Measurement error and reliability of three available 3D superimposition methods in growing patients

Maxillary protraction anchored on miniplates versus miniscrews: three-dimensional dentoskeletal comparison

OBJECTIVE

This retrospective study aimed to compare the three-dimensional (3D) outcomes of the novel miniscrew-anchored maxillary protraction (MAMP) therapy and the bone-anchored maxillary protraction (BAMP) therapy.

METHODS

The sample comprised growing patients with skeletal Class III malocclusion treated with two skeletal anchored maxillary protraction protocols. The MAMP group comprised 22 patients (9 female, 13 male; 10.9 ± 0.9 years of age at baseline) treated with Class III elastics anchored on a hybrid hyrax expander in the maxilla and two mandibular miniscrews distally to the permanent canines. The BAMP group comprised 24 patients (14 female, 10 male; 11.6 ± 1.1 years of age at baseline) treated with Class III elastic anchored in two titanium miniplates in the infra-zygomatic crest and two miniplates in the mesial of the mandibular permanent canines. Three-dimensional displacements were measured in the pre- and post-treatment cone-beam computed tomography scans superimposed on the cranial base using the Slicer Automated Dental Tools module of 3D Slicer software (www.slicer.org). Mean differences (MD) between groups and 95% confidence interval (CI) were obtained for all variables. Intergroup comparison was performed using the Analysis of Covariance (P < .05).

RESULTS

Both groups showed improvements after treatment. The MAMP group showed a smaller anterior (MD: -1.09 mm; 95% CI, -2.07 to -0.56) and 3D (MD: -1.27 mm; 95% CI, -2.16 to -0.74) displacements of the maxilla after treatment when compared with BAMP. Both groups showed negligible and similar anteroposterior changes in the mandible (MD: 0.33 mm; 95% CI, -2.15 to 1.34). A greater increase in the nasal cavity width (MD of 2.36; 95% CI, 1.97-3.05) was observed in the MAMP group when compared with BAMP.

LIMITATIONS

The absence of an untreated control group to assess the possible growth impact in these findings is a limitation of this study.

CONCLUSION

Both BAMP and MAMP therapies showed adequate 3D outcomes after treatment. However, BAMP therapy produced a greater maxillary advancement with treatment, while MAMP therapy showed greater transversal increases in the nasal cavity.

Effects of orthognathic surgery on respiratory function during sleep: A prospective longitudinal study

When treating patients with orthognathic surgery, there might be a risk of obstructive sleep apnoea (OSA) due to soft tissue changes in the upper airways, especially in patients treated with isolated mandibular setback or mandibular setback in combination with maxillary advancement. In the present study, we assessed respiratory function during sleep with home cardiorespiratory polygraphy in 62 patients who had not been previously been diagnosed with OSA at three times: prior to orthognathic surgery for aesthetic and functional indications, and then 3 months and 1 year after surgery. We evaluated surgical displacement based on measurements in three dimensions using pre- and post-operative computed tomography. There were only minor changes in the respiratory parameters such as the apnoea-hypopnoea index (AHI), the apnoea-hypopnoea index in the supine position (AHIsup), the oxygen saturation index (ODI) and the snore index. There was no significant correlation between surgical displacement and the AHI, AHIsup and ODI. There was a weak but significant correlation between vertical displacement of the anterior mandible and the snore index. Within the limitations of the present study, the risk for iatrogenic obstruction of the upper airways seems to be low in patients without OSA treated with orthognathic surgery.

Effect of angulation on the 3D trueness of conventional and digital implant impressions for multi-unit restorations

PURPOSE

The study aimed to determine the influence of implant angulation on the trueness of multi-unit implant impressions taken through different techniques and strategies.

MATERIALS AND METHODS

As reference models, three partially edentulous mandibular models (Model 1: No angulation; Model 2: No angulation for #33, 15-degree distal angulation for #35 and #37; Model 3: No angulation for #33, 25-degree distal angulation for #35 and #37) were created by modifying the angulations of implant analogues. Using a lab scanner, these reference models were scanned. The obtained data were preserved and utilized as virtual references. Three intraoral scanning (IOS) strategies: IOS-Omnicam, ISO-Quadrant, and IOS-Consecutive, as well as two traaditional techniques: splinted open tray (OT) and closed tray (CT), were used to create impressions from each reference model. The best-fit alignment approach was used to sequentially superimpose the reference and test scan data. Computations and statistical analysis of angular (AD), linear (LD), and 3D deviations (RMS) were performed.

