Browsing by Author "Ghoneima, Ahmed"

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3D superimposition of dental casts based on coloured landmark detection using combined computer vision and 3D computer graphics techniques
(2019) Ghoneima, Ahmed
Abstract: The aim of this study was to evaluate the validity and reliability of three-dimensional (3D) landmark-based palatal superimposition of digital dentalmodels using the customized software Ortho Mechanics Sequential Analyzer (OMSA) revised by the addition of a computer vision algorithm. The sample consisted of pre- and post-treatment digital maxillary dental models of 20 orthodontic cases. For each case, the pre- and posttreatment digital models were superimposed using colour detection capabilities of a computer vision algorithm added to OMSA. The same set of parameters was measured on the superimposed 3D data by the two software versions for comparison. Agreement in the superimposition outcomes among the two superimposition methods was evaluated with Dahlberg error (DE), intraclass correlation coefficients (ICCs) using two-way ANOVA mixed model for absolute agreement and Bland–Altman agreement limits (LOA). Repeatability was excellent for all variables (all ICCs over 0.99 with the lower 95% confidence limit ≥0.95). The Dahlberg error (DE) ranged from 0.14mmto 0.36mm. The absolute error did not exceed 0.5mmfor any variable. The results indicate that OMSA with computer vision algorithms offers a valid and reliable tool for 3D landmark-based digital dental model superimposition using colour detection of three reference points marked along the mid-palatal raphe.
Accuracy and reliability of landmark- based, surface- based and voxel- based 3D cone- beam computed tomography superimposition methods
(2017) Ghoneima, Ahmed
Objectives: To evaluate and compare the accuracy and reliability of 3 different methods of three- dimensional cone- beam computed tomography scans (3D CBCTs) superimpositions: landmark- based, surface- based and voxel- based. Materials and Methods: Pre and post orthodontic treatment CBCTs (T1 and T2) of 20 subjects with a mean age of 11 years were obtained. Seven points on the zygomatic arch and supraorbital region were selected to perform landmark- based superimposition. Surface- based and voxel- based superimpositions were performed using the anterior cranial base as a reference. Each superimposition method of T1 and T2 scans was repeated twice to assess the reliability. Accuracy of each technique was tested by superimposing duplicated sets of T1 scans. A total of 11 landmarks on the anterior cranial base, maxilla and mandible were located, and deviations of these landmarks on superimposed data were quantified to assess reliability and accuracy of all superimpositions. Results: There were no significant differences from zero when duplicated sets of T1 scans were superimposed using surface- based and voxel- based methods. Statistical significant differences were detected in several parameters when evaluating the accuracy of the landmark superimposition. Superimposition of T1 and T2 scans for testing the reliability revealed intraclass correlation coefficients greater than 0.90 for all measurements except for ACP- x and PNS- y of landmark- based method as well as ANS- x of voxel- based method. Conclusions: Surface- based and voxel- based superimposition methods using the anterior cranial base as a reference structure were accurate and reliable in detecting changes in landmark positions when superimposing. Landmark- based superimposition method was reliable but less accurate than the other methods.
Accuracy of three-dimensional dental resin models created by fused deposition modeling, stereolithography, and Polyjet prototype technologies: A comparative study
(2018) Ghoneima, Ahmed
Objectives: The aim of this study was to assess the dimensional accuracy of fused deposition modeling (FDM)–, Polyjet-, and stereolithography (SLA)–produced models by comparing them to traditional plaster casts. Materials and Methods: A total of 12 maxillary and mandibular post treatment orthodontic plaster casts were selected from the archives of the Orthodontic Department at the Indiana University School of Dentistry. Plaster models were scanned, saved as stereolithography files, and printed as physical models using three different three-dimensional (3D) printers: Makerbot Replicator (FDM), 3D Systems SLA 6000 (SLA), and Objet Eden500V (Polyjet). A digital caliper was used to obtain measurements on the original plaster models as well as on the printed resin models. Results: Comparison between the 3D printed models and the plaster casts showed no statistically significant differences in most of the parameters. However, FDM was significantly higher on average than were plaster casts in maxillary left mixed plane (MxL-MP) and mandibular intermolar width (Md-IMW). Polyjet was significantly higher on average than were plaster casts in maxillary intercanine width (Mx-ICW), mandibular intercanine width (Md-ICW), and mandibular left mixed plane (MdL-MP). Polyjet was significantly lower on average than were plaster casts in maxillary right vertical plane (MxR-vertical), maxillary left vertical plane (MxL-vertical), mandibular right anteroposterior plane (MdR-AP), mandibular right vertical plane (MdR-vertical), and mandibular left vertical plane (MdL-vertical). SLA was significantly higher on average than were plaster casts in MxL-MP, Md-ICW, and overbite. SLA was significantly lower on average than were plaster casts in MdR-vertical and MdL-vertical. Conclusions: Dental models reconstructed by FDM technology had the fewest dimensional measurement differences compared to plaster models.
