Buccal Alveolar Crest Research Articles

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.

Protocolo de tratamento ortodôntico em adultos jovens com endognatia maxilar utilizando o expansor rápido palatino ancorado em mini-implante

Introduction: Maxillary endognathia is a skeletal malocclusion that, if left untreated, can evolve into a complex malocclusion, which hinders facial development and creates breathing problems due to nasal constriction. In 2010, Lee and collaborators created a mini-implant-assisted rapid maxillary expansion (MARPE) technique. Objectives: To describe the MARPE protocol and its clinical effects. Materials and methods: A bibliographic search was carried out in the Pubmed, Science Direct, Scielo and Google Scholar databases referring to the last 10 years. Results: The search strategies described enabled 150 articles to be obtained which went through various selection stages. In the end, 15 articles were evaluated and selected for this review. Discussion: The MARPE technique has reduced the skeletal, dento-alveolar and periodontal side effects caused by conventional appliances, optimizing the potential for skeletal expansion in individuals with advanced stages of skeletal maturation. Conclusion: The MARPE appliance has bone and dental anchorage. The clinical effects include the opening of the maxilla in the frontal plane, an increase in the volume of the nasal cavity after expansion, an increase in the interzygomatic distance, an increase in the average width of the face and the width of the alar base and widening of the nose. There was also a decrease in buccal bone thickness and alveolar crest height and a buccal inclination in the premolars and molars. In carrying out this research, we found that there are few or practically no studies on the effect on the pulp cavity, root resorption and orbital volume.

Evaluation of dentoalveolar changes following maxillary incisor intrusion with one vs two anterior miniscrews in subjects with gummy smile: a randomized clinical trial.

To examine dentoalveolar changes following intrusion of maxillary incisors with one or two anterior miniscrews in subjects with gummy smile and deep bite. Forty-three subjects were selected and divided into two groups: group I (22 subjects: 15 women, 7 men; mean age 30 ± 10 years) received one miniscrew between the upper central incisors, and group II (21 subjects: 16 women, 5 men; mean age 30 ± 10 years) received two miniscrews between the canines and lateral incisors. Dentoalveolar parameters, including amount of intrusion, root resorption, incisor inclination, alveolar bone thickness, and buccal alveolar crest height (cementoenamel junction to labial alveolar crest), were evaluated using cone-beam computed tomography scans obtained before and after intrusion. The intergroup comparison was analyzed using a paired t-test and unpaired t-test to determine significant changes within and between groups. The amount of intrusion was significantly greater in group II than in group I (P < .05). No statistically significant differences were found between groups I and II for changes in incisor inclination, labial bone thickness, and buccal alveolar crest height (P > .05). Maxillary central and lateral incisor intrusion was significantly greater in subjects treated with two miniscrews. Root resorption of the maxillary central incisors was notably greater in subjects with one miniscrew, while maxillary lateral incisor resorption was greater in subjects treated with two miniscrews.

Finite element analysis of the angle range in trans-inferior alveolar nerve implantation at the mandibular second molar

BackgroundTrans- inferior alveolar nerve (IAN) implantation technique was wildly used while the potential appropriate angle range in which the residual alveolar bone can bear the stress without absorption are currently unclear. This study aimed to evaluate the stress distribution pattern of the interface between bone and implant by finite element analysis (FEA) to determine the appropriate range of the implant tilt angle.MethodsCone beam computed tomography (CBCT) images of 120 patients with missing mandibular second molars and vertical bone height < 9 mm in the edentulous area were selected. The distances from the mandibular nerve canal to the buccal cortex, the lingual cortex and the alveolar ridge crest were measured by using a combination of software. The angular ranges of the buccal-lingual inclination of simulated trans-IAN implants were measured and three-dimensional finite element models were constructed in the mandibular second molar area according to the differences of the inclination angles. A vertical load (200N) was then applied to analyze the biomechanical conditions of the implant-bone interface during median occlusion.ResultsThe distance at the second molar from the nerve canal to the buccal cortex, lingual cortex and alveolar crest were 6.861 ± 1.194 mm, 2.843 ± 0.933 mm and 7.944 ± 0.77 mm. Trans-IAN implantation was feasible in 73.33% of patients. The minimum angle and maximum angles of the buccal-lingual inclination of the simulated implant were 19.135 ± 6.721° and 39.282 ± 6.581°. When a vertical static load of 200N was applied, the tensile stress in cortical bone gradually increased with the increase of the implant tilt angle. When the inclination angle reached 30°, the tensile stress (105.9 MPa) exceeded the yield strength (104 MPa) of cortical bone. Compared with the conventional implants, the stress peak value of the vertical ultra-short implant in cortical bone was greater than the stress peak value of the conventional implants at 10°(79.81 MPa) and 20°(82.83 MPa) and was smaller than the stress of the implant at 30°(105.9 MPa) and 40°(107.8 MPa). Therefore, when the bone mass allows, conventional-length implants should be selected whenever possible, and an operative range of the trans-IAN implantation in the mandibular second molar could be retained with an inclination angle of < 30°.ConclusionsThe mandibular nerve canal at the mandibular second molar was obviously biased to the lingual side, which ensured sufficient bone mass at the buccal side. In most patients with severe mandibular atrophy, it was possible to maintain a safe distance from the nerve canal with conventional-length implants via the trans-IAN implantation technique.

