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Keywords:

  • maxilla;
  • hiatus;
  • volume;
  • septa;
  • cadaver

Abstract

  1. Top of page
  2. Abstract
  3. MATERIAL AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. LITERATURE CITED

This study measured maxillary sinus volume, evaluated the location of the semilunar hiatus in correlation to the nasal floor, and the incidence, location, and height of antral septa and discusses their clinical implications. Maxillary sinus volume was quantified in 65 cadavers (130 sinuses) by water application through the semilunar hiatus and measuring the used amount. The location of the semilunar hiatus was identified as distance from the nasal floor. The septa were counted, evaluated, and the size measured from the antral floor. The medium maxillary sinus volume was 12.5 mL (range, 5–22 mL). The medium location of the semilunar hiatus was 25.6 mm above the nasal floor (range, 18–35 mm). Thirty-five septa were counted in 130 maxillary sinuses. This equals an incidence of 27%. The medium height of the septa was 5.4 mm (2.5–11 mm). The main location of the septa was the region of the first molar (29%), the second molar (23%), and the second premolar (23%). The height, location, and number of septa as well as the height of the semilunar hiatus and volume of the maxillary sinus have to be taken into consideration to correctly plan the procedure and amount of grafting material in maxillary sinus floor elevation operations. Anat Rec, 292:352–354, 2009. © 2009 Wiley-Liss, Inc.

The edentulous maxillary alveolar ridge is affected by bone resorption leading to horizontal and vertical bone loss. For that reason, preimplantological sinus floor augmentation is often necessary before placing dental implants in the maxilla. There are various surgical techniques available for this procedure. On the one hand septa can hamper the preparation and elevation of the bony window in the anterior-lateral antral wall at the procedure of Tatum (Tatum,1986), on the other hand the minimal invasive approach as described by Summers can also be compromised (Summers,1994a,b,c; Krennmair et al.,1997). Septa can make the complete preservation of the sinus membrane more difficult (Shibli et al.,2007).

Maxillary sinus operations also demand exact anatomical knowledge to decide whether a transnasal or transoral approach is preferable (Fatterpekar et al.,2008; Marquez,2008). Septa can harm the endoscopic view when transnasal approach is chosen (Krennmair et al.,1997; Caylakli et al.,2006).

This study examined the volume of maxillary sinus, the exact location of the semilunar hiatus in comparison with the nasal floor, and the incidence, location, and height of antral septa.

The location and height of septa are important aspects when planning sinus lift procedures as septa can hamper the preservation of the Schneiderian membrane. The height of the semilunar hiatus as well as the sinus volume defines the maximum amount of possible grafting material within the sinus as interference may cause problems in sinus ventilation (Ulm et al.,1995; Krennmair et al.,1997,1999; Kim et al.,2006).

MATERIAL AND METHODS

  1. Top of page
  2. Abstract
  3. MATERIAL AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. LITERATURE CITED

We examined 65 cadaver heads (130 maxillary sinuses) obtained from the collection of the Department of Anatomy of the University of Cologne. The specimens were stored in 10% neutral formalin for 1–6 months. Thirty-two male and 33 female Caucasian heads were examined, with the age at death ranging from 50 to 97 years (median: 78 years).

All examinations on the cadaver heads were done in a standardized manner and in compliance with all ethical guidelines. One sagittal cut was made in the middle of the head. At first the semilunar hiatus was examined and the distance from the nasal floor to the middle of the ostium was measured.

Second, the maxillary sinus was filled with water and thus the real ventilated volume was obtained by measuring the volume of this water filling. Thereafter, the maxilla was cut from the head slightly beneath the infraorbital rim. The specimens were subsequently mechanically freed of soft tissue and afterwards put into Biozym®-Se to eliminate any left soft tissue. The obtained pure bone material was further investigated.

The classification of the septa location was done by using the FDI–System (Federal Dentaire International). The height of the septa was measured as distance from the sinus floor taking the more inferior point of the two possible sides of the septum. To identify a real septum in contrast to a bottom lath of the sinus floor after loss of teeth, a minimum level of 2.5 mm was set as critical value (Ulm et al.,1995).

