Level Of Alveolar Crest Research Articles

Evaluation of the Alveolar Crest and Cemento-Enamel Junction in Periodontitis Using Object Detection on Periapical Radiographs.

The severity of periodontitis can be analyzed by calculating the loss of alveolar crest (ALC) level and the level of bone loss between the tooth's bone and the cemento-enamel junction (CEJ). However, dentists need to manually mark symptoms on periapical radiographs (PAs) to assess bone loss, a process that is both time-consuming and prone to errors. This study proposes the following new method that contributes to the evaluation of disease and reduces errors. Firstly, innovative periodontitis image enhancement methods are employed to improve PA image quality. Subsequently, single teeth can be accurately extracted from PA images by object detection with a maximum accuracy of 97.01%. An instance segmentation developed in this study accurately extracts regions of interest, enabling the generation of masks for tooth bone and tooth crown with accuracies of 93.48% and 96.95%. Finally, a novel detection algorithm is proposed to automatically mark the CEJ and ALC of symptomatic teeth, facilitating faster accurate assessment of bone loss severity by dentists. The PA image database used in this study, with the IRB number 02002030B0 provided by Chang Gung Medical Center, Taiwan, significantly reduces the time required for dental diagnosis and enhances healthcare quality through the techniques developed in this research.

Comparative evaluation of transverse width indices for diagnosing maxillary transverse deficiency

ObjectivesThis study aimed to compare and evaluate different transverse width indices for diagnosing maxillary transverse deficiency (MTD), a common malocclusion characterized by uncoordinated dental arches, crossbites, and tooth crowding.Materials and methodsSixty patients aged 7–12 years were included in the study, with 20 patients diagnosed with MTD and 40 normal controls. Transverse width indices, including maxillary width at the buccal alveolar crest and lingual midroot level, as well as at the jugal process width, were measured. Differences between these indices and their corresponding mandibular indices were used as standardized transverse width indices. The reference range of these indices was determined and evaluated. Receiver operating characteristic (ROC) analysis was performed to evaluate their diagnostic ability.ResultsThe transverse width indices and standardized transverse width indices of the MTD group were significantly smaller than those of the control group, except for the jugal process width. The evaluation of the reference range and ROC analysis revealed that the difference of the maxillomandibular width at buccal alveolar crest was the most accurate diagnostic method.ConclusionsThe jugal point analysis method may not be suitable for diagnosing MTD. Instead, measuring the difference in maxillomandibular width at the buccal alveolar crest proves to be a more reliable and accurate diagnostic method for MTD.

Effect of Slow Maxillary Expansion and Alternative Rapid Maxillary Expansion Protocols on Airway Volume in Cleft Palate Cases: A Cone Beam Computed Tomography Based Study.

A total of 22 patients with cleft palate aged 8 to 12 years were selected and categorized into two groups: the first group was treated with alternate rapid maxillary expansion and constriction (Alt-RAMEC) using an expander with differential opening (EDO) and facemask, while the second group was treated using slow maxillary expansion (SME) using an EDO. Finally, the pharyngeal airway volume in the two groups was compared using cone beam computed tomography (CBCT). CBCT scans were performed before expansion and six months following the expansion. Alveolar crest level, maxillary breadth, nasal cavity width, arch width, inclination of the molar teeth, buccal and palatal alveolar bone thickness, and maxillary alveolar width were all assessed. Paired t-tests (p=0.05) were applied to compare interphase data. The two groups showed a non-significant difference in terms of nasopharyngeal volume (cm3), oropharyngeal volume (cm3), and overall pre- and post-treatment results (p>0.005). Results of comparison of pre- and post-treatment periods in the Alt-RAMEC group revealed a significantly higher cleft volume (cm3) (p=0.001). Results of comparison of pre- and post-treatment periods in the SME group revealed a substantial rise in cleft volume (cm3) (p=0.003).Results from a comparison of the cleft volume (cm3) between the two study groups pre- and post-intervention revealed a non-significant difference (p=0.200 and 0.054, respectively).

Clinical and Radiographic Evaluation of Calcium Phosphate-Poly(lactide-co-glycolide) Graft in Regeneration of Intrabony Defects: Randomized Control Trial.

