Effect of different tetra pack juices on microhardness of direct tooth colored-restorative materials

Purpose

To examine the effect of apple and orange juices on the surface hardness of direct tooth-colored restorative materials.

Materials and methods

The materials included resin-modified glass ionomer cement (Vitremer 3M™ ESPE™ Core buildup restorative) and composite resin (Filtek™ 3M™ ESPE™ Z350). A total of 45 disks of each restorative material were prepared. The disks were divided into groups of 15, which were immersed for 7 days in deionized water (G1/G4, control group), apple juice (G2/G5), or orange juice (G3/G6). The pH of the apple juice was approximately 4.8 and the pH of the orange juice was approximately 4.9. Surface hardness tests were performed before immersion and at various times following immersion. Statistical analysis included two-way ANOVA with repeated measurement and Tukey’s test.

Results

Exposure to juices significantly reduced the hardness of both materials (p < 0.05), while deionized water did not affect the surface hardness of either material. The ionomer cement experienced a greater reduction than the composite resin (p = 0.000). There was no significant difference in the effect of apple and orange juices.

Conclusion

Juice box-type fruit juices reduced the hardness of direct tooth-colored restorative materials. Material selection should be considered when planning restorations in patients who have experienced tooth surface loss. In terms of the materials evaluated in this study, the composite material provides greater durability under acidic conditions.     

The influence of resin infiltration system on enamel microhardness and surface roughness: An in vitro study

Objective

To investigate the effect of a resin infiltrant on the surface microhardness and roughness of healthy enamel and, as a subsidiary aim, to compare it with a fissure sealant.

Materials and methods

Twenty freshly extracted premolars were used. Sound enamel surfaces were treated with a resin infiltrant (Icon) or fissure sealant (Seal-Rite). The average roughness (R_a, μm) of the specimens was measured with a profilometer (Surtronic 10 Tylor Hobson). Surface hardness was determined by utilizing Vicker’s surface hardness (VHN) with a Micromet II Microhardness tester. Each specimen acted as its own control. Data were analyzed with 2-way analysis of variance (ANOVA), and mean values were compared with independent t-test. All analyses were performed with the SPSS program version 16 (USA). Differences with a P-value of ⩽0.05 were considered statistically significant.

Results

Comparison of enamel surfaces before and after application of resin infiltrant revealed no significant differences in surface hardness; however, enamel surfaces treated by infiltrant showed significantly higher VHN (244.0 ± 79.8) values than those treated with fissure sealant (37.5 ± 14.2). Surface roughness did not differ before and after application of either material to sound enamel. Enamel surfaces treated with fissure sealant (5.3 ± 1.4) were significantly smoother than those treated with infiltrant (6.9 ± 2.0).

Conclusion

Within the limitations of the study, the results showed that enamels treated with the resin infiltrant showed approximately the same microhardness and surface roughness as sound enamel, indicating that this material might be suitable for the treatment of enamel subsurface lesions.     

Influence of extended light exposure time on the degree of conversion and plasticization of materials used as pit and fissure sealants

Aim: To evaluate the conversion and plasticization of fissure sealer materials, as influenced by extended curing time. Methods: Twenty specimens (n = 5) of a pit and fissure sealant and a flowable composite at two curing times (20 and 60 sec) were photocured with the Bluephase 16i light‐emitting diode. The conversion was determined by Fourier transform infrared/attenuated total reflection spectroscopy 24 h after polymerization. Hardness was measured, and samples were stored in absolute ethanol for 24 h. A second hardness measurement was executed after storage to assess plasticization by the percentage of hardness decrease. Data were analyzed by analysis of variance and Pearson’s correlation (α = 0.05). Results: The pit and fissure sealant showed lower degree of conversion than the flowable composite. The 60‐sec curing time increased the conversion only for the flowable composite. Plasticization was lower for the flowable composite than for the pit and fissure sealant. The 60‐sec light exposure time showed a similar percentage of hardness decrease of 20 sec. A low correlation between the conversion and plasticization was found. Conclusion: Extended curing time improved the conversion only for the flowable composite. The pit and fissure sealant presented lower conversion and higher plasticization than the flowable composite.     