The C‑shaped root canal systems in mandibular second molars in an Emirati population
(2021) Khawaja, Summayah; Chaudhry, Jahanzeb; Hassan Khamis, Amar; El Abed, Rashid; Ghoneima, Ahmed; Jamal, Mohamed
Abstract: Our study aimed to describe the root and canal morphology of mandibular second molars in Emirati population and to study the prevalence and types of morphological change in C-shaped canal confguration along the root length in an efort to describe C-shaped molars as a unit. Cone beam computed tomography (CBCT) scans of Emirati patients were analyzed in multiple plans and root and canal confguration of mandibular second molars were evaluated. Moreover, specifc types of morphological change in C-shaped canal confguration along root length were studied and reconstructed using 3D reconstruction software. A total of 508 mandibular second molars were evaluated. Among the non-C-shaped mandibular second molars, two separate roots were the most prevalent root morphology (78.3%). The mesial root’s most common root canal confguration was Vertucci Type II (46.5%), and in the distal root, Vertucci Type I (90.5%). The prevalence of C-shaped mandibular second molars was 17.9% and was signifcantly prevalent (P< 0.001) in females. Specifc types of morphological change in C-shaped molars along the root length were observed and described for the frst time, in which the most common types of morphological change were C1-C2-C3d (18%), C1-C3c-C3d (15.4%), C4-C3c-C3d (7.7%), and C3c-C3c-C3d (7.7%). This study showed wide variations in the root and canal morphology in mandibular second molars in Emirati population with a relatively high prevalence of C-shaped canal confguration (17.9%). Moreover, specifc types of morphological change in C-shaped confguration were detected and described for the frst time in this population.
Computer aided finite element model for biomechanical analysis of orthodontic aligners
(2022-08) Ghoneima, Ahmed; Abuzayda, Moosa
Objectives: To design a finite element (FE) model that might facilitate understanding of the complex mechanical behaviour of orthodontic aligners. The designed model was validated by comparing the generated forces — during 0.2-mm facio-lingual translation of upper left central incisor (Tooth 21) — with the values reported by experimental studies in literature. Materials and methods: A 3D digital model, obtained from scanning of a typodont of upper jaw, was imported into 3-matic software for designing of aligners with different thicknesses: 0.4, 0.5, 0.6, 0.7 mm. The model was exported to Marc/Mentat FE software. Suitable parameters for FE simulation were selected after a series of sensitivity analyses. Different element classes of the model and different rigidity values of the aligner were also investigated. Results: The resultant maximum forces generated on facio-lingual translation of Tooth 21 were within the range of 1.3–18.3 N. The force was direction-dependent, where lingual translation transmitted higher forces than facial translation. The force increases with increasing the thickness of the aligner, but not linearly. We found that the generated forces were almost directly proportional to the rigidity of the aligner. The contact normal stress map showed an uneven but almost repeatable distribution of stresses all over the facial surface and concentration of stresses at specific points. Conclusions A validated FE model could reveal a lot about mechanical behavior of orthodontic aligners. Clinical relevance: Understanding the force systems of clear aligner by means of FE will facilitate better treatment planning and getting optimal outcomes.