RESULTS

  1. Top of page
  2. Abstract
  3. MATERIAL AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. LITERATURE CITED

The volume of the maxillary sinus ranged from 5 to 22 mL (mean: 12.5 mL). Comparing the maxillary sinus volume with gender, female predominance in the small volume class (5–9 mL) was noted (25% male, 75% female). In the middle volume classes (10–14 mL, 15–19 mL), we found a well-balanced gender contribution (53.5% male, 46.5% female). A statement about the high volume class (20–24 mL) was not made due to the small number of specimens.

Linear distances between the nasal floor and the semilunar hiatus were between 18 and 35 mm (mean: 25.6 mm). For gender difference we found comparable results as stated above, for volume differences. The distance was usually slightly smaller in female than in male specimens (Fig. 1).

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Figure 1. Gender related distance to the middle of the semilunar hiatus measured from the nasal floor.

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Antral septa were found in 24 (27%) of the 65 patients. Altogether 35 septa were found in 24 upper jaws. Fourteen upper jaws showed one septum (21%), nine (14%) showed two, and one (1.5%) showed three septa. The antral septa were located as follows: One septa was found in the region of the canine (region 13/23), six septa were found in the region of the first premolar (region 14/24), and eight in the region of the second premolar (region 15/25). In the posterior region 10 septa were found in the region of the first molar (region 16/26), eight septa in the region of the second molar (region 17/27), and two septa in the region of the third molar (region 18/28). Thus, most septa were located in the region of the first molar (28.6%) followed by the region of the second molar (22.9%) and second premolar (22.9%) and the first premolar (17.1%). Few septa were found in the region of the third molar (5.7%) and the canine (2.9%).

Slightly more septa were found in the right sinuses (20) than in the left sinuses (15).

The measured heights of each individual septum varied among 2.5 and 11 mm (mean 5.4 mm). For a better overview the septa were classified within groups as seen in Fig. 2. There was no gender difference concerning the distribution of septa. Eighteen septa were found in male and 17 in female specimens.

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Figure 2. Gender related height of antral septa measured from the more inferior side of the antral floor. The septa were classified in groups to gain a better overview.

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DISCUSSION

  1. Top of page
  2. Abstract
  3. MATERIAL AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. LITERATURE CITED

The present study analyzed maxillary sinus volume, location of the semilunar hiatus, and antral septa by examining 130 maxillary sinuses.

A mean sinus volume of 12.5 mL found in our study was similar to previous examinations (Ariji et al.,1994; Uchida et al.,1998). We noticed a gender related difference of maxillary sinus volume descriptively, with men having a slightly bigger volume than women. Other authors could not find significant differences concerning side, sex, and age (Ariji et al.,1994; Uchida et al.,1998; Shibli et al.,2007).

The distance measurement for semilunar hiatus referring to the nasal floor was chosen because this orientation point is mostly located higher than the maxillary floor. Therefore, an appropriate planning of the augmentation material volume is possible if our results are taken into account and interference of the augmented material with the semilunar hiatus can be avoided.

It was observed that atrophy of the maxillary alveolar ridge proceeded irregularly in different regions, leaving bony crests on the maxillary sinus floor also know as secondary septa, which can be considered as a result of tooth loss and atrophy (Vinter et al.,1993). Therefore, studies examining antral septa differentiate sometimes between primary or congenital septa and secondary or acquired septa (Kim et al.,2006). Secondary septa usually do not exceed 2.5 mm (Ulm et al.,1995). We did not take secondary septa into account by eliminating septa smaller than 2.5 mm. The reason is that the small secondary septa are not of clinical relevance for sinus floor elevation, because they do not interfere with the surgical procedure. If those are also taken into account, edentulous jaws usually show a higher prevalence of septa than dentated upper jaws.

We observed a septa prevalence of 27% in our study. Krennmaier et al. (1997) counted 32 antral septa in 200 maxillary sinuses using CT imaging (16% prevalence) (Krennmair et al.,1997). In a later examination on anatomic specimens he reported a prevalence of 26.3%, finding 51 septa in 194 sinuses (Krennmair et al.,1999). Velasquez-Plata et al. (2002) found a prevalence of 22% (69 septa in 312 sinuses) using 3-D scan (Velasquez-Plata et al.,2002). Kim et al. (2006) found 53 septa in 200 sinuses using CT-scan (prevalence 26.5%) (Kim et al.,2006). The main septum location found in our study, first molar followed by the region of the second molar and second premolar is also in line with literature (Ulm et al.,1995).

There was no difference concerning age, gender or side of the maxillary sinus, which is also confirmed by literature (Uchida et al.,1998; Shibli et al.,2007).

