Internal structural analysis of the nasomaxillary complex in patients with skeletal class III asymmetry: A study on asymmetry patterns

OBJECTIVES

To investigate the internal structure of the nasomaxillary complex, including the maxillary sinus, nasal cavity and nasal septum according to the facial asymmetry pattern and to evaluate its correlation with external maxillomandibular asymmetry in Class III patients based on cone-beam computerized tomography (CBCT) images.

MATERIALS AND METHODS

Facial asymmetry was analysed in a total of 100 Class III patients aged 16 years or older using CBCT scans. Patients were categorized into subgroups based on asymmetry pattern. Measurements of the nasomaxillary complex were obtained from the CBCT scans, including the volume and width of the maxillary sinuses and nasal cavities on deviated and non-deviated sides, as well as the displacement of the nasal septum. Statistical analysis was performed to compare the internal nasomaxillary variables within and between groups, and regression analysis was conducted to evaluate the correlation between facial asymmetry and the internal nasomaxillary variables.

RESULTS

Group comparisons showed that there were no significant differences in the volume of the maxillary sinus and nasal cavity. However, the direction and extent of nasal septum deviation, as well as the width of the nasal cavity, varied depending on the maxillary asymmetry pattern. Regression analysis indicated a correlation between nasal septum deviation and the difference in maxillary height, while the difference in nasal cavity width was correlated with the difference in maxillary width.

CONCLUSION

A comprehensive evaluation of the internal nasal anatomy is vital for understanding the intricate relationship between nasal structure and maxillary growth.

The comparison of visibility of the maxillary sinus septa between cone-beam computed tomography scans and panoramic radiograph images as dependent on the cortical bone thickness: a retrospective comparative study

PURPOSE

To analyze the visibility of the maxillary sinus septa (MSS) in panoramic radiography (PR) versus cone beam computed tomography (CBCT) and to investigate whether the buccal cortical bone thickness (BT) or the septa dimensions influence their visibility.

METHODS

Corresponding PR and CBCT images of 355 patients were selected and examined for MSS visibility. The septa dimensions (width, height, depth) and the BT were measured. Results were analysed statistically.

RESULTS

Comparing the corresponding regions on CBCT and PR, 170 MSS were identified; however, only 106 of these were also visible using PR. The MSS visibility was significantly higher on CBCT versus PR images (P1: p = 0.039, P2: p = 0.015, M1: p = 0.041, M2: p = 0.017, M3: p = 0.000), except region C (p = 0.625). Regarding the measurements of MSS dimensions, only the height in region M1 (p = 0.013) and the width in region P2 (p = 0.034) were significantly more visible on CBCT. The BT in the area of the MSS was found to have a marginal influence on its visibility on the PR images only in regions M3 and M1 (M3: p = 0.043, M1: p = 0.047). In terms of MSS visibility based on the dimensions, significance was found for all three influencing variables only in region P2 (width; p = 0.041, height; p = 0.001, depth; p = 0.007). There were only isolated cases of further significance: M3 for width (p = 0.043), M2 for height (p = 0.024), and P1 for depth (p = 0.034), no further significance was noted.

CONCLUSION

MSS visibility appears significantly higher on CBCT versus PR images. It is concluded that the septa dimensions and BT can influence MSS visibility on PR images just in certain regions.

Anatomical Possibilities of the Alveolar Bone at the Upper Second Premolar Level

Background and Objectives: The upper posterior teeth are typically regarded as being exclusively inferior to the maxillary sinus (MS). The expansion of the nasal fossa above the maxillary alveolar base (MAB) needs better investigation. The hypothesis was raised that the MAB in the upper premolar region, which is usually addressed by surgeons for the elevation of the antral floor, is not exclusively beneath the MS. Therefore, we aimed to document the possible upper relations of the MAB as antral, nasal, or both. Materials and Methods: A total of 145 CBCT scans were used to study four types of MAB: type 1-antral; type 2-antral with a palatal recess; type 3-antral and nasal; type 4-nasal. In type 2, the orthoradial width of the alveolar bone, the rectilinear width of the antral floor, and the maximum depth of the palatal recess were measured. For type 3, the MAB width and the straight widths of the antral and nasal segments of the MAB were measured. Results: Type 1 was found in 67.24%, type 2 in 13.45%, type 3 in 16.21%, and type 4 in 3.1% of the 290 MSs investigated. Palatal recesses were found in 11.72% of the MSs on the right side and 15.17% of the MSs on the left side. Types 1 and 2 exhibited strongly statistically significant bilateral symmetry (Pearson's Chi2 = 86.42, p < 0.001). Type 3 correlated equally with contralateral types 1 and 3. The bilateral symmetry for types 1-3 was stronger in the males (Pearson's Chi2 = 47.83, p < 0.001) than in the females (Pearson's Chi2 = 56.96, p < 0.001). There were no statistically significant associations between sex and the unilateral anatomical type. Conclusions: The MAB in the upper second premolar area should not be considered to be exclusively antral during surgeries or in anatomical teaching.

Minimally Anterior Medial Maxillary Approach (MAMMA): a novel technique for a wide access to the maxillary sinus

PURPOSE

To describe a novel endoscopic technique to approach the maxillary sinus (MS), the Modified Anterior Medial Maxillary Approach (MAMMA), preserving the inferior turbinate (IT) and the nasolacrimal duct (NLD). To perform radiological measurements and describe a case series to study the feasibility and limits of MAMMA.

METHODS

Computed tomography (CT) scans (n = 150 nasal cavities) were used to calculate areas of the MAMMA to define surgical limits and extensions. Measurement of distances to critical anatomy landmarks and total area for the MAMMA were calculated. An instructional case illustrating the surgical technique and outcome was also included.

RESULTS

Radiological analysis showed a mean distance from the Piriform Aperture (PA) to the anterior limit of the NLD of 1.03 ± 0.18 cm (range 0.59-1.48) and a mean distance from de PA to the posterior limit of the NLD of 1.57 ± 0.22 cm (range 1.02-2.11). The mean distance from the nasal floor to the Hasner's valve was 1.61 ± 0.27 cm (range 1.06-2.52) and the distance from the nasal floor to the insertion of the IT was 2.20 ± 0.36 cm (range 1.70-3.69). Finally, the mean total area for the MAMMA was 4.04 ± 0.52 cm2 (range 3.17-5.53). No complications or recurrence of the pathology were observed in operated patients.

CONCLUSION

The MAMMA provides a wide surgical field of the MS walls comparable to more aggressive techniques, with preservation of the sinonasal and lacrimal function. MAMMA is an effective alternative to treat different MS pathologies including benign recurrent maxillary sinus tumors.

Growth and microanatomy of the paranasal sinuses in two species of New World monkeys

Paranasal sinuses of living apes and humans grow with positive allometry, suggesting a novel mechanism for bone enlargement. Here, we examine the paranasal sinuses of the owl monkey (Aotus spp.) and a tamarin (Saguinus midas) across postnatal development. The prediction that paranasal sinuses grow disproportionately faster than the main nasal chamber is tested. We used diffusible iodine-based contrast-enhanced computed tomography and histology to study sinuses in eight Aotus and three tamarins ranging from newborn to adult ages. Sinuses were segmented at the mucosa-air cavity interface and measured in volume. All sinuses were lined by a ciliated respiratory epithelium, except for the ethmoid air cells in Aotus, which are lined in part by olfactory epithelium. An age comparison indicates that only the maxillary sinus and ethmoid air cells are present in newborns, and two additional sinuses (invading the orbitosphenoid and the frontal bone), do not appear until late infancy or later. Comparing newborns and adults, the main nasal airway is 10 times larger in the adult Aotus and ~ 6.5 times larger in adult Saguinus. In contrast, the maxillary sinus far exceeds this magnitude of difference: 24 times larger in the adult Aotus and 46 times larger in adult Saguinus. The frontal sinuses add significantly to total paranasal space volume in both species, but this growth is likely delayed until juvenile age. Results suggest ethmoid air cells expand the least. These results support our prediction that most paranasal sinuses have a distinctly higher growth rate compared to the main nasal chamber.

Cone-beam computed tomographic analysis of maxillary sinus septa among Yemeni population: a cross-sectional study

BACKGROUND

Maxillary sinus septa increase perforation risk of Schneiderian membrane during the sinus floor elevation (SFE). Cone Beam Computed Tomography (CBCT) allows for a more precise assessment of the septal position; thus, preoperative CBCT analysis is substantial to avoid possible complications. This study aims to investigate the 3D characteristics of the maxillary sinus septa based on CBCT images. To our knowledge, no study reported the CBCT-based investigation for the sinus septa among Yemeni population.