Development and Comparison of Conventional and 3D-Printed Laboratory Models of Maxillary Defects
(2023) Alanezi, Ahmad; Aljanahi, May; Moharamzadeh, Keyvan; Ghoneima, Ahmed; Tawfik, Abdel Rahman; Hassan Khamis, Amar; Abuzayda, Moosa
Background: Recording accurate impressions from maxillary defects is a critical and challenging stage in the prosthetic rehabilitation of patients following maxillectomy surgery. The aim of this study was to develop and optimize conventional and 3D-printed laboratory models of maxillary defects and to compare conventional and digital impression techniques using these models. Methods: Six different types of maxillary defect models were fabricated. A central palatal defect model was used to compare conventional silicon impressions with digital intra-oral scanning in terms of dimensional accuracy and total time taken to record the defect and produce a laboratory analogue. Results: Digital workflow produced different results than the conventional technique in terms of defect size measurements which were statistically significant (p < 0.05). The time taken to record the arch and the defect using an intra-oral scanner was significantly less compared with the traditional impression method. However, there was no statistically significant difference between the two techniques in terms of the total time taken to fabricate a maxillary central defect model (p > 0.05). Conclusions: The laboratory models of different maxillary defects developed in this study have the potential to be used to compare conventional and digital workflow in prosthetic treatment procedures.
Does maxillary sinus proximity affect molar root resorption during distalization using Invisalign? a CBCT study
(2023) Ghoneima, Ahmed
Background: This study aimed to assess the correlation between maxillary sinus proximity to root apices of maxillary molars and root resorption during molar distalization using clear aligner therapy (CAT). Materials and methods: Thirty-eight cone beam computed tomography scans (CBCTs) obtained pre- (T0) and post-treatment (T1) from 19 adult patients (36.68±13.50 years), who underwent maxillary molar distalization using Invisalign® aligners (Align Technology, Inc., San José, CA, USA) with a minimum of 2 mm distalization, were evaluated in this study At least 22 h of aligner wear per day was a main inclusion criterion. Sinus proximity and changes in root lengths were measured for 61 molars (183 roots). Spearman coefficient analysis was used for assessing correlation between sinus proximity and root resorption. The level of significance was set at p≤0.05. The reproducibility of measurements was assessed by intraclass correlation coefficient (ICC). Results: Spearman coefficient revealed no significant correlation between sinus proximity and molar root resorption for mesiobuccal, distobuccal or palatal roots (p=0.558, p=0.334, p=0.931, respectively). Conclusion: There was no correlation between maxillary sinus proximity to root apices of maxillary molars and root resorption.
The effect of cigarette smoke on the shear bond strength of metallic and ceramic orthodontic brackets: An in vitro study
(2019) Omar, Haidi; Ghoneima, Ahmed
Objective: The bond strength between enamel and the bracket base is influenced by exposure to the oral environment. The aim of the current study was to determine the effect of cigarette smoke on the shear bond strength (SBS) of bonded metallic and ceramic orthodontic brackets. Materials and methods: Sample of 60 sound extracted premolars were divided into four groups (n = 15 each) as follows: group (A): ceramic brackets without smoke exposure, (B): metallic brackets without smoke exposure, (C): ceramic brackets with smoke exposure, (D): metallic brackets with smoke exposure. Smoking exposure was simulated using the British American Tobacco's exposure chamber manufactured by Curbridge Engineering (Hampshire, UK). Metallic and ceramic brackets were bonded to the enamel using conventional acid etching technique. SBS (MPa) was tested using the universal Instron testing machine at a constant cross head speed of 1 mm/min until failure. Kolmogorov-Smirnov test was used to test the normality of the measurements. One-way analysis of variance (ANOVA) was used to compare the means of SBSs between the four groups, Post-hoc with least significance difference was used to perform a pairwise comparison between means. Statistical significance was set at P < 0.05. Results: The highest SBS corresponded to the ceramic type brackets bonded to a non-smoking sample (15.7 _ 9.5) while the lowest levels of SBS was related to metallic type brackets bonded to smoke exposed sample (2.8 _ 0.7) and the difference was statistically significant (P < 0.05). Conclusion: Cigarette smoke consumption has significant effects on the SBS of orthodontic brackets. SBS levels were significantly lower in the smoke exposure groups and the lowest values corresponded to the cigarette smoke exposed metallic brackets.