Curing efficiency of various resin-based materials polymerized through different ceramic thicknesses and curing time

PURPOSE

The aim of this in vitro study was to examine the curing efficiency of various resin-based materials polymerized through ceramic restorations with 3 different thicknesses. Curing efficiency was evaluated by determining the surface microhardness (VHN) of the resin specimens.

MATERIALS AND METHODS

Four kinds of resin materials were used. Z350 (3M ESPE Filtek™ Z350: A2 Shade), Z250 (3M ESPE Filtek™ Z250: A2 Shade) and Variolink® II (VL: Ivoclar vivadent, base: transparent) either with or without a self-curing catalyst (VLC: Ivoclar vivadent, catalyst: low viscosity/transparent) were filled into the silicone mold (10 mm diameter, 1 mm thick). They were cured through ceramic discs (IPS e.max Press MO-0 ingot ivoclar vivadent, 10 mm diameter, 0.5, 1 and 2 mm thicknesses) by LED light-curing units for 20 and 40 seconds. Vicker''s microhardness numbers (VHNs) were measured on the bottom surfaces by a microhardness tester. Data were analyzed using a 3- way analysis of variance (ANOVA) at a significance level of 0.05.

RESULTS

The thickness of ceramic disc increased, the VHNs of all four resin types were decreased (P<.05). The mean VHN values of the resins light cured for 40 seconds were significantly higher than that of LED for 20 seconds in all four resin materials (P<.05). VLC showed significantly higher VHN values than VL regardless of other conditions (P<.05). Z350 and Z250 showed higher values than VL or VLC (P<.01).

CONCLUSION

Thinner ceramic disc with increased curing time resulted higher VHN values of all resin materials. The use of a catalyst produced a greater hardness with all polymerization methods. Restorative resin materials (Z350, Z250) showed higher VHN values than resin cement materials (VL, VLC).     

Assessment of Osstell? and Periotest? systems in measuring dental implant stability (in vitro study)

Objectives

The objectives of this in vitro study were to investigate the sensitivity and reliability of the Osstell™ systems (Resonance Frequency Analysis – RFA) compared to the Periotest® system in implant bone simulated conditions. Three conditions were simulated: (1) the direct fixture-bone contact and fibrous tissue fixture contact, (2) The different levels of horizontal bone loss, and (3) The hardening implant–bone interface.

Materials and methods

Forty-nine dental implant fixtures were placed in the center of acrylic cubes. In Part I seven fixtures were placed in direct contact with acrylic and another seven were placed in contact with polyvinyl siloxane impression material as soft interface. Part II: four sets of 0, 2, 4 and 6 mm horizontally exposed fixture samples were made (seven fixtures in each set). Part III: seven fixtures were placed in contact with a thin mix of autopolymerizing resin. The stability of these fixtures was measured using Osstell™ and Periotest® systems.

Results

The mean Periotest® value(PTV) and Osstell™ measurements showed a significant difference between the direct contact and soft interface (P < 0.001). These values also showed statistically significant difference between the different levels of horizontally exposed fixture groups (P < 0.001). The level of horizontal fixture exposure was strongly correlated with the PTVS (r = 0.967) and strongly negatively correlated with Implant Stability Quotient (r = −0.946). A strong correlation was found between the Osstell™ readings and the change in the stiffness of the autopolymerizing resin fixture interface group (r = 0.986).

Conclusions

Both Osstell™ and Periotest® systems proved to be sensitive in measuring dental implant stability in hard and in soft interfaces. Osstell™ also proved to be sensitive in detecting changes in the fixture interface stiffness. Osstell™ system proved to be more reliable compared to Periotest® system in measuring dental implant stability in hard and in soft interfaces.     

