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Quantitative evaluation of alveolar cortical bone density in adults with different vertical facial types using cone-beam computed tomography

Objective The purpose of this study was to quantitatively evaluate the cortical bone densities of the maxillary and mandibular alveolar processes in adults with different vertical facial types using cone-beam computed tomography (CBCT) images. Methods CBCT images (n = 142) of adult patients (20-45 years) were classified into hypodivergent, normodivergent, and hyperdivergent groups on the basis of linear and angular S-N/Go-Me measurements. The cortical bone densities (in Hounsfield units) at maxillary and mandibular interdental sites from the distal aspect of the canine to the mesial aspect of the second molar were measured on the images. Results On the maxillary buccal side, female subjects in the hyperdivergent group showed significantly decreased bone density, while in the posterior region, male subjects in the hyperdivergent group displayed significantly decreased bone density when compared with corresponding subjects in the other groups (p<0.001). Furthermore, the subjects in the hyperdivergent group had significantly lower bone densities on the mandibular buccal side than hypodivergent subjects. The maxillary palatal bone density did not differ significantly among groups, but female subjects showed significantly denser palatal cortical bone. No significant difference in bone density was found between the palatal and buccal sides in the maxillary premolar region. Overall, the palatal cortical bone was denser anteriorly and buccal cortical bone was denser posteriorly. Conclusion Adults with the hyperdivergent facial type tend to have less-dense buccal cortical bone in the maxillary and mandibular alveolar processes. Clinicians should be aware of the variability of cortical bone densities at mini-implant placement sites.

Orthodontic bonding to acid- or laser-etched prebleached enamel

Objective Bonding forces of brackets to enamel surfaces may be affected by the procedures used for bleaching and enamel etching. The aim of this study was to investigate the bonding strength of orthodontic brackets to laser-etched surfaces of bleached teeth. Methods In a nonbleached control group, acid etching (group A) or Er:YAG laser application (group B) was performed prior to bracket bonding (n = 13 in each group). Similar surface treatments were performed at 1 day (groups C and D; n = 13 in each subgroup) or at 3 weeks (groups E and F; n = 13 in each subgroup) after 38% hydrogen peroxide bleaching in another set of teeth. The specimens were debonded after thermocycling. Results Laser etching of bleached teeth resulted in clinically unacceptable low bonding strength. In the case of acid-etched teeth, waiting for 3 weeks before attachment of brackets to the bleached surfaces resulted in similar, but not identical, bond strength values as those obtained with nonbleached surfaces. However, in the laser-etched groups, the bonding strength after 3 weeks was the same as that for the nonbleached group. Conclusions When teeth bleached with 38% hydrogen peroxide are meant to be bonded immediately, acid etching is preferable.

Evaluation of facial hard and soft tissue asymmetry using cone-beam computed tomography.

INTRODUCTION The purposes of this study were to (1) evaluate facial asymmetry 3 dimensionally using cone-beam computed tomography (CBCT) and (2) compare the right and left facial hard and soft tissues volumetrically and their interferences on each other. METHODS The CBCT data of 49 asymmetric (soft tissue menton deviation, ≥4 mm; distance from the facial midline) (mean age, 19.9 ± 5.6 years) and 39 symmetric patients (soft tissue menton deviation, <4 mm) (mean age, 17.8 ± 5.5 years) were exported to the MIMICS software program (version 13.0; Materialise, Leuven, Belgium). Linear, surface distance, angular, volumetric, and surface area measurements were performed 3 dimensionally to assess and compare intragroup and intergroup differences. RESULTS In the asymmetry group, linear measurements such as ramus height, mandibular effective and corpus length, and absolute mandibular volumetric measurements were significantly decreased (P <0.001), whereas facial mandibular, and soft and hard tissue volumetric measurements made on 3-dimensional images, and linear measurements on 2-dimensional images were increased (P <0.001) on the deviation side. CONCLUSIONS Facial hard and soft tissue asymmetries can be precisely quantified using CBCT. However, especially in the gonial region where the surface topography shows alterations caused by asymmetry, many anatomic landmarks should be chosen for the assessment of asymmetry. At the gonial level, the compensation of the soft tissues for the hard tissues was found on 2-dimensional images; nevertheless, 3-dimensional right and left volumetric soft tissue evaluations provide evidence for asymmetry.

