maxillary sinus elevation in order to avoid complications, triggers of bleeding, and inflammatory conditions of the maxillary sinus.21-25 Therefore, knowing its location is vital to avoid sinus elevation problems when planning dental implant placement.12,26,27
CONCLUSION
The subantral maxillary segment height affects the location of the PSAA. According to Ella's international classification, the highest degree of localization of this artery was found when there was a greater degree of the subantral maxillary segment height according to Misch's classification in the partial edentulous space.
ACKNOWLEDGMENTS
This research was carried out thanks to the support provided by the Facultad de Ciencias de la Salud/Odontología-Huancayo de la Universidad Continental. We also thank the Scientific Research Unit for the technical, academic and financial support.
REFERENCES
Simsek Kaya G, Daltaban O, Kaya M, Kocabalkan B, Sindel A, Akdag M. The potential clinical relevance of anatomical structures and variations of the maxillary sinus for planned sinus floor elevation procedures: A retrospective cone beam computed tomography study. Clin Implant Dent Relat Res. 2019; 21 (1): 114-121.
AFFILIATIONS
1 Profesor de Periodoncia, Universidad Continental, Huancayo, Perú.
2 Profesor de Periodoncia, Universidad Nacional Mayor de San Marcos, Perú.
CORRESPONDENCE
Lizeth Villaverde Moscol. E-mail: lvillaverde@continental.edu.peReceived: Abril 2020. Accepted: Mayo 2020.