Analysis of the Morphology of Maxillary Sinus Septa on Reconstructed Cone-Beam Computed Tomography Images

Accepted Manuscript Analysis of the morphology of maxillary sinus septa on reconstructed cone-beam computed tomography images Liang Qian, MDS, Resident, Xiao-mei Tian, MDS, Resident, Li Zeng, MDS, Resident, Yao Gong, DDS, Professor, Bin Wei, DDS, Professor PII:

S0278-2391(15)01556-6

DOI:

10.1016/j.joms.2015.11.019

Reference:

YJOMS 57043

To appear in:

Journal of Oral and Maxillofacial Surgery

Received Date: 28 April 2015 Revised Date:

19 November 2015

Accepted Date: 19 November 2015

Please cite this article as: Qian L, Tian X-m, Zeng L, Gong Y, Wei B, Analysis of the morphology of maxillary sinus septa on reconstructed cone-beam computed tomography images, Journal of Oral and Maxillofacial Surgery (2015), doi: 10.1016/j.joms.2015.11.019. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

ACCEPTED MANUSCRIPT

Analysis of the morphology of maxillary sinus septa on reconstructed cone-beam computed tomography images

RI PT

Liang Qian, MDS, Resident a,1 Xiao-mei Tian, MDS, Resident a,1 Li Zeng, MDS, Resident a Yao Gong, DDS, Professor b Bin Wei, DDS, Professor a,∗ a Stomatology Special Consultation Clinic, Department of Prosthodontics, Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, 200011, China


SC

b Department of Orthodontics, Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, 200011, China

M AN U

∗Corresponding author. Tel: +86 021 23271699x5276;fax: +86 021 63133174 E-mail addresses: [email protected]

1Both authors have contributed equally to this work

Purpose: Preoperative assessment of maxillary sinus anatomy may prevent

TE D

complications associated with sinus grafting or implant procedures. The purpose of this study was to measure the frequency, numbers, locations, orientations and heights of maxillary sinus septa. Materials and Methods: Reconstructed cone-beam computed tomography (CBCT) images of 1012

EP

sinuses were analyzed using NewTom VG software (NNT 2.21, ImageWorks). This cross-sectional study included patients who underwent radiography at the

AC C

Department of Radiology. And presence, numbers, locations, orientations and heights of septa were then analyzed. To establish the multiple predictors in this study, groups were defined according to the different radiographic features of the septa. The differences between the gender groups and edentulous/dentulous groups were tested with chi-square tests, and the level of significance was set at 5%. Results: The sample consisted of 506 patients including 168 men and 338 women with an average age of 35.1 years. A significantly (P<0.05) greater occurrence rate of 57.4% was observed in the edentulous group compared with

1

ACCEPTED MANUSCRIPT

the rate of 39.7% observed in the dentulous group. Conclusions: The difference in the prevalence of maxillary sinus septa between the edentulous and dentulous groups was statistically significant (P<0.05), and the septa exhibited variable characteristics. It is essential and effective to analyze CT images of sinuses to

RI PT

evaluate the characteristics of septa before performing surgical procedures. Key words: antral septa, reconstructed images, maxillary sinus, dental implantation

The maxillary sinus septum is a thin wall of cortical bone inside of the

SC

maxillary sinus that separates the maxillary sinus into two or more basins and plays a role in strengthening the bone structure of the sinus. After tooth loss, the

M AN U

alveolar process of the posterior maxilla can often be affected by resorption. Such bone resorption varies from one person to another, often resulting in inadequate volume and density for the placement of implants. A surgical procedure for maxillary sinus elevation was first reported in 1980 and it is performed to restore the alveolar ridge to achieve the appropriate bone height

TE D

for implantation. However, the appearance of maxillary sinus septa interferes with the procedure[1]and increases the risk of perforation of the Schneiderian

elevation.

EP

membrane[2]. Thus, it is essential to carefully assess the maxillary sinus prior to

The development of the maxillary sinus septum was first described by

AC C

Underwood in 1910.He held the view that the origin of the septum was relevant to the growth and eruption of the teeth[3]. The septa that he described were later defined as the primary septa. In 1999, Krennmair et al. identified another type of septa, the secondary septa, which are thought to arise from irregular pneumatization of the sinus floor[4]. Some studies have reported the characteristics of the septa. Lugmayr et al. observed 26 septa in 200 sinuses with a prevalence of 13%[5]. Kasabah et al. reported a prevalence of 35.9% based on analysis of cone-beam computed

2

ACCEPTED MANUSCRIPT

tomography (CBCT) images of 68 sinuses[6]. The reported locations of the septa varied in the relevant references. Underwood noted that the most common location was the posterior region[3]. However, according to Lee et al., the majority of septa are located in the middle region[7]. Regarding the orientation

RI PT

of the septa, Pommer et al. and Jang et al. have found that the buccopalatal type is the most common[8-9]. The heights of the septa have also been measured.