光固化流体树脂窝沟封闭防龋疗效的评价

目的比较光固化流体树脂与光固化窝沟封闭剂在儿童新生恒牙窝沟封闭预防龋坏的临床效果。方法临床选取150名7~10岁,双侧下颌第一恒磨牙无龋坏的儿童。每个儿童随机选取一侧作为试验组,用光固化流体树脂进行窝沟封闭,另一侧为对照组,用传统光固化窝沟封闭剂进行封闭。封闭治疗后6、12、24个月复查,检查封闭剂在牙面的保留率及龋病发生率,并进行统计学分析。结果 2年后试验组光固化流体树脂脱落率和龋病发生率分别为7.80%和2.13%,对照组传统窝沟封闭剂的脱落率和龋病发生率分别为21.43%和7.09%,两组封闭剂脱落率和龋病发生率均有显著性差异(P<0.05)。结论光固化流体树脂在窝沟封闭预防龋坏治疗效果确切,值得临床推广。     

Impact of extended radiant exposure time on polymerization depth of fluoride-containing fissure sealer materials

Physical properties such as surface hardness of dental materials are directly linked to their clinical behavior. The aim of this study was to investigate the influence of extended curing time on the polymerization depth offluoride-containing materials used as pit and fissure sealants. Conventional and extended exposure times (20 and 60 seconds) were used to photoactivate a gold-standard pit and fissure sealant (Fluroshield, Dentsply) and a flowable composite (PermaFlo, Ultradent). Twenty square-shaped samples (n=5) were prepared using a LED device (Bluephase 16i, Ivoclar). The Knoop Hardness Number (KHN) was calculated for the top and bottom surface of each sample 24 hours after polymerization. Bottom/top hardness ratio (B/T KHN) was than calculated. Averages were analyzed by two-way ANOVA and Tukey test (alpha=0.05). The flowable composite had higher KHN than conventional pit and fissure sealant for all experimental conditions (p<0.05). The 60-second photoactivation time increased KHN at the bottom surface and B/T KHN only of composite specimens. The flowable composite had better physical properties than the pit and fissure sealant, and they were improved by extended curing time.     

Elastic modulus and flexural strength comparisons of high-impact and traditional denture base acrylic resins

Background

Fractures of acrylic resin dentures are a common occurrence in clinical dentistry. The denture may be fractured accidentally when dropped or while in service in the mouth due to flexural fatigue.

Objectives

The aim of this study was to compare the elastic modulus and the flexural strength between two heat-cured acrylic resins used in denture bases: a high-impact resin (Lucitone 199) and a traditional resin (Rodex).

Materials and methods

Rectangular strips of Lucitone 199 and Rodex (10 samples each) were fabricated and stored in artificial saliva at 37 °C for 2 weeks. The specimens were subjected to a three-point flexural test. The data were statistically analysed with Student’s t-test (p ⩽ .05).

Results

The high-impact acrylic resin had a lower elastic modulus (p = .000) and higher flexural strength (p = .001) compared to the traditional acrylic resin.

Conclusion

Within the limitations of this study, it can be concluded that the high-impact acrylic resin is a suitable denture base material for patients with clinical fracture of the acrylic denture.     

Clinical comparison of a flowable composite and fissure sealant: A 24-month split-mouth,randomized, and controlled study

Objectives

The aim of this clinical study was to evaluate the retention rate and caries-prevention effect of a flowable composite compared to a conventional resin-based sealant in a young population over a 24-month period.

Methods

Thirty-four patients, ranging in age from 16 to 22 years, diagnosed with at least 2 non-cavitated pit-and-fissure caries in the first and second molars were selected for this randomized split-mouth design trial. A total of 220 sealants, were placed in 117 upper molars and 103 lower molars. The teeth were sealed with a flowable resin composite (Tetric Evo Flow) or a sealant material (Helioseal F). Each restoration was independently evaluated in terms of retention and the presence of caries at baseline and at 1, 6, 12, and 24 months. Data were analyzed using non-parametric Mann–Whitney U and Friedman 1-way ANOVA tests at p < 0.05.

Results

Tetric Evo Flow showed complete retention with 100%, 95.5%, 93.8%, and 88.5% at 1, 6, 12, and 24-month evaluations, respectively, while Helioseal F retention rates were 98.1%, 95.5%, 94.8%, and 85.4%, respectively, for the same evaluation periods. At the 24-month recall, 4 (4.2%) total losses were observed in subjects treated with Tetric Evo Flow and 2 total losses (2.1%) for Helioseal F, respectively. No significant differences were observed between the materials in retention rates or caries incidence for each evaluation period (p > 0.05).

