Irreversible Hydrocolloid Research Articles

3D cone-beam C.T. imaging used to determine the effect of disinfection protocols on the dimensional stability of full arch impressions

AimThis study aimed to investigate the dimensional stability of irreversible hydrocolloid and polyvinylsiloxane (P.V.S.) impressions after exposure to four commercial disinfectants using cone-beam computed tomography (CBCT). Materials and MethodsTwo different impression materials were tested: irreversible hydrocolloid and P.V.S. Four disinfection solutions were applied: BirexSE, Opti-Cide3, COEfect MinuteSpray, and CaviCide Spray. Distilled water was used as a control group. Each solution remained in contact with the impression for 5 min. Additional contact time of 5 min compromises time for scanning. The materials were evaluated for dimensional stability after the impression of a maxillary complete edentulous template via CBCT before and after being in contact with the disinfectant agents. Measurements were assessed on the digital models from A-B, B-C, and C-A points. Paired analyses (Wilcoxon Signed Rank test or paired Student's t-test) were used to analyze each measurement before and after the contact with the disinfectant agents. The variance for each measurement was also analyzed via a one-way analysis of variance or Kruskal-Wallis. ResultsOverall, there were no statistical differences among the points measurements in the irreversible hydrocolloid or P.V.S. between initial and final assessments (p > 0.05). The used disinfectant agents in this study did not influence each measurement's variation on irreversible hydrocolloid or P.V.S. (p > 0.05). All agents showed an effect on the dimensional stability of both impression materials. The differences in the three dimensions ranged between 0.34 and 1.54%. ConclusionWithin 10 min of removing the impression from the master cast, is study's findings indicated that the four commercially available disinfectants did not influence the dimensional stability of irreversible hydrocolloid or P.V.S. Further studies should be performed to elucidate the antimicrobial effect of these solutions applied as a spray on the surface of irreversible hydrocolloid and P.V.S. impressions.

Effects of Water/Powder Ratio of Irreversible Hydrocolloid on Dimensional Stability of Impressions

Effects of Water/Powder Ratio of Irreversible Hydrocolloid on Dimensional Stability of Impressions

Alternative impression technique for edentulous anterior maxillary flabby tissue

This present study describes an impression technique to rehabilitate patients with flabby ridge in pre-maxilla through complete dentures. The proposed technique consists on the association of nondisplacive impression of the flabby area in the primary and functional impression. Therefore, a primary impression was performed with irreversible hydrocolloid with a dual impression. The impression material was removed at the region corresponding to the flabby area, characterizing a window, where a re-impression was conducted with the same material in a more fluid consistency. The functional impression was executed with a custom tray with perforations at the flabby area fabricated over a primary anatomic cast previously relieved. As a result, an anatomic impression with reduced compression over the flabby ridge was obtained. Moreover, an accentuated decrease of the mucosa compression was obtained through the material overflow from the custom tray perforations at the functional impression. After the acrylization of the prosthetic piece, a delimited box corresponding to the flabby mucosa in the prosthesis base was verified. Thus, it is concluded that the association of techniques proposed in this study reduced the compression over the flabby ridge area resulting in a complete denture copying anatomically the flabby area at rest. Thereby, in this case through a precise negative reproduction, a more favorable retention of the maxillary complete denture was obtained in patients with flabby ridge at the pre-maxillary area.

Evaluation of the Surface Characteristics of Irreversible Hydrocolloid Impression Material Incorporated with Silver Nanoparticles at Different Concentrations- An Invitro Study

Background: Incorporation of Silver nano-particles in irreversible hydrocolloid impression materials to improve the antimicrobial property, could influence the surface characteristics of the impression material. Aim:To evaluate the surface roughness and surface detail reproduction of irreversible hydrocolloid impression material incorporated with silver nano-particles at different concentrations. Materials and Methods: A total of 80 samples were selected and were grouped randomly into four groups of 20 samples each. The Group I (C.G), Group II (T.G 1) Group III (T.G 2) & Group IV (T.G 3) samples were casts poured from irreversible hydrocolloid impression material without AgNp, with 1% of AgNp, 1.5% of AgNp& with 2% concentration of AgNp respectively. The samples were employed for evaluating the surface detail reproduction and Surface Roughness.Chi square test and Kruskal wallis testwere used to analyze the surface texture statistically both within and between the test groups. Results: The surface detail reproduction was satisfactory with all the four groups. Statistically significant changes was observed in Groups IV test sample and a statistically insignificant surface change was observed in Groups I ,II and III test samples. There was a negligible change in surface roughness in Groups I, II, and III test samples with a slight increase in surface roughness in Group IV samples. Conclusion: All the test groups produced satisfactory surface detail reproduction on irreversible hydrocolloid impressions. 2% AgNp group alone have resulted in statistically significant changes in surface detail reproduction. All the test samples except 2% AgNp group showed increase in surface roughness values. (AgNp- silver nanoparticles, T.G-Test group, C.G –Control group)

In silico evaluation of the peripheral and inner seals in complete denture master impressions using a custom-developed 3D software.