MATERIALS AND METHODS

This is a retrospective cross-sectional analysis of 880 sinus CBCT images 440 patients. The septa prevalence, locations, orientations, morphology, and associated factors were analyzed. The effect of age, gender, and dental status on the sinus septa and the relationship between sinus membrane pathology and sinus septa were also analyzed. Anatomage (Invivo version 6) was used for CBCT images analysis. Descriptive and analytical statistics were performed, and a P-value < 0.05 was significantly considered.

RESULTS

The maxillary sinus septa were found among 63.9% of patients and 47% of sinuses. The average septa height was 5.2 mm. 15.7% of patients had septa in the right maxilla, 18% in the left, and 30.2% in both. Gender, age, and dental condition had no influence on the presence of septa, and septa presence did not influence sinus membrane pathology. Many septa originated from the floor (54.5%), located in the middle (43%), with coronal orientation (66%) and complete configuration (58.2%).

CONCLUSION

Based on our findings, the septa prevalence, locations, orientations, and morphology were significant and equivalent to the highest recorded in the literature yet. Thus, when sinus floor elevation is planned, CBCT imaging of the maxillary sinus is recommended for safe dental implantation.

Are maxillary sinus variations related to maxillary sinus diameters?

OBJECTIVES

The reasons why the maxillary posterior region is challenging for dentists are its structure and anatomical variations. For this reason, it is necessary to have complete knowledge about the anatomy of this region. In dentistry, necessary information for the desired evaluation in this region can be provided by CBCT. The fact that it provides a three-dimensional evaluation and has measurement reliability emphasizes its importance in surgical applications. The septa, haller cell, and accessory ostium are variations of the maxillary sinus. There are few studies in the literature examining the relationship between maxillary sinus diameters and its variations. The aims of this study are to determine the prevalence of maxillary sinus variations and the average of maxillary sinus diameters, to examine their relationships according to age and gender, and to evaluate the effects of maxillary sinus diameters on variations.

METHODS

In this retrospective study, CBCT images of 212 patients were examined. The examined CBCT images were analysed and recorded in more than one section. Descriptive statistics, chi-square tests, independent t test, one-way Anova tests were used to evaluate the data.

RESULTS

As a result, a statistically significant difference was observed between the variations, gender and age groups in terms of morphometric characteristics of the maxillary sinus. The most common variation was observed to be accessory ostium.

CONCLUSIONS

The rate of patients with at least one anatomical variation was 77.8%. For this reason, a detailed analysis should be performed to avoid complications before surgical procedures are performed in the area.

Comparison of biological and mechanical properties of different paranasal sinus mucosa in goat

OBJECTIVE

The present study was designed to explore endurable pressure intensity of different paranasal sinus mucosa in goats.

METHOD

Mucosa commonly involved in maxillary sinus augmentation, including mucosa from maxillary sinus crest, maxillary sinus floor, and frontal sinus, were harvested in a computed tomography-guided manner. The obtained mucosa was then sectioned into square and irregular ones for maximum endurable pressure intensity determination and morphological observation, respectively.

RESULTS

Thickness of paranasal sinus mucosa, as determined under morphological staining by an optical microscope with a graduated eyepiece, were calculated. And the results showed that the average thickness of maxillary sinus crest mucosa, floor mucosa, and frontal sinus mucosa in goats were 410.03 ± 65.97 μm, 461.33 ± 91.37 μm and 216.90 ± 46.47 μm, respectively. Significant differences between maxillary sinus crest and frontal sinus, maxillary sinus floor, and frontal sinus were observed (P < 0.05). Maximum endurable pressure intensity was determined by utilizing a self-made clamp device and the results revealed maximum endurable pressure intensity of maxillary sinus crest mucosa, floor mucosa and frontal sinus mucosa in goats were 260.08 ± 80.12Kpa, 306.90 ± 94.37Kpa and 121.72 ± 31.72Kpa, respectively. Also, a statistically significant difference was observed when comparing the endurable pressure intensity between maxillary sinus crest and frontal sinus, maxillary sinus floor, and frontal sinus (P < 0.05). Further correlation analysis also revealed a positive correlation between the thickness of mucosa of the maxillary sinus and frontal sinus and maximum endurable pressure intensity (P < 0.05).

CONCLUSION

Mucosal thickness and maximum endurable pressure intensity of maxillary sinus crest and floor were larger than that of frontal sinus mucosa and a positive correlation between the thickness of mucosa and endurable pressure intensity was observed. Our results thus might provide an experimental basis and guidance for mucosa-related problems involved maxillary sinus augmentation.

Anatomical Changes in a Case with Asymmetrical Bilateral Maxillary Sinus Hypoplasia

Background and Objectives: The maxillary sinus hypoplasia (MSH) is an occasional variation of the maxilla, occurring either unilaterally or bilaterally. Previous studies dealing with MSH have not detailed the consequent anatomical changes of the maxilla and adjacent fossae. Materials and Methods: A 58-year-old female case was scanned in Cone Beam Computed Tomography and found to have asymmetrical bilateral MSH, who was then further evaluated anatomically. Results: The maxillary sinuses were hypoplastic and had mild mucosal thickenings. The orbital floors were curved. The uncinate process and the ethmoidal infundibulum were laterally displaced beneath the orbit floor. On each side, the lateral nasal wall protruded within the respective maxillary bone to reach above the vestibular cortical plate of the alveolar process. This expansion of the lateral nasal walls was limited to the premolar and first molar regions. The inferior turbinates were laterally curved. The perpendicular palatine plate was building a postero-lateral nasal wall in front of the pterygopalatine fossa. Conclusions: The classification systems of MSH should be detailed to indicate whether the normal uncinate process is medial or inferior to the orbit. The lateral expansion of the lateral nasal wall in MSH is limited to the anterior part of that wall. The laterally expanded nasal fossa could reach anterior to the pterygopalatine fossa in MSH. Seemingly, CBCT is a better tool than CT to evaluate the detailed anatomy of the modified anatomical structures in MSH; as such, it could be of help in a surgical approach.

Evaluation of the Relationship of Dimensions of Maxillary Sinus Drainage System with Anatomical Variations and Sinusopathy: Cone-Beam Computed Tomography Findings

OBJECTIVE

The aim of this study was to evaluate the correlation between the length of the infundibulum and ostium height with the anatomic variations of osteomeatal complex (OMC) and sinus pathology using cone-beam computed tomography (CBCT).

METHODS

CBCT images of 204 patients (408 maxillary sinuses) were evaluated retrospectively. The height of the ostium and the length of the infundibulum were measured. The presence of maxillary sinus pathology, nasal septal deviation, Haller cells, concha bullosa, and sinus septa were analyzed. The correlation between the size of the maxillary sinus drainage system and anatomic variations was compared using the t test, Fisher's exact test, and χ2 test. The effect of tooth loss on the length of the infundibulum and ostium height was also analyzed using ANOVA.

RESULTS

The height of the ostium and the maximal septal deviation angle were found to be significantly greater in males (p < 0.05). As ostium height increased, the presence of maxillary sinus septa increased (p < 0.05). No statistically significant association was detected between other variations and the length of infundibulum or ostium height. The relationship between tooth loss and both the length of the infundibulum and ostium height were found to be insignificant (p > 0.05).

CONCLUSIONS

Radiographic examination, especially on CBCT images, is important for an evaluation of maxillary sinuses. here, we demonstrated a significant relationship between ostium height and the presence of maxillary sinus septa. However, it was found that nasal septal deviation, concha bullosa, Haller cells, and other sinusopathies did not have a major effect on the size of the maxillary sinus drainage system.

Anatomical evaluation of the relationship between the maxillary posterior teeth and maxillary sinus

Knowledge of the anatomical relationships between the maxillary sinus (MS) and posterior teeth is important to prevent complications when endodontic or oral surgical procedures are performed. The aim of this study was to evaluate the relationships between the root apices of maxillary posterior teeth and the MS floor. Three oral radiologists evaluated 851 posterior teeth (1969 roots) imaged with cone beam computed tomography. The roots were analyzed individually in parasagittal sections, on which the most superior point of the apex was observed. A qualitative evaluation was performed, and each root was assigned a proximity score: 1, root invaginating the MS; 2, root in close contact with the MS floor; 3, root with no relationship with the MS; and 4, root with a measurable proximity to the MS. For roots classified as score 4, the distance to the MS floor was measured (quantitative analysis). Student t tests, 1-way analysis of variance, and simple linear regression analysis were performed (P < 0.05). The qualitative analysis revealed that the mesiobuccal root of the second molar had a pronounced proximity to the MS. The quantitative analysis revealed no differences in distance to the MS between right and left posterior teeth or between the different roots of the same tooth. In relation to the MS, the second molar was positioned closest, followed by the first molar, second premolar, and first premolar. Except for the comparison between mean distances of the second premolar and first molar (P = 0.11), the differences between groups of teeth were statistically significant (P < 0.05). Simple linear regression analysis showed that the more posterior the tooth was in relation to the midline, the shorter the mean distance from the root apex to the MS floor (P < 0.05). The mesiobuccal roots of second molars were closest to the MS. Second molars exhibited the shortest distances between their root apices and the MS and the greatest number of roots that were invaginating or in close contact with the MS. Therefore, second molars require special attention when endodontic or oral surgical approaches involve those regions.