RESULTS

Model type, impression technique, as well as interaction factor, all demonstrated a significant influence on AD and LD values for all implant locations (P < .05). The Model 1 and SOT techniques displayed the lowest mean AD and LD values across all implant locations. When considering interaction factors, CT-Model 3 and SOT-Model 1 exhibited the highest and lowest mean AD and LD values, respectively. Model type, impression technique, and interaction factor all revealed significant effects on RMS values (P ≤ .001). CT-Model 3 and SOT-Model 1 presented the highest and lowest mean RMS values, respectively.

CONCLUSION

Splinted-OT and IOS-Omnicam are recommended for multi-unit implant impressions to enhance trueness, potentially benefiting subsequent manufacturing stages.

Reliability and reproducibility of CBCT assessment of mandibular changes before and after treatment for Class III growing patients - an easy and quick way for evaluation

The objective of this study was to evaluate intraobserver reliability and inter-observer reproducibility of a 3-dimensional (3D) assessment method for mandibular changes of growing patients after orthodontic treatment for Class III malocclusion.Methods Cone-beam computed tomography (CBCT) scans were performed before and after orthodontic treatment for 27 patients. During the scan, the patient was positioned such that his/her mandibular plane was parallel to floor. Three observers independently worked on the DICOM data, reconstructed the pre- and post-treatment 3D models in software, selected the stable anatomical structures (basal bone area from the lingual surface of the symphysis to the distal aspect of the first molars) to guide the automated superimposition process. Then, each observer registered 14 anatomical landmarks on the virtual models, for three times after suitable interval, to generate 3 sets of coordinates; the mean was taken as the coordinates for that particular landmark. The intraobserver reliability and inter-observer reproducibility of the method were analyzed.Results The ICCs was > 0.90 for 25 (92.6%) of the intraobserver assessments. The precision of the measurement method was < 0.3 mm in 24 (88.9%) cases. The interobserver reproducibility errors were < 0.3 mm in 21 of the 27 cases.Conclusions The intraobserver reliability and inter-observer reproducibility of 3D assessment of mandibular changes using the virtual models were excellent.

Is Parental Rating of Child's Oral Health Associated with Caries Experience in Children? A Cross-Sectional Study

Aim

The Parents' view to the oral health of their children is a significant factor that can impact oral health practices and behaviors. The aim of this research was to investigate how parental assessment of their child's oral health associates with caries experience in children receiving dental treatment at the hospital of Taibah University Dental College.

Materials and Methods

This cross-sectional study enrolled 127 children who underwent dental treatment at Taibah University Dental College and Hospital during 2020-2021. Dental caries experience was assessed using the dmft/DMFT index, and parental rating of oral health was obtained through a questionnaire. Three logistic regression models were used to assess the correlation between dental caries experience and parental rating of oral health while controlling for sociodemographic and behavioral factors.

Results

Most parents rated the oral health of their child as good (60.4%), followed by excellent (18.8%) and very good (15.6%). The mean dmft/DMFT score was 3.47 ± 3.46, with 43.8% of children having high/very high dental caries experience. Logistic regression analysis showed that children whose parents rated their oral health as poor were more likely to have high/very high dental caries experience compared to those rated as excellent/very good/good/fair (adjusted odds ratio = 4.45, 95% confidence interval 1.23-16.07).

Conclusion

This study suggests a link between parental assessment of their child's oral health and an elevated prevalence of dental caries in children. The study found that children whose parents rated their oral health as suboptimal had higher odds of having high dental caries experience. These findings emphasize the significance of parental perception of their child's oral health and suggest a necessity for customized interventions to enhance parental knowledge and practices concerning children's oral health.

