Nr Krishnaswamy

Evaluation of craniofacial morphology in patients with obstructive sleep apnea using lateral cephalometry and dynamic MRI

CONTEXT Obstructive sleep apnea (OSA) is a potentially life-threatening disorder, characterized by repeated collapse of the upper airway during sleep with cessation of breathing. The altered mouth breathing produces morphological changes in craniofacial region. AIM This study was designed to compare and validate the craniofacial morphological characteristics in patients with OSA using lateral cephalometry and to investigate the dentofacial characteristics of patients with OSA with respect to the obstructive sites determined by dynamic magnetic resonance imaging (MRI) to more accurately clarify the pathophysiological features. MATERIALS AND METHODS 10 patients with OSA were divided into two groups of five each according to their obstructive site determined by dynamic MRI. (1) Obstruction at the retropalatal and retroglossal region (Rp + Rg group) and (2) obstruction at the retropalatal region (Rp group). Lateral cephalogram both in upright and supine position was taken for all the subjects. In addition, dynamic MRI was performed to identify the sites of obstruction of the upper airway. STATISTICAL ANALYSIS USED Independent t-test was performed to evaluate the significant difference in the upright cephalometric variables between the study and control group and between the two groups. The changes in skeletal and soft tissue parameters with change in posture was assessed within the study and control group by paired t test. P value of ≤ 0.05 was considered as statistically significant. RESULTS The study indicated that the first group of patients with both retropalatal and retroglossal obstruction showed signs of skeletal discrepancy that predisposed to obstruction at the retroglossal level and the soft tissue components like the soft palate and tongue that contributed to retropalatal obstruction. However, the second group of patients with only retropalatal obstruction had primarily soft tissue components associated with increased BMI that contributed to retropalatal obstruction. CONCLUSION Evaluation of craniofacial morphology in OSA patients is bound to help the concerned specialist in recognizing the morphological changes induced by altered sleep pattern so as to provide the appropriate treatment.

Root damage and repair in patients with temporary skeletal anchorage devices

INTRODUCTION The aim of this study was to evaluate the reparative potential of cementum histologically after intentional root contact with a temporary skeletal anchorage device. METHODS Seventeen patients (8 male, 9 female; mean age, 16.2 years; range, 13.5-21.6 years) who were scheduled for extraction of 4 first premolars as part of their orthodontic treatment participated in this study. The roots of the premolars were intentionally injured with a temporary skeletal anchorage device. The teeth were extracted at 4, 8, or 12 weeks after the injury. Root contact with the temporary skeletal anchorage device was confirmed by using a stereomicroscope. Histologic samples were prepared. Demineralized serial sections were stained with eosin and hematoxylin, and cementum repair was assessed histomorphometrically. RESULTS Despite varying depths of the injuries, including involvement of dentin, reparative cementum formation was observed in all sections. Healing cementum was almost exclusively of the cellular type; 70% of all the teeth exhibited good repair by the end of week 12. CONCLUSIONS This study established that healing of cementum takes place after an injury with a temporary skeletal anchorage device, and it is a time-dependent phenomenon.

Corticotomy-assisted retraction: An outcome assessment

BACKGROUND To assess the efficiency and treatment outcome of patients treated with corticotomy-assisted en-masse orthodontic retraction as compared with the en-masse retraction without corticotomy. MATERIALS AND METHODS Forty adult patients with bimaxillary protrusion requiring correction of bidental proclination constituted the sample. The study group consisted of 22 patients (male 11, female 11) willing to undergo surgery to reduce the duration of their orthodontic treatment and 18 patients (male 9, female 9) desirous of undergoing conventional orthodontic treatment without surgical intervention constituted the control group. Comparison of rate of retraction and anchor loss between the study and the control group was assessed. RESULTS Average rate of space closure of 1.8 mm/month in the maxilla and 1.57 mm/month in the mandible was observed in the study group compared to 1.02 mm/month in the maxilla and 0.87 mm/month in the mandible in the control group. The rate of retraction accelerated during the first 2 months of retraction. Molar anchor loss of approximately 0.6 mm occurred in the study group, and 1.8 mm occurred in the control group during the 4 months. CONCLUSION The rate of retraction with study group was twice as faster when compared to the control group, accelerating during the first 2 months of retraction. There was better anchorage control with the undecorticated molar segment during the retraction period but was found to increase as time advanced.