If septa are present on the sinus floor, they can complicate both, the inversion of the bone plate and elevation of the Schneiderian membrane during sinus floor elevation procedure. When maxillary sinus surgery is performed endoscopically via a transnasal approach, pronounced septa on the sinus floor can hamper visibility and specimen harvesting (Krennmair et al.,1997,1999). A transoral approach would then be favorable.

The present study showed that at least one septum occurs in 25% of all maxillary sinuses. This is highly important for all sinus lift procedures to avoid complications. Another aspect of the results is the medial height of the semilunar hiatus being 25 mm. An interference of the augmentation material with the semilunar hiatus is therefore not likely. The third information of this study was the mean sinus volume of 12.5 mL. This provides enough space for the necessary amount of augmentation material. Still the great variability found in sinus volume should be taken into account.

Detailed knowledge of the maxillary sinus volumes as well as the location, morphology, and height of antral septa is relevant for maxillary sinus surgery or sinus floor elevation procedures.

LITERATURE CITED

  1. Top of page
  2. Abstract
  3. MATERIAL AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. LITERATURE CITED
  • Ariji Y,Kuroki T,Moriguchi S,Ariji E,Kanda S. 1994. Age changes in the volume of the human maxillary sinus: a study using computed tomography. Dentomaxillofac Radiol 23: 163168.
  • Caylakli F,Yavuz H,Cagici AC,Ozluoglu LN. 2006. Endoscopic sinus surgery for maxillary sinus mucoceles. Head Face Med 2: 29.
  • Fatterpekar GM,Delman BN,Som PM. 2008. Imaging the paranasal sinuses: where we are and where we are going. Anat Rec 291: 15641572.
  • Kim MJ,Jung UW,Kim CS,Kim KD,Choi SH,Kim CK,Cho KS. 2006. Maxillary sinus septa: prevalence, height, location, and morphology. A reformatted computed tomography scan analysis. J Periodontol 77: 903908.
  • Krennmair G,Ulm C,Lugmayr H. 1997. Maxillary sinus septa: incidence, morphology and clinical implications. J Craniomaxillofac Surg 25: 261265.
  • Krennmair G,Ulm CW,Lugmayr H,Solar P. 1999. The incidence, location, and height of maxillary sinus septa in the edentulous and dentate maxilla. J Oral Maxillofac Surg 57: 667671; Discussion 671–662.
  • Marquez S. 2008. The paranasal sinuses: the last frontier in craniofacial biology. Anat Rec 261: 13501361.
  • Shibli JA,Faveri M,Ferrari DS,Melo L,Garcia RV,d'Avila S,Figueiredo LC,Feres M. 2007. Prevalence of maxillary sinus septa in 1024 subjects with edentulous upper jaws: a retrospective study. J Oral Implantol 33: 293296.
  • Summers RB. 1994a. A new concept in maxillary implant surgery: the osteotome technique. Compendium 15: 152, 154–156, 158 passim; quiz 162.
  • Summers RB. 1994b. The osteotome technique: Part 2—The ridge expansion osteotomy (REO) procedure. Compendium 15: 422, 424, 426, passim; quiz 436.
  • Summers RB. 1994c. The osteotome technique: Part 3—Less invasive methods of elevating the sinus floor. Compendium 15: 698, 700, 702–694 passim; quiz 710.
  • Tatum H,Jr. 1986. Maxillary and sinus implant reconstructions. Dent Clin North Am 30: 207229.
  • Uchida Y,Goto M,Katsuki T,Akiyoshi T. 1998. A cadaveric study of maxillary sinus size as an aid in bone grafting of the maxillary sinus floor. J Oral Maxillofac Surg 56: 11581163.
  • Ulm CW,Solar P,Krennmair G,Matejka M,Watzek G. 1995. Incidence and suggested surgical management of septa in sinus-lift procedures. Int J Oral Maxillofac Implants 10: 462465.
  • Velasquez-Plata D,Hovey LR,Peach CC,Alder ME. 2002. Maxillary sinus septa: a 3-dimensional computerized tomographic scan analysis. Int J Oral Maxillofac Implants 17: 854860.
  • Vinter I,Krmpotic-Nemanic J,Hat J,Jalsovec D. 1993. Does the alveolar process of the maxilla always disappear after tooth loss? Laryngorhinootologie 72: 605607.