3D assessment of alveolar bone alterations in orthodontic movement among Indians

Apical root resorption, which is characterised as a biological or abnormal phenomenon that shortens the length of the root apex, is additional typical iatrogenic impact of orthodontic tooth movement that may jeopardise the effectiveness of treatment and tooth lifespan. The main goals of the current retrospective investigation were to assess the dimensions of alveolar bone alterations that come along with orthodontic movement and to look into the frequency and extent of resorption of root in maxillary incisors across categories that were similarly managed with clear aligners (OCA) and fixed appliances (OFA) using CBCT. The study included 50 subjects who were divided into two categories with 25 study subjects in each category. Category OFA: Subjects receiving OFA (n=25). A CBCT scan was used to get three-dimensional pictures at the beginning of therapy as well as at the end of therapy. The overall resorption of root at apical region in OFA group was 0.63±0.21 mm. The overall resorption of root at apical region in OCA group was 0.32 ±0.36 mm. The difference in observation was statistically significant (p= 0.000) with reduced resorption of root at apical region in clear aligners. It was concluded that the decrease in thickness of alveolar bone was greater in orthodontic fixed appliances group as compared to clear aligners. The resorption of root at apical region was lesser in clear aligners group as compared to fixed appliances.

Effectiveness of motion graphic-based narrative therapy with a cognitive-behavioral approach in reducing fluoride varnish therapy anxiety for six-year-old children

BACKGROUND

Fluoride varnish therapy (FVT) is a dental caries preventive service that its effectiveness has been well documented. A lot of children, especially the five-year-old and six-year-old ones, are suffering with anxiety during this service and do not readily allow it. The present study aimed to cast light on the effect of motion graphic-based narrative story with a cognitive-behavioral approach in reducing FVT anxiety among six-year-old children.

MATERIALS AND METHODS

This study was an intervention trial type that was conducted in Ardabil city and among school students. Five children suffering from FVT anxiety were randomly selected for the intervention. First, Venham and Gaulin-Kremer's anxiety scale was completed for them. The motion graphic-based narrative therapy was implemented for six weeks. Session 1 was assigned to filling the questionnaire and collecting data. The motion graphic-based narrative therapy started from the second session. The anxiety scale was filled for the children every ten days for a total of four times. The results were analyzed by Blanchard and Schwarz's progress formula and control charts. The intervention sessions included gathering information, watching motion graphics, relaxation skills, watching the process of performing fluoride varnish therapy, teaching the advantages of fluoride varnish therapy, and in the last session performing fluoride varnish therapy with the technique of attention diversion while watching motion graphics.

RESULTS

The motion graphic-based narrative therapy by the cognitive-behavioral approach proved effective in reducing anxiety. At the end of the intervention sessions, the level of anxiety decreased from 8 to 2.2 and the statistical control chart of the process shows that the intervention process is stable and the stability in order to reduce anxiety and the results are within the control limits.

CONCLUSION

The results show that motion graphic-based narrative therapy can be a psychotherapy method for reducing the symptoms of dental anxiety among children.

Evaluation of an artificial intelligence-based algorithm for automated localization of craniofacial landmarks

OBJECTIVES

Due to advancing digitalisation, it is of interest to develop standardised and reproducible fully automated analysis methods of cranial structures in order to reduce the workload in diagnosis and treatment planning and to generate objectifiable data. The aim of this study was to train and evaluate an algorithm based on deep learning methods for fully automated detection of craniofacial landmarks in cone-beam computed tomography (CBCT) in terms of accuracy, speed, and reproducibility.

MATERIALS AND METHODS

A total of 931 CBCTs were used to train the algorithm. To test the algorithm, 35 landmarks were located manually by three experts and automatically by the algorithm in 114 CBCTs. The time and distance between the measured values and the ground truth previously determined by an orthodontist were analyzed. Intraindividual variations in manual localization of landmarks were determined using 50 CBCTs analyzed twice.

RESULTS

The results showed no statistically significant difference between the two measurement methods. Overall, with a mean error of 2.73 mm, the AI was 2.12% better and 95% faster than the experts. In the area of bilateral cranial structures, the AI was able to achieve better results than the experts on average.

CONCLUSION

The achieved accuracy of automatic landmark detection was in a clinically acceptable range, is comparable in precision to manual landmark determination, and requires less time.

CLINICAL RELEVANCE

Further enlargement of the database and continued development and optimization of the algorithm may lead to ubiquitous fully automated localization and analysis of CBCT datasets in future routine clinical practice.