Gingival phenotype determination: Cutoff values, relationship between gingival and alveolar crest bone thickness at different landmarks

Background/purposeGingival phenotype (GP) has been reported to influence the treatment planning and clinical outcomes in several dental specialties. This study aimed to investigate optimal cutoff values for gingival thickness (GT) measurement at different landmarks to determine GP. The correlations between GT and bone thickness (BT) of buccal alveolar crest were also analyzed. Materials and methodsA total of 600 teeth were included. GP was clinically determined by the transparency of a periodontal probe through the gingival margin (TRAN). Measurements for free gingival thickness (GT1), cementoenamel junction gingival thickness (GT2), supracrestal gingival thickness (GT3), subcrestal 1 mm gingival thickness (GT4) and BT at 1, 3 mm apical from the alveolar crest edge (BT1 and BT2) were assessed on cone-beam computed tomography (CBCT) images. Spearman's correlation coefficient was used to evaluate correlations between GT and BT. ResultsThe optimal cutoff values of GT using CBCT method to discriminate GP were 0.75 mm for GT1, 0.85 mm for GT2, 1.15 mm for GT3 and 0.45 mm for GT4. There was significantly positive correlation between GT and BT at all levels (r: 0.375–0.903). The correlations between GT3 and BT (r: 0.789–0.903) were strong, while correlations between GT4 and BT were weak (r: 0.375–0.467). ConclusionThe optimal cutoff values of gingival thickness using CBCT method to discriminate gingival phenotype at each gingival landmark were determined. The supracrestal gingival thickness might be an indicator of buccal alveolar crest bone thickness, which could provide valuable perspectives on clinical diagnosis, treatment planning and decision-making.

A Surgical Approach to Root Coverage and Correction of Mucogingival Conditions and Deformities in Mandibular Incisors with Isolated Gingival Recession: Free Mucogingival Graft. A Pilot Prospective Cohort Study.

The aim of this study was to present a periodontal plastic surgery approach to treat gingival recessions (GRs) and correct mandibular incisor mucogingival conditions and deformities. Isolated deep GRs (≥ 3 mm) in the mandibular incisors (n = 24 teeth) were treated: 66.6% of sites were recession types 2 or 3, and 58.3% of teeth were malpositioned. Recessions were treated using free mucogingival grafts (FMGs) harvested from the buccal aspect of donor teeth with altered passive eruption or healthy periodontal support, with < 3 mm between the cementoenamel junction and the buccal alveolar crest. Clinical parameters (GR, clinical attachment level, interproximal papilla tip location, keratinized tissue, vestibule depth) and root coverage esthetic score were evaluated at 9 months. FMG significantly reduced GR (P < .001) and increased keratinized tissue (P < .001) without loss of vestibule depth (P > .05). Mean root coverage was 94.37% ± 10.60%, mean residual GR was 0.08 ± 0.65 mm, and the mean root coverage esthetic score was 8.9 ± 1.24. Recession types 2/3 showed significant interproximal clinical attachment gain (P < .05). The interproximal papilla was significantly augmented at sites with papilla loss (P < .001). No clinical attachment loss (P = .346) was detected at donor sites. These results suggest that FMG is a promising root coverage approach for recession types 1, 2, and 3, correcting mucogingival conditions and deformities and reconstructing the interproximal papilla.