Despite the complexity of the edentulous anatomy, little evidence exists as to what impression techniques and materials should be employed for an optimal result. The aim of this in silico study was to evaluate the trueness of peripheral and inner seals of different edentulous jaw impressions. Twelve maxillary edentulous participants (male = 8, female = 4; age 68.5 ± 11.7 years) participated in this study. Four different impression materials and techniques, irreversible hydrocolloid (Alginate; Blueprint X-Crème, Dentsply Sirona, PA, USA), polyvinyl siloxane impression (PVS; Aquasil Ultra+ Medium, Dentsply Sirona, PA, USA), and subsequently modified with ZnOE (PVSM) and an optical impression (Optical; 3Shape A/S, Copenhagen, Denmark), were tested against a control impression: low-fusing impression compound border molding (Kerr Corp., CA, USA) followed by a ZnOE impression (ZnOE; SS White impression paste, S.S. White Group, Gloucester, England). All impressions were scanned and analyzed using a custom-built 3D comparison software analyzing the vertical and horizontal trueness. The vertical discrepancy (peripheral seal) of the impression surface was significantly more true for PVSM than Alginate (p = 0.001), PVS (p = 0.019), and Optical groups (p < 0.001). Where the horizontal discrepancy (inner seal) was compared, the impression surface was more true for PVSM than Alginate (p < 0.001) and Optical (p < 0.001). PVS group was also significantly more true than Optical (p = 0.015). Impression techniques and materials may significantly influence the peripheral and inner seal of an edentulous jaw impression. When using a polyvinylsiloxane impression material for master edentulous impressions, a selective inner seal reline with a conventional zinc oxide eugenol impression paste can improve the inner seal.

IMPRESSION TECHNIQUES FOR PERIODONTALLY COMPROMISED TEETH – CASE SERIES

Patients might have teeth that are extremely mobile and/or misaligned. If multiple teeth are retained with different long axes, retrieving the impression could dislodge some of the teeth for which the long axes are inconsistent with the path of removal. In this case series, three different impression materials are used, which are low viscosity PVS (Polyvinylsiloxane), PE (Polyether) and irreversible hydrocolloid. The impression has been made to record Grade III mobile teeth. These materials quickly polymerize and do not adhere to each other intraorally. The impression is separated in three different directions to prevent any movement of the mobile teeth and reassembled extra orally before pouring. This article describes various simple and safe methods to make impressions of extremely mobile teeth. Keywords: Periodontally compromised teeth, Mobile teeth, Impression techniques, PVS (polyvinylsiloxane), PE (polyether), irreversible hydrocolloid, immediate dentures.

Is a two-step impression mandatory for complete denture fabrication on the severely resorbed mandible? A randomized trial on mastication, patient satisfaction and adjustments

ObjectivesTo compare one- vs two-step impression procedures for the provision of conventional complete dentures (CCDs) for edentulous individuals with severe mandibular resorption, in terms of (1) masticatory performance and ability; (2) satisfaction with mandibular CCDs; and (3) post-delivery adjustments. MethodsFifty-two patients requiring maxillary + mandibular CCDs were randomly divided into two parallel arms according to the impression method of the mandibular ridge: (SI) single impression with stock trays (irreversible hydrocolloid); (TI) two-step impression in custom trays, with border molding (impression compound) followed by the impression itself (polyether). Mastication performance was evaluated by a colorimetric test, whereas patients answered questions on masticatory ability and satisfaction with mandibular CCDs (100-mm visual analogue scale). The number of post-delivery sessions for adjustments were also quantified. Outcomes were assessed at 3 and 6 months after delivery. ResultsThe masticatory performance was similar for both groups, regardless of time (3 months, P = 0.62; 6 months, P = 0.61). No significant difference was found for patient-reported (P > 0.05), i.e. masticatory ability (general ease of chewing and quality of grinding food; ability to chew specific foods), general satisfaction with the mandibular CCD (general satisfaction, comfort, aesthetics, ability to speak and to perform correct cleaning, retention and stability). Both methods resulted in a similar number of post-delivery adjustment sessions [SI: 3.8 (1.7); TI: 3.2 (1.4); P = 0.09]. ConclusionsCompared to a traditional approach, CCDs obtained from a single impression achieve similar masticatory performance/ability and patient satisfaction, even in patients with severely reabsorbed mandibular ridge. Both methods demand the same amount of post-delivery adjustment. Clinical significanceA simplified impression technique which eliminates the secondary impression can provide CCDs of good clinical quality, which influences the OHRQoL, and satisfaction in the same extent they would by a two-step procedure, even for patients with severely reabsorbed mandibular ridges (ClinicalTrials.gov: NCT02339194).