Inferior alveolar nerve canal position among South Indians: A cone beam computed tomographic pilot study

Purpose: To document a clinically relevant position of the inferior alveolar nerve (IAN) in complete dentate south Indian patients in the age group of 20–29 years using cone beam computerized tomograms. Materials and Methods: The investigators used a cross-sectional study design and a study sample of subjects who had a radiographically identifiable IAN canal with complete set of 28 permanent teeth excluding 3rd molars. Predictor variables were age, tooth position, and side. Outcome variables were the linear distances between the buccal and lingual aspect of the IAN canal, buccal and lingual cortical thickness, IAN canal diameter, and the superior aspect of the IAN canal from the periapex of first and second mandibular molar. Descriptive statistics and Mann–Whitney U test were performed. P value of ≤ 0.05 was taken as significant. Results: The study sample was composed of 10 male and 10 female patients with a mean age of 24.2 ± 3.00 years. On average, the lingual cortical thickness was 1.68 mm at 1st molar and 1.44 at 2nd molar level. Gender and side influenced the outcome with varying statistical significance. Conclusions: The range of linear dimension of mandibular canal, cortical bone thickness, and distance between tooth apex and IAN canal have been presented for the South Indian population in the age group of 20–29 years. The implications of the findings will influence on the course of surgery. Further large-scale studies are needed to validate the findings of this study.

Chlorhexidine varnishes effectively inhibit Porphyromonas gingivalis and Streptococcus mutans - An in vivo study

Background: Chlorhexidine varnish (Cervitec- Ivoclar Vivadent- Liechtenstein) is a sustained-release delivery system that can provide protection against white spots and gingivitis, which are common iatrogenic side effects of orthodontic treatment. Chlorhexidine in varnish form does not depend on patient compliance, does not stain teeth or alter taste sensation like the mouth rinse. Materials and Methods: A split-mouth technique was followed in the treatment of 30 patients selected by stringent selection criteria, evaluating a single application of the test varnish on two randomly allotted quadrants along with a placebo on the other two quadrants. Streptococcus mutans counts responsible for white spots and P. gingivalis count [using PCR test] responsible for gingivitis were done at the start of the study, and then 1 and 3 months later. Results: The chlorhexidine varnish reduced the Streptococci mutans count at the end of 1 month, and this reduction was statistically significant. At the end of 3 months, there was no difference in the S. mutans counts between the two groups. There was a statistically significant reduction in the P. gingivalis count at the end of both 1 and 3 months in comparison to the placebo group. Conclusion: Chlorhexidine varnishes are capable of reducing S. mutans and P. gingivalis and gingivitis, thus improving the overall oral health of the patient. The side effects of chlorhexidine mouth rinses are not seen with this varnish. An application schedule of at least once a month is recommended as the effectiveness is reduced comparatively at the end of 3 months.

Quantitative assessment of palatal bone thickness in an ethnic Indian population: a computed tomography study.

CONTEXT Variations in palatal bone thickness (PBT) at various locations have caused considerable problems when using these sites for anchorage purposes. AIMS To find the comparative thickness of the palatal bone at different locations and to validate its morphology for anchorage purposes using mini-implants (MI). SETTINGS AND DESIGN This investigation was undertaken to compare the mean PBT and level of significance of differences between male and female subjects and between two different age-groups. MATERIALS AND METHODS The computed tomography (CT) data for 60 patients (30 males and 30 females) in two different age-groups (group A: 15-24 years; group B: 25-35 years) were imported into CAD-based medical software, (MIMICS; Materialise, Belgium) for multiplanar reconstruction. The measurements were made in two planes- transverse and sagittal-and at different positions in each of the planes. STATISTICAL ANALYSIS The mean and standard deviations of the PBT at different points were calculated. The Students t-test and Mann-Whitney U test were used for comparisons between the groups. RESULTS Significant variations were observed in the thickness of the palatal bone for both groups tested, with the anterior region at 4 mm behind the incisive papilla showing the maximum thickness. CONCLUSIONS Despite the palatal bone being thickest in the mid-palatal suture (MPS) region, this is not the ideal site for anchorage purposes due to inadequate calcification and interposition of connective tissue, especially in young growing children. So, the alternate optimum position is the paramedian region, 3 mm lateral to the MPS and 4 mm from the incisive foramen (IF).