This study aims to evaluate the efficacy of calcium phosphate-poly(lactide-co-glycolide) composite graft in the regeneration of intrabony defects in chronic periodontitis patients over a period of 12 months. A total of 11 systemically healthy chronic periodontitis patients with 22 graftable sites were treated with calcium phosphate cement (CPC) bone graft (control group) and CPC-poly(lactic-co-glycolic acid)(PLGA) composite (test group) after flap reflection and debridement. Clinical parameters such as probing pocket depth (PPD) and clinical attachment level (CAL) were recorded at baseline and 3, 6, 9, and 12 months. Bone probing depth (BPD) and radiographic parameters such as defect depth (DD), changes in alveolar crest level (ALR), defect depth reduction (DDR), and percentage in defect depth reduction (PDDR) were calculated at baseline, and 6 and 12 months. The data were recorded and statistically analyzed. On intragroup comparison, there was a significant improvement in all the parameters over a period of 1 year (clinically and radiographically). However, there was no statistically significant difference between the two groups in any of the parameters though there was a slightly higher bone fill noted in the test group. Even though the CPC-PLGA composite bone graft showed a slight improvement in clinical and radiographic parameters as compared to the CPC graft, it was not statistically significant. A major drawback of Calcium Phosphate cements as bone grafts is their poor degradability. The PLGA microspheres degrade to expose macropores and interconnected pores in the graft substrate which in turn would promote the ingrowth of osteoblasts. Also, this composite graft is mouldable, and resorbable and has been shown to snugly fit into the defects making them a suitable scaffold material. How to cite this article: Ojha M, Pawar Chandrashekara Rao D, Gowda V. Clinical and Radiographic Evaluation of Calcium Phosphate-Poly(lactide-co-glycolide) Graft in Regeneration of Intrabony Defects: Randomized Control Trial. J Contemp Dent Pract 2023;24(12):921-927.

CBCT Compared to Transgingival Probing as a Tool for Estimating Alveolar Bone Crest Level in Patients with Altered Passive Eruption.

Alveolar bone crest level is essential in determining the need for bone removal in subjects with altered passive eruption (APE). This study assessed the validity of Cone Beam Computed Tomography (CBCT) and transgingival probing. Patients presenting with APE were assessed. Transgingival probing was performed to clinically assess the distance between the cementoenamel junction (CEJ) and the crest of the bone at the mid-point of upper anterior teeth. CBCT was used to assess this distance at the same point. Upon reflection of a full mucoperiosteal flap the actual distance was measured. Similar actual and CBCT measurements of the distance between the CEJ and bone crest at upper right 3, upper left 2 and upper left 3 (P>0.05) were recorded. However, in upper right 2, upper right 1 and upper left 1 the distance was significantly greater on CBCT (P<0.05). No significant difference was detected between transgingival probing and the actual distance at all teeth assessed. Careful transgingival probing provides an accurate measure of the distance between the CEJ and crest of the Bone. CBCT gives an accurate estimate, However, it might not be justified for each patient in the presence of safer methods.

Role of ferroptosis in periodontitis: An animal study in rats.

This study aimed to investigate (1) the temporal pattern of ferroptosis, an iron-dependent cell death, in ligation-induced rat periodontitis and (2) the effect of ferrostatin-1, a ferroptosis inhibitor, on the model. Ferroptosis may contribute to various diseases. However, the role of ferroptosis in periodontitis is still fully understood. In the first experiment, 25 rats with ligation-induced periodontitis were sacrificed on days 0, 1, 2, 7, and 10. Gingivae were obtained to determine tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and ferroptotic biomarkers, including solute carrier family 3 member 2 (SLC3A2) and solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (Gpx4), via immunoblotting. Using microcomputed tomography (μCT) and histology, the periodontal soft and hard tissue lesions, including dental alveolar bone crest level, bony characteristics of the surrounding alveolus, periodontal tissue inflammation, and periodontal tissue losses, were evaluated. In study two, 16 rats with induced periodontitis were grouped according to ferrostatin-1 treatment. The rats were intraperitoneally injected with solvent or ferrostatin-1 (1.5 mg/kg/day) 1 day before ligation and sacrificed on days 7 and 10. Gingival protein changes and periodontal tissue damage were also examined. In study one, SLC3A2/SLC7A11 and Gpx4 decreased since day 1; however, TNF-α/IL-1β increased on days 7 and 10. Moreover, the μCT/histology revealed resorptive bony characteristics, inflamed gingival tissue, and periodontal attachment loss. In study two, ferrostatin-1-injected rats exhibited significantly increased SLC3A2/SLC7A11 and Gpx4 but decreased TNF-α/IL-1β than vehicle rats. They also revealed lessened bone resorption, tissue inflammation, and attachment loss. This study highlights the role of ferroptosis, via the system Xc/Gpx4 pathway, in experimental periodontitis and may serve as a regulatory strategy.