A CBCT Based Assessment of Canine Eruption and Development Following Alveolar Bone Grafting in Patients Born With Unilateral Cleft lip and/or Palate

To three-dimensionally assess and visualize the eruption path and development of the maxillary canine following alveolar bone grafting in patients born with cleft lip and palate. A further objective of this analysis was to assess how the presence of the lateral incisor impacts the eruption path of the canine.

Observational follow-up study.

Stockholm Craniofacial Team, Karolinska University Hospital, Sweden.

Thirty children born with non-syndromic unilateral cleft lip with or without palate were consecutively included.

CBCT scans of the maxilla were taken six months before and six months after the alveolar bone-grafting surgery for each patient.

Canine eruption (angulation and vertical movement) and canine development (length and volume).

There was a significant difference pre- and post-operatively of the canine angulation between the cleft and non-cleft sides. The mean angulation on the cleft side was 14.7° (SD  =  11.1°) while on the non-cleft side, it was 4.9° (SD  =  9.2°). No significant differences were noted between cleft-side and non-cleft side canines in terms of amount of vertical eruption and volumetric development. Absence of the lateral incisor did not significantly contribute to either canine angulation or its vertical eruption on the cleft-side.

Higher angulation of the canine on the cleft side indicates a higher risk of future canine impaction. Presence or absence of the lateral incisor did not significantly affect canine angulation or its vertical eruption. Increased age and children born with total cleft lip and palate imply a higher risk of angulated canines on the cleft side.

Osteogenic Differentiation Effect of BMP-9 with Phenamil and Simvastatin on Intact Human Amniotic Epithelial Stem Cells

Background

Background: Bone tissue engineering has shown to be a promising strategy for repairing bone defects without causing harmful side effects to the patient. Three main building blocks of tissue engineering, including seeding cells, scaffold, and signaling molecules, are required for adequate bone regeneration. The human amniotic membrane (hAM) is the innermost of the placental membranes. In addition to providing a source of stem cells and growth factors, hAM has several features that make it an appropriate scaffold containing stem cells for use in tissue engineering purposes. The present investigation aimed to assess the effect of bone morphogenetic protein-9 (BMP-9) combined with phenamil and simvastatin on osteogenic induction of hAM with its human amniotic membrane epithelial cells (hAECs).

Method

Methods: Using six different osteogenic medium (OMs), we cultured hAM for 14 days. The basic OMs were chosen as the first group and other media were made by adding BMP-9, phenamil, simvastatin, BMP-9 alongside phenamil, and BMP-9 alongside simvastatin to the basic OMs. Finally, viability assay, tissue mineralization, calcium and phosphate content determination, and measurement of lactic acid dehydrogenase (LDH), and alkaline phosphatase (ALP) activity were performed.

Results

Results: Among all study groups, groups containing simvastatin showed a significantly lower level of viability. Although all media could induce osteogenic features, the hAECs cultured in media containing BMP-9 and phenamil demonstrated a wider area of mineralization and a significantly higher level of calcium and phosphate content, LDH, and ALP activity.

Conclusion

Conclusion: Our findings indicated that the use of phenamil together with BMP-9 could synergistically show in situ osteogenic induction in hAECs, which could be a new insight into translational medicine.

3D Cephalometric Normality Range: Auto Contractive Maps (ACM) Analysis in Selected Caucasian Skeletal Class I Age Groups

The objective of this paper is to define normal values of a novel 3D cephalometric analysis and to define the links through an artificial neural network (ANN). Methods: One hundred and fifteen CBCTs of Class I young patients, distributed among gender-adjusted developmental groups, were selected. Three operators identified 18 cephalometric landmarks from which 36 measurements were obtained. The repeatability was assessed through the ICC. Two-dimensional values were extracted by an automatic function, and the mean value and standard deviation were compared by paired Student’s t-tests. Correlation coefficient gave the relationships between 2D and 3D measurements for each group. The values were computed with the ANN to evaluate the parameters normality link and displayed by Pajek software. Results: The ICC assessed an excellent (≥0.9) repeatability. Normal values were extracted, and compared with 2D measurements, they showed a high correlation on the mid-sagittal plane, reaching 1.00, with the lowest 0.71 on the lateral plane. The ANN showed strong links between the values with the centrality of the go-sagittal plane compared to the rest. Conclusions: The study provides a set of 3D cephalometric values obtained by the upper and lower 95% CI for the mean divided into the developmental stage subgroups. The two-dimensional measurements showed variable concordance, while the ANN showed a centrality between the parameters.