Orthodontic and orthognathic management of a complex mandibular asymmetry.

The application of a combined surgical-orthodontic procedure for the treatment of major facial deformities (eg, asymmetries) and associated malocclusions has become an increasingly prevalent treatment modality over the past few decades. Development of sound conjoint treatment principles made possible the correction of skeletal and dental dysplasias that were unyielding to either surgical or orthodontic treatment alone. The presence and severity of dentofacial asymmetries has been the subject of many commentaries and investigations. Treatment of facial asymmetry has always been a challenge with respect to the cause and the rationale behind the corrective procedures adopted. This case report describes a 23-year-old male patient whose chief complaint was attributed solely to the clinically discernible facial asymmetry. A combined orthodontic and surgical approach was done to correct both the dental and skeletal asymmetry. The reasons for selecting this treatment protocol and the 5-year postretention stability of the final results obtained are highlighted in this report.

Comparison of shear bond strength of self-etching fluoride releasing adhesives with and without pumice prophylaxis

CONTEXT Despite the advances in orthodontic material and treatment mechanics, the placement of fixed appliances increases the risk of enamel demineralization. The development of fluoride release adhesives has attracted considerable interests because the combined use of antimicrobials and fluoride enhances the cariostatic effect. AIM To compare the shear bond strength (SBS) of fluoride release adhesives with established orthodontic adhesives and assess failure mode using adhesive remnant index (ARI). SETTINGS AND DESIGN The present study included 80 maxillary premolars which were randomly divided into four groups (n = 20) and were further subdivided into two subgroups A - Pumice prophylaxis (PP) and subgroup B - No PP (n = 10). MATERIALS AND METHODS Stainless steel brackets were bonded with Transbond XT, Transbond plus (TP) color change adhesive, Light Bond, and Clearfil protect bond. After debonding, the ARI was used to assess the mode of bracket failure. STATISTICAL ANALYSIS The data were analyzed using two-way analysis of variance, Post-hoc Tukey Honest significant differences test, and Chi-square test. RESULTS The mean SBS of Group 4 was comparably higher regardless of PP. Brackets bonded with TP showed a comparable SBS to conventional Transbond XT. The ARI scores were predominately 2. CONCLUSIONS Fluoride releasing adhesives combined with antibacterial monomer can play a vital role in reducing white spot lesions by enhancing the cariostatic effect especially in noncompliant\medically compromised patients.

Gingival tissue proliferation into the tooth following iatrogenic miniscrew insertion: A newer underreported complication

Miniscrew implant (MSI) has been reported to be an excellent, supportive orthodontic anchorage tool. The placement of MSI is not free from complication and foremost of which is penetration of MSI into the vital tooth structures. This case report is probably the first to report a newer underreported complication. Interestingly, a small bit of gingival tissue was found deep inside the dentin of the tooth, surviving and proliferating in the MSI-damaged zone. This case report is probably the first to give direct histological evidence in humans that a MSI can cause implantation phenomenon which has the potential to give rise to numerous pathologies including pulpal, periodontal, and cystic transformation. Through this report, it is emphasized that clinicians should have a structured, formal MSI placement training to avoid such instances and also underlines the need to develop protocols to be followed in the instance of an inadvertent MSI penetration.

Treatment of a unilateral complete lingual crossbite in an adult with skeletal anchorage assisted orthodontics

An asymmetry caused by a complete lingual crossbite can compromise aesthetics and impair occlusal function. The following case report describes the correction of a complete lingual crossbite using orthodontic mini implants and mini-plates to achieve absolute anchorage. A comprehensive correction of the crossbite and re-establishment of the buccal occlusion was achieved.