Comparison between Measurements of Clinical Attachment Level and Transgingival Probing with Alveolar Bone Crest Level in Chronic Periodontitis Patients

Background: Periodontitis is an inflammatory disease of the supporting tissues of the teeth that leads to crucial changes in the bony architecture. Early detection is of great practical significance so that treatment may be administered before irreversible destruction could occur. Differences exist between different diagnostic methodology concerning the relationship between the measurements and the level of the lesion. The aim of this study was to assess relationship between clinical attachment level (CAL) and alveolar bone crest level (ABCL), reliability of transgingival bone probing level (TBL) for ABCL measurement, and clinical biologic width (CBW) measurement in chronic periodontitis patients. Methods: An analytical cross-sectional study was conducted on 238 periodontal sites in 25 chronic periodontitis patients, aged 20–60 years who were planned for periodontal flap on residual pocket depth of 5-8mm after four weeks of non-surgical therapy. Stent was used for coronal fixed reference point. The relative attachment level (RAL), relative transgingival bone probing level (RTBL), relative alveolar bone crest level (RABCL), and CBW were measured at six sites per tooth excluding third molars. Descriptive and inferential statistical analysis was done. Probability of significance (p-value) was set at 5%. Results: Overall RAL, RTBL and RABCL (mean ± SD) were 8.08 ± 1.23, 10.82 ± 1.1, and 11.15 ± 1.36 mm respectively. Overall CBW (mean ± SD) was 3.06 ± 0.634 mm. Conclusions: There was a significant positive correlation of CAL and TBL with ABCL. Also, the CBW was greater than that of standard histologic BW.

Three-Dimensional Analysis of Alveolar Bone Morphological Characteristics in Skeletal Class II Open Bite Malocclusion: A Cone-Beam Computed Tomography Study.

This cross-sectional research evaluated the morphological characteristics of alveolar bone in skeletal class II open-bite individuals compared to skeletal class II and class I non-open-bite individuals. A sample of 82 patients (all were in cervical vertebral stage 6) was divided into three groups (class II OB group, n = 29; class II NOB group, n = 29; class I NOB group, n = 24) according to bilateral molar relationship, ANB angle, and anterior overbite measured by cephalometric analysis. The evaluation was performed with specialized software (Mimics 21.0) and initial cone-beam computed tomography (CBCT) data. The alveolar bone height and thickness of the whole dentition area and alveolar crest level and root apex position of the incisors were measured with a series of appropriate CBCT images. One-way analysis of variance followed by the Tukey post hoc test and the Kruskall−Wallis test were performed for statistical comparisons. The class II open-bite group had increased alveolar bone height for the maxillary first molar and decreased alveolar bone height for mandibular molars compared to the class II non-open-bite group (p < 0.05 for both). Furthermore, there were significant negative correlations between the alveolar bone heights of the upper first and second molars (A6-height, A7-height) and overbite (both p < 0.01). The alveolar thicknesses of all measured teeth were generally reduced in the class II OB group.