Fabrication of Silk Scaffold Containing Simvastatin-Loaded Silk Fibroin Nanoparticles for Regenerating Bone Defects

BACKGROUND

In the present study, a tissue engineered silk fibroin (SF) scaffold containing simvastatin-loaded silk fibroin nanoparticles (SFNPs) were used to stimulate the regeneration of the defected bone.

METHODS

At first, the porous SF scaffold was prepared using freeze-drying. Then simvastatin-loaded SFNPs were made by dissolvation method and embedded in the SF scaffold. Afterwards, the scaffold and the NPs were characterized in terms of physicochemical properties and the ability to release the simvastatin small molecule.

RESULTS

The results exhibited that the SF scaffold had a porous structure suitable for releasing the small molecule and inducing the proliferation and attachment of osteoblast cells. SFNPs containing simvastatin had spherical morphology and were 174 ± 4 nm in size with -24.5 zeta potential. Simvastatin was also successfully encapsulated within the SFNPs with 68% encapsulation efficiency. Moreover, the small molecule revealed a sustained release profile from the NPs during 35 days. The results obtained from the in vitro cell-based studies indicated that simvastatin-loaded SFNPs embedded in the scaffold had acceptable capacity to promote the proliferation and alkaline phosphatase production of osteoblast cells while inducing osteogenic matrix precipitation.

CONCLUSION

The SF scaffold containing simvastatin-loaded SFNPs could have a good potential to be used as a bone tissue-engineered construct.

Comparison of surface- and voxel-based registration on the mandibular ramus for long-term three-dimensional assessment of condylar remodelling following orthognathic surgery

OBJECTIVES

The purpose of the present study was to validate and compare the accuracy and reliability of surface- and voxel-based registration on the mandibular rami for long-term three-dimensional (3D) evaluation of condylar remodelling following Orthognathic Surgery.

METHODS

The mandible was 3D reconstructed from a pair of superimposed pre- and postoperative (two years) cone-beam computerized tomography scans and divided into the condyle, and 21 ramal regions. The accuracy of surface- and voxel-based registration was measured by the absolute mean surface distance of each region after alignment of the pre- and postoperative rami. To evaluate the reliability, mean absolute differences and intra class correlation coefficients (ICC) were calculated at a 95% confidence interval on volumetric and surface distance measurements of two observers. Paired t-tests were applied to statistically evaluate whether the accuracy and reliability of surface- and voxel-based registration were significantly different (p < 0.05).

RESULTS

A total of twenty subjects (sixteen female; four male; mean age 27.6 years) with class II malocclusion and maxillomandibular retrognathia, who underwent bimaxillary surgery, were included. Surface-based registration was more accurate and reliable than voxel-based registration on the mandibular ramus two years post-surgery (p < 0.05). The inter observer reliability of using surface-based registration was excellent, ICC range [0.82-1.00]. For voxel-based registration, the inter observer reliability ranged from poor to excellent [0.00-0.98]. The measurement error introduced by applying surface-based registration for assessment of condylar remodelling was considered clinical irrelevant (1.83% and 0.18 mm), while the measurement error introduced by voxel-based registration was considered clinical relevant (5.44% and 0.52 mm).

CONCLUSIONS

Surface-based registration was proven more accurate and reliable compared to voxel-based registration on the mandibular ramus for long-term 3D assessment of condylar remodelling following Orthognathic Surgery. However, importantly, the performance difference may be caused by an inappropriate reference structure, proposed in the literature, and applied in this study.

What Do We Know Beyond Reliability in Voxel-Based Registration? Validation of the Accuracy of Regional Voxel-Based Registration (R-VBR) Techniques for Orthognathic Surgery Analysis

PURPOSE

Despite having excellent reproducibility, the accuracy of regional voxel-based registration (R-VBR) techniques used for postoperative orthognathic surgical analysis has not been validated. The purpose of this study was to validate the accuracy of R-VBR.