Skeletal, Dentoalveolar and Dental Changes after "Mini-Screw Assisted Rapid Palatal Expansion" Evaluated with Cone Beam Computed Tomography.

The purpose of this study was to evaluate skeletal, dentoalveolar and dental changes after Mini-screw Assisted Rapid Palatal Expansion (MARPE) using tooth bone-borne expanders in adolescent patients after analyzing different craniofacial references by Cone beam computed tomography (CBCT) and digital model analysis. This prospective, non-controlled intervention study was conducted on fifteen subjects (mean age 17 ± 4 years) with transversal maxillary deficiency. Pre (T1) and post-expansion (T2) CBCTs and casts were taken to evaluate changes at the premolars and first molar areas. To compare means between two times, paired samples t- or Wilcoxon test were used following criteria. Significant skeletal changes were found after treatment for Nasal width and Maxillary width with means of 2.1 (1.1) mm and 2.5 (1.6) mm (p < 0.00005). Midpalatal suture showed a tendency of parallel suture opening in the axial and coronal view. For dentoalveolar changes, a significant but small buccal bone thickness (BBT) reduction was observed in all teeth with a mean reduction of 0.3 mm for the right and left sides, especially for the distobuccal root of the first molar on the left side (DBBTL1M) [IC95%: (−0.6; −0.2); p = 0.001] with 0.4 (0.4) mm. However, a significant augmentation was observed for the palatal bone thickness (PBT) on the left side. The buccal alveolar crest (BACL) and dental inclination (DI) showed no significant changes after treatment in all the evaluated teeth. MARPE using tooth bone-borne appliances can achieve successful skeletal transverse maxillary expansion in adolescent patients, observing small dentoalveolar changes as buccal bone thickness (BBT) reduction, which was not clinically detectable. Most maxillary expansions derived from skeletal expansion, keeping the alveolar bone almost intact with minor buccal dental tipping.

Comparison of Transverse Dentofacial Dimensions in Adults with Skeletal Class I and Class II Malocclusion, Horizontal Growth Pattern and Mild to Moderate Periodontitis using CBCT- A Retrospective Study

Introduction: Knowledge of transverse dentofacial dimensions is crucial for accurate diagnosis and treatment planning. Periodontitis can alter the widths of the arches by causing pathological migration of teeth and the concurrent bone loss can affect the transverse width of the arches. Aim: To compare the transverse dentofacial widths in adults with skeletal class I and class II malocclusions with horizontal growth pattern and with mild to moderate periodontitis using Cone Beam Computed Tomography (CBCT). Materials and Methods: This retrospective observational study was conducted in Department of Orthodontics, Faculty of Dental Sciences, Ramaiah University of Applied Sciences, Bengaluru, Karnataka, India, from January 2019 to January 2021. Total 96 CBCT samples (48 skeletal Class I, 48 skeletal Class II) of patients between age group of 25-35 years, patients having mild to moderate periodontitis based on bone loss seen on CBCT and patients having a horizontal growth pattern with the angle between sella-nasion and mandibular plane less than 320 degrees were included in the study. Transverse dentofacial measurements were made on the coronal plane of the CBCT scans. Data were analysed using Statistical Package for Social Sciences (SPSS) version 20. Chi-square test and Student’s t-test were used to compare age, linear measurements and angular measurements between the skeletal class I and skeletal Class II groups. A p-value of &lt;0.05 was considered statistically significant at 95% class interval. Results: In this study the mean age of patients with skeletal class I and class II was 30.89±3.23 and 30.97±3.28 years, respectively. There were 24 females and 24 males belonging to class I and class II groups, each. There was a statistically significant difference in the mean interjugal width and the antegonial width. The mean interjugal width in skeletal Class I and Class II group was 56.95±5.68 mm and 51.28±5.94 mm respectively (p-value was &lt;0.001). The maxillomandibular difference (p-value=0.002), the mean maxillary buccal alveolar crest width difference (p-value &lt;0.001) and mandibular buccal alveolar crest width difference (p-value &lt;0.001) was also statistically significant. The palatal height in skeletal Class I group (21.77 mm) was significantly higher (p value &lt;0.001) and the mean maxillary palatal alveolar crest width in skeletal Class I (36.47 mm) was lower than in the Class II group (37.97 mm). Conclusion: The dentofacial transverse widths such as the interjugal width, antegonial width, maxillomandibular difference, maxillary buccal alveolar crest width and mandibular buccal alveolar crest width were higher in skeletal Class I groups compared to skeletal Class II groups. The maxillary palatal alveolar crest width was higher in skeletal Class II groups compared to skeletal Class I group.