Complications in sinus lift

Prosthetic rehabilitation of atrophic maxillary implants often requires grafting owing to vertical and transversal bone deficiency. The use of this procedure in order to insert implants was introduced by Tatum and published as a clinical study by Boyne and James. It can be performed via a lateral or crestal approach. This surgery is now widespread, with good results in terms of bone augmentation and implant osseointegration. Nevertheless, there is a small proportion of patients who have infectious complications with an incidence ranging from 3.5% to 10.5%. We observe that maxillary sinus augmentation is a successful preprosthetic technique for augmentation of the edentulous posterior maxilla. Preoperative assessment of the anatomy of the sinus reduces the rate of complications considerably.

Frequency, location, and morphology of accessory maxillary sinus ostia: a retrospective study using cone beam computed tomography (CBCT)

PURPOSE

To evaluate the reliability of cone beam computed tomography (CBCT) imagining in the assessment of the frequency, location, and morphological characteristics of accessory maxillary ostia (AMOs), and to analyze a potential association with sinus and dentoalveolar pathologies.

METHODS

CBCT scans with bilateral maxillary sinuses that were acquired from September 2016 to September 2018 were initially screened. A total of 160 CBCT scans (320 sinuses) that fulfilled the inclusion criteria were included for further analysis. The presence, location, and morphological characteristics of the AMOs were evaluated in axial, coronal, and sagittal CBCT views. The findings were correlated with age, gender, sinus, and dentoalveolar pathology to assess for potential influencing factors on AMOs.

RESULTS

An AMO was present in 151 (47.2%) of the 320 sinuses. Most of the AMOs were located within the region of the nasal fontanelle or hiatus semilunaris (81.1%) presenting with an ovaloid (48.4%) or a round shape (39.0%). The average length of the AMOs was 2.33 ± 1.42 mm, occupying an area of 3.43 ± 4.51 mm², respectively. Morphological changes of the maxillary sinus mucosa were positively associated with length and area of AMOs. Furthermore, the status of the dentition in the posterior maxilla seemed to be an influencing factor on AMO shape.

CONCLUSIONS

Nearly half of the maxillary sinuses assessed in the present study population had an AMO. Pathologies of the maxillary sinus seem to have an impact on AMOs, which is demonstrated here by morphological changes of the sinus mucosa being associated with an increase in length and area of accessory ostia.

A Retrospective Evaluation of Factors Influencing the Volume of Healthy Maxillary Sinuses Based on CBCT Imaging

The aim of this study was to evaluate the factors influencing the volume of healthy maxillary sinuses by means of cone beam computed tomography (CBCT). The sinus volumes in bilateral CBCT images of healthy maxillary sinuses of patients aged 18 years or older were evaluated using dedicated 3D volumetric software. Differences in volume based on gender, age, sinus side, and dental status were analyzed statistically. The study included 174 healthy maxillary sinuses in 87 patients (60 women and 27 men) aged between 18 to 82 years with a mean age of 29.5 years. There were 73 dentate sinuses and 101 partially dentate or edentulous sinuses. Males had significantly larger maxillary sinus volumes compared to females. Subjects below the median age of 24.3 years had a significantly larger sinus volume than older subjects. There was no difference in sinus volume between left and right sides. When partially dentate and edentulous cases were pooled together and compared to dentate cases, there was no difference in sinus volume. Gender and age influence healthy maxillary sinus volume, while sinus side and dental status do not. Neither tooth loss nor increasing age could be correlated with ongoing pneumatization of the maxillary sinus in the present population. Thus, the reported increase of the maxillary sinus volume over life and following extraction of posterior teeth in the upper jaw might be considered a misconception. To prove this hypothesis, prospective studies comparing sinus volumes using standardized time intervals before and after tooth extraction in the posterior maxilla are needed.

Anatomical analyses for maxillary sinus floor augmentation with a lateral approach: A cone beam computed tomography study

BACKGROUND

Various anatomical references and structures should be analyzed prior approaching a surgery in the maxillary sinus. The objective of the present study was to evaluate the anatomical structures and references involved in sinus floor elevation with a lateral approach.

MATERIALS AND METHODS

Seventy-five patients planned for sinus floor elevation were included in the study. Eighty-eight maxillary sinuses were evaluated using cone beam computed tomographies (CBCTs). The nasal floor was used as main reference (X) and sinus mucosa width, bone crest height, palatal-nasal recess angle (PNR), sinus width at the level of the nasal floor, distance from the nasal floor to the base of the sinus (X-F), position of the posterior superior alveolar artery (PSAA height) and diameter (PSAA diameter), lateral bone wall width at 3mm (LW 3mm) and 9mm (LW 9mm) from the base of the sinus (F), patency of the ostium (OP), and presence and position of septa have been evaluated.

RESULTS

The mean dimensions and standard deviations were the following: mucosa thickness was 2.0±1.4mm, bone crest height 2.8±1.4mm, distance X-F 8.3±1.9mm, PNR angle 135.5±23.1, sinus width 12.6±4.2mm, X-F 8.3±1.9mm, PSAA height 14.4±2.9mm, PSAA diameter 1.1±0.4mm, LW 3mm 1.5±1.2, LW 9mm 1.3±0.6mm, OP 1.9±0.4mm. Septa were present in 19.3% of the sinuses evaluated and were located mostly in the molar region.

CONCLUSIONS

In conclusion, the analysis of the CBCT before sinus floor elevation allows the identification of anatomical structures and references that might be used for the planning of the surgical approach, aiming to improve the outcome of the treatment and to avoid possible complications.

Posterior Maxillary Sinus Wall: A Landmark for Identifying the Sphenoid Sinus Ostium

IMPORTANCE

Safe entry into sphenoid sinus is critical in endoscopic sinus and skull base surgery. A number of surgical landmarks have been used to identify the sphenoid sinus ostium during endoscopic endonasal surgery with variable reliability and intraoperative feasibility.

OBJECTIVE

To determine if the posterior wall of the maxillary sinus is a reliable landmark to determine the depth of the sphenoid sinus ostium during anterior to posterior dissection.

DESIGN, SETTING, AND PARTICIPANTS

Prospective study of adult patients undergoing endoscopic sinus surgery between August 2016 and September 2017. Measurements were made intraoperatively between the depth of the posterior maxillary sinus wall and sphenoid sinus ostium.

MAIN OUTCOMES AND MEASURES

The primary measurement is the distance between the depth of the posterior maxillary sinus wall and sphenoid sinus ostium. Additional data points included age, gender, surgical indication, and primary versus revision endoscopic sinus surgery.

RESULTS

Forty-five patients (38% male, 62% female) with an average age of 56 were enrolled, resulting in 88 operated sides. The average distance between the depth of the posterior wall of the maxillary sinus and the sphenoid ostium was 1.5 mm ± 1.4 mm. The most common position of the sphenoid sinus ostium was posterior to the level of the posterior maxillary sinus wall (54%), followed by same level (23%) and anterior (23%). There was no significant difference between different disease states (P = .75) and between primary and revision cases (P = .13).

CONCLUSIONS AND RELEVANCE

The posterior wall of the maxillary sinus serves as an adjunctive intraoperative landmark to determine the depth of the sphenoid sinus ostium. While the posterior wall of the maxillary sinus approximates the depth of the sphenoid sinus ostium, the relative position is variable and can be anterior or posterior.

The Sinus Membrane-Maxillary Lateral Wall Complex: Histologic Description and Clinical Implications for Maxillary Sinus Floor Elevation

Maxillary sinus floor elevation has been documented as a safe and predictable procedure for gaining vertical bone height in the atrophic posterior maxillae. Conversely, there is a lack of basic research on the characteristics of the union between the sinus membrane (SM) and the bone. Clinical implications of an impaired union in healthy or pathologic membranes remain unknown. The objective of this study was to present a comprehensive histologic and morphologic description of the sinus membrane-lateral bone wall complex. In 14 fresh cadaver heads, 28 lateral wall sinus augmentation procedures were performed to obtain SM samples. Samples were assessed using hematoxylin-eosin, Masson trichrome, and toluidine blue staining and immunofluorescence and immunohistochemistry procedures. Specimens were coded and studied by a trained examiner using an optical microscope at ×4, ×10, ×40, and ×100 objectives. Thickness and inflammation status were assessed in these samples. Overall SM thickness of the samples was 0.40 ± 0.12 mm and was positively correlated to the inflammatory condition of the membranes. Such low values are the consequence of limited inflammation. Most of the fibers and cells in the deeper layers of the SM ran in a horizontal direction, oriented parallel to the underlying bone wall. In the immunohistochemistry study, 3 out of 7 samples showed a certain degree of nestin expression, suggesting osteogenic potential in spite of the elderly specimens. Large variations in thickness across the SM were found. These were noted to be partially correlated to the SM inflammatory status. The vast majority of the fibers were oriented parallel to the maxillary lateral wall, and only a few isolated areas showed a stronger perpendicular attachment. This might indicate the surpassing importance of the SM inflammatory status, operator skill, and other anatomical factors over the sinus membrane-maxillary lateral wall complex interface. Moreover, about half of the SM investigated were positive for nestin, indicating their osteogenic potential.