Is a two-step impression mandatory for complete denture fabrication on the severely resorbed mandible? A randomized trial on patient perception and denture quality

ObjectivesTo evaluate the effectiveness of CCDs produced by two impression procedures for the mandibular ridge, in patients with severe mandibular atrophy. MethodsFifty-two completely edentulous patients with severely resorbed mandibles were randomly allocated into two groups according to the impression procedure of the mandibular ridge: SI - single impression (stock tray and irreversible hydrocolloid); TI - two-step impression (custom tray, border molding with compound, and polyether). Assessments of oral health related quality of life (OHRQoL, primary outcome) and denture satisfaction were performed by using validated questionnaires. Denture quality was evaluated by means of functional tests. ResultsRegardless of the technique, participants reported better OHRQoL (P < 0.001) in both follow-up periods (3 and 6 months after denture delivery), and groups resulted in similar OHIP-EDENT scores in its different domains (P > 0.05). Between-group differences were insignificant for general satisfaction (3 months, P = 0.699, 6 months, P = 0.392), as well as for aspects such as esthetics, comfort, mastication, speech, and prosthesis retention (P > 0.05). Overall clinical quality of the CCDs (P = 0.383) was similar between-group, as well as in specific aspects – interocclusal distance, occlusion, articulation, retention of the maxillary denture, and stability of both maxillary and mandibular dentures (P > 0.05). ConclusionsMandibular CCDs based on a single impression technique showed quality levels comparable to those generated by a two-step impression, both from the patient and clinician perspective. Clinical significanceA simplified impression technique which eliminates the secondary impression can provide CCDs of good clinical quality, which influences the OHRQoL, and satisfaction in the same extent they would by a two-step procedure, even for patients with severely reabsorbed mandibular ridges. (ClinicalTrials.gov: NCT02339194).

The influence of undercut depths on the accuracy of casts poured from irreversible hydrocolloid impression materials

ObjectivesTo evaluate the elastic recovery of a typical irreversible hydrocolloid impression material in terms of the amount of undercut identified and additional thickness of spacer provided before custom tray fabrication. MethodsThis study surveyed the undercut depths of the teeth surfaces and lingual sulci of one hundred partially dentate mandibular dental casts which were subsequently scanned and the data exported as STL files. A typical cast from each undercut category (0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 4mm, 5mm) was 3D printed. Three custom trays were constructed with spacer thicknesses representing 20%, 30% and 50% compression against the wall of the custom trays on removal, impressions recorded, and casts fabricated in dental stone. Measurements for elastic recovery of irreversible hydrocolloid were done using an internal caliper and a digital caliper. All measurements were done by the principal investigator. Non-parametric analyses were used for comparisons of the undercut values between the 3D printed and poured casts to determine the amount of elastic recovery of the irreversible hydrocolloid impression material. ResultsThere was no statistically significant difference in measurements between the original 3D printed casts and the poured casts, irrespective of percentage compression (p > 0.05). ConclusionsIn removable partial denture construction, casts should be blocked out parallel to the path of insertion and then an additional 3mm of spacer applied as a standard technique before custom tray fabrication to ensure elastic recovery of the irreversible hydrocolloid impression. Clinical implicationsIn severe undercut situations, accurate impressions can be taken using irreversible hydrocolloid by blocking out all undercut surfaces on the teeth and lingual sulci before adapting additional three-millimetre wax spacer on casts when constructing custom trays thereby ensuring accurate and reliable impressions for removable prosthesis construction.