Enamel Hypomineralization in Children With Clefts and the Relationship to Treatment: A Cross-sectional Retrospective Study
(2018) Ghoneima, Ahmed
Objective: The aim of this study was to determine whether molar incisor hypomineralization (MIH) is greater in patients with cleft lip and palate (CLP) who underwent primary alveolar grafting (PAG) as compared with CLP waiting for secondary alveolar grafting (SAG) and with controls. Design: A retrospective analysis of intraoral photographs of 13 CLP patients who underwent a PAG, 28 CLP prior to SAG, and 60 controls without CLP was performed. Mantel-Haenszel χ tests were used to compare the 3 groups for differences in MIH scores, and Wilcoxon rank sum tests were used to compare the groups for differences in average MIH scores. A 5% significance level was used for all tests. Results: Molar incisor hypomineralization scores were significantly higher for the PAG and SAG groups compared with the control group (P < 0.001). The PAG group had significantly higher incisor MIH (P = 0.016) compared with the SAG group. Molar incisor hypomineralization average scores were significantly higher for the 2 graft groups compared with the controls (P < 0.0001). The PAG group had significantly higher average MIH score and average MIH score for incisors compared with the SAG group (P = 0.03). Conclusions: Cleft lip and palate patients have significantly greater MIH compared with controls, and CLP patients with PAGs have significantly greater MIH in the incisor region compared with CLP patients with SAGs, indicating that subjects with PAGs have more severely affected dentition.
Evaluation of two-dimensional lateral cephalogram and three-dimensional cone beam computed tomography superimpositions: a comparative study
(2019-04) Ghoneima, Ahmed
Abstract: Superimposition of radiographic imaging is used to evaluate patient growth and the effects of surgical and/or orthodontic treatment. The purpose of this study was to compare the outcomes of superimposition between two-dimensional (2D) and three-dimensional (3D) superimpositions. 2D lateral cephalograms were generated from the initial and final cone beam computed tomography scans (CBCT) of 18 patients and superimposed. Both 3D CBCT and 2D CBCT generated lateral cephalograms were oriented to the Frankfort horizontal plane and superimposed according to the American Board of Orthodontics recommendations. Changes in landmark position were quantified from the resulting superimposition outcomes via linear measurements made with Dolphin software. Differences between the two methods were analyzed using paired t-tests. Measurements were repeated twice for 10 randomly selected scans to assess reliability by intra-class correlation coefficient (ICC) analysis. Intra-examiner reliability was high for all measurements (ICC>0.84). Agreement between 2D and 3D superimposition outcomes, as measured by P-values, was low for ANS (P=0.026), B-point (P<0.001), ST Upper lip (P=0.019), U1 tip (P=0.010), and U1 apex (P=0.026). 2D measurements were significantly higher than 3D measurements for ANS, B-point, ST Upper lip, U1 tip, and U1 apex. Findings indicated that both methods of superimposition (2D and 3D) are highly reliable. Statistical differences between 2D and 3D superimposition outcomes were below the threshold of clinical significance.
Improving the accuracy of publicly available search engines in recognizing and classifying dental visual assets using convolutional neural networks
(2020) Ghoneima, Ahmed
Aim: To assess the accuracy of DigiBrain4, Inc (DB4) Dental Classifier and DB4 Smart Search Engine* in recognizing, categorizing, and classifying dental visual assets as compared with Google Search Engine, one of the largest publicly available search engines and the largest data repository. Materials and methods: Dental visual assets were collected and labeled according to type, category, class, and modifiers. These dental visual assets contained radiographs and clinical images of patients’ teeth and occlusion from different angles of view. A modified SqueezeNet architecture was implemented using the TensorFlow r1.10 framework. The model was trained using two NVIDIA Volta graphics processing units (GPUs). A program was built to search Google Images, using Chrome driver (Google web driver) and submit the returned images to the DB4 Dental Classifier and DB4 Smart Search Engine. The categorical accuracy of the DB4 Dental Classifier and DB4 Smart Search Engine in recognizing, categorizing, and classifying dental visual assets was then compared with that of Google Search Engine. Results: The categorical accuracy achieved using the DB4 Smart Search Engine for searching dental visual assets was 0.93, whereas that achieved using Google Search Engine was 0.32. Conclusion: The current DB4 Dental Classifier and DB4 Smart Search Engine application and add-on have proved to be accurate in recognizing, categorizing, and classifying dental visual assets. The search engine was able to label images and reject non-relevant results.