Ridge Volume Stability of Maxillary Anterior Implants Placed with Simultaneous Lateral Guided Bone Regeneration during Healing: a Radiographic Analysis.

To assess bone volume stability and identify critical bone graft thickness for guided bone regeneration (GBR) simultaneous to implant placement in the maxillary anterior region. Eighteen patients were included in the study and received placement of one maxillary anterior implant combined with GBR using deproteinised bovine bone mineral (DBBM) and resorbable collagen membrane. The multilevel buccal bone thickness (BT) was measured by CBCT 1 to 2 weeks and 5 to 8 months post-implantation (at implant uncovering surgery). Significant buccal alveolar crest collapse (ACCb 1.20 to 1.70 mm) occurred during the mean healing period of 5.3 months (P = 0.000). A greater percentage of ACCb occurred at the coronal aspect of the implant, with 59.24% ± 19.22% at the implant platform and 34.10% ± 30.50% 6.0 mm below the implant platform, respectively. Linear regression analysis demonstrated that if BT was 1.8 to 2.0 mm at the implant platform at uncovering surgery, then it was estimated to have been 4.1 to 4.5 mm immediately post-implantation. ACCb after maxillary anterior implant placement with simultaneous GBR occurred more coronally than apically. Excessive alveolar ridge augmentation, up to 4.0 mm of hard tissue buccal to the implant platform, should be achieved at the time of surgery to compensate for this potential resorption.

Short-term skeletal and dentoalveolar effects of overexpansion.

To evaluate whether the amount of rapid maxillary expansion differentially affects the skeletal and dentoalveolar changes that occur. This randomized controlled trial included 23 patients who had rapid maxillary expansion (RME). Subjects were randomly assigned to a conventional expansion control group (n = 12) or an overexpansion group (n = 11), who started treatment at 13.2 ± 1.5 and 13.8 ± 1 years of age, respectively. Cone beam computed tomography scans (11 cm) were obtained prior to rapid maxillary expander (RME) delivery and approximately 3.7 months later. Initial hand-wrist radiographs were used to determine the participants' skeletal maturity. The RME screws were activated 5.6 ± 1.2 mm and 10.1 ± 0.6 mm in the conventional and overexpansion groups, respectively. Overexpansion produced significantly greater expansion of the nasal cavity (2.1X-2.5X), maxillary base (2.3X), buccal alveolar crest (1.4X), and greater palatine foramina (1.9X). Significantly greater intermolar width increases (1.8X) and molar inclination (2.8X) changes were also produced. The nasal cavity and maxillary base expanded 23%-32% as much as the screws were activated. Skeletal expansion was positively correlated with RME screw activation (R = 0.61 to 0.70) and negatively correlated (R = -0.56 to -0.64) with the patients' skeletal maturation indicators (SMIs). Together, screw activation and the patients' SMI scores explained 48%-66% of the variation in skeletal expansion. This pilot study shows that overexpansion produces greater changes than conventional expansion, with greater skeletal effects among less mature patients.

Orthopedic outcomes of hybrid and conventional Hyrax expanders.

To compare the effects of a hybrid miniscrew-supported expander versus a conventional Hyrax (CH) expander in growing patients. Forty patients were randomized into two groups: a hybrid Hyrax (HH) expander group using a Hyrax expander with two miniscrews and a CH expander group. The final sample had 18 subjects (8 female, 10 male; initial age of 10.8 years) in the HH group and 14 subjects (6 female, 8 male; initial age of 11.4 years) in the CH group. Cone-beam computed tomography examinations and digital dental models were obtained before expansion and 11 months postexpansion. The primary outcomes included the orthopedic transverse effects of expansion. Intergroup comparison was performed using analysis of covariance (P < .05). Significantly greater increases in the nasal cavity width, maxillary width, and buccal alveolar crest width were found for the HH group. No intergroup differences were observed for dental arch width or shape changes. The HH group showed greater increases in the nasal cavity width, maxillary width, and buccal alveolar crest width. No differences were observed for intermolar, interpremolar, or intercanine widths; arch length; or arch perimeter. Arch size and shape showed similar changes in both groups.