Diastema closure and papillary induction technique with additions in composite resin: case report

Diastemas happen due to several factors, among them, discrepancy in the size of the teeth and abnormal insertion of the labial frenum. These changes directly affect the harmony of the smile, generating aesthetic dissatisfaction. This article aims to discuss the direct technique of closing diastemas and papillary induction as a way to prevent the formation of dark triangles. Young patient, 22 years old, female, student, sought care at the Faculty of Dentistry of the Federal University of Para, reporting dissatisfaction with her smile, caused by the space present between the upper central incisors. Anamnesis, clinical assessment intra and extra oral, intra oral photos, periapical radiography and distance measurement between the distal faces element 11 and 21 to determine the ideal midline, the case continued with the molding of the arches with irreversible hydrocolloid and obtaining the plaster model, diagnostic waxing, guide with condensation silicone, selection of composite resins Trans-N and A2 restoration, photoactivation using the blue photoactivator LED with light intensity of 1,100mW / cm2 / 15 seconds, and a wavelength of 420 -480nm. The contact point was adequate, while the restoration was made, there were additions in the cervical region of the teeth to change the papillary contour. In the finishing, abrasive strips and a sequence of diamond polishing tips 2135F and 2135FF were used and in the Enhance System polishing, a sequence of medium and fine grained sanding discs and felt discs with polishing paste, achieving adequate aesthetics and function as well as satisfaction of the patient.

A comparative study on the antimicrobial activity of irreversible hydrocolloid mixed with silver nanoparticles and chlorhexidine

Impressions taken from patients have the potential of cross-transmission of infection among dentistry personnel. The present study aimed to compare the antimicrobial activity of chlorhexidine (CHX) and silver nanoparticles (AgNPs) combined with irreversible hydrocolloid. This experimental study examined the in vitro antimicrobial effects of irreversible hydrocolloid mixed with silver nanoparticles and chlorhexidine using four groups, namely CHX (0.2%) solution and mouthwash mixed with irreversible hydrocolloid Groups 1 and 2), AgNPs (0.1 and 0.2%) (Groups 3 and 4), and specimens mixed with distilled water as a control group (Group 5) on bacterial strains, namely, Staphylococcu saureu s,Enterococcu sfaecali s,Pseudomona saeruginos a,Escherichi acoli, andStaphylococcu sepidermidi s through disc diffusion method. There were three replications per bacterial species. As data were not normally distributed, Kruskal-Wallis test was used at a significance level of 0.05. No antimicrobial activity was observed in the control groups. In S. aureus, CHX mouthwash had the highest antimicrobial activity, and AgNPs 0.1% and 0.2% groups had lower antimicrobial activity, and there was a significant difference between the two concentrations of AgNPs (P < 0.05). InE.faecali s, the effects of CHX compounds and AgNPs 0.2% were similar to each other and were higher than the effect of AgNPs 0.1% (P < 0.05). In E. coli, CHX compounds exhibited the highest efficacy relative to other materials (P < 0.05), and the AgNPs had no effect. In P. aeruginosa, AgNPs showed the highest growth inhibition zone, which had a significant difference compared to other materials (P ≤ 0.01), whereas the CHX compounds were not effective. InS.epidermidi s, the effect of CHX compounds was similar to one another and was higher than the effect of AgNPs (P ≤ 0.01). According to our observations, the antimicrobial activity of AgNPs at 0.1 and 0.2% against five tested bacterial strains was similar to those of pure CHX 0.2% solution and CHX 0.2% mouthwash.

PERAWATAN OBSTRUKSI SALURAN AKAR MENGGUNAKAN EDTA PADA GIGI PASKA RESTORASI AMALGAM

Root canal calsification can occur due to prolonged trauma, aging, or restorations with pressure on the teeth for a long time, and causes root canal obstructed. The purpose of this case report to evaluate the results of root canal treatment with obstructed root canal post amalgam restoration, continue with unimetrix post and PFM crown. Thirty three years old female patient has come to dental clinic to treat her left mandibular molar tooth that have big amalgam restoration in the occlusal and tooth fracture at lingual side, but there was no pain when he came. Clinical examination on tooth 36 is necrosis pulpa. Radiographs showed radiopaque area from occlusal until pulp chamber floor and no periapical lesions were found. Rewalling lingual wall was done before the procedure of multivisit root canal treatment with EDTA, that consists of three obstructed root canal. Preparation and insertion of tapered self threading dowel (unimetrix, Dentsply) and build up core with cement resin at once. Core preparation were done for PFM jacket crown, and then mold with irreversible hydrocolloid for maxilla and double impression material for the mandible. PFM jacket crown was cemented using resin cement. The evaluation after six months, there were no complaints of pain and good marginal adaptation of restoration has performed. Selection cases and the right diagnosis with treatment procedures and adequate restoration, root canal treatment can be effective and durable.