Velásquez-Plata et al. have reported a mean height of 3.5 mm for the lateral

SC

region, 5.9 mm for the middle region, and 7.6 mm for the medial region[10].

Large numbers of implants are placed in China each year. The purpose of this study was to obtain additional insights into the morphologies of the septa at

M AN U

the individual level. The investigators hypothesize that the morphology of maxillary sinus septa can vary among individuals. The specific aims of this study were as follows: 1) to measure variables related to the sinus septa, e.g., the prevalence, numbers, locations, orientations and heights on reconstructed

TE D

CBCT images; and 2) to determine whether differences in these characteristics exist among individuals.

[Materials and Methods]

This study was approved and supported by the Shanghai Leading Academic

EP

Discipline Project (Project Number: T0202, S30206) and the Science and Technology Committee of Shanghai (08DZ2271100, 12441903001 and

AC C

13140902701). Study Sample

The subjects of this study were patients who underwent radiography at the Department of Radiology at the Shanghai Ninth People’s Hospital from January 2010 to June 2013. For inclusion in the study sample, the patients had to present pneumatization of both maxillary sinuses. Patients were excluded if any indications of pathologies originating in the dental structures or respiratory system were found.

3

ACCEPTED MANUSCRIPT

Variables A maxillary sinus septum was identified as a cortical bone of at least 2.5 mm in height[11]. The location of each maxillary sinus septum was classified as beginning in the anterior region, medial region or posterior region (Figure 1).

RI PT

The anterior region has also been termed “the premolar region,” and it extends from the anterior wall of the maxillary sinus to the distal region of the second premolar. The medial region extends from the distal aspect of the second

premolar to the distal aspect of the second molar. The posterior region extends

SC

from the distal region of the second molar to the posterior wall of the maxillary sinus. The septa were categorized as buccopalatal, sagittal or transverse types

M AN U

according to their orientations (Figure 2). The buccopalatal type runs in the buccopalatal direction in the arch and connects the buccal and palatal floors. The sagittal type runs parallel to the sagittal plane. The transverse type runs parallel to the sinus floor. The height of a septum was measured by first defining a baseline that passed underneath the septum’s adjacent basins

TE D

simultaneously, and the vertical distance was then measured between the peak of the septum and this baseline (Figure 3). The groups were defined according to different study variables, e.g., gender, dentulous/edentulous status, and the

EP

numbers, locations, and orientations of the septa. Furthermore, the differences in the prevalence rates of septa between the genders and edentulous and

AC C

dentulous groups were tested. Data Collection Methods

Each image was reconstructed and analyzed with NewTom VG software (NNT 2.21, ImageWorks). Data Analysis The differences in the prevalence of septa between the genders and between the edentulous and dentulous groups were tested with chi-square tests, and the level of significance was set at 5%. [Results] 4

ACCEPTED MANUSCRIPT

The sample consisted of 168 men and 338 women ranging in age from 12 to 79 years old with an average age of 35.1 years. Prevalence Based on the number of patients, the prevalence of septa was 48.2%. However,

RI PT

this value dropped to 32.6% based on the number of sinuses included. The patient-based prevalence rates were 45.2% for the men and 49.7% for the

women, and the corresponding sinus-based rates were 31.8% for the men and 33.0% for the women, respectively. These differences were not statistically

SC

significant (P>0.05). The edentulous group had an occurrence rate of 57.4%,

significant (P<0.05, Table 1). Numbers of septa

M AN U

and the edentulous group had an occurrence rate of 39.7%; this difference was

A total of 390 septa were found in 330 maxillary sinuses.Among them, 277 sinuses contained only a single septum (84.0%), 46 contained two septa (13.9%), and 7 contained 3 septa (2.2%)( Table 2).