Assessment of alveolar bone height in adolescents utilizing Cone Beam Computed Tomography: a retrospective radiographic analysis

Background: To assess the alveolar bone crest level (ABCL) by Cone Beam Computed To-mography (CBCT) and to investigate several variables as predictors for the height of the alveolar bone in adolescents. Materials and methods: Age, sex, and ethnic groups were rec-orded for each patient. CBCT images were used to obtain measurements of the interproximal alveolar bone level from the cementoenamel junction (CEJ) to the alveolar crest. The highest measurement in each sextant was recorded along with any presence of a vertical bone defect or calculus. Results: Total of 720 measurements were recorded for 120 subjects. No vertical bony defects or calculus were observed radiographically. Statistically significant (P&lt; 0.05) differences were observed between ABCL measurements of males as compared to females, posterior teeth compared to anterior teeth and maxillary sextants in comparison to man-dibular ones. Additionally, value of ABCL significantly increased in relation to sex (r=0.309), maxillary posterior (r=0.509) and mandibular posterior sextants (r=0.506). Linear regression analysis indicated that the latter variables can predict the height of marginal bone, other independent variables were considered redundant. Conclusions: There was a low-profile of marginal bone loss among adolescents. Male sex, posterior teeth, and maxillary teeth have higher tendency for decreasing alveolar bone height.

A 3-year prospective randomized clinical trial of alveolar bone crest response and clinical parameters through 1, 2, and 3\xa0years of clinical function of implants placed 4 months after alveolar ridge preservation using two different allogeneic bone-grafting materials

PurposeThe aim of this study was to longitudinally evaluate changes in alveolar bone crest (ABC) levels and differences in resorption rates (RR) between the tested grafting materials following alveolar ridge preservation (ARP) after tooth extraction after 1, 2, and 3 years (T1–T8) of clinical function.MethodsPatients were randomly assigned to two different bone allografts (group 1 maxgraft®, group 2 Puros®) for ARP. Non-restorable teeth were minimal traumatically extracted. Sockets were augmented with the tested materials and covered with a pericardium membrane. After 4 months of healing, 36 implants were placed and sites were clinically and radiographically monitored in the mesial (ABC-M), the distal (ABC-D, T1–T8), the bucco-lingual (ABC-BL), buccal (ABC-B) and oral (ABC-O) aspect (T1–T4).ResultsChanges in (ABC-M), (ABC-D), (ABC-BL), (ABC-B), and (ABC-O) levels showed statistically highly significant differences between T1 and T2 for both bone allografts (p < 0.001). Changes at the ABC-M and ABC-BL levels between T2 and T3 of group 1 showed a statistically significant difference (p < 0.001). Both groups achieved and maintained increased ABC levels without statistically significant differences throughout the monitoring periods of 1–3 years (T6–T8) of clinical function. No failures or adverse events were observed.ConclusionsTo the best of our knowledge, this study is within its limitations the first study to directly compare ABC-changes and differences in RR of two different allogeneic grafting materials for a period of 3 years after ARP. It was demonstrated to be, despite significant differences in RR, a successful method of preserving increased ABC levels through 1, 2, and 3 years of clinical function.Trial registration DRKS00013010, registered 07/30/2018, http://apps.who.int/trialsearch

Significance Of Various Etiological Factors As An Indicator For The Persistence Of Median Diastema

Maxillary midline diastemas are a common esthetic problem that dentists must treat. This study was performed to quantify the width of median diastema and level of bone crest and to determine the type of inter-maxillary suture, familial prevalence, spacing in upper anterior region, axial inclination of upper centeral incisors, and low frenal attachment as the most contributing factors associated with median diastema. A standardized periapical radiographs using a paralleling technique with a film holder were taken to the (99) maxillary and/or mandibular centeral incisors with median diastema and to the (85) maxillary incisors with no diastema as a control group in adults with age range from 18-25 years old. Diastema width between 0.5-1 mm has a higher percent while diastema above 2 mm has a least percent. There is a non-significant difference in the level of alveolar crest of central incisor in both control and diastema groups. Type I intermaxillary suture type was the most common in control group while type II and III were the most common in diastema. There is a relationship between spacing and type of intermaxillary suture which can use as an indicator for the persistence of diastema from childhood in addition to familial history while frenum may has no effective role in developing median diastema. Axial inclination of central incisors is one of important factors that should be taken in consideration during treatment of median diastema

Influence of Root Canal Fillings on Alveolar Bone Crest Level—An Observational Cross Sectional CBCT Analysis