Marginal adaptation of provisional crowns made of acrylic and bisacrylic resins using different impression materials

Aim: To evaluate the marginal adaptation of provisional crowns made of acrylic and bisacrylic resins using different impression materials. Methods: a metal die and a matrix applied through a direct technique were used to fabricate the specimens. The impression materials used as a matrix were divided into four groups: Irreversible hydrocolloid (IH), laboratory silicone (LS), condensation silicone (CS), and addition silicone (AS). After the impression procedures, each matrix was loaded with the provisional prosthetic materials, Alike, Duralay, Protemp 4, and Structur 3 (n = 12). Marginal discrepancy was evaluated using a stereomicroscope at ×45 magnification. The images obtained were transferred to the Corel Draw X7 program, and the distances from the cervical margins of the specimen to the reference lines at the metal die were measured vertically. The data were analyzed by using 2-way ANOVA followed by the Tukey test (α=.05). Results: the acrylic resins had higher values ​​of marginal discrepancy compared to the bisacrylic resins. A statistically significant difference was found between all impression materials, and the irreversible hydrocolloid presented higher values of discrepancy (303.28–613.31 μm), whereas addition silicone had the lowest (48.61–190.06 μm). Conclusions: the bisacrylic resins had a better marginal adaptation compared to the acrylic resins. The addition silicone promoted a better marginal adaptation of the provisional prosthetic materials tested, followed by condensation silicone, laboratory silicone, and irreversible hydrocolloid.

Effect of storage time on mechanical properties of extended-pour irreversible hydrocolloid impression materials

Statement of problemRecent commercial extended-pour irreversible hydrocolloid impression materials (EPIHIMs) claim to maintain dimensional stability up to 120 hours. However, data regarding their mechanical properties and performance after 120 hours of storage are lacking. PurposeThe purpose of this in vitro study was to test the elastic recovery, strain in compression, and tear strength properties of 5 commercially available EPIHIMs, immediately after preparation and after 120 hours of storage under specific storage conditions. Material and methodsA total of 150 specimens were prepared in accordance with the ISO 21563:2013 standard from 5 commercially available EPIHIMs (Blueprint Xcreme, Kromopan, Alginmax, Hydrogum 5, and Alginelle). The specimens were subjected to elastic recovery, strain in compression, and tear strength tests immediately after specimen preparation (n=5) and after 120 hours of storage inside clear plastic zipper bags held at 23 °C (n=5). Data were analyzed with a multivariate analysis of variance (MANOVA) test for brand and duration parameters. Normality of data was analyzed with the Shapiro-Wilk test. The Duncan test or Games-Howell test was used for multiple comparisons (α=.05). ResultsElastic recovery and strain in compression values of the EPIHIMs tested were affected by brand and duration parameters (P<.001). Tear strength values of the EPIHIMs tested were affected by brand (P<.001); however, they were not affected by duration (P>.05). Data distribution was normal except for Alginmax in terms of the elastic recovery values and Blueprint Xcreme in terms of the strain in compression values (P<.05). Significant interactions were present between brand and duration for the strain in compression and tear strength values of the EPIHIMs tested (P<.05). Statistically significant difference was not found among mean elastic recovery values of the tested EPIHIM brands (P<.001). Moreover, a statistically significant increase was present in elastic recovery values of the tested EPIHIMs after 120 hours of storage (P<.001). Statistically significant difference was not found among mean strain in compression values of the tested EPIHIM brands tested immediately after preparation (P>.05). However, 120 hours of storage led both to a statistically significant decrease in mean strain in compression values of the tested EPIHIMs (P<.001) except for Alginelle (P>.05) and a statistically significant difference among mean strain in compression values of the tested EPIHIM brands (P<.001). Storage time did not influence mean tear strength values of the EPIHIMs tested (P>.05). However, statistically significant differences were present among mean tear strength values of the tested EPIHIM brands tested immediately after preparation (P<.001) and after 120 hours of storage (P<.001). ConclusionsDespite variations in elastic recovery, strain in compression, and tear strength properties of the EPIHIMs tested, all the materials fulfilled the requirements to comply with the ISO 21563:2013 standard even after 120 hours of storage.

