Adaptational changes in clear aligner fit with time:

ABSTRACT Objectives To analyze adaptational changes in clear aligner fit after intraoral usage at different sets of time. Materials and Methods Eight Invisalign appliances (Align Technology, San Jose, California, USA) were collected after intraoral usage. Acrylic imprints of the lower incisor region were constructed for each appliance at T0 (unused appliance). Two appliances were then used intra-orally for each of the following defined periods of time: 3 days, 7 days, 10 days, or 15 days. Used aligners were adapted on its T0 imprint and both were sectioned buccolingually from the distal surfaces of each incisor at the attachment area. Eight surfaces were collected for each set of time (n = 32 surfaces). Microphotographs of obtained sections and micrometric measurements of aligner fit were recorded at five different levels using scanning electron microscopy (SEM). Mean values of the fit changes (gap width) and group comparisons were statistically analyzed using analysis of variance and Tukey's post hoc tests. Significance level was set at P < .05. Results Highly significant differences in aligner fit were found at the different time points assessed (P < .001) with the least mean gap width at 15 days (176 ± 98 μm) and the highest at 7 days (269 ± 145 μm). Significant differences in aligner fit at different attachment levels were also found (P < .01) with the least mean gap width at the middle of the labial surface of the attachment (187 ± 118 μm). Conclusions The 15-day period of intraoral aligner wear might still be recommended as it showed the best adaptation and least gap width between the aligner and the attachment.

Incisor position and alveolar bone thickness:

ABSTRACT Objectives To evaluate incisor position and its relationship to alveolar bone in untreated optimal occlusions and in untreated Class II malocclusions. Materials and Methods Fifty-seven lateral cephalograms of individuals with naturally occurring optimal occlusions (mean age = 23 years) were used to assess positions of central incisors and their relationships to alveolar bone. Data were compared to a sample of 57 individuals with untreated Class II malocclusions with concurrent anterior-posterior (AP) skeletal discrepancies (mean age = 16.9 years). Results Significant intergroup differences were found for AP jaw relationship, maxillary alveolar bone thickness, mandibular incisor inclination, maxillary incisor root distance to labial surface of alveolar bone, and mandibular incisor root apex distance to labial surface of alveolar bone. Small differences between females and males existed for several variables. In both samples, maxillary incisor roots were located closer to the labial surface of alveolar process than to the palatal surface by roughly a 2:1 ratio. Mandibular incisor root apices were generally equidistant from the labial and lingual surfaces of the alveolus in the optimal sample but closer to the lingual surface in the Class II sample. Conclusions Maxillary incisors tend to occupy the anterior one-third of the alveolus in untreated individuals, regardless of AP interarch dental relationships or AP jaw relationships. Mandibular incisor root apices tend to be centered within the alveolus in untreated optimal occlusions but are more positively inclined, and their root apices are more posterior in untreated Class II malocclusions.

Comparison of color difference and reliability of two intraoral spectrophotometers

Aim: to evaluate the intra and inter-device reliability of two intraoral spectrophotometers in measuring the Commission Internationale de l’Éclairage (CIE) L*a*b* color coordinates and to compare the color difference (ΔE) between both devices. Methods: the central region of the labial surface of the maxillary central incisor of 31 participants was measured twice by each of the devices (VITA EasyShade and Degudent Shadepilot) by one examiner. CIE L*a*b* color coordinates were obtained for all teeth and ΔE was measured and compared. Intraclass correlation coefficient (ICC) and Mann-whitney U test were used to analyze the data (p<0.05). Results: inter-device reliability ICCs in measuring CIE L*a*b* color coordinates ranged between 0.08-0.49 with significant difference between devices only concerning the b coordinate (p<0.05). While intra device reliability ICCs ranged between 0.86-0.89 for VITA EasyShade and 0.81-0.86 for Degudent Shadepilot. The mean ΔE for CIE L*a*b* color coordinates of VITA EasyShade was 3.61 (±1.93) compared to 3.60 (± 1.45) for Degudent Shadepilot with insignificant difference between both devices (p>0.05). Conclusions: high intra device reliability in measuring CIE L*a*b* color coordinates was achieved particularly of Vita EasyShade, and both devices had clinically acceptable color difference (ΔE <3.7) however, inter device reliability was low to moderate. Consequently, the same spectrophotometer should be used throughout the steps of performing any tooth- colored restoration.

Integrated clinical treatment of external cervical resorption: Case report

External cervical resorption (ECR) has an inflammatory nature and the proximity to the gingival sulcus favors contamination and progression of the lesion. Change in crown color, inflammation of the marginal gingiva or even the presence of secretion in the gingival sulcus are the main clinical signs. Being an asymptomatic lesion, it can be neglected and its progression can jeopardize the tooth involved. This report describes the treatment of a patient who presented two teeth with ECR. On clinical examination, the crown of tooth 17 showed a pinkish translucency on the occlusal surface. On tooth 12, this spot was dark and located in the cervical third of the labial surface of the crown. Both the teeth were asymptomatic, and the radiographic examination showed an image comparable with root resorption in the cervical third of the crown. On tooth 17, the middle and cervical third of the crown was compromised and the pulp vitality test was negative. The treatment for the case was extraction. A tomographic examination of tooth 12 demonstrated pulpal involvement and biologic width violation. The vitality test was positive. After endodontic treatment, the tooth was extruded by 4 mm, the resorbed area was exposed and restored with composite resin. A 39-month clinical and radiographic control showed integrity of the root surface and the periodontium. It was found that early diagnosis influences the prognosis of treatment considering the speed of progression of resorption. It emphasizes the importance of clinical and radiographic control of the clinical conditions that predispose to ECR.

