Mesures volumétriques des bases osseuses maxillaires et des cavités aériennes de la face en imagerie 3D

Usefulness of Hard Palate Measurements in Predicting Airway Dimensions in Patients Referred for Cone Beam CT

Purpose:

The aim of the study was to evaluate the usefulness of hard palate measurements in predicting airway dimensions in patients referred for cone-beam CT (CBCT).

Materials and Methods:

Six hundred forty-three patients (239 males and 404 females) were examined by CBCT. Using dedicated CBCT software (Kodak CS 3D imaging version 3.8.6, Carestream, Rochester, NY, USA); different hard palate (palatal interalveolar length, palatal arch depth, maxillo-palatal arch angle, and alveolar width) and airway measurements (airway volume, minimum cross-sectional area, minimum anteroposterior distance, minimum right to left distance and airway length) were obtained and correlated using Pearson’s correlation coefficients and regression analysis.

Results:

Although the correlation between hard palate and airway measurements was weak (Pearson coefficient (r) < 0.40), there were significant (P < 0.05) additive effects for hard palate measurements in predicting airway dimensions. Maxillo-palatal arch angle was the only hard palate measurement that had no effect in predicting airway dimensions.

Conclusion:

Hard palate measurements are considered useful in predicting airway dimensions in patients referred for CBCT.

Evaluation of upper airway volume and craniofacial volumetric structures in obstructive sleep apnoea adults: A descriptive CBCT study

OBJECTIVE

The aim of this investigation was to assess, with a descriptive three-dimensional evaluation, the volume of upper airway (UAWV) and the volume of craniofacial structures in adult patients suffering from obstructive sleep apnoea (OSA) and compare them to the corresponding findings in adults with no sleep disorders.

MATERIALS AND METHODS

The sample consisted of 54 adult males, 27 suffering from OSA diagnosed by means of the Apnoea Hypopnea Index and 27 with no history of sleep disorders. All subjects had a cone beam computerized tomography scan performed with the same head position. UAWV was assessed with the Amira® software, and craniofacial volumes by means of a specially developed data-processing program, which allowed the construction of tetrahedrons using anatomical landmarks. Assessed volumes were naso-maxillary, cranium upper anterior, oral cavity, post-oral cavity, hyoid to mandible, and post-hyoid. SPSS (version 19.0) was used for the statistical analysis. The Levene's test for Equality of Variance, the t-test for Equality of Means and the Mann-Whitney test were used to evaluate the variables. The level of significance was set at P ≤ 0.05.

RESULTS

The mean value of UAWV was smaller in the OSA group. The post-hyoid volume, the calculated posterior volume, and the ratio of posterior to total volume showed differences between the groups.

CONCLUSIONS

Craniofacial structures did not show significant differences between the groups, but in the OSA group the posterior space released for upper airway was significantly bigger and UAWV was significantly smaller.

Sonic aerosol therapy to target maxillary sinuses

AIM

Intranasal aerosol administration of drugs is widely used by ENT specialists. Although clinical evidence is still lacking, intranasal nebulization appears to be an interesting therapeutic option for local drug delivery, targeting anatomic sites beyond the nasal valve. The sonic nebulizer NL11SN associates a 100Hertz (Hz) sound to the aerosolization to improve deposition in the nasal/paranasal sinuses. The aim of the present study was: to evaluate in vivo the influence of associating a 100Hz sound on sinus ventilation and nasal and pulmonary aerosol deposition in normal volunteers, and; to quantify in vitro aerosol deposition in the maxillary sinuses in a plastinated head model.

MATERIAL AND METHODS

Scintigraphic analysis of (81m)Kr gas ventilation and of sonic aerosol ((99m)Tc-DTPA) deposition using the NL11SN was performed in vivo in seven healthy volunteers. In parallel, NL11SN gentamicin nebulization was performed, with or without associated 100Hz sound, in a plastinated human head model; the gross amount of gentamicin delivered to the paranasal sinuses was determined by fluorescence polarization immunoassay.

RESULTS

Associating the 100Hz sound to (81m)Kr gas ensured paranasal sinus ventilation in healthy volunteers. (99m)Tc-DTPA particles nebulized with the NL11SN were deposited predominantly in the nasal cavities (2/3, vs 1/3 in the lungs). In vitro, the use of NL11SN in sonic mode increased gentamicin deposition threefold in the plastinated model sinuses (P<0.002); the resulting antibiotic deposit would be sufficient to induce a local therapeutic effect.

CONCLUSION

The NL11SN nebulizer ensured preferential nasal cavity aerosol deposition and successfully targeted the maxillary sinuses.