Conclusion

Placement of flowable composite as fissure sealants in the younger population seems to be as effective as conventional fluoride containing fissure sealants for the prevention of fissure caries.

Clinical relevance

The use of a flowable composite as a fissure sealant material, in conjunction with a total-etch, single bottle adhesive, yielded better retention than did the conventional fluoride containing resin-based fissure sealant over a 24-month period in young patients.     

两种光固化材料行窝沟封闭术后3年临床效果

目的 比较2种光固化材料用于第一恒磨牙窝沟封闭的临床效果.方法 6～8岁的儿童150例600颗健康的第一恒磨牙分为2组:试验组用光固化Filtek Z350流动纳米树脂进行一侧窝沟封闭术;对照组用光固化窝沟封闭剂Estiseal F作为自身对照.随诊3年.结果 术后1、 2、 3年复查,试验组的封闭材料完全保留率分别为95.71%、 89.83%、 80.56%,对照组分别为87.50%、 80.51%、 69.44%,试验组术后1、 2、 3年的封闭材料完全保留率高于对照组(P<0.01),差异有统计学意义.术后1、 2年龋病发生率,差异无统计学意义(P>0.05),但术后3年试验组龋病发生率为1.67%,对照组为6.67%,差异有统计学意义(P<0.05).结论 光固化Filtek Z350流动纳米树脂是一种可靠的恒牙窝沟封闭材料,值得临床推广使用.     

Effect of low pull headgear on head position

Objective

To evaluate changes in head position following the use of low pull headgear (LHG) and compare these changes with an untreated control group.

Subjects and methods

The test group comprised pre-treatment and post-treatment lateral cephalograms of 30 males, aged 11 ± 1.5 years, who were receiving LHG therapy for correction of Class II malocclusion. Pre-observation and post-observation lateral cephalograms of 25 untreated male subjects, aged 11 ± 1.6 years, served as controls. The average treatment time for the treatment group was 12 ± 2.02 months and the average observation period for the control group was 11 ± 1.03 months. Four postural variables (NSL/CVT, NSL/OPT, CVT/HOR, OPT/HOR) were measured to evaluate the head position in all subjects pre- and post-observations.

Results

There was no significant difference in all the measurements concerning the head position within each group (p > 0.05). The mean differences of pre- and post-observations of 4 postural variables in the LHG group were 1.43, 0.9, −1.13, and −1.08, while those of the control group were 1.56, −0.32, −0.24, and 0.04, respectively. There was no significant difference between the headgear and control groups for any of the postural variables measured (p = 0.924, 0.338, 0.448, and 0.398, respectively).

Conclusions

Although postural variables showed considerable variability in both groups, head position exhibited no significant changes over a period of 11–12 months either in the control or headgear group.     

儿童恒磨牙早期窝沟龋3种充填方法临床疗效比较

目的：观察光固化流体树脂、光固化复合树脂和窝沟封闭剂充填儿童恒磨牙早期窝沟龋的临床疗效。方法：分别用光固化流体树脂、光固化复合树脂和窝沟封闭剂充填儿童恒磨牙窝沟龋并随访观察疗效。结果：光固化流体树脂、光固化复合树脂和窝沟封闭剂3组充填后1年的充填物完全保留率分别为95．O％、91．7％和83．3％,三者比较差异无统计学意义。充填后2年光固化流体树脂、光固化复合树脂和窝沟封闭剂3组的充填物完全保留率分别为89．8％、75．4％和70．7％,光固化流体树脂的完全保留率高于光固化复合树脂组和窝沟封闭剂组,差异有统计学意义（P〈0．05）。结论：光固化流体树脂是一种较好的年轻恒牙早期窝沟龋充填材料,值得在临床推广应用。     

In vitro evaluation of fracture strength of zirconia restoration veneered with various ceramic materials

PURPOSE

Fracture of the veneering material of zirconia restorations frequently occurs in clinical situations. The purpose of this in vitro study was to compare the fracture strengths of zirconia crowns veneered with various ceramic materials by various techniques.