Management of mandibular incisors crowding by using passive lower lingual holding arch: a case series and literature review
(2023) Habib, Ahlam; Ghoneima, Ahmed; Diar-Bakirly, Samira
Abstract: Mandibular incisor crowding is a frequently encountered problem in daily orthodontic treatment. Success of the treatment greatly depends on the orthodontist’s ability to manage the factors contributing to the existing crowding and implementing the proper interceptive means. The passive lower lingual holding arch (LLHA) helps maintain the position of the permanent first molars after the exfoliation of primary molars and canines. Thus, relieving the mandibular incisor crowding during transitional dentition. Four case reports age ranged from 11–13.5 years old were used to report the effect of using LLHA on mandibular incisor crowding. Little’s Irregularity Index (LII) was used to assess the severity of mandibular incisors crowding as well as to compare the severity of the crowding before and after the use of LLHA. Passive LLHA could be considered the appliance of choice for space maintenance during the mixed dentition. Mandibular incisor crowding was reduced as measured by LII after the use of the passive LLHA over a duration of twenty months.
Physiochemical and mechanical characterisation of orthodontic 3D printed aligner material made of shape memory polymers (4D aligner material)
(2023) Ghoneima, Ahmed; Elshazly, Tarek
Abstract: Objectives: To conduct a physiochemical and mechanical material analysis on 3D printed shape-memory aligners in comparison to thermoformed aligners. Materials and methods: Four materials were examined, including three thermoformed materials: CA Pro (CP), Zendura A (ZA), Zendura FLX (ZF), and one 3D printed material: Tera Harz (TC-85). Rectangular strips measuring 50 × 10 × 0.5 mm were produced from each material. Five tests were conducted, including differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), shape recovery tests, three-points bending (3 PB), and Vickers surface microhardness (VH). Results: DSC recorded glass transition temperatures (Tg) at 79.9 ◦C for CP, 92.2 ◦C for ZA, 107.1 ◦C for ZF, and 42.3 ◦C for TC-85. In DMA analysis at 20–45 ◦C, a prominent decrease in storage modulus was observed, exclusively for TC-85, as the temperature increased. Notably, within the temperature range of 30–45 ◦C, TC-85 exhibited substantial shape recovery after 10 min, reaching up to 86.1 %, while thermoformed materials showed minimal recovery (1.5–2.9 %). In 3 PB test (at 30, 37, 45 ◦C), ZA demonstrated the highest force at 2 mm bending, while TC-85 exhibited the lowest. Regarding VH at room temperature, there was a significant decrease for both ZA and ZF after thermoforming. ZA had the highest hardness, followed by ZF and TC-85, with CP showing the lowest values. Conclusions: TC-85 demonstrates exceptional shape memory at oral temperature, improving adaptation, reducing force decay, and enabling, together with its higher flexibility, extensive tooth movement per step. Additionally, it maintains microhardness similar to thermoformed sheets, ensuring the durability and effectiveness of dental aligners.
Precision of the virtual occlusal record
(2019) Ghoneima, Ahmed
Objectives: To evaluate the precision of the virtual occlusal record using the Carestream CS3600 Intraoral Scanner (Carestream Dental, Atlanta, Ga). Materials and Methods: A total of 20 participants were recruited for this prospective study using preestablished inclusion/exclusion criteria. A complete intraoral scan and two bite registrations were obtained. The participants were instructed to bite with normal pressure when bite registrations were acquired. Contact locations, size (circumference), and intensity were identified on the maxillary first molars and canines. Agreement between contact size and intensity was assessed with intraclass correlation coefficients. Kappa statistics evaluated agreement in contact locations. Statistical significance was set at P , .05. Results: All participant data were included for statistical analysis. Between the two bite registrations, nonstatistically significant differences were observed in the proportion of locations with contacts (P¼ .7681). A nonstatistically significant difference (_0.25 mm, P¼.8416) in mean contact circumference size was observed. A statistically significant difference in mean contact intensity was observed (P ¼ .0448). When evaluating agreement between the bite registrations, a weak correlation for size (intraclass correlation coefficient ¼ 0.35) and intensity (intraclass correlation coefficient ¼ 0.32) was observed as well as a moderate agreement for contact location (j coefficient ¼ 0.67). Conclusions: The findings suggest that the Carestream intraoral scanner software possesses adequate precision when acquiring the location and size of the contacts in bite registrations. The scanner failed to demonstrate adequate precision when acquiring contact intensities in bite registrations. Additional research is warranted to further investigate the precision of virtual occlusal records with currently available software systems.