The use of hyaluronic acid as a support of two different micronized biomaterials in crestal sinus lift procedures. A report on two case studies with volume comparison

In the context of the trans crestal maxillary sinus lift, a wide variety of biomaterials have been used to fill the sub-antral space over the years. The materials that have a pasty consistency and are smooth and free from lumps are the most suitable to come into contact with the Schneiderian membrane which, if torn, cannot perform its graft containment function. In this study, a micronized heterologous bone in a collagen matrix of two different percentages was used in order to fill the maxillary sinus. Before using biomaterial as filler, a spray form of hyaluronic acid was used to disinfect the surgical site before and after the surgery, along with more consistent and pasty form of gel of hyaluronic acid being used in order to facilitate the detachment of the membrane. The surgical procedures were designed and carried out using computer-planned surgery. The filling volume obtained was measured with a comparative software programme and using an ellissoid formula. This technique allows the surgery to be performed in a way that is both minimally traumatic and invasive, fully careful of the membrane and represents a viable alternative to those surgical techniques for crestal sinus lift currently in use.

Impact of Sex, Age, and Season on Sinus Membrane Thickness

PURPOSE

Sinus membrane thickness has been associated with the incidence of membrane perforation during the sinus elevation procedure. Understanding the sinus membrane thickness is essential for prevention of this specific surgical complication. Therefore, the aim of this retrospective study was to investigate the impact of sex, age, and season on the membrane thickness.

MATERIALS AND METHODS

The charts of 144 healthy patients were included in the study. Cone beam computed tomography (CBCT) images from these patients were analyzed to determine the sinus membrane thickness in the coronal and sagittal views. Sex, age, and season were correlated with the membrane thickness.

RESULTS

The mean thickness of the sinus membrane was 1.81 ± 1.66 mm (range: 0.47 to 9.49 mm). In 22.12% of the CBCT images, the sinus membrane was not visible. Membrane thickness of less than 2 mm was found in 70.8% of the cases. Age was found to be strongly correlated (P < .05) with sinus membrane thickness but not sex or season.

CONCLUSION

Based on CBCT assessment, age was found to be a factor influencing sinus membrane thickness but not sex or season.

Graft-Free Maxillary Sinus Floor Elevation: A Systematic Review and Meta-Analysis

BACKGROUND

This systematic review and meta-analysis aims to investigate survival rates of dental implants placed simultaneously with graft-free maxillary sinus floor elevation (GFSFE). Factors influencing amount of vertical bone gain (VBG), protruded implant length (PIL) in sinus at follow-up (PILf), and peri-implant marginal bone loss (MBL) are also evaluated.

METHODS

Electronic and manual searches for human clinical studies on simultaneous implant placement and GFSFE using the lateral window or transcrestal approach, published in the English language from January 1976 to March 2016, were conducted. The random-effects model and mixed-effect meta-regression were used to analyze weighted mean values of clinical parameters and evaluate factors that influenced amount of VBG.

RESULTS

Of 740 studies, 22 clinical studies were included in this systematic review. A total of 864 implants were placed simultaneously with GFSFE at edentulous sites having mean residual bone height of 5.7 ± 1.7 mm. Mean implant survival rate (ISR) was 97.9% ± 0.02% (range: 93.5% to 100%). Weighted mean MBL was 0.91 ± 0.11 mm, and it was significantly associated with the postoperative follow-up period (r = 0.02; R2 = 43.75%). Weighted mean VBG was 3.8 ± 0.34 mm, and this parameter was affected significantly by surgical approach, implant length, and PIL immediately after surgery (PILi) (r = 2.82, 0.57, 0.80; R2 = 19.10%, 39.27%, 83.92%, respectively). Weighted mean PILf was 1.26 ± 0.33 mm (range: 0.3 to 2.1 mm).

CONCLUSION

Within limitations of the present systematic review, GFSFE with simultaneous implant placement can achieve satisfactory mean ISR of 97.9% ± 0.02%.

Location of Posterosuperior Alveolar Artery and Correlation with Maxillary Sinus Anatomy

The blood supply to both the lateral wall of the maxillary sinus and the overlying membrane originates from the posterosuperior alveolar artery (PSAA) and the infraorbital artery. The purpose of the present study was to evaluate the anatomic characteristics of the PSAA in a large number of subjects of the Lebanese population. Images of 696 sinuses were analyzed using cone beam computed tomography (CT). Coronal, axial, and sagittal CT images were evaluated for the presence of an osseous canal in the lateral wall of the sinus, and the prevalence, position, and location of the canal were studied and presented.

Maxillary sinus volume in patients with impacted canines

OBJECTIVES

To evaluate the maxillary sinus volumes in unilaterally impacted canine patients and to compare the volumetric changes that occur after the eruption of canines to the dental arch using cone beam computed tomography (CBCT).

MATERIALS AND METHODS

Pre- (T0) and posttreatment (T1) CBCT records of 30 patients were used to calculate maxillary sinus volumes between the impacted and erupted canine sides. The InVivoDental 5.0 program was used to measure the volume of the maxillary sinuses. The distance from impacted canine cusp tip to the target point on the palatal plane was also measured.

RESULTS

Right maxillary sinus volume was statistically significantly smaller compared to that of the left maxillary sinus when the canine was impacted on the right side at T0. According to the T1 measurements there was no significant difference between the mean volumes of the impaction side and the contralateral side. The distance from the canine tip to its target point on the palatal plane were 17.17 mm, and the distance from the tip to the target point was 15.14 mm for the left- and right-side impacted canines, respectively, and there was a significant difference between the mean amount of change of both sides of maxillary sinuses after treatment of impacted canines.

CONCLUSIONS

Orthodontic treatment of impacted canines created a significant increase in maxillary sinus volume when the impacted canines were closer with respect to the maxillary sinus.

The relationship of the medial roof and the posterior wall of the maxillary sinus to the sphenoid sinus: a radiologic study

Introduction

The medial maxillary sinus roof is a ridge formed by the superior margin of the maxillary sinus antrostomy. The posterior wall of the maxillary sinus is always included in operative fields.

Objective

To perform a radiologic study assessing the utility of the medial maxillary sinus roof and the posterior wall of the maxillary sinus as fixed landmarks for providing a safe route of entry into the sphenoid sinus.

Methods

We reviewed 115 consecutive paranasal sinus Computed Tomographic scans (230 sides) of Korean adult patients performed from January 2014 to December 2014. Using the nasal floor as a reference point, the vertical distances to the highest point of the medial maxillary sinus roof, the sphenoid ostium and anterior sphenoid roof and floor were measured. Then the vertical distances from the highest point of the medial maxillary sinus roof to the sphenoid ostium and anterior sphenoid roof and floor were calculated. The coronal distance from the posterior wall of the maxillary sinus to the sphenoid ostium was determined.

Results

The average height of the highest point of the medial maxillary sinus roof relative to the nasal floor was measured to be 33.83 ± 3.40 mm. The average vertical distance from the highest point of the medial maxillary sinus roof to the sphenoid ostium and anterior sphenoid roof and floor was 1.79 ± 3.09 mm, 12.02 ± 2.93 mm, and 6.18 ± 2.88 mm respectively. The average coronal distance from the posterior wall of the maxillary sinus to the sphenoid ostium was 0.78 mm. The sphenoid ostium was behind the coronal plane of the posterior wall of the maxillary sinus most frequently in 103 sides (44.4%). It was in the same coronal plane in 68 sides (29.3%) and in front of the plane in 61 sides (26.3%).

Conclusions

The medial maxillary sinus roof and the posterior wall of the maxillary sinus can be used as a reliable landmark to localize and to enable a safe entry into the sphenoid sinus.

A new Strategy to Improve Drug Delivery to the Maxillary Sinuses: The Frequency Sweep Acoustic Airflow

PURPOSE

Enhancement of intranasal sinus deposition involves nebulization of a drug superimposed by an acoustic airflow. We investigated the impact of fixed frequency versus frequency sweep acoustic airflow on the improvement of aerosolized drug penetration into maxillary sinuses.