The aim of this study was to compare the alveolar bone crest (ABC) level of root canal filled (RCF) teeth without apical periodontitis with corresponding non-filled teeth in the same individual using three-dimensionally cone-beam computed tomography (CBCT) data. Two hundred and thirty-five matching pairs of RCF teeth and corresponding teeth without RCF were selected from a pool of 580 random CBCT-images (voxel size 160–200 µm). Teeth with apical periodontitis, perio-endodontic lesions or surgical endodontic treatment were excluded. The distance between the cemento–enamel-junction (CEJ) and the ABC was assessed centrally mesial, distal, palatal/lingual and buccal at each tooth (∑1880 measuring points) in a standardized manner. Topographic, gender, and age-related relationships were also noted. Data were analyzed using the Kruskal–Wallis-test. The ABC-level between RCF teeth (2.64 ± 1.25 mm) and teeth without RCF (2.61 ± 1.16 mm) did not differ significantly (p &gt; 0.05). No differences concerning localization (maxilla/mandible, tooth type) and gender (p &gt; 0.05) occurred. Overall, ABC-level in the maxilla (2.74 ± 1.48 mm) was significantly lower (p &lt; 0.001) compared to mandibular teeth (2.50 ± 1.41 mm). Patients &gt; 41 years had significantly lower ABC-levels than younger patients (p &lt; 0.05). Men showed a reduced bone level compared to women (p &lt; 0.05). In conclusion, RCF teeth are identical to their non-RCF counterparts, at least in terms of crestal bone level, regardless of the location or type of tooth and the gender of the patient. Thus, root canal treatment is an essential pillar for long-term tooth preservation.

Correlation analysis of periodontal tissue dimensions in the esthetic zone using a non-invasive digital method.

PurposeDirect intraoral scanning and superimposing methods have recently been applied to measure the dimensions of periodontal tissues. The aim of this study was to analyze various correlations between labial gingival thickness and underlying alveolar bone thickness, as well as clinical parameters among 3 tooth types (central incisors, lateral incisors, and canines) using a digital method.MethodsIn 20 periodontally healthy subjects, cone-beam computed tomography images and intraoral scanned files were obtained. Measurements of labial alveolar bone and gingival thickness at the central incisors, lateral incisors, and canines were performed at points 0–5 mm from the alveolar crest on the superimposed images. Clinical parameters including the crown width/crown length ratio, keratinized gingival width, gingival scallop, and transparency of the periodontal probe through the gingival sulcus were examined.ResultsGingival thickness at the alveolar crest level was positively correlated with the thickness of the alveolar bone plate (P<0.05). The central incisors revealed a strong correlation between labial alveolar bone thickness at 1 and 2 mm, respectively, inferior to the alveolar crest and the thickness of the gingiva at the alveolar crest line (G0), whereas G0 and labial bone thickness at every level were positively correlated in the lateral incisors and canines. No significant correlations were found between clinical parameters and hard or soft tissue thickness.ConclusionsGingival thickness at the alveolar crest level revealed a positive correlation with labial alveolar bone thickness, although this correlation at identical depth levels was not significant. Gingival thickness, at or under the alveolar crest level, was not associated with the clinical parameters of the gingival features, such as the crown form, gingival scallop, or keratinized gingival width.

Predictive Factors Affecting the Maxillary Alveolar Bone Thickness: A Cone-Beam Computed Tomography Study.

PurposeMany important structures are associated with the maxillary alveolar bone and should be considered during orthodontic tooth movement. The purpose of this study was to investigate the correlation between the anterior maxillary alveolar bone thickness (AMABT), inclination of the central incisors, and the incisive canal (IC), as well as changes in the thickness based on age and sex of the patients.MethodsThis cross-sectional study was conducted using archived cone-beam computed tomography (CBCT) records categorized according to age and sex. The parameters measured were; AMABT at three levels: alveolar crest, mid-root, and apex; incisor to palatal plane (Inc/PP) angle and IC width at palatal opening. OnDemand 3D Imaging software was utilized for image reconstruction and measurement. Data were analyzed using linear regression analysis and Mann–Whitney test. A P-value of <0.05 was considered significant.ResultsOut of the 300 CBCT images assessed, only 135 images (70 males and 65 females; age range=17–63 years) fulfilled the inclusion criteria. The Inc/PP angle had a significant effect on the AMABT at the alveolar crest and mid-root levels (P<0.01). Width of the IC at palatal opening had a significant effect on AMABT at the mid-root and apex level (P<0.01). Age had a significant effect on AMABT at three levels (P<0.05). Males demonstrated significantly greater AMABT at all levels than females (P<0.01).ConclusionThere was an association between AMABT and the Inc/PP angle, width of the IC at palatal opening, age, and sex of the patients.