MATERIALS AND METHODS

A 1.2 mm, 360° chamfer preparation and occlusal reduction of 2 mm were performed on a first mandibular molar, and 45 model dies were fabricated in a titanium alloy by CAD/CAM system. Forty-five zirconia copings were fabricated and divided into three groups. In the first group (LT) zirconia copings were veneered with feldspathic porcelain by the layering technique. In the second group (HT) the glass ceramic was heat-pressed on the zirconia coping, and for the third group (ST) a CAD/CAM-fabricated high-strength anatomically shaped veneering cap was sintered onto the zirconia coping. All crowns were cemented onto their titanium dies with Rely X™ Unicem (3M ESPE) and loaded with a universal testing machine (Instron 5583) until failure. The mean fracture values were compared by an one-way ANOVA and a multiple comparison post-hoc test (α=0.05). Scanning electron microscope was used to investigate the fractured interface.

RESULTS

Mean fracture load and standard deviation was 4263.8±1110.8 N for Group LT, 5070.8±1016.4 for Group HT and 6242.0±1759.5 N for Group ST. The values of Group ST were significantly higher than those of the other groups.

CONCLUSION

Zirconia crowns veneered with CAD/CAM generated glass ceramics by the sintering technique are superior to those veneered with feldspathic porcelain by the layering technique or veneered with glass ceramics by the heat-pressing technique in terms of fracture strength.     

Agreement between orthodontist and patient perception using Index of Orthodontic Treatment Need

Objectives

The primary objective of the study was to assess the agreement between orthodontist and patient perception regarding the Aesthetic Component of the Index of Orthodontic Treatment Need (IOTN-AC) at pre-orthodontic treatment levels. The secondary objective was to determine how well the subjective assessment of malocclusion (IOTN-AC) correlated with the normative Dental Health Component of the IOTN (IOTN-DC).

Materials and methods

A cross-sectional analytical study was conducted on patients between the ages of 16 and 25, presenting for initiation of orthodontic treatment with no history of prior orthodontic treatment. The mean age of the total sample population was 19.50 ± 3.15 years. The mean age of the males was 19.05 ± 3.09 years and for females it was 19.75 ± 3.18 years. The sample consisted of 41 males and 80 females. Patients were shown their pretreatment monochrome intraoral frontal photographs to rate according to the IOTN-AC. Simultaneously, the orthodontist reviewed the photographs with each patient. The IOTN-DHC of pretreatment casts was also recorded by the orthodontist. The frequency of specific traits that had led to increased severity of malocclusion was also identified. All readings were recorded manually on a data collection form. The data were assessed using the chi-square test, Spearman’s correlation and Cohen’s kappa test. Intra- and inter-examiner reliability was assessed using Spearman’s correlation.

Results

A significant positive relationship (p < 0.05) was observed between orthodontist and patient perception (r = 0.516), orthodontist perception and the normative need (r = 0.430), and between the patient perception and the normative need (r = 0.252). A statistically significant level of agreement was observed between orthodontist and patient perception (kappa = 0.339, p ⩽ 0.001, 95% CI, 0.207–0.470) and between orthodontist perception and the normative need (kappa = 0.331, p ⩽ 0.001, 95% CI, 0.197–0.424). A weak and insignificant level of agreement was observed between patient perception and normative treatment need (kappa = 0.107, 95% CI, 0.02–0.187).

Conclusions

Patient understanding of their treatment need or aesthetic classification may not always be as accurate as that of orthodontists. This may be a cause for concern when an orthodontist finds a certain condition to be severe, and a patient who does not agree may limit their treatment needs.     

An effect of immediate dentin sealing on the shear bond strength of resin cement to porcelain restoration

PURPOSE

The aim of this study was to determine differences in shear bond strength to human dentin using immediate dentin sealing (IDS) technique compared to delayed dentin sealing (DDS).

MATERIALS AND METHODS

Forty extracted human molars were divided into 4 groups with 10 teeth each. The control group was light-cured after application of dentin bonding agent (Excite® DSC) and cemented with Variolink® II resin cement. IDS/SE (immediate dentin sealing, Clearfil™ SE Bond) and IDS/SB (immediate dentin sealing, AdapterTM Single Bond 2) were light-cured after application of dentin bonding agent (Clearfil™ SE Bond and Adapter™ Sing Bond 2, respectively), whereas DDS specimens were not treated with any dentin bonding agent. Specimens were cemented with Variolink® II resin cement. Dentin bonding agent (Excite® DSC) was left unpolymerized until the application of porcelain restoration. Shear strength was measured using a universal testing machine at a speed of 5 mm/min and evaluated of fracture using an optical microscope.