Comparison of anterior maxillary and mandibular alveolar parameters in African American and Caucasian women: A retrospective pilot study

PurposeThe primary objective of this study was to analyze the thickness and height of alveolar bone around the maxillary and mandibular incisors. Additionally, this study aimed to compare bone parameters between Caucasian (CC) and African American (AA) female patients.Materials and MethodsIn this retrospective pilot study, 50 female subjects (25 CC and 25 AA) were included. The inclusion criteria were AA or CC women between the ages of 18 and 50 with a normo-divergent facial pattern and Angle's class I, end-on class II, or mild class III malocclusion. The distance from the cementoenamel junction (CEJ) to the buccal and lingual alveolar crest; the alveolar ridge thickness at the mid-root and apex; and the buccal and lingual bone thickness at 3, 6, and 9 mm from the CEJ were measured.ResultsNo significant difference was found (P>0.05) in the cortical bone thickness at 3 mm, 6 mm, or 9 mm from the alveolar crest between CC and AA populations for most measurements. A significant difference in bone thickness was found (P<0.05) for the lingual surface of the central incisor, with maxillary bone thickness found to be higher than mandibular bone thickness. The measurements of lingual thickness were larger than those of buccal thickness for both races.ConclusionThere were no differences in maxillomandibular anterior alveolar bone measurements between normo-divergent adult AA and CC women, except for a few parameters at varying locations. However, future studies can be planned based the current pilot study data, which may provide valuable information.

Measurements of buccal gingival and alveolar crest thicknesses of premolars using a noninvasive method.

Knowledge of gingival thickness (GT) and alveolar crest thickness (ACT) is essential for performing various surgical and non-surgical procedures in oral healthcare. However, a noninvasive, no-radiation and reproducible method for measuring GT and ACT is not yet determined. This study aimed to measure the buccal GT and ACT of premolars using 15-MHz B-mode ultrasonography (US) and to explore the relationship between GT and ACT. The GT in four swine mandibles was measured using15-MHz B-mode US and using K-file needles to gauge the accuracy of US. B-mode US at 15 MHz was also used to measure periodontal tissue structures including buccal GT3 (3 mm apical to the gingival margin) and ACT in 400 premolars of 50 human participants with healthy periodontium. There was a strong positive correlation between US and invasive K-file needle measurements of GT in swine mandibles (p<0.05). The correlation between buccal GT3 and ACT of premolars was moderately positive (p<0.05). The gingiva of the maxillary premolars and ACT of the maxillary first premolars were thicker in men than in women (p<0.05). B-mode US at 15 MHz is a valid and reliable method for measuring GT and ACT and for evaluating their relationship.

Cone beam computed tomography analysis of accessory canals of the canalis sinuosus: A prevalent but often overlooked anatomical variation in the anterior maxilla

Statement of problemAccessory canals of the canalis sinuosus, a bony canal carrying the anterior superior alveolar nerve and vessels, can often be present but overlooked in the anterior maxilla. Dental implant placement in this area may damage neurovascular branches if this anatomic variation is not carefully identified, resulting in unexpected complications. PurposeThe purpose of this retrospective study was to identify accessory canals of the canalis sinuosus and analyze their relationship to the terminal canalis sinuosus and anterior maxilla in Chinese patients to provide a warning for surgeons operating in the anterior maxilla. Material and methodsCone beam computed tomography (CBCT) scans of 1007 Chinese patients were examined to identify the prevalence and size of accessory canals with at least 1.0-mm diameter. Axial position of this canal was classified referring to the nasal cavity and adjacent teeth. Its sagittal position was determined by the distance from the bifurcation site of canalis sinuosus to the buccal alveolar crest and the distance from the canal opening to the palatal alveolar crest. Diameter of the terminal canalis sinuosus, distance from the terminal canalis sinuosus to the buccal alveolar crest, and anterior maxillary volume were measured on all scans. Binary logistic regression and the Spearman rank correlation coefficient were used for prevalence and diameter analysis. ResultsThe prevalence of the accessory canal was 36.9%, positively correlated the anterior maxillary volume (OR 1.408) and negatively correlated with the distance from the terminal canalis sinuosus to the buccal alveolar crest (OR 0.921). Average diameter of such canal was 1.1 ±0.1 mm, significantly higher in men, positively correlated with the diameter of terminal canalis sinuosus (rs=0.163) and the distance from the canal opening to the palatal alveolar crest (rs=0.192). All accessory canals started below the buccal cortical bone, 19.3 ±2.7 mm away from the buccal alveolar crest. There were 61.9% accessory canals opened between the central and the lateral incisors. Openings here and in the central incisor region were closer to the alveolar crest than that between the lateral incisor and the canine (P<.05). ConclusionsAccessory canals of the canalis sinuosus have high prevalence in the anterior maxilla in a Chinese population. Large anterior maxillary volume has been demonstrated as a risk factor associated with the presence of such canals. The region between the central and the lateral incisors was a predominant location. Openings in this region were closer to the alveolar crest than those between the lateral incisor and the canine.