Study of Alveolar Bone Status in Alcoholic Patients by Cone-Beam Computed Tomography

Background: Alcohol has a negative effect on humans, whether it is on the healthy or even economic side. It is considered a serious condition for the occurrence of many diseases threatening human life or may contribute to increasing their severity in addition to the negative impact on some parts of the human body. Aim of the study: To evaluate the alveolar bone status by measuring the alveolar bone crest level of the interproximal teeth in alcohol drinker individuals on CBCTs. Material and Methods: The current study included randomly selected male patients (n=294) who admitted to radiology units in some dentistry centers in Baghdad city, between the ages of 25 and 45 years. The selected male subjects were divided into three groups: control group (n=120), light alcohol drinking group (n=98) and heavy alcohol drinking group (n=76). The measurements of alveolar crest level were done on CBCT images by measuring a distance between the crest of alveolar bone and the “cementoenamel junction” in the interproximal teeth region. Results: Statistical analysis showed that there was a significant reduction in the alveolar bone crest level in the alcohol drinker groups as compared to the control non-drinker group at p-value ?0.05. In addition, the study also showed that there was a significant reduction of alveolar bone crest level in the maxilla as compared to the mandible between the alcohol drinker groups at p-value ?0.05. Conclusion: The study found there was a negative effect of “alcohol consumption” on the alveolar bone as it causes a reduction of alveolar bone crest level in the interproximal areas of teeth. Clinical significance: The study confirms the damage of alveolar bone reduction as a result of the long-term consumption of alcohol.

Comparison of Regenerative Potential of Platelet-rich Fibrin Alone and in Combination with Bovine Bone Graft in Intraosseous Defect by Single Flap Approach: A Clinical and Radiographic Study.

ABSTRACTAim:To compare the regenerative potential of platelet-rich fibrin alone and in combination with bovine bone graft in intraosseous defect by the single flap approach.Materials and Methods:A total of 32 sites of intrabony defects were selected and were treated with platelet-rich fibrin (PRF) alone or in combination with bovine bone graft. Clinical parameters [Gingival index (GI), probing depth (PD), clinical attachment level (CAL), Gingival recession, and radiographic parameters (defect fill, alveolar crest level, and defect depth)] were recorded at baseline, 3 months, and 6 months.Results:Statistical analysis was done by independent and paired t-test. There were statistically significant changes in GI, PD reduction, CAL gain, defect fill, alveolar crest level changes, and defect depth resolution from baseline, 3 months, and 6 months in both the groups (P < 0.001). On intergroup comparison, Group II showed statistically significant changes in a reduction in pocket depth and defect depth resolution at P < 0.001.Conclusion:PRF in combination with bovine bone graft was more effective in the treatment of intrabony defects.

Tomographic evaluation of dentoskeletal effects of rapid maxillary expansion using Haas and Hyrax palatal expanders in children: A randomized clinical trial.

BackgroundRapid maxillary expansion (RME) is a usual procedure for correcting the transversal maxillary deficiency. Among the most used appliances are the Haas type (tooth-tissue-borne) and Hyrax (tooth-borne) whose main difference is the design. This study aimed to evaluate the dentoskeletal effects of RME using two different expanders in children. Material and MethodsThe sample was composed of 42 children of both gender presenting unilateral or bilateral posterior crossbite with mean age 9.49 (SD± 1.35). Patients were randomized into two groups according to the type of expander: Hyrax (n= 21, 9 boys and 12 girls) and Haas (n= 21, 11 boys and 10 girls). Multiplanar coronal and axial slices obtained from cone-beam computed tomography images (i-Cat, Hartsfield, PA, USA) were used at pretreatment (T1) and after 6 months when the expander was removed (T2). Measurements were performed on Dolphin Imaging Systems 11.7 software (Chatsworth, California, USA). The following variables were evaluated: inclinations of the posterior teeth, transverse skeletal widths, length of maxillary dental arch, buccal bone thickness and level of buccal alveolar crest. Statistical analysis performed using chi-squared test to compare the sex ratios between groups and independent t test with the Bonferroni correction for multiple tests. ResultsRME increased all maxillary transverse dimensions, regardless of the type of expanders used. Subjects in the Hyrax group experienced significantly increase in the lingual bone thickness (0.94 mm) compare to Haas group (0.21 mm). ConclusionsThe Hyrax-type expander produced greater increase in the lingual bone thickness than did the Haas-type expander, but this effect might not be clinically significant. Both appliances presented similar transversal gain and tended to produce similar orthopedic and orthodontic effects. Key words:Cone-beam computed tomography, palatal expansion technique, palate.