Development of an Impression Material with Antimicrobial Properties for Dental Application.

To evaluate the antimicrobial activity and physico-mechanical properties of an irreversible hydrocolloid in which nanostructured silver vanadate decorated with silver nanoparticles (AgVO3 ) was added at various concentrations (0% - control, 2.5%, 5%, and 10% by weight). The agar diffusion method (n = 10) was used to evaluate the inhibitory effect on the following species: Streptococcus mutans, Staphyloccocus aureus, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans. The gelation time, flow capacity and plastic deformation were verified (n = 10). The data were analyzed using the Kruskal-Wallis test followed by the Dunn post-test, or via one-way ANOVA with multiple comparisons with a Bonferroni adjustment depending on the distribution (α = 0.05). All percentages of the nanomaterial were able to promote the antimicrobial activity of a hydrocolloid, with the formation of an inhibition zone (p < 0.05). In general, there was a dose-dependent effect on antimicrobial activity: higher concentrations of the nanomaterial promoted greater action except in the cases of P. aeruginosa (p < 0.001; F = 51.74) and S. aureus (p < 0.001), where the highest inhibition was for the 2.5% group. No difference was found in the gelation time when the control was compared with the groups with AgVO3 (p > 0.05). The difference was between the 5% and 10% groups (p = 0.007), and the latter promoted an increase in time. The flow capacity of the hydrocolloid with 5% of AgVO3 was significantly lower when compared with the control (p = 0.034). The AgVO3 influenced the plastic deformation (p < 0.001) in such a way that concentrations of 5% (p = 0.010) and 10% (p < 0.001) promoted an increase in this property when compared with the control. AgVO3 can be incorporated into an irreversible hydrocolloid as an antimicrobial agent without promoting adverse effects on physical-mechanical properties when used in concentrations of 2.5%.

Studies on Surface Morphology of Irreversible Hydrocolloid Impression Material Based on Brown Algae Type Padina sp.

This study aimed to investigate the potential of brown algae (Padina sp.). The investigation focused on surface morphology of the brown algae as preparation for making sodium alginate-based impression materials to obtain standardized impression materials. The sample was a natural sodium alginate type Padina sp. taken from South Sulawesi, Indonesia. The extraction process was conducted to attain the sodium alginate extract. Subsequently, an irreversible hydrocolloid impression material was fabricated by mixing some of the impression material composition and sodium alginate from Padina sp. The test of physical characteristic was conducted by describing the surface morphology of impression materials using scanning electron microscope (SEM). The data analysis of the SEM images showed that there was a difference in the surface morphology structure of the impression materials of the brown algae of the type of Padina sp. and standard impression materials showing a rough surface. Furthermore, the particles had no binding with other particles for all samples.

Efficacy of gender on the width-length ratio of maxillary anterior teeth in an Egyptian population and establishment of a guideline for esthetical accepted ratio of teeth dimensions to gingival display

Aim: The present study aims to correlate between gender and width-length ratio of maxillary anterior teeth in a sample of Egyptian population and to obtain an optimal esthetical accepted ratio of teeth dimensions to gingival display. Materials and Method: Stone casts were poured from irreversible hydrocolloid impressions of 100 adult Egyptian participants. These casts were used to measure the maximum mesiodistal width, maximum crown length and the width/length ratio for each maxillary anterior tooth. In addition, two frontal photographs were taken for each participant and the visible anterior teeth width, length and width/length ratio were measured. Finally, a sample with gummy smile was selected and the gingival display of the original image was digitally manipulated to create a series of five images with different gingival displays, then these images were subjected to assessment by 50 dentists and 50 laypersons using a numerical rating scale. Results: There was statistically significant difference between female and male group for all teeth width values and W/L ratio of lateral incisor and canine. There was no significant difference between dentists and laypersons perception except for the smile with -4 mm gingival display. Conclusion: Gender affects actual teeth width values as well as actual and apparent W/L ratios of lateral incisor and canine. Laypersons considered 0mm and -2mm gingival display the most attractive situation, on the other hand dentists considered 0 mm gingival display the most attractive one, while all participants agreed that 4mm gingival display is the least attractive one.