RESULTS

The mean shear bond strengths of control group and IDS/SE group were not statistically different from another at 14.86 and 11.18 MPa. Bond strength of IDS/SE group had a significantly higher mean than DDS group (3.14 MPa) (P < .05). There were no significance in the mean shear bond strength between IDS/SB (4.11 MPa) and DDS group. Evaluation of failure patterns indicates that most failures in the control group and IDS/SE groups were mixed, whereas failures in the DDS were interfacial.

CONCLUSION

When preparing teeth for indirect ceramic restoration, IDS with Clearfil™ SE Bond results in improved shear bond strength compared with DDS.     

Change of Lip and Occlusal Cant After Simultaneous Maxillary and Mandibular Distraction Osteogenesis in Hemifacial Microsomia

Background

The purpose of this study was to investigate the lip and occlusal cant changes in hemifacial microsomia (HFM) cases after simultaneous maxilla and mandibular distraction osteogenesis (DO) of the mandible.

Patients and Methods

Retrospective analysis of all HFM cases at Balaji Dental and Craniofacial Hospital were performed. Patient of either gender with all medical imaging records and pre and post-operative (6 months) facial photographs in natural head position were included in the study. The lip cant change was assessed by the angle of each labial commissure and the bi-pupillary reference line. The line joining the frontozygomatic unions and a parallel line is drawn at the level of anterior nasal spine. The occlusal plane is then traced. A vertical line is traced perpendicular to the frontozygomatic union. The deviation of the occlusal plane from the horizontal is measured as the occlusal cant and a change, between pre and post-operative records was considered as the angle and linear measurements.

Result

With the linear measurement, the mean change in occlusal cant was 7.18 ± 1.47 mm while for the mean change in lip cant was 3.31 ± 0.52 mm (P = 0.120). For the angular measurement, the mean angle change in occlusal cant was 13.86 ± 2.69° and mean change in angle of lip cant was 8.54 ± 0.7° (P = 0.01).

Discussion and Conclusion

For type1HFM, DO corrects the occlusal and lip cant. In present study, the lip cant change relative to occlusal cant change was 47.54 ± 10.71% in linear measurements while for angular measurements it was 63.19 ± 10.07% (P = 0.476; Pearson’s correlation coefficient = −0.241).keywords: Hemifacial microsomia, Distraction osteogenesis, Lip cant, Occlusal cant     

Influence of surface modification techniques on shear bond strength between different zirconia cores and veneering ceramics

PURPOSE

Veneering porcelain might be delaminated from underlying zirconia-based ceramics. The aim of this study was the evaluation of the effect of different surface treatments and type of zirconia (white or colored) on shear bond strength (SBS) of zirconia core and its veneering porcelain.

MATERIALS AND METHODS

Eighty zirconia disks (40 white and 40 colored; 10 mm in diameter and 4 mm thick) were treated with three different mechanical surface conditioning methods (Sandblasting with 110 µm Al₂O₃ particle, grinding, sandblasting and liner application). One group had received no treatment. These disks were veneered with 3 mm thick and 5 mm diameter Cercon Ceram Kiss porcelain and SBS test was conducted (cross-head speed = 1 mm/min). Two and one way ANOVA, Tukey''s HSD Past hoc, and T-test were selected to analyzed the data (α=0.05).

RESULTS

In this study, the factor of different types of zirconia ceramics (P=.462) had no significant effect on SBS, but the factors of different surface modification techniques (P=.005) and interaction effect (P=.018) had a significant effect on SBS. Within colored zirconia group, there were no significant differences in mean SBS among the four surface treatment subgroups (P=0.183). Within white zirconia group, "Ground group" exhibited a significantly lower SBS value than "as milled" or control (P=0.001) and liner (P=.05) groups.

CONCLUSION

Type of zirconia did not have any effect on bond strength between zirconia core and veneer ceramic. Surface treatment had different effects on the SBS of the different zirconia types and grinding dramatically decreased the SBS of white zirconia-porcelain.     