METHODS

Fixed frequency and frequency sweep acoustic airflow were generated using a nebulizing system of variable frequency. The effect of sweep cycle and intensity variation was studied on the intranasal sinus deposition. We used a nasal replica created from CT scans using 3D printing. Sodium fluoride and gentamicin were chosen as markers.

RESULTS

Studies performed using fixed frequency acoustic airflow showed that each of maxillary sinuses of the nasal replica required specific frequency for the optimal aerosol deposition. Intranasal sinus drug deposition experiments under the effect of the frequency sweep acoustic airflow showed an optimal aerosol deposition into both maxillary sinus of the nasal replica. Studies on the effect of the duration of the sweep cycle showed that the shorter the cycle the better the deposition.

CONCLUSIONS

We demonstrate the benefit of frequency sweep acoustic airflow on drug deposition into maxillary sinuses. However further in vivo studies have to be conducted since delivery rates cannot be obviously determined from a nasal replica.

Anatomic variation in the pterygopalatine angle of the maxillary sinus and the maxillary bulla

Bulges of the most posterior ethmoid air cells into the maxillary sinus were termed maxillary bullæ by Onodi. With few exceptions, they have since been ignored by anatomists through time. Likewise, Sieur cells-the spheno-ethmoido-maxillary air cells-are uncommonly found in anatomical texts. We therefore aimed to perform a retrospective cone beam computed tomography study on 50 patients to document the possibilities of anatomic variation in the situs of the orbital process of palatine bone-a variation related anatomically with the pterygopalatine fossa (PPF) and the respective angle of the maxillary sinus. Commonly occurring pneumatizations in this situs were the Sieur cell (58 %/64 % right/left side), and the maxillary recess of the sphenoidal sinus (20 %/22 % right/left side). Alone or in combination, these determined, but not exclusively, the maxillary bullæ. Uncommon pneumatizations in the anterior wall of the PPF were also found, such as a sphenoidal recess of the maxillary sinus, and lateral (maxillary, or pterygopalatine) recesses of the middle and superior, respectively, nasal meatuses. In two different cases, non-Haller, and non-Sieur posterior ethmoid air cells were found extruded posterior to the maxillary sinus. Significant statistical association indicated bilateral symmetry of Sieur's cell and of the maxillary recess of the sphenoidal sinus. It is important to identify such variant pneumatizations on a case-by-case basis in different surgical procedures and endoscopic corridors.

[The progress of research about anatomy of posterolateral wall of maxillary sinus in endoscopic surgery]

As an important landmark, the posterolateral wall of maxillary sinus can help to locate numbers of significant signs such as maxillary artery and its branches, maxillary nerve and infraorbital nerve, infratemporal fossa and pterygopalatine fossa etc. in the endoscopic surgery for paranasal sinuses and lateral skull base. This article reviewed related researches about the anatomy and endoscopic surgery of posterolateral wall of maxillary sinus.

[Computer-assisted anatomical evaluation of the nasal sinuses in 1-2 years old children]

OBJECTIVE

To analyze the anatomical and developmental characteristics of nasal sinuses in 1-2 years old children; and provide potential evidence for the diagnosis and treatment of sinusitis in 1-2 years old children.

METHOD

Coronal CT scans of 60 cases (1-2 years old children) were studied with the imaging station. Reference datas were identified on these images using imaging station. The gasification conditions of the sinuses were identified and measured.

RESULT

100% of the frontal sinuses were not developed, while 100% of the maxillary sinuses were developed. The mean of the transverse and vertical diameters for the left side of the maxillary sinuse was (13.32 ± 2.88) mm and (13.55 ± 2.43) mm, respectively. While those for the right side were (13.63 ± 2.75) mm and (13.59 ± 2.13) mm, respectively. The anterior and posterior ethmoid sinuses were 100% developed. The mean transverse and vertical diameters for the left side of the anterior ethmoid sinus were (3.94 ± 0.86) mm and (11.92 ± 1.67) mm, respectively. While those mean for its right side were (3.88 ± 0.88) mm and (12.18 ± 1.86) mm, respectively. The mean transverse and vertical diameters for the left side of the posterior ethmoid sinus were (6.02 ± 1.07) mm and (10.51 ± 1.43) mm, respectively. While those for the right side were (5.91 ± 1.20) mm and (10.51 ± 1.55) mm, respectively. 88.3% (106 sides) of the sphenoid sinuses were developed, while 11.7% (14 sides) were not developed. The mean transverse and vertical diameters for the left side of the sphenoid sinus were (5.18 ± 2.15) mm and (5.78 ± 1.86) mm, respectively. While those for the right side were (4.91 ± 2.24) mm and (5.89 ± 2.03) mm, respectively.

CONCLUSION

The nasal sinuses in 1-2 years old children have been already developed. The development of the maxillary and ethmoid sinuses was clear and definite. The pneumatization of the sphenoid sinus was defined in many babies; however, the pneumatization of the frontal sinus was not defined in all babies. Acute rhinosinusitis in 1-2 years old children is not uncommon. Therefore, definite diagnosis and positive treatment of such cases are essential for avoidance of serious complications.

[Study on the correlation between the ostia diameter changes and airflow characteristics in maxillary sinus]

OBJECTIVE

To investigate the relationship between the maxillary sinus flow field, temperature field and the maxillary sinus ostium size, and to provide a reference for endoscopic surgery according to the maxillary sinus scope.

METHODS

One case of adult female CT image data was obtained, and used to build a three-dimensional model of nasal cavity and maxillary sinus. Computational fluid dynamics method was used to study the airflow and temperature of the maxillary sinus, as well as the physiological function of the maxillary sinus. Simulation surgery by means of different maxillary sinus diameters (normal, 8 mm, 10 mm, 12 mm and 15 mm) was used to describe the maxillary sinus airflow and temperature change.

RESULTS

It was found that by numerical simulation the airflow of maxillary sinus and nasal cavity showed lower speed (average speed 0.062 m/s) than that in the middle nasal meatus (average speed of 3.260 m/s), and the average temperature in the normal maxillary sinus was 34°C, which was higher than that in the middle nasal meatus (temperature 28.7°C). With the increase of the diameter of the maxillary sinus, the air temperature change was not obvious.

CONCLUSIONS

The physiological function of the maxillary sinus can be studied through the numerical simulation. With the increase of the ostia diameter of maxillary sinus, the sinus temperature and ventilation is not affected. It provides a reference for quantification of clinical endoscopic maxillary sinus surgery.

Effects of Le Fort I Osteotomy on the Nasopharyngeal Airway-6-Month Follow-Up

PURPOSE

The literature discussing the impact of a single Le Fort I osteotomy on nasopharyngeal airways is limited. This study assessed the volumetric changes in the nasopharyngeal airway after a single Le Fort I osteotomy and explored the correlation between these changes and 3-dimensional surgical movements of the upper jaw.

MATERIALS AND METHODS

This retrospective study was conducted in 40 patients who had undergone a single Le Fort I (maxillary advancement with or without impaction) to correct Class III malocclusion with maxillary hypoplasia. Preoperative (T1) and 6-month postoperative (T2) cone-beam computed tomographic (CBCT) scans of these patients were used for analysis. Maxillary surgical movements and volumetric changes in the nasopharyngeal airway were measured. The reproducibility of the measurements was evaluated using paired t tests and intraclass correlation coefficients. The Wilcoxon test and Pearson correlation coefficient were applied to evaluate the volumetric changes in the nasopharyngeal airway space and assess the correlations of these changes to the maxillary surgical movements.

RESULTS

Six patients were excluded from the study owing to major differences (>5°) in their head and neck posture between the T1 and T2 CBCT scans. The errors of the repeated measurements were insignificant (P > .05), with a high level of agreement (r = 0.99; P < .05) between the repeated digitization of the landmarks. There was a statistically significant impact of a Le Fort I osteotomy on the right maxillary sinus (decreased by 17.8%) and the lower retropalatal space (expanded by 17.3%; P < .05). The correlation between the change in airway volume and the magnitude of surgical maxillary movements was moderate (r = .4). Similarly, there was a moderate correlation between changes in the upper nasopharynx and those in the hypopharynx.

CONCLUSION

The single Le Fort I osteotomy was found to increase the retroglossal airway volume. This could be important for the treatment of obstructive sleep apnea in patients with maxillary deficiency. A long-term follow-up assessment of a larger sample with a functional assessment of airway would be beneficial to confirm these findings.

Maxillary sinus and success of dental implants: an update

The maxillary sinus augmentation procedure has been gaining more acceptance among dental professionals. The aim of this review article is to provide an update about various aspects of anatomy, physiology, and common pathological conditions of the maxillary sinus and their clinical relevance to the sinus augmentation procedure and subsequent implant placement.