The 3-dimensional zone of the center of resistance of the mandibular posterior teeth segment

We sought the 3-dimensional (3D) zone of the center of resistance (ZCR) of mandibular posterior teeth groups (group 1: first molar; group 2: both molars; group 3: both molars and second premolar; group 4: both molars and both premolars) with the use of 3D finite element analysis. 3D finite element models comprised the mandibular posterior teeth, periodontal ligament, and alveolar bone. In the symmetric bilateral model, a 100-g midline force was applied on a median sagittal plane at 0.1-mm intervals to determine the anteroposterior and vertical positions of the ZCR (where the applied force induced translation). The most reliable buccolingual position of the ZCR was then determined in the unilateral model. The combination of the anteroposterior, vertical, and buccolingual positions was defined as the ZCR. The ZCRs of groups 1-4 were, respectively, 0.48, 0.46, 0.50, and 0.53 of the mandibular first molar root length from the alveolar crest level and located slightly distobuccally at anteroposterior ratios of 2:3.0, 2:2.3, 2:2.4, and 2:2.5 to each sectional arch length and at buccolingual ratios of 2:1.5, 2:1.1, 2:1.6, and 2:2.4 to the first molar's buccolingual width. The ZCR can be a useful reference for 3D movement planning of mandibular posterior teeth or segments.

Determining the accuracy of measurement of alveolar bone crest level and bone plate thickness with cone-beam computed tomography using different voxel size

Determining the accuracy of measurement of alveolar bone crest level and bone plate thickness with cone-beam computed tomography using different voxel size

Effect of orthodontic treatment and comorbidity risk factors on interdental alveolar crest level: A radiographic evaluation.

Alveolar bone loss is regarded as a potential adverse event during orthodontic treatment, especially in adults. The purposes of this study were to evaluate the prevalence and severity of interdental alveolar crest height loss in adult orthodontic patients compared with an untreated control group and to identify comorbidity risk factors for such bone loss (high BMI score, high blood pressure, high cholesterol levels, and smoking). Standardized bitewing radiographs of patients' buccal segments were taken before and after treatment of 34 consecutive adults treated in an orthodontic clinic. The control group included 29 patients from the operative dental clinic matched according to age and sex. Mean ages of the participants before treatment were 35.7±6.7 and 35.6±7.3years for the control and treatment groups, respectively. Before orthodontic treatment, the patients were evaluated, treated as needed, and approved by a periodontist. They were periodontically healthy before treatment. Interdental alveolar crest height loss was calculated by subtracting the distance on a bitewing x-ray from the cementoenamel junction to the interdental alveolar crest at each interproximal tooth surface from the mesial aspect of the first premolar to the distal aspect of the secondmolar (8 sites per quadrant). Changes in interdental alveolar crest height were calculated by subtracting the cementoenamel junction-interdental alveolar crest distance before treatment from the corresponding distance after treatment. The mean individual bone losses of all interproximal surfaces were 0.130±0.192 and 0.072±0.280mm in the treatment and control groups, respectively. These differences did not reach statistical significance (P=0.353). Twenty-two patients (65%) from the treatment group and 10 patients (34%) from the control group had an increase in the cementoenamel junction-interdental alveolar crest distance of more than 1mm in at least 1 site, with borderline significance between the groups (P=0.079). Notably, no association was observed between bone loss with any comorbidity factor. The results of this study correspond to the conventional understanding in the orthodontic and periodontal literature that orthodontic tooth movement per se does not cause attachment loss. However, orthodontists should always be aware of the possibility of periodontal deterioration during orthodontic treatment. Therefore, comprehensive periodontal examination is necessary during orthodontic treatment, especially in adults.