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.

Analysis of the Buccal Bone Plate, Root Inclination and Alveolar Bone Dimensions in the Jawbone. A Descriptive Study Using Cone-Beam Computed Tomography.

ABSTRACTObjectivesThis study aims to determine if there are enough buccal alveolar bone thickness to perform an immediate dental implant placement in anterior and posterior maxillary teeth.Material and MethodsA total of 1463 teeth were examined, from 202 cone-beam computed tomography scans with voxel sizes of 0.15 mm. On each tooth, the following measures were determined: the alveolar bone thickness in two locations; the vertical distance between the buccal alveolar crest and cementoenamel junction; the angle between the tooth’s long axis and the alveolar bone axial inclination in the sagittal plane.ResultsIn the most coronal location of maxillary teeth, the thickness of alveolar bone was lower than 0.6 (SD 0.6) mm in 50% of the teeth, and in the middle of the root the bone thickness was, on average, 0.96 (SD 0.6) mm. For the same maxillary teeth, the vertical distance between the buccal alveolar crest and cementoenamel junction and the angulation measured were, on average, 3.6 (SD 1.2) mm and 12.1º (SD 1.4º), respectively.ConclusionsThe present study revealed that in most cases the thickness of buccal alveolar bone was less than 1 mm. Consequently, in such cases, immediate dental implant placement operation is not recommended, or should be combined with bone regeneration techniques.

Comparison between two bone substitutes for alveolar ridge preservation after tooth extraction: Cone-beam computed tomography results of a non-inferiority randomized controlled trial.

To test the non-inferiority of demineralized bovine bone mineral (DBBM) compared to DBBM with 10% collagen (DBBM-C) for maintenance of bone volume after tooth extraction in the anterior maxilla. Sixty-six patients were randomly treated with DBBM or DBBM-C, both of which were covered with a collagen matrix for ridge preservation in the anterior maxilla. Cone-beam computed tomographic analysis was performed immediately and 4months after treatment. The primary outcome, for which non-inferiority of DBBM was tested, was change in the horizontal ridge width 1mm below the buccal alveolar crest (HW-1) 4months after extraction. Four months after extraction, HW-1 measured -1.60mm±0.82mm for DBBM-C, while the DBBM group showed a mean loss of -1.37mm±0.84mm (p=0.28, 0.23 [95% CI: -0.19; 0.64]). The horizontal ridge width at 3mm (HW-3) showed -0.98mm (±0.67mm) for DBBM-C and -0.84mm (±0.62mm) for DBBM (p=0.40, 0.12 [95% CI: -0.19; 0.45]), and the horizontal ridge width at 5mm (HW-5) showed -0.67mm (±0.47mm) for DBBM-C and -0.56mm (±0.48mm) for DBBM (p=0.36, 0.11 [95% CI: -0.13; 0.34]). The present clinical trial demonstrated non-inferiority of DBBM compared to DBBM-C for maintenance of alveolar bone volume 4months after tooth extraction in the anterior maxilla.

Assessment of lower incisor alveolar bone width using cone-beam computed tomography images in skeletal Class III adults of different vertical patterns.