The genetic basis of dental anomalies and its relation to orthodontics

The interruption of odontogenesis by any etiological factor may result in dental anomalies. Apart from the environmental factors, the impact of genetics in dental anomalies was found to be a factor in different levels. Many authors had questioned a common genetic defect resulting in different phenotypic conditions such as absent, malformed, malposed or ectopic teeth. Because the multidisciplinary treatment of these dental anomalies such as hypodontia, impaction etc., involves orthodontic intervention, orthodontists must be aware of the etiology and possible correlative conditions with dental anomalies.

Maxillary buccal cortical plate inclination at mini-screw insertion sites

OBJECTIVE To evaluate whether buccal cortical bone inclination varies for the maxillary alveolar processes of adult patients with decreased, normal, and increased facial heights. MATERIALS AND METHODS Cone-beam computed tomography images of 135 adult patients, including 49 hypodivergent subjects (26 women, 23 men), 40 hyperdivergent subjects (24 women, 16 men), and 46 normodivergent (25 women, 21 men) were analyzed. Cortical bone inclination measurements were made relative to the occlusal plane. Cross-sectional slices of the maxilla were taken at interdental sites from the distal aspect of maxillary canine to the mesial aspect of maxillary second molar. RESULTS Analysis of variance indicated significant differences (P < .05) between the angles formed by the line tangent to the cortical bone and the occlusal plane among the vertical facial types for the regions between canine and first premolar and between second premolar and first molar at miniscrew insertion sites. CONCLUSION The results of this study indicate that vertical facial pattern should be taken into consideration when adjusting the insertion angle of miniscrews at the maxillary buccal region.

Evaluation of Oxygen Saturation and Heart Rate During Intraoral Impression Taking in Infants With Cleft Lip and Palate.

Objective:The aim of the study was to evaluate the changes in oxygen saturation and heart pulse during intraoral impression taking from infants with cleft lip and palate (CLP) at onset of presurgical orthopedic therapy. Subjects and Methods:In our study, 21 uni- and bilateral infants with CLP (9 female, 12 males, mean age 5.90 ± 2.46 days) were monitored and heart pulse and oxygen saturation were measured under operating conditions before any intervention (T1), after delivery of 50% supplemental oxygen (T2), during impression taking with oxygen support (T3), and immediately before the discharge from the operating room (T4). Results:Statistically significant differences were found in the average oxygen saturation levels (P < 0.01), but not in heart rates (P > 0.05) between T1, T2, T3, and T4. Decreases in the oxygen levels from T2 to T3 were noted (P < 0.01). Overall, oxygen levels increased from T1 to T4 (P < 0.01). Conclusions:Oxygen saturation levels may decrease during intraoral impression taking in infants with CLP despite the supplemental oxygen under operating conditions. No changes in the heart rate during the procedure showed that the cardiac output was sufficient, whereas the decrease in oxygen saturation demonstrated hypoventilation because of the anatomic structure and impression-taking process. It may be advised that the impression should be taken under the supervision of the anesthetist, with monitoring of, and supplying oxygen to, the infant with CLP.

Evaluation of buccolingual molar inclinations among different vertical facial types

Objective The aim of this study was to compare the buccolingual inclination of maxillary and mandibular molars in adults with different vertical facial types. Methods Cone-beam computed tomography images of 135 adult patients (age, 20–45 years) with skeletal Class I maxillomandibular relationships were assigned to normodivergent (n = 46), hypodivergent (n = 49), and hyperdivergent groups (n = 40) according to linear and angular sella-nasion/gonion-menton measurements. The normodivergent group consisted of 24 females and 22 males, hypodivergent group of 26 females and 23 males, and hyperdivergent group of 24 females and 16 males. Buccolingual inclination of the maxillary and mandibular first and second molars was measured relative to the occlusal plane. One-way analysis of variance was used for intergroup comparison. Gender differences were evaluated using independent t-tests. Results Buccolingual molar inclinations did not differ significantly between females and males (p > 0.05). There were no statistically significant differences among the buccolingual inclinations of the first and second maxillary and mandibular molars of the groups (p > 0.05). Conclusions Buccolingual inclinations of maxillary and mandibular molars are similar in normodivergent, hyperdivergent, and hypodivergent adults with Class I sagittal relationships.