Comparing the influence of crestal cortical bone and sinus floor cortical bone in posterior maxilla bi-cortical dental implantation: a three-dimensional finite element analysis

OBJECTIVE

This study aimed to compare the influence of alveolar ridge cortical bone and sinus floor cortical bone in sinus areabi-cortical dental implantation by means of 3D finite element analysis.

MATERIALS AND METHODS

Three-dimensional finite element (FE) models in a posterior maxillary region with sinus membrane and the same height of alveolar ridge of 10 mm were generated according to the anatomical data of the sinus area. They were either with fixed thickness of crestal cortical bone and variable thickness of sinus floor cortical bone or vice versa. Ten models were assumed to be under immediate loading or conventional loading. The standard implant model based on the Nobel Biocare implant system was created via computer-aided design software. All materials were assumed to be isotropic and linearly elastic. An inclined force of 129 N was applied.

RESULTS

Von Mises stress mainly concentrated on the surface of crestal cortical bone around the implant neck. For all the models, both the axial and buccolingual resonance frequencies of conventional loading were higher than those of immediate loading; however, the difference is less than 5%.

CONCLUSION

The results showed that bi-cortical implant in sinus area increased the stability of the implant, especially for immediately loading implantation. The thickness of both crestal cortical bone and sinus floor cortical bone influenced implant micromotion and stress distribution; however, crestal cortical bone may be more important than sinus floor cortical bone.

Gender assessment through three-dimensional analysis of maxillary sinuses by means of cone beam computed tomography

OBJECTIVE

The availability of a low dose radiation technology such as Cone Beam Computed Tomography (CBCT) in dental practice has increased the number of scans available for forensic purposes. Moreover, specific software allows for three-dimensional (3D) characterization of the maxillary sinuses. This study was performed to determine whether sinus maxillary volumes can be useful to identify gender after validating the use of the Dolphin software as a tool for volumetric estimation of maxillary sinus volumes.

PATIENTS AND METHODS

The validation was performed by four different operators measuring the volume of six phantoms, where the real volume was already known. The maxillary sinus volumes of 52 patients (26 males and 26 females) mean age 24.3 were calculated and compared between genders and sagittal skeletal class subdivision. The measurements for patients and phantoms were based on CBCT scans (ILUMA™) processed by Dolphin 3D software.

RESULTS

No statistical difference was observed between the real volume and the volume measurements performed by the operators. No statistical difference was found in patient's maxillary sinus volumes between gender.

CONCLUSIONS

Based on our results, it is not possible to support the use of maxillary sinuses to discern sexual difference in corpse identification.

[Radiographic study of maxillary sinus associated with molars in adult]

OBJECTIVE

to explore the relationship between the maxillary sinus volume and the amount of alveolar bone, and the effect of molar loss upon the maxillary sinus was further analyzed,by measuring adult maxillary sinus volume, sinus ridge distance, and calculating the gasification coefficient of maxillary sinus.

METHOD

One hundred and ninety cases (361 maxillary sinus) with CT examinations were collected, they were divided into group A and group B, 121 cases (242 maxillary sinus) of normal subjects served as group A, 42 cases (65 maxillary sinus) with molar part off were B group, in which 31 maxillary sinus with a molar loss were group B1,22 maxillary sinus with two molar loss were B2 group,12 maxillary sinus with three molar loss (one molar remains) were B3 group, 27 cases (54 maxillary sinus) with upper teeth off were C group. Bymeasureing the maxillary sinus volume, sinus ridge distance and the size of the maxillary sinus, calculating the gasification coefficient, we analyzed the relationship between maxillary volume and sinus ridge distance, and comparatively analyzed the differences among the three groups in the size, gasification coefficient, volume of maxillary sinus and sinus ridge distance.

RESULT

In the normal group,the volume of maxillary sinus and sinus ridge distance had a correlation coefficient of -0. 63,(P< 0.05); Sinus ridge distance in group A was larger than the other two groups (P<0.05), and larger in B group than in C group (P<0. 05), anteroposterior maxillary sinus diameter and reft-right diameter in C group was greater than in A group and B group(P<0.05), group C gasification coeffiecent was less than A group and B group (P<0. 05).

CONCLUSION

The volume of maxillary sinus is negatively correlated with the amont of alveolar bone; Upper teeth's shedding promotes maxillary sinus deformation; Maxiuary sinus volume has a tendency to decrease.

[The maxillary sinus morphology that affect the vision of nasal endoscopy in maxillary sinus surgery]

OBJECTIVE

To observe the gasification of the maxillary sinus which might affect the vision of the maxillary sinus surgery with endoscope.

METHOD

The diameters of 2 000 maxillary sinus were observed and measured hy normal sinus CT scan. The maxillary sinus were then genotyped with the data.

RESULT

Morphology of the medial wall of maxillary sinus played an important role in maxillary sinus surgery. According to the horizontal position CT data, the middle part of maxillary sinus medial wall included two shapes: 857 triangle (85.7%) and 143 semicircular (14.3%). According to the coronal CT data, the middle part of maxillary sinus medial wall varied a lot, there were also two shapes of them: 341 convex type (31.1%) and 659 straight type (65.9%). In contrast, the former and back parts varied a little. Therefore, we genotyped the maxillary sinus according to the morphology of maxillary sinus medial wall and the gasification level. There were 3 types of our genotyping: 662 of I type (66.2%), 265 of II type (26.5%), 73 of III type (7.3%).

CONCLUSION

The medial wall of maxillary sinus should be considered before the surgery of nasal endoscopy because of the great affections of which to endoscopy version.

Cone beam CT evaluation of maxillary sinus septa prevalence, height, location and morphology in children and an adult population

OBJECTIVE

The purpose of this study was to determine the prevalence, height, location and morphology of maxillary sinus septa in dentate, partially dentate and edentulous adults as well as in mixed dentition children using cone beam computed tomography (CBCT) for maxillary sinus surgical interventions.

SUBJECTS AND METHODS

Five hundred and fifty-four sides in the CBCT scans of 272 patients (30 children and 242 adults) were retrospectively analyzed. The prevalence, location and morphology were assessed in axial, sagittal, cross-sectional and panoramic 3-dimensional images. The height of septa was measured with the angle between the direction of the septum and median palatine suture. The differences among age, localization and measurements were statistically analyzed.

RESULTS

The prevalence of maxillary sinus segments with septa was 58%. There were a total of 13 (3.2%) septa of completely edentulous (CE), 198 (53.9%) septa of edentate and 14 (3.8%) septa of the mixed dentition maxillary segments. The location of septa observed in all study groups demonstrated a greater prevalence (69.1%) in the middle region than in the anterior and posterior regions. No statistically significant differences were observed with regard to gender or age, for septum height (p > 0.05). However, maxillary sinus septa are higher in partially edentulous patients than edentate and CE ones (p < 0.05).

CONCLUSION

Septa of various heights and courses developed in all parts of the maxillary sinus, therefore to prevent possible complications during sinus surgery, extensive evaluation with an appropriate radiographic technique was indispensable.

Effectiveness of piezoelectric surgery in preparing the lateral window for maxillary sinus augmentation in patients with sinus anatomical variations: a case series

PURPOSE

The present article sought to evaluate the effectiveness of a piezoelectric surgical unit for maxillary sinus augmentation surgeries in avoiding perforation of the sinus membrane and other possible procedural complications in patients with anatomical variations of the sinus.

MATERIALS AND METHODS

Twenty-five patients presenting sinus anatomical variations, who were indicated for a total of 40 sinus grafting procedures performed by the lateral window approach with a piezoelectric device, were analyzed. After 6 months of healing, implants were placed. Information collected included clinical and computed tomographic information on anatomical variations in the sinus bone walls, in the size of the sinus, and in the thickness of the sinus membrane. Occurrence of sinus membrane perforation and computed tomographic measurements of the amount of bone height gained with the grafting procedures were also recorded.

RESULTS

Only two patients presented a small perforation (less than 5 mm in diameter) of the sinus membrane, which occurred only after osteotomies of the lateral windows and did not compromise the surgical outcome. No implants were lost during a mean follow-up period of 19 months.

CONCLUSION

The use of piezoelectric surgery allowed for the accomplishment of all rehabilitation treatments within the follow-up period of this study.

Influence of lateral window dimensions on vital bone formation following maxillary sinus augmentation

PURPOSE

The aim of this study was to evaluate the influence that lateral window dimensions may have on maxillary sinus augmentation outcomes.

MATERIALS AND METHODS

Patients requiring maxillary sinus augmentation by a lateral window approach and delayed implant placement were recruited in this study. Approximate window dimensions (AWD) were calculated in mm2 at the time of the surgical intervention. In all cases, a mixture of cortical and cancellous allograft particles was used as the sole grafting material. Patients were followed for 6 months. At the time of implant placement, bone core biopsies were harvested. Transversal circular samples were histomorphometrically analyzed. Proportions of vital bone (VB), remaining allograft particles (RA), and nonmineralized tissue (NMT) were quantified. Analysis of correlation of AWD with %VB, %RA, and %NMT was performed using a statistical model.