Influence of Kinesiologic Tape on Post-operative Swelling After Orthognathic Surgery

Introduction

Orthognathic surgery involves making several osteotomies that lead to varying degrees of post-operative swelling. The use of KT may be beneficial for postoperative treatment after head and neck surgery, accelerating drainage of tissue reaction or haemorrhages. The goal of this study was to find out if the application of KT prevents or improves swelling, pain and trismus after orthognathic surgery, improving patients’ postoperative quality of life.

Materials and Methods

In this double-blinded, randomized, control trial, 24 patients in whom bimaxillary orthognathic surgery was indicated, were included. Before surgery each patient alternatively was randomly included in the study group (treated with K-Taping^® and corticosteroid) or in the control group (treated with corticosteroid). In the present study a MakerBot^® Digitizer 3D™ was used to assess accurate volume measurements. All swelling measurements were expressed as total 3-D area of the landmarks (cm² ) in T0 pre-operative, T1 fourth day after surgery.

Results

The differences T0–T1 are highly significant (p < 0.01) between group 1 or study group (treated with K-taping^®) and group 2 (control group).

Discussion

The use of KT appears promising, because it is simple to carry out, less traumatic, economical, can be performed everywhere in the world, free from side effects on the body. Even when swelling persists, KT gives patients the impression of a minor swelling detracting them from their pain and morbidity. Further studies have to be performed to find out if KT can reduce or replace the need for additional medications such as the use of steroids.     

影响窝沟封闭材料渗透性和边缘密合性的多因素分析

目的：通过观察窝沟封闭材料的渗透性和边缘密合性，进一步探讨可能影响窝沟封闭效果的多种因素以及各因素的作用效果。方法：选取离体恒磨牙48个，随机分成24组，分别采用不同的方法和材料封闭窝沟。通过染料浸染法和体视显微镜观察封闭材料渗入情况以及与牙面的密合程度。分析窝沟釉质成形术、黏结剂、光照方法、材料种类、固化时间各因素对封闭效果的影响。结果：窝沟釉质成形术（EST）、黏结剂、封闭材料三方面因素对窝沟封闭材料的渗透性有影响，作用效果依次降低。黏结剂是否光照、封闭材料的光照时间对封闭的渗透性无影响。本实验的多种窝沟封闭方法边缘密合性均较好，无微渗漏。结论：窝沟釉质成形封闭术、黏结剂与Dyractflow流动复合体联合应用进行窝沟封闭具有很好的临床应用价值，值得推广。     

Polymerization behavior and thermal characteristics of two new composites at five temperatures: refrigeration to preheating

PURPOSE

Heat of composite polymerization (HP) indicates setting efficacy and temperature increase of composite in clinical procedures. The purpose of this in vitro experimental study was to evaluate the effects of 5 temperatures on HP of two new composites.

MATERIALS AND METHODS

From each material (Core Max II [CM] and King Dental [KD]), 5 groups of 5 specimens each were prepared and their total HPs (J/gr) were measured and recorded, at one of the constant temperatures 0℃, 15℃, 23℃, 37℃ and 60℃ (2 × 5 × 5 specimens) using a differential scanning calorimetry (DSC) analyzer. The data were analyzed using a two-way ANOVA, a Tukey''s test, an independent-samples t-test, and a linear regression analysis (α=0.05).

RESULTS

No polymerization reactions occurred at 0℃; then this temperature was excluded from statistical analyses. The mean HP of the remaining 20 KD specimens was 20.5 ± 14.9 J/gr, while it was 40.7 ± 12.9 J/gr for CM. The independent-samples t-test showed that there were significant differences between the HP of the two materials at the temperatures 15℃ (P=.0001), 23℃ (P=.0163), 37℃ (P=.0039), and 60℃ (P=.0106). Linear regression analysis showed statistically significant correlations between environment temperatures and HP of CM (R²=0.777).

CONCLUSION

Using CM is advantageous over conventional composite because of its better polymerization capacity. However due to its high HP, further studies should assess its temperature increase in vivo. Preheating KD is recommended. Refrigerating composites can negatively affect their polymerization potential.