Nasolabial Morphology Following Nasoalveolar Molding in Infants With Unilateral Cleft Lip and Palate

AIM The aim of the present study is to evaluate the effects of nasoalveolar molding (NAM) therapy on nasolabial morphology three dimensionally, and compare the nasolabial linear and surface distance measurements in infants with unilateral cleft lip and palate. METHODS Facial plaster casts of 42 infants with unilateral cleft lip and palate taken at the onset (pre-NAM) and finishing stage (post-NAM) of NAM were scanned with 3dMDface stereophotogrammetry system (3dMD, Atlanta, GA). Nineteen nasolabial linear and surface distance measurements were performed on three-dimensional images. In addition to standard descriptive statistical calculations (means and SDs), pre- and post-NAM measurements were evaluated by paired t test. RESULTS All measurements except lip gap, nostril floor width, and nostril diameter increased between pre-NAM and post-NAM. Nostril and lip height increased significantly on the cleft side (P < 0.05). No differences were present between linear and surface distance measurements except for nasal width measurement. CONCLUSIONS Nasal and lip symmetry improved with NAM. The use of surface distance measurements may be advised particularly for continuous and curved anatomic structures in which circumference differences are expected.

Comparison of Oxygen Saturation During Impression Taking Before and After Presurgical Orthopedic Therapy in Babies With Cleft Lip and Palate

Aim: The objective of this study was to (1) evaluate the oxygen saturation (SpO2) levels during intraoral and extraoral impression taking and (2) compare the SpO2 levels during impression taking before and after presurgical orthopedic therapy (POT) of infants with cleft lip and palate (CLP). Patients and Methods: In our study, 31 babies with CLP before (mean age 7.6 ± 3.2 days) and after (mean age 108.3 ± 24.2 days) POT were monitored, and SpO2 levels were measured under operating conditions before any intervention (T1), after oxygenation (T2), during taking intraoral (T3), and extraoral (T4) impressions with oxygen support and immediately before the discharge from the operating room (T5). Results: In both groups, statistically significant differences in SpO2 measurements at T1, T2, T3, T4, and T5 stages were found (P < .01). For the pre‐POT measurements, increases in SpO2 levels from T1 to T2 and T4 to T5 (P < .05) and decreases from T2 to T3 and T3 to T4 (P < .01) were noted. Similarly, SpO2 levels decreased significantly from the intraoral (T3) to extraoral (T4) post‐POT impression periods (P < .01). Comparisons of pre‐ and post‐POT measurements revealed that the SpO2 level of each time period was higher at the post‐POT impression taking except for stages T2 and T5 (P < .01). Conclusion: The SpO2 values were low at the onset of POT in infants with CLP before any intervention. Oxygen saturation levels may decrease particularly during extraoral impression taking in infants with CLP despite the supplemental oxygen. SpO2 measurements were higher during post‐POT intraoral and extraoral impression taking when compared with pre‐POT measurements.

Treatment Options, Timing and Sequencing: Orthodontics

The treatment of diastema either by orthodontics, restorative dentistry, periodontology or a combination of these disciplines should be focused on the aetiological factors, patient needs, aesthetics and stable results. Identification of the aetiological factors and consideration of the dentofacial characteristics of the patient are essential for the appropriate therapy. Following diagnosis and individualised treatment planning, satisfactory treatment outcomes can be achieved with different orthodontic mechanics and approaches. This chapter will present management of spacing with orthodontics alone or as a part of interdisciplinary treatment depending on the causative factors. The timing and sequencing of the orthodontic treatment and retention protocol at the end of therapy will also be explained.