RESULTS

A total of 24 maxillary sinus augmentation procedures were performed in 21 patients. One patient developed an infection after grafting and was excluded. Histomorphometric analysis showed that mean %VB was 21.69% ± 16.30%, %RA was 23.51% ± 16.33%, and %NMT was 55.08% ± 8.52%. A strong negative correlation was observed between AWD and %VB (r = -0.621; P = .0007), a marked positive correlation was found between AWD and %RA (r = 0.565; P = .002), and a minimal positive correlation, without statistical significance, was found between AWD and %NMT (r = 0.076; P = .365).

CONCLUSIONS

The results of this study suggest that AWD may have an important influence on the maturation and consolidation of a mixture of cortical and cancellous allograft in the maxillary sinus.

[The anatomy research of expanding vision of endoscopic maxillary sinus operation]

OBJECTIVE

To get the anatomical method of expanding vision of endoscopic maxillary sinus operation to providing guidance for the satisfactory surgical vision by measurement of nasal cavity and maxillary sinus relative structure.

METHOD

By anatomical measurement from 30 human cranium preparations (21 male, 9 female), which were marinated by 10% formaldehyde solution, we tried to find out anatomical factors that influence expanding vision of endoscopic maxillary sinus operation.

RESULT

Measurement of cranium preparations: respective distance between bone nasolacrimal canal anterior wall superior extremity, central extremity, bottom extremity and borderline of maxillary sinus anterior wall and medial wall were 0 mm, (1.90 +/- l.03) mm, (3.29 +/- 1.04) mm. Distance between anterior inferior part of bone nasolacrimal canal and anterior edge of inferior concha was (5.13 +/- 0.62) mm, and vertical distance between anterior inferior part of bone nasolacrimal canal and nasal bottom was (16.89 +/- 0.97) mm. The difference between right and left side had no significant statistic sense (P > 0.05). Removal of the bone area: the upper and lower diameter of part of the inferior turbinate attachment was (9.43 +/- 1.72) mm, anteroposterior diameter from top to bottom was (9.76 +/- 0.83) mm, (11.39 +/- 0.50) mm, (12.85 +/- 0.66) mm, the upper and lower diameter of the following part of the inferior turbinate attachment was (13.52 +/- 0.83) mm, anteroposterior diameter from top to bottom was (19.89 +/- 1.37) mm, (16.59 +/- 0.77) mm, (12.48 +/- 0.91) mm.

CONCLUSION

Dissection from inferior turbinate anterior part approach to maxillary sinus could expand the endoscopic operation vision.

Reassessment of Dolichopithecus (Kanagawapithecus) leptopostorbitalis, a colobine monkey from the Late Pliocene of Japan

In the original description of Dolichopithecus (Kanagawapithecus) leptopostorbitalis, Iwamoto, Hasegawa and Koizumi, 2005, a moderately large-sized colobine monkey from the Late Pliocene of central Japan, affinities to the European Dolichopithecus rather than to the Transbaikalian Parapresbytis were noted based on the similarities in cranial morphology. Computed tomography scans confirm the presence of the maxillary sinus in the holotype, whereas it is probably absent in specimens of the European Dolichopithecus ruscinensis, the type species of this genus. This feature is either present or absent homogeneously in any given genus of living anthropoids. Its presence or absence is unknown in Parapresbytis, but the distinct morphology of the maxillary incisors in this taxon suggests that this form had different feeding habits from the Japanese colobines. These findings suggest that the Japanese colobine should be referred to henceforth as Kanagawapithecus leptopostorbitalis. Kanagawapithecus shares many important facial and dental features with Dolichopithecus rather than with Parapresbytis, but this association depends largely on the limited availability of comparable materials for the latter. Among colobines, the presence of the maxillary sinus is recorded only in Libypithecus and Cercopithecoides. The maxillary sinus is absent in all modern Asian colobines, implying that Kanagawapithecus is an isolated form without any relationship to living forms. Nevertheless, such phylogenetic interpretations are largely dependent on the restricted fossil evidence from the Pliocene and Pleistocene of eastern Eurasia and will be reexamined when new findings are made.

Mechanical stress induces bone formation in the maxillary sinus in a short-term mouse model

OBJECTIVES

Clinicians occasionally face the challenge of moving a tooth through the maxillary sinus. The objective of this study was to evaluate tissue remodeling during tooth movement into the maxillary sinus, more specifically as regards to bone formation.

MATERIALS AND METHODS

The maxillary first molar of 20 male mice was moved toward the palatal side by a nickel-titanium super elastic wire for 1 to 14 days, and the bone remodeling around the root was evaluated using histomorphometry and immunodetection of bone-restricted Ifitm-like (Bril) protein, a novel marker of active bone formation.

RESULTS

When mechanical stress was applied to the tooth, the periodontal ligament on the palatal side was immediately compressed to approximately half of its original width by the tipping movement of the tooth. At the same time, osteoblasts deposited new bone on the wall of the maxillary sinus prior to bone resorption by osteoclasts on the periodontal side, as evidenced by the high level of expression of Bril at this site. As a result of these sequential processes, bone on the sinus side maintained a consistent thickness during the entire observation period. No root resorption was observed.

CONCLUSIONS

Bone formation on the surface of the maxillary sinus was evoked by mechanotransduction of mechanical stress applied to a tooth over a 2-week period, and was induced ahead of bone resorption on the periodontal ligament side.

CLINICAL RELEVANCE

Mechanical stress can be exploited to induce bone formation in the maxillary sinus so that teeth can be moved into the sinus without losing bone or causing root damage.

Sinus lift procedures: an overview of current techniques

For more than 30 years the maxillary sinus augmentation graft has been a mainstay of implant-directed maxillary reconstruction. The purpose of this article is to review the fundamentals of maxillary sinus reconstruction including anatomy and physiology of the sinus, indications for surgery, preoperative evaluation, surgical techniques, and management of complications. While there are some relative contraindications for the procedure, there are almost no absolute contraindications. With preparation, education, and experience, the maxillary sinus augmentation/elevation graft is a procedure that greatly benefits the patient, with a predictable outcome.

Relationship between subsinus bone height and bone volume requirements for dental implants: a human radiographic study

PURPOSE

To analyze the vertical dimension of subsinus alveolar bone that is available for placement of endosseous implants.

MATERIALS AND METHODS

Subsinus alveolar bone height (SBH) was determined via radiographs and categorized into three groups: Group A corresponded to SBH < 5 mm; group B SBH of 5 to 9 mm; and group C, SBH > 9 mm. Statistical analysis was carried out using the Wilcoxon paired test with the threshold for statistical significance set at P < .05.

RESULTS

Five hundred eighty-three panoramic radiographs of edentulous maxillae were analyzed. In 96.9% of radiographs, the anterior border of the maxillary sinus was above the first premolar. Mean SBH values for canine, first premolar, second premolar, first molar, and second molar sites were 11.4 ± 6.2 mm, 10.6 ± 3.8 mm, 5.9 ± 2.5 mm, 3.3 ± 2.2 mm, and 4.5 ± 2.4 mm, respectively. Representations of groups A, B, and C in the canine region were 14.3%, 21.4%, and 64.3%, respectively; in the first premolar region they were 8.3%, 22.3%, and 69.4%, respectively; in the second premolar region, these were 31.6%, 60.9%, and 7.5%, respectively; in first molar region, the values were 73.1%, 25.4%, and 1.5%, respectively; and in the second molar region they were 54.2%, 41.7%, and 4.1%, respectively.

CONCLUSIONS

The mean SBH is the highest in the area of the anterior border of the sinus; it declines significantly toward the posterior maxilla, reaches its minimum in the area of the first molar, and increases again significantly in the second molar region. From a clinical point of view, the lateral window technique of sinus elevation remains the dominant augmentative procedure in the molar area, whereas in the premolar area, less invasive alternative methods may be more appropriate.

Sex identification in Egyptian population using Multidetector Computed Tomography of the maxillary sinus

Forensic anthropology involves the building of an antemortem profile of an individual from skeletal remains. This includes sex, race determination, and age and stature estimation. Because most bones that are conventionally used for sex determination are often recovered either in a fragmented or incomplete state, it has become necessary to use denser bones that are often recovered intact, eg, the maxillary sinus. The present work was performed to investigate the possibility of estimation of sex from some radiologic measurements among a known cross-section of Egyptian population. In this study, by the use of Multidetector Computed Tomography (MDCT) scan, eight maxillary sinus measurements were assessed in 96 living non-pathologic Egyptians comprising 48 males and 48 females aged 20-70 years referred to the Radiology Department. These were subjected to statistical analysis. Two variables showed significant differences: cephalo-caudal and size of the left maxillary sinus. The study concluded that the correct predictive accuracy was 70.8% in males and 62.5% in females. In conclusion, MDCT measurements of cephalo-caudal and size of the left maxillary sinuses are useful feature in gender determination in Egyptians.