Predictors of orthodontic residency performance: An assessment of scholastic and demographic selection parameters
(2019) Ghoneima, Ahmed
Objective: To evaluate the association between resident selection criteria, including Graduate Record Examination (GRE) scores, and student performance in an orthodontic residency program. Materials and Methods: This retrospective study evaluated the academic records of 70 orthodontic residency graduates from the Indiana University School of Dentistry. The following demographic and scholastic data were extracted from the student academic records: applicant age, gender, ethnicity, race, country of origin, dental school graduation year, GRE score, and graduate orthodontic grade point average (GPA). In addition, student American Board of Orthodontics (ABO) written examination quintiles were obtained from the ABO. Scatterplots, analysis of variance, and correlation coefficients were used to analyze the data. Statistical significance was established at .05 for the study. Results: No associations were found with any component of the GRE, except with the quantitative GRE section, which displayed a weak association with ABO module 2 scores. Dental school GPA demonstrated weak correlations with all ABO modules and moderate correlations with overall and didactic orthodontic GPAs. When assessing demographic factors, significant differences (P , .05) were observed, with the following groups demonstrating higher performance on certain ABO modules: age (younger), race (whites), and country of origin (US citizens). Conclusions: Findings suggest the GRE has no association with student performance in an orthodontic residency. However, dental school GPA and/or class rank appear to be the strongest scholastic predictors of residency performance. (Angle Orthod. 2019;89:488–494.)
Preliminary Performance of the Advanced Dental Admission Test (ADAT): Association Between ADAT Scores and Other Variables for Applicants to Residency Programs at a U.S. Dental School
(2018) Ghoneima, Ahmed
Abstract: Historically, dental residency programs have used numerical assessment criteria to evaluate and identify qualified candidates for admission. Recent elimination of such assessment tools has undermined many programs’ holistic evaluation process. The Advanced Dental Admission Test (ADAT) was developed and recently piloted in hopes of addressing this issue. The aim of this study was to evaluate the preliminary performance and validity of the ADAT by exploring the association between ADAT scores and other variables for a sample of applicants to residency programs. The WebAdMIT admissions database was used to identify the test scores and educational and demographic information of 92 individuals who completed the pilot ADAT and were seeking a 2017 postgraduate specialty position at Indiana University School of Dentistry. The results showed that the ADAT had strong to weak correlations with certain applicant variables (p<0.05). No significant differences were found for age, race, school location, or country of origin. However, males performed better than females (p<0.05), and non-Hispanics performed better than Hispanics (p<0.01). ADAT component scores were also higher for individuals with a history of research activity (p<0.05). This study found that significant associations existed between the ADAT and indices typically associated with competitive applicants. These findings suggest that the ADAT may serve as a useful numerical assessment instrument, with the potential to identify highperforming candidates. Furthermore, the ADAT seemed to be a plausible option for programs seeking to incorporate a quantitative assessment instrument as part of a holistic candidate selection process.
The Relationship Between Hard Tissue and Soft Tissue Dimensions of the Nose in Children: A 3D Cone Beam Computed Tomography Study
(2018) Ghoneima, Ahmed
Abstract: This study using three-dimensional cone beam computed tomography (CBCT) images of children determined relationships between nasal skeletal and soft tissue measurements and assessed the association with sex, age, and skeletal maturation stage. Following reliability studies, skeletal and soft tissue parameters were measured on coded CBCTs of 73 children (28M: 45F; 6–13 yoa). Pearson and Mantel correlations were used to analyze associations between skeletal and soft tissues. Partial Mantel correlations were used to study the associations between skeletal and soft tissue, adjusting for sex, age, and skeletal maturation. Linear regression analyses were used to predict soft tissues sizes. Logistic regression was used to study the relationships between soft and skeletal tissue symmetry. Except for nasal aperture width and interalar width, skeletal landmarks best predicted corresponding soft tissue landmarks. Significant positive associations existed between skeletal and soft tissues after adjusting for sex, skeletal maturation, and age. Children’s nasal skeletal tissues predicted nasal soft tissue reasonably well.