Linear dimensional stability of irreversible hydrocolloids with and without disinfection at different storage times

Irreversible hydrocolloids have been used in dental practice for decades and their pouring time has been suggested to be as short as possible; however the latest generation of alginates exhibit better properties, which could influence the fidelity of the casts. Objective: To evaluate the linear dimensional stability of stone casts obtained using two irreversible hydrocolloid brands (Cavex ColorChange and Jeltrate) after disinfection. Material and methods: Samples were divided into 16 groups (n = 10) according to brand, storage time and disinfection. Impressions were taken of a metallic master model made of stainless steel with two abutments. Cast models were obtained using type IV gypsum, after disinfection with sodium hypochlorite at 1% or without any disinfection followed by storage for four different times (immediate pouring, and after 24, 72 or 120 hours storage after obtaining the impressions) and the models were measured with a digital caliper. Data were submitted to ANOVA 3-way followed by Tukey’s test (α &lt; 0.05). Results: A statistically significant difference was detected with Jeltrate Plus after 72 and 120 hours in storage (with and without disinfection), as well as Cavex without disinfection. Differences were found for Cavex with disinfection/24 hours storage, when compared to immediate pouring (P &lt; 0.05). The alginates presented similar behavior regarding disinfection for the same time (P &gt; 0.05). Conclusion: Storage longer than 24 hours affects the fidelity of casts. Disinfection does not promote significant alteration at any of the experimental times with either material.

Ocular Impression-Taking-Which Material Is Best?

To assess the efficacy and effect on clinical signs of a polyvinylsiloxane (Tresident; Shütz Dental Group GmbH, Germany) compared with an irreversible hydrocolloid (Orthoprint; Zhermack SpA, Badia Polesine, Italy) for ocular impression-taking. Twenty subjects were recruited (13 female and 7 male), with mean age 31.1±4.6 years (SD) (range 25.8-39.7). Subjects attended for 2 sessions, each of 1-hr duration, on 2 separate days. Each session was scheduled at the same time on each day. At each visit, the subject underwent an ocular impression procedure, using either Tresident or Orthoprint, in random order and to one eye only. Investigator 2 was blind to this assignment. Two experienced practitioners conducted the study, investigator 1 performed the ocular impression procedures and investigator 2 observed and assessed the clinical signs: logMAR visual acuity, ocular surface staining, tear break-up time (TBUT), and ocular hyperemia. Visual acuity was unaffected by either material; TBUT was marginally disrupted by both materials, but was not clinically significant according to published criteria; ocular redness increased with both materials; and corneal staining was significantly greater after Orthoprint impression. Less redness and clinically insignificant staining after impression-taking, with fewer clinical complications, was found after use of Tresident. Tresident offers a quicker, more effective, and clinically viable method of obtaining ocular impression topography compared with the traditional Orthoprint, and Orthoprint causes significantly more superficial punctuate staining of the corneal epithelium than Tresident.

Evaluation of alpha-adrenomimetic agents for gingival retraction: A randomized crossover clinical trial.

Context:The displacement of the gingiva around the tooth allows proper access during preparation, precise impression taking, and cementation procedures that has a direct bearing on the health of the periodontium. Several methods and agents are used for this purpose.Aims:The primary aim of the study was to clinically evaluate the efficacy of naphazoline as a gingival retraction agent. The secondary aim was to compare it with tetrahydrozoline and aluminum chloride.Settings and Design:Fifteen patients participated in a randomized crossover clinical trial at the Army College of Dental Sciences, Secunderabad, Telangana, India.Subjects and Methods:Preliminary maxillary impressions were made with irreversible hydrocolloid for all patients to fabricate custom trays. After that, baseline impressions and cast for control group measurements were prepared. Gingival displacement was carried out in the right maxillary central incisor for all, with retraction cord soaked in three agents, either, aluminum chloride, tetrahydrozoline, or naphazoline. These agents were used in all patients with a washout period of 14 days. Elastomeric monophase impressions and die stone casts were recorded for each group. The central incisors were sectioned, and gingival retraction was measured using a measuring stereomicroscope.Statistical Analysis Used:The gingival displacement was statistically analyzed using one-way ANOVA and post hoc Bonferroni.Results:Naphazoline had the highest retraction (138.160 μm) followed by tetrahydrozoline (136.039 μm) and aluminum chloride (130.759 μm).Conclusions:Naphazoline, tetrahydrozoline, and aluminum chloride show a clinically and statistically significant amount of displacement when compared to control. Among the three agents, naphazoline showed maximum displacement and maybe a good alternative with fewer side effects.