[Sexual dimorphism and facial cavities: a 3D imaging volumetric study]

INTRODUCTION

The aim of this study was to investigate the sexual dimorphism in facial cavity's volumes of untreated young adults.

METHODS

Sixty subjects, ages between 18 to 30 years, were selected and divided in two groups according to the gender. Volumes of orbital, nasal, sinusal and buccal cavities were measured from CT scans with AMIRA(®)software. The statistical studies were performed using Kolmogorov-Smirnov test for normality followed by Student "t" test (p < 0.05).

RESULTS

The gender comparison reflected statistically significant differences between the volumes of orbital, nasal, sinusal and buccal cavities, volumes being larger in males. Sexual dimorphism did not appear in the ratio of each cavity volume on the total facial volume.

CONCLUSION

Absolute volume of facial cavities are larger in males, but no sexual dimorphism is detected comparing volume ratios. A difference in size, but not in shape, between genders might exist.

[Facial volumes and vertical facial type: a three dimensional comparative study]

INTRODUCTION

The purpose of this study was to compare the volume of facial cavities in untreated young subjects with long- and short-faces.

METHODS

Two groups of thirty subjects each, one with low (GoGn-SN < or = 28 degrees), and the other with high (GoGn-SN > or = 36 degrees) mandibular plane angles, ages between 18 to 30 years, were selected. For each subject, volumes of orbital, sinusal and buccal cavities were measured from CT scans with the AMIRA software. The statistical studies were performed using Kolmogorov-Smirnov, followed by Student "t" test (p < 0.05).

RESULTS

Results suggest that there is no statistically significant difference between the volume of facial cavities in long- and short-face subjects. Only the ratio of nasal cavity volume to the total volume is significantly smaller in the short-face group.

CONCLUSION

A compensatory phenomenon might exist between the three directions of growth to equilibrate an excess or deficit of the vertical dimension, thus maintaining constant the volume of facial cavities.

[Three-dimensional 14 point-cephalometric analysis: compensation of maxillofacial dysmorphisms]

The eight points cephalometric Treil model and the alveolodental parameters already allows an initial description of the maxillofacial framework and the teeth. Added six points allows taking into consideration an intermediate level: the maxillary and mandibular skeletal basis. So, the 14 points complete model allows a complete craniofacial anatomy description in three analysis levels: the framework or envelope, the osseous bases, the alveolodental arch. The correlation study between the 3D parameters at different levels defines the compensation notion. It allows understanding how skeletal disharmony may be distributed among the different levels. Only vertical direction compensations are analysed here.

[Three-dimensional cephalometry: applications in clinical practice and research]

A 3D cephalometric analysis method from scanner acquisition has been developed thanks to a long collaboration between Dr Treil and the Department of Orthodontics in Toulouse III University. It allows a perfect knowledge of maxillo-facial architecture using fourteen landmarks related to the neuromatricial axis of facial growth. These landmarks can be identified without ambiguity. The marking of each tooth relative to dental arches (gravity centre coordinates and torque and tipping of each tooth), and the location of arches relative to maxillo-facial frame are given by the analysis. Description and reconstruction of dental and maxillo-facial anatomy are possible with three levels: maxillo-facial frame, maxillar and mandibular bases and dentoalveolar level. The method not only gives more precise information than conventional cephalometrics in anteroposterior and vertical directions, but it allows transversal analysis and asymmetry measurement. Applications are numerous in research as well as in clinical medicine: analyses of cases border line surgery, surgical set-up, facial asymmetry, analysis of dentoalveolar compensations, definition of therapeutic aims, occlusal analysis and set-up, study of evolution in anthropology-primatology, study of growth etc. This method of description using a pattern of landmarks is perfectly adapted to the last developments of modern research techniques: morphometric geometry with Procustes superimpositions, EDMA, TPS, FEM.

[Correlations between the volume of the sinuses and the facial bones and parameters of 3D cephalometry]

The goal of this work is to study, using a sample of 95 persons, the parameters of the 14 points of the 3D Treil cephalometric analysis and to compare them to the facial volumes of these subjects. The 3D parameters are described on three levels and for all three dimensions of space; they are also defined statistically for each class of occlusion, and indications are given for sagittal two-dimensional variables. The correlations between all these variables and facial bones and air cavity volumes are also analyzed. The antero-posterior and vertical variables showed more statistically significant relationships with volumes than with transverse parameters. It appears that a Class III occlusion is primarily related to the vertical and antero-posterior position of the mandible and its morphology and not to its size, while Class II Division 1 types are associated with increased size of the maxillary sinuses. It also appears that facial hyper-divergence is related to a decrease in the size of the maxilla and the mandible.