Retrospective CBCT analysis of airway volume changes after bone-borne vs tooth-borne rapid maxillary expansion
(2019) Ghoneima, Ahmed
Objectives: To compare changes in upper airway volume after maxillary expansion with bone and tooth-borne appliances in adolescents and to evaluate the dentoskeletal effects of each expansion modality. Materials and Methods: This retrospective study included 36 adolescents who had bilateral maxillary crossbite and received bone-borne maxillary expansion (average age: 14.7 years) or tooth-borne maxillary expansion (average age: 14.4 years). Subjects had two cone beam computed tomography images acquired, one before expansion (T1) and a second after a 3-month retention period (T2). Images were oriented, and three-dimensional airway volume and dentoskeletal expansion were measured. Analysis of variance was used to test for differences between the two expansion methods for pretreatment, posttreatment, and prepost changes. Paired t-tests were used to test for significance of prepost changes within each method. Results: Both groups showed significant increase only in nasal cavity and nasopharynx volume (P,.05), but not oropharynx and maxillary sinus volumes. Intermolar and maxillary width increased significantly in both groups (P ,.05); however, the buccal inclination of maxillary molars increased significantly only in the tooth-borne group (P ,.05). There was no significant difference between tooth- and bone-borne expansion groups, except for the significantly larger increase in buccal inclination of the maxillary right first molar after tooth-borne expansion. Conclusions: In adolescents, both tooth- and bone-borne RME resulted in an increase in nasal cavity and nasopharynx volume, as well as expansion in maxillary intermolar and skeletal widths. However, only tooth-borne expanders caused significant buccal tipping of maxillary molars.
Three dimensional evaluation of the holographic projection in digital dental model superimposition using HoloLens device
(2019) Ghoneima, Ahmed
Objective: To assess validity and reliability of palatal superimposition of holograms of 3D digital dental models using a customized software, (Ortho Mechanics Sequential Analyzer OMSA), installed on Microsoft HoloLens device as compared to the OMSA application running on a regular computer screen. Methods: The sample consisted of pre- and post- treatment digital maxillary dental models of 20 orthodontic cases (12.3 ± 1.9 years) treated by rapid maxillary expansion (two turns per day). For each case, the pre- and post-treatment digital models were superimposed using hand gestures for marking the dental models holograms in mixed reality using the Microsoft HoloLens. The same models were then superimposed using the conventional landmark- based method with OMSA software running on a regular computer screen. The same set of dental arch parameters was measured on the superimposed 3D data by the two software versions for comparison. Agreement in the superimposition outcomes among the two superimposition methods was assessed using Dahlberg error (DE), concordance correlation coefficients (CCCs) using two- way ANOVA mixed model for absolute agreement and Bland-Altman analysis. Results: Repeatability was acceptable for all variables based on the high values of CCCs over 0.99 with a lower 95% confidence limit over 0.95 for any variable. The DE ranged from 0.14 mm to 0.36 mm. The absolute error did not exceed 0.5 mm for any variable. Conclusion: Using the depth vision capabilities of the Microsoft HoloLens, 3D digital dental models can be reliably superimposed allowing virtual assessment of orthodontic treatment outcomes.
Three-dimensional computed tomography analysis of airway volume in growing class II patients treated with Frankel II appliance
(2024) Ahmed, Marwa Jameel; Diar-Bakirly, Samira; Hassan, Amar; Ghoneima, Ahmed
Objective: The purpose of this retrospective study was to assess the airway volume changes associated with the use of Frankel appliance (FR II) in Class II malocclusion patients using three-dimensional cone beam computed tomography (3D CBCT) imaging. Materials and methods: The sample consisted of 31 Class II malocclusion patients (mean age 9.24±1.93 years old, 17 males (54.8%) and 14 females (45.2%)) treated with FR II appliance by the same orthodontist for an average of 9 months±20 days. CBCT images were taken before and after treatment and upper airway volume changes were measured using Dolphin 3D software version11.0 (Dolphin Imaging, Chatsworth, CA) and statistically compared. Results: Airway volume of nasal cavity, nasopharynx, oropharynx, hypopharynx and the total airway volume significantly increased after the use of FR II appliance. In addition, significant increase was reported in maxillary base, inter-molar, inter-premolar and inter-canine width. Significant increase in soft tissue thickness was only recorded opposite to CV2. Conclusion: The use of the FR II appliance in growing subjects with Class II malocclusion led to a significant increase in the upper airway volume in addition to the anticipated dental and skeletal transverse expansion effects.