METHODS

Preoperative (T0) and postoperative (T1) cone beam computed tomography (CBCT) of consecutive patients treated at a single center with nonsegmental LeFort I and bilateral sagittal split osteotomy were included. T1 CBCTs were oriented to match that of the standardized T0, and thus were assigned a known rotational transformation matrix in pitch/roll/yaw (P/R/Y), to create T1'. A copy of T1 (cT1) was made and was superimposed to T1' using R-VBR for 4 regions of interest (ROI): maxilla, distal mandible, right proximal mandible, and left proximal mandible, to create cT1'. The transformation matrix for each of the ROI was compared to those of T1' using paired t test and Bland-Altman analysis.

RESULTS

Twenty-eight eligible subjects' CBCTs were analyzed. Mean difference between T1' and cT1' ranged from -0.08 to 0.14° (maximum 0.73°), with no statistically significant differences (P = 0.216 to 1). Mean absolute difference ranged from 0.13 to 0.31° (maximum 0.73°). Bland-Altman analysis showed good agreement between T1' and cT1', indicating excellent accuracy.

CONCLUSIONS

R-VBR using the maxilla, distal mandible, and the bilateral proximal mandibular segments as ROI has excellent accuracy in terms of rotational measurements.

Does the choice of the reference model affect the results of 3D-3D superimposition procedure? A comparison of different protocols for personal identification

In literature, 3D-3D superimposition has been widely recognized as a valid method for personal identification. However, very little information is available about possible variability due to differences in protocols of registration of 3D models and calculation of RMS (root mean square) point-to-point distance. Frontal sinuses from 50 CT scans were segmented twice through the ITK-SNAP software and grouped in two samples (1 and 2). Maximum breadth, height and volume were measured. 3D models belonging to the same subject were then superimposed one on each other in 50 matches. In addition, superimposition of 50 random mismatches was performed. For each superimposition, the procedure was repeated four times choosing different reference models both for registration and calculation of RMS. Differences in RMS value among protocols of registration and RMS calculation were assessed through paired Student's t-test (p < 0.05). Possible correlations between differences in RMS among groups and differences in frontal sinus size between the superimposed models were analysed through calculation of Pearson's correlation coefficient (p < 0.05). Results showed that RMS calculation did not yield significant differences according to which 3D model is used as reference; on the other hand, RMS values from registration procedure significantly differ according to which model is chosen as reference, but only in the mismatch group (p < 0.001). Differences in RMS value according to RMS calculation are dependent upon all the three measurements, whereas differences according to registration protocols were significantly related only with the breadth of frontal sinuses but only in mismatches (p < 0.001). In no case, superimpositions of RMS values were found between matches and mismatches. This article for the first time proves that the protocol of registration and calculation of RMS significantly influences the results of 3D-3D superimposition only in case of mismatches.

Voxel-based superimposition of Cone Beam CT scans for orthodontic and craniofacial follow-up: Overview and clinical implementation

INTRODUCTION

The increasing use of three-dimensional (3D) imaging in orthodontics has led to the development of 3D superimposition techniques. These techniques use stable anatomic structures as references in order to compare Cone Beam CT (CBCT) scans of the same subject at different time-points. Three methods have been described in the literature: landmark-based, surface-based and voxel-based 3D superimpositions.

OBJECTIVE

This article focuses on the voxel-based approach, which is the most described and the only one that can be fully automatized. The aim of this paper is to offer clinicians a practical tutorial on craniofacial voxel-based 3D superimposition.

MATERIAL AND METHODS

We provide an updated overview of the available implementation methods, describing their methodology, validations, main steps, advantages and drawbacks. The historical open-source method is the most widespread for research purposes, but takes around three hours to achieve for an experienced operator. Several commercially-available software perform superimpositions in a few minutes.

RESULTS

We used two of the available methods to conduct the superimposition process with three representative clinical cases in order to illustrate the different types of results that can be obtained.

CONCLUSIONS

Commercially-available software provide user-friendly and fully automatized superimposition methods, allowing clinicians to perform it easily and helping to reduce human error in image analysis. Still, quantitative evaluation of the results remains the main challenge of this technique.