Platelet Rich Fibrin in the Treatment of Localised Gingival Recession: A Case Report

Root recession presents a matter of aesthetic concern in every dental practice. Also it may illicit sensitivity and is more prone to caries than the covered root surfaces. Platelet- rich fibrin is a second generation platelet concentrate. It is basically autologous leukocyte and platelet-rich fibrin biomaterial. The use of PRF in combination with coronally advanced flap in the treatment of gingival recession has shown promising results and is gaining immense popularity among the dental practitioners. This case reports the use of PRF membrane in root coverage on the labial surface of maxillary canine. Keywords: Coronally advanced flap, platelet rich fibrin, gingival recession, growth factors.

Accuracy of 3D Curvilinear Measurements on Digital Models Generated by Light Emitting Diode Scanned Impressions: ACross-sectional Study

Introduction: The advantages of digital models include customisation of appliances such as retainers, expanders, and indirect bracket setups for which measurements made along a curved line (curvilinear), would offer clinically more relevant information as opposed to linear measurements. Aim: The purpose of this study was to evaluate and compare the accuracy of 3 Dimensional (3D) curvilinear measurements on Digital models generated from Light Emitting Diode (LED) scanned impressions, with manual measurements on study models. Materials and Methods: The cross-sectional study consisted of maxillary arch rubber based impressions of eight patients selected on inclusion criteria of intact dentition having complete set of teeth with erupted second molar. These impressions were scanned with LED scanner (Medit Identica) and converted to Stereolithography (STL) files to generate 3D models. With the help of Ansys software curvilinear measurements were obtained from these models. These impressions were poured in dental stone to prepare study models and manual measurements were directly carried out on it with the help of brass wire and digital caliper. Measurements were made on different locations on the dental arch in various directions as the labial and palatal surface of central incisors and canine on left side along the long axis of the tooth from the cusp tip to the gingival margin and the buccal and palatal surface between the two interdental contact points of 2nd premolars. Unpaired t test was used to check the significant difference in means of different parameters. Results: No significant differences were found between central incisors labial surface (p=0.845) and palatal surface (p=0.722) and the canine measurements labial surface (p=0.721) and palatal surface (p=0.544) on digital models compared to study models, whereas significant difference was observed in premolar measurements (p-value≤0.05). Conclusion: STL files obtained by LED scanning the impressions did not exhibit significant deformation or loss of information while curvilinear measurements were evaluated, and higher accuracy was seen in the premolar measurement on palatal surface with digital models.

Study about mechano-chemical gingival displacement with single-cord technique.

Introduction: Besides abutment preparation, the impression is essential in order to achieve an esthetical and functional prosthetic restoration. Proper gingival displacement and abutment finish line exposure is crucial for the proper impression technique.The study aims are to investigate the vertical gingival displacement and if the free gingival margin returns to its original position after seven days by using a retraction cord impregnated with different chemical substances.Materials and method: Our clinical study evaluated on digital photos the modification of the healthy, free gingival margin position on the labial surface of two upper central incisors in the same female patient during the sulcus enlargement with the mechano-chemical method.Results: Statistically significant differences were obtained by comparing the mean values of vertical gingival displacement obtained using a non-impregnated and an impregnated retraction cord with different chemical at each time of the measurements.Conclusion: The mechano-chemical technique is an efficient method for gingival displacement regardless the impregnating solution used.

Vital tooth bleaching- A case report

Nothing could be more desirable than a sparkling white smile. A shining, beautiful smile has been a symbol of health & vitality since the centenary. Discoloration of a tooth is a common esthetic problem caused by either extrinsic or intrinsic factor. The normal color of tooth can be re-established by decolorizing the stain with the powerful oxidizing agent such as 35 percent hydrogen peroxide, which is directly placed on the labial surface of the tooth to be treated. Dental bleaching offers a conservative & simplified approach to change the color of discolored teeth. This case report reflects the remarkable change of tooth color by in-office bleaching.

Porcelain veneer for a simple and esthetic treatment on anterior teeth with enamel hypoplasia: a case report

Introduction: the esthetic factor should be considered for every patient who seeks a comprehensive dental treatment, especially for women. The anterior teeth deformities will diminish the levels of confidence and decrease self-esteem of the patients. The tooth development disturbances, such as enamel hypoplasia, may present an esthetic problem. Enamel hypoplasia is an alteration of organic matrix formation which characterized by the defect or porosity on the enamel surface. It can be restored with a variety of restorative treatment options including indirect porcelain veneers. Case: a 30 years old female patient was referred with chief complaint of anterior teeth discoloration. Clinical examination on the maxillary left central and lateral incisors revealed the defects on nearly half of the labial surface. Case management: the incisal lapping technique were chosen to prepared teeth #21 and #22 for indirect porcelain veneer fabrications. Conclusion: indirect porcelain veneers established an excellent esthetic result and restored the size, shape and color of anterior teeth with long term stability.

Interdisciplinary Approach to Treat Unusual Development of Dens Evaginatus: A Case Report

The present case report describes a rare case of dens evaginatus on the labial surface of mandibular incisor and interdisciplinary management including endodontic and periodontal treatment. A 10-year-old girl presented unusual whitish tubercle-like structure penetrated through the buccal gingiva of mandibular later incisor. In cone-beam computed tomographic view, pulpal tissue was extended from the principal root to the tubercle. Following full thickness flap reflection, the tubercle was carefully removed, resulting in dentin and pin-point pulp exposure. In order to prevent pulp necrosis and facilitate periodontal attachment to this area, Biodentine and enamel matrix derivative were applied. Gingival defect was compensated using a collagen matrix. Up to 2 years, harmonious gingiva state and no loss of tooth vitality were observed. In summary, dens evaginatus on mandibular later incisor could be successfully treated by means of interdisciplinary approach.