A radiographic study of the position and prevalence of the maxillary arterial endosseous anastomosis using cone beam computed tomography

PURPOSE

This study was designed to investigate the prevalence and course of the vascular canals in the maxillary sinus walls and to measure the distance between the sinus floor, the edentulous alveolar crest, and the vascular canal using cone beam computed tomography (CBCT).

MATERIALS AND METHODS

The maxillary sinus CBCT scans of 250 patients scheduled for implant surgery were examined. The vertical and mediolateral positions of the vascular canals or notches were investigated on the CBCT images. The location of each tooth was confirmed using a diagnostic template for implant placement. Statistical analyses were performed to verify whether the mean artery position was significantly different according to each tooth location, gender, and age.

RESULTS

A maxillary arterial endosseous anastomosis was observed in 52.8% of patients. The mean perpendicular distance from the sinus floor to the vascular canal was shortest in the first molar region (7.58 ± 3.19 mm) and longest in the first premolar region (9.2 ± 3.22 mm). The mean distance from the alveolar crest to the vascular canal was shortest in the first molar region (14.79 ± 4.04 mm) and longest in the first premolar region (18.92 ± 4.86 mm). These distances were significantly different according to tooth position. The mean distances from the alveolar crest and the sinus floor to the vascular canal did not decrease with age. The mediolateral position of the canals was also significantly different depending on tooth position.

CONCLUSION

With this information about the branch of the posterior superior alveolar artery from CBCT, unnecessary bleeding during implant placement should be more easily preventable. The use of CBCT is recommended as a routine procedure prior to sinus floor elevation.

Maxillary sinus floor augmentation using a nano-crystalline hydroxyapatite silica gel: case series and 3-month preliminary histological results

The aim of this case series is to histologically examine a new hydroxyapatite in sinus lift procedure after 3 months. Ten 2-stage sinus lifts were performed in 10 healthy patients having initial bone height of 1-2mm and bone width of 5mm, asking for a fixed implant-supported rehabilitation. After graft material augmentation, a rough-surfaced mini-implant was inserted to maintain stability of the sinus widow. A bioptical core containing a mini-implant was retrieved 3 months after maxillary sinus augmentation with NanoBone(®) and processed for undecalcified histology. From the histomorphometric analysis, NanoBone(®) residuals accounted for the 38.26% ± 8.07% of the bioptical volume, marrow spaces for the 29.23% ± 5.18% and bone for the 32.51% ± 4.96% (new bone: 20.64% ± 2.96%, native bone: 11.87% ± 3.27%). Well-mineralized regenerated bone with lamellar parallel-fibred structure and Haversian systems surrounded the residual NanoBone(®) particles. The measured bone-to-implant contact amounted to 26.02% ± 5.46%. No connective tissue was observed at the implant boundary surface. In conclusion, the tested material showed good histological outcomes also 3 months after surgery. In such critical conditions, the use of a rough-surfaced mini-implant showed BIC values supposed to be effective also in case of functional loading. Although longer follow-up and a wider patient size are needed, these preliminary results encourage further research on this biomaterial for implant load also under early stage and critical conditions.

Drainage of the maxillary sinus: a comparative anatomy study in humans and goats

OBJECTIVE

The maxillary sinuses are the most frequently infected paranasal sinuses in humans. It has been suggested that infection occurs relatively commonly in the maxillary sinuses owing to the position of their ostia high on their superomedial walls, which may be suboptimal for natural drainage. This may represent evolutionary lag, whereby the ostia remained in a quadrupedal position as bipedal humans evolved from their primate ancestors. This study examined the hypothesis that drainage of the maxillary sinus is optimal in the quadrupedal position.

DESIGN

The drainage of the human maxillary sinus and an analogous quadruped, the goat, was examined and compared in the upright, quadrupedal, and intermediate positions.

SETTING

Department of Anatomy, King's College London.

METHODS

Cadaveric human and goat maxillary sinuses were filled with saline in each position and the volume at which saline overflowed through the ostia was noted.

MAIN OUTCOME MEASURE

Volume at which spontaneous drainage occurred through ostia.

RESULTS

The volume of saline instilled before drainage was maximal in the upright position and reduced with each increase in anterior tilt, with drainage occurring most easily at 90° for both human and goat sinuses. Drainage was significantly better in the quadrupedal head position than upright in both species (p < .01).

CONCLUSIONS

This study demonstrated that human maxillary sinuses exhibit better passive drainage through their ostia when tilted anteriorly to mimic a quadrupedal head position. This may be an example of an evolutionary lag phenomenon and could be one etiologic factor in the prevalence of maxillary sinusitis in humans.

A proposed classification for zygomatic implant patient based on the zygoma anatomy guided approach (ZAGA): a cross-sectional survey

PURPOSE

The aim of the present cross-sectional study was to propose a classification system based on a cross-sectional survey of zygomatic implant cases.

MATERIALS AND METHODS

Cone beam computerised tomography (CBCT) postoperative images and clinical intra-surgery photographs of 200 sites corresponding to 100 patients, treated with a total of 198 zygomatic implants in the maxilla according to an anatomy-driven prosthetic approach, were reviewed with regard to anatomy and pathway of the zygomatic implant body. The patients were consecutively selected independently of the type of surgery performed, with the unique requirement of a post-surgical CBCT performed at the moment of selection. Of special interest was the morphology of the lateral sinus wall, residual alveolar crest and the zygomatic buttress. An attempt was made to divide the patients into groups, describing typical anatomies and implant pathways.

RESULTS

Five basic skeletal forms of the zygomatic buttress-alveolar crest complex and subsequent implant pathways could be identified in a sample of 100 patients. Out of them, 62% were female and 38% male, with ages varying between 36 and 83 years (mean age 59.6, SD: 9.67). The five groups were classified as ZAGA 0 to 4 representing 15%, 49%, 20.5%, 9% and 6.5% of the studied sites, respectively. Intra-individual anatomical differences affecting the zygomatic buttress-alveolar crest complex was also found in 58% of the patients.

CONCLUSIONS

Five typical anatomical and implant pathway situations could be identified. A classification system comprising five groups named ZAGA 0 to 4 is proposed. Anatomical intra-individual differences were also found in the 58% of the studied population. It is believed that the proposed classification system is useful for categorising zygomatic implant cases for therapy planning and for scientific follow-up purposes.

Observing the bony canal structure of the human maxillary sinus in Japanese cadavers using cone beam CT

We observed the location of the posterior superior alveolar artery (PSAA) and nerve at the macroscopic level between the maxillary sinus (MS) and surrounding bone of the anterior region of the maxilla. This study was completed using cone beam computed tomography (CBCT) imaging of 19 human cadavers with 38 sides of Japanese origin (ranging in age from 59-94 years, mean 77.7 +/- 9.8 years) that were prepared for this study. The bony canal structure of the inner surface of the maxilla was clearly apparent in our results, and the bony canals were classified into three types according to the structure along the course of the PSAA: canal-like, ditch-shaped tunnel and fragmented, and the lest sides were undefined. Calcitonin gene-related peptide (CGRP)-positive fibers were identified along the PSAA in the bony canal of the maxilla by immunohistochemistry. The presence of the bony structure and CGRP-positive nerve fibers along the PSAA suggests that there is risk to the PSAA during surgery involving graft implant in the floor of the maxillary sinus.

Simulation of sinus floor augmentation with symphysis bone graft using three-dimensional computerized tomography

The objective of this study was to evaluate the maximum amount of harvestable bone graft in the mandibular symphysis and the augmentation volume needed for different sinus lift levels (from 10 to 18 mm), in addition to calculating which sinus lift level can be acquired using the individual's symphysis bone graft volume with three-dimensional computerized tomography (3D CT) and software. Data from 15 CT scans was obtained from 15 adult patients (10 males, five females). The CT data, in DICOM format, was read into Mimics software from Materialize (Leuven, Belgium), with a slice thickness of 0.5 mm. The mandibular symphysis bone graft volumes and different levels of sinus lift augmentation volumes were calculated on the 3D images using Mimics software. It was determined that the average symphysis bone volume (3491.08+/-772.12 mm(3)) could provide approximately 14 mm of sinus lift height (3167.84+/-1067.65). 3D CT techniques and software can be used to calculate the required graft volume for sinus floor augmentation and symphysis bone graft volume, and the mandibular symphysis region can provide adequate bone volume for sinus lift augmentation.