TE D

Locations and orientations

Analysis of the locations of the septa revealed that 136 septa were in the anterior, 160 were in the medial and 94 were in the posterior areas. Among all

EP

390 septa, 366 (93.8%) displayed buccopalatal orientations. In addition, nineteen septa were classified as the sagittal type, and 5 were classified as the

AC C

transverse type (Table 2). Heights

The heights of the buccopalatal septa varied across the different regions. The average heights of the septa located in the lateral, middle and medial regions were 4.39 mm, 5.56 mm and 6.44 mm, respectively. [Discussion] Although maxillary sinus septa were first identified and described by Underwood in 1910[3], they received limited attention in the subsequent decades. The purpose of this study was to describe the morphologies of septa at 5

ACCEPTED MANUSCRIPT

the level of the individual patient. The investigators hypothesize that a sound knowledge of the septa is required to avoid the occurrence of certain complications. The specific aims of this study were to examine some of the characteristics of the septa and to determine whether inter-individual differences

RI PT

in their characteristics existed. The overall prevalence of the septa observed in this study was 48.2% based on the number of patients included, and the

prevalence was 32.6% based on the number of sinuses included. The difference in the prevalence of septa between the male and female patients was not

SC

statistically significant. In contrast, a statistically significant difference in prevalence was observed between the edentulous and dentulous groups

M AN U

(P<0.05).

Importantly, the majority of the sinuses (84.0%) harbored only a single septum. The greatest proportion of septa was observed in the middle region (41.0%), followed by the anterior region (34.8%) and posterior region (24.2%). Evaluations of the orientations of the septa revealed that the buccopalatal type

TE D

was the most common (93.8%). According to their 3-dimensional structures, the heights of septa should be measured in the lateral, middle and medial regions. This criterion is accepted by the majority of researchers. In the present study,

EP

the mean heights of the lateral, middle and medial regions were 4.39, 5.56 and 6.44 mm, respectively.

AC C

Many studies have indicated that the prevalence of septa varies from 13 to 35.9% when based on the number of sinuses[4-6,10-14] and from 21.6 to 69% when based on the number of patients[2,10,12-15]. The results of the present study are in agreement with those of previous studies. The difference in prevalence between the edentulous and dentulous groups was significant, which may be attributable to the possibility that secondary septa develop due to the irregular pneumatization of the sinus floor that accompanies tooth loss. Lee et al. reported prevalence rates of 50.0% in the middle region, 27.3% in the anterior

6

ACCEPTED MANUSCRIPT

region, and 22.7% in the posterior region. These authors assumed that the septa were most frequently located in the middle region due to the earlier loss of the maxillary molars relative to the premolars, which might lead to the development of secondary septa[7]. Pommer B et al. and Jang SY et al. have found that the

RI PT

buccopalatal type is the most common[8-9]. Velásquez-Plata et al. have concluded that the mean heights of the lateral, middle, and medial regions are 3.5, 5.9, and 7.6 mm in [10]. These authors have also reported that the average height of the medial aspect is generally greater than that of the lateral aspect,

SC

and a similar result was observed in the present study.

M AN U

The CT images used in this study were obtained from patients who visited Shanghai Ninth People’s Hospital. Due to its strong reputation, thousands of patients from across the country come to this hospital for treatment. Therefore, the sample diversity of the present study was high. Additionally, our team used the highly accurate NNT program to reconstruct the images.

TE D

[Conclusions]

It is necessary to perform careful and extensive evaluations of septa to prevent avoidable complications during the maxillary sinus elevation process in

EP

dental implantation. Furthermore, analyzing CT images could be an effective and accurate method for evaluating the characteristics of septa.

AC C

[Conflicts of interest]

No potential conflicts of interest relevant to this article exist. [Acknowledgements]

This study was supported by the Shanghai Leading Academic Discipline Project (Project Number: T0202 and S30206) and the Science and Technology Committee of Shanghai (08DZ2271100, 12441903001 and 13140902701). The authors thank the Department of Radiology of the Shanghai Ninth People’s Hospital. [References] 7

ACCEPTED MANUSCRIPT

[1] Zijderveld SA, van den Bergh JP, Schulten EA. Anatomical and surgical findings and complications in 100 consecutive maxillary sinus floor elevation procedures. J Oral Maxillofac Surg. 2008 Jul; 66(7): 1426-38. [2] Shibli JA, Faveri M, Ferrari DS. Prevalence of maxillary sinus septa in 1024

2007; 33(5): 293-6.

RI PT

subjects with edentulous upper jaws:a retrospective study. J Oral Implantol.

[3] Underwood AS. An inquiry into the Anatomy and Pathology of the Maxillary Sinus. J Anat Physiol. 1910; 44: 354-69.