ObjectiveThis study was performed to investigate the alveolar bone of lower incisors in skeletal Class III adults of different vertical facial patterns and to compare it with that of Class I adults using cone-beam computed tomography (CBCT) images.MethodsCBCT images of 90 skeletal Class III and 29 Class I patients were evaluated. Class III subjects were divided by mandibular plane angle: high (SN-MP > 38.0°), normal (30.0° < SN-MP < 37.0°), and low (SN-MP < 28.0°) groups. Buccolingual alveolar bone thickness was measured using CBCT images of mandibular incisors at alveolar crest and 3, 6, and 9 mm apical levels. Linear mixed model, Bonferroni post-hoc test, and Pearson correlation analysis were used for statistical significance.ResultsBuccolingual alveolar bone in Class III high, normal and low angle subjects was not significantly different at alveolar crest and 3 mm apical level while lingual bone was thicker at 6 and 9 mm apical levels than on buccal side. Class III high angle group had thinner alveolar bone at all levels except at buccal alveolar crest and 9 mm apical level on lingual side compared to the Class I group. Class III high angle group showed thinner alveolar bone than the Class III normal or low angle groups in most regions. Mandibular plane angle showed negative correlations with mandibular anterior alveolar bone thickness.ConclusionsSkeletal Class III subjects with high mandibular plane angles showed thinner mandibular alveolar bone in most areas compared to normal or low angle subjects. Mandibular plane angle was negatively correlated with buccolingual alveolar bone thickness.

Soft-tissue cone-beam computed tomography (ST-CBCT) technique for the analysis of skeletal, dental and periodontal effects of orthopedic rapid maxillary expansion.

BackgroundOrthopedic rapid maxillary expansion (RME) is a common treatment of choice for managing transverse deficiency of the maxilla. This approach may have desired and undesired skeletal, dental and periodontal effects that may be assessed clinically or through imaging techniques. This study aims to investigate the dental, skeletal and periodontal effects of orthopedic RME using the soft-tissue cone-beam computed tomography (CBCT) technique.Material and MethodsThe sample consisted of 10 patients (5males and 5 females) aged between 10 and 14 years (mean age: 12.5 years) treated with Hyrax orthopedic device. CBCT scans set for the registration of soft tissue (ST-CBCT) were taken from each patient before (T1) and 120 days after (T2) RME. Skeletal (n=10), dental (n=1) and periodontal (n=4) parameters measured in ST-CBCT were compared between T1 and T2 using t-test within a significance level of 5%.ResultsThe skeletal parameters with statistically significant increase (p<0.05) in T2 were the width of the buccal alveolar bone crest, the external width of the dental arch at the level of buccal cusps, and the width of the dental arch at the level of most prominent dental surface contour. Representing the dental parameter, the inclination of the anchor teeth was statistically significant for premolars (p<0.05). The only statistically significant outcome in periodontal parameters was the decrease in buccal bone plate thickness of first molars (p<0.05).ConclusionsDentists must be aware of the ST-CBCT technique for the analysis of hard and soft tissue after orthodontic and orthopedic treatments. This technique revealed that the RME reached optimal skeletal and dental effects with minimal periodontal side effects. Key words:Cone-beam computed tomography, imaging, orthodontics, orthopedics.

Long-term changes of alveolar buccal bone after rapid maxillary expansion in an adolescent patient

Besides the orthopedic effect of midpalatal suture split, rapid maxillary expansion causes buccal movement of supporting teeth by tipping and bodily translation. The orthodontic effect leads to periodontal changes such as reduction of buccal alveolar bone plate thickness and buccal alveolar crest level. The question that remains is whether any long-term bone regeneration occurs in the buccal bone plate after expansion. This report describes the longitudinal changes in the alveolar crest level of the maxillary posterior teeth after rapid maxillary expansion (RME) in an 11-year-old patient. This patient was included in a sample of a previous publication and initially presented with a unilateral posterior crossbite on the left side in her permanent dentition. After the RME procedure with use of a tooth-tissue-borne Haas-type expander, the patient experienced extensive buccal bone dehiscences in the supporting teeth. After expansion, she underwent comprehensive orthodontic treatment. Approximately 8 years after the expansion, orthodontic follow-up showed that the orthodontic outcomes, including the posterior crossbite correction, remained stable. The patient then underwent cone beam computed tomography (CBCT) for extraction of her third molars. Buccal bone dehiscences remained in the first maxillary premolars and in the mesial roots of the maxillary first molars. Also, gingival recession was observed in many maxillary and mandibular teeth. This case report suggests that alveolar bone dehiscence that develops immediately after RME tends to remain in the long term and predispose gingival recession. Factors related to this variable longitudinal behavior should be elucidated by future studies.