SC

[4] Krennmair G, Ulm CW, Lugmayr H. The incidence, location, and height of

Surg. 1999; 57: 667-71.

M AN U

maxillary sinus septa in the edentulous and dentate maxilla. J Oral Maxillofac

[5] Lugmayr H, Krennmair G, Holzer H. The morphology and incidence of maxillary sinus septa. Rofo. 1996; 165: 452-4.

[6] Kasabah S, Slezák R, Simůnek A. Evaluation of the accuracy of panoramic radiograph in the definition of maxillary sinus septa. Acta Medica (Hradec

TE D

Kralove). 2002; 45: 173-5.

[7] Lee WJ, Lee SJ, Kim HS. Analysis of location and prevalence of maxillary sinus septa. J Periodontal Implant Sci. 2010 Apr; 40(2): 56-60.

EP

[8] Pommer B, Ulm C, Lorenzoni M. Prevalence,location and morphology of maxillary sinus septa:systematic review and meta-analysis. J Clin Periodontol

AC C

2012; 39: 769-773.

[9] Jang SY, Chung K, Jung S. Comparative study of the sinus septa between dentulous and edentulous patients by cone beam computed tomography. Implant Dent. 2014 Aug; 23(4): 477-81. [10] Velásquez-Plata D, Hovey LR, Peach CC. Maxillary sinus septa: a 3dimensional computerized tomographic scan analysis. Int J Oral Maxillofac Implants. 2002; 17: 854-60.

8

ACCEPTED MANUSCRIPT

[11] Ulm CW, Solar P, Krennmair G, Matejka M. Incidence and suggested surgical management of septa in sinus-lift procedures. Int J Oral Maxillofac Implants. 1995; 10: 462-5. [12] Krennmair G, Ulm C, Lugmayr H. Maxillary sinus septa: incidence,

RI PT

morphology and clinical implications. J Craniomaxillofac Surg. 1997; 25: 2615.

[13] Kim MJ, Jung UW, Kim CS. Maxillary sinus septa: prevalence, height, location, and morphology. A reformatted computed tomography scan analysis. J

SC

Periodontol. 2006; 77: 903-8.

[14] González-Santana H, Peñarrocha-Diago M, Guarinos-Carbó J. A study of

M AN U

the septa in the maxillary sinuses and the subantral alveolar processes in 30 patients. J Oral Implantol. 2007; 33: 340-3.

[15] van Zyl AW, van Heerden WF. A retrospective analysis of maxillary sinus septa on reformatted computerized tomography scans. Clin Oral Implants Res.

AC C

EP

TE D

2009 Dec; 20(12): 1398-401

9

ACCEPTED MANUSCRIPT

Table 1 Prevalence of septa according to variable groups No. of septa (%)

Gender (For patients) Men Women

168 338

76(45.2) 168(49.7)

(For sinuses) Men Women

336 676

Edentulous subjects Dentulous subjects

244 262

RI PT

Number

107(31.8) 223(33.0)

SC

140(57.4) 104(39.7)

M AN U

There was no significant difference (P>0.05) in the prevalence of septa between the genders. A significant difference in prevalence was observed between the edentulous and dentulous groups (P<0.05). The values are given as n(%)

TE D

Table 2 Summary of characteristics of septa among individuals Number One

Three

AC C

Location

EP

Two

No. of septa(%) 330(100.0) 277(84.0) 46(13.9) 7(2.1)

390(100.0)

Anterior

136(34.9)

Medial

160(41.0)

Posterior

94(24.1)

Orientation

390(100.0)

Buccopalatal

366(93.8)

Sagittal

19(4.9)

Transverse

5(1.3)

The values are given as n(%) 10

ACCEPTED MANUSCRIPT

Figure Legends: Figure 1a. The locations of the septa were divided into anterior, medial and posterior regions.

Figure 1c. A septum in the medial region. Figure 1d. A septum in the posterior region.

Figure 2b. Septa in the sagittal orientation.

SC

Figure 2a. A septum in the buccopalatal orientation.

RI PT

Figure 1b. A septum in the anterior region.

M AN U

Figure 2c. A septum in the transverse orientation.

Figure 3a. Measurement of the height of a septum in the lateral region. Figure 3b. Measurement of the height of a septum in the middle region.

AC C

EP

TE D

Figure 3c. Measurement of the height of a septum in the medial region.

11

AC C

EP

TE D

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT