Comparison of different techniques for obturating experimental internal resorptive cavities

Abstract – Forty extracted maxillary central incisors were instrumented at the working length to a #50 file. The roots were sectioned transversely with a diamond disk at 7 mm from the anatomical apex. At the opening of the root canal of each section, hemi‐circular cavities were drilled with a specially designed bur. The corresponding root sections were cemented with glue, thus obtaining root canals with similar cavities that simulated internal resorptions. Teeth were embedded in plaster casts to facilitate their handling. The specimens were randomly separated into four groups of 10. The following obturation techniques were evaluated: lateral compaction (group A), hybrid technique (group B), Obtura II (group C), and Thermafil (group D). AH26 was used as the sealer. After obturation, the plaster was removed and the teeth were radiographed in buccolingual and mesiodistal directions to evaluate the quality of the obturation at the IRC. The incisors were then cut with a scalpel at the same level as the previous section, to examine, under a stereomicroscope, the type of material that filled the IRC. Obtura II gave the best results and in most of the specimens obturated with this technique, the IRC were filled mainly with gutta‐percha. Statistical analysis of the data indicated that the differences between group C and the other groups were significant (P<0.05).     

Effectiveness of different gutta-percha techniques when filling experimental internal resorptive cavities

Aim To determine the quality of root fillings in teeth with artificial internal resorptive cavities filled with Thermafil, JS Quick‐Fill, Soft Core, System B and Microseal, and by cold lateral compaction (LC) technique. Methodology Sixty maxillary incisor teeth were selected. After access cavity preparation and root canal instrumentation, the roots were sectioned horizontally and artificial internal resorption cavities were prepared on the canal walls. The tooth sections were cemented together and the root canals were filled using one of six different techniques: Thermafil, JS Quick‐Fill, Soft Core, System B and Microseal, and by LC. The roots were then divided at the level of the previous section and each root surface was photographed. Image analysis program was used to calculate the percentage of sealer, gutta‐percha and void in the internal resorptive cavities. All measurements were analysed statistically using One‐way anova and Newman–Keuls tests. Results The Microseal technique filled 99% of the artificial resorptive area followed by LC (92%), SystemB (89%), Quick‐Fill (88%), Thermafil (74%) and Soft‐Core (73%). Warm gutta‐percha compaction techniques filled the resorption areas with more gutta‐percha than sealer (Microseal 68%, System B 62%) compared to the other techniques (LC 48%, Quick Fill 41%, Soft Core 34%, Thermafil 35%). In addition, core techniques left a considerable volume of voids in the resorptive areas (Quick‐Fill 12%, Thermafil 26%, Soft Core 27%). Conclusions Warm gutta techniques filled artificial resorption cavities significantly better than the other gutta‐percha techniques.     

Quality of different gutta‐percha techniques when filling experimental internal resorptive cavities: A micro‐computed tomography study

The purpose of this ex vivo study was to determine the quality of root fillings in experimental internal resorptive cavities filled using cold lateral condensation (CLC), vertical condensation and Thermafil techniques. Forty‐five extracted maxillary canine teeth were selected. After root canal instrumentation, the roots were sectioned horizontally and experimental internal resorption cavities were prepared. The root sections were re‐approximated with a luting agent and randomly assigned to three groups (n = 15) to be filled using CLC, vertical condensation and Thermafil, respectively. Assessment of obturation quality in the internal resorptive cavity was performed using a desktop X‐ray micro focus computed tomography scanner, and the percentage of gutta‐percha (GP), sealer and voiding was calculated for each specimen. Data were statistically analysed using non‐parametric tests, with P < 0.05 denoting a statistically significant difference. Vertical condensation filled 96.25 ± 8.31% of the total artificial cavity, and was superior to CLC (63.20 ± 16.87%) and Thermafil (59.26 ± 18.47%). The mean percentage of voids was 3.75 ± 8.31% in the vertical condensation group, 37.09 ± 17.13% in the CLC group and 41.06 ± 18.60% in the Thermafil group. We conclude that obturation of experimental resorption cavities is significantly better when using vertical condensation than when using other GP‐based techniques.     

不同根管充填技术对椭圆形根管充填效果的比较

目的:通过比较3种不同方法充填椭圆形根管后的牙胶充填面积百分数来评价各种充填法的效果。方法:选取人离体单根管前磨牙30个,手用ProTaper预备后随机分为3组,分别用冷牙胶侧方加压法、热塑牙胶注射加压法(ObturaⅢ)和连续波充填法(System B+ObturaⅢ)进行充填,然后分别在距根尖2、5、8 mm处横断,各个横断面在手术显微镜下拍照,再用图像分析软件记录横断面的根管面积和牙胶充填面积,从而计算出牙胶充填面积百分数。结果:在2 mm处,3种充填法的牙胶充填面积百分数无显著性差异(P>0.05);在5 mm处,ObturaⅢ组和SystemB+ObturaⅢ组无显著性差异(P>0.05),但都显著大于冷牙胶侧压组(P<0.05),8 mm与5 mm处结果相同。结论:在5,8 mm水平,ObturaⅢ和SystemB+ObturaⅢ充填法的效果好于冷牙胶侧压法,而在2 mm水平,3种充填法的的效果无明显差别。     

Comparison of two tooth-saving preparation techniques for one-surface cavities

The atraumatic restorative treatment technique (ART) is based on removing infected tooth material using only hand instruments and filling the subsequently cleaned cavity with adhesive material such as glass ionomer. As its name suggests, the ART technique should be atraumatic during treatment, as well as for the tooth itself as for the patient. It was primarily developed for treating people living in underserved areas of the world where resources and facilities such as electricity and trained manpower are limited. Many studies have evaluated the ART technique and the results have supported its application. However, a very limited number of studies have compared ART with more conventional techniques. For that reason, a study was conducted in Pakistan, to compare the ART technique with another more conventional treatment technique. The results of this study show that the preparations with hand instruments resulted in smaller sized cavities and therefore may be less traumatic to the tooth. It was also associated with less pain reactions compared to the more conventional technique. Although preparations with hand instruments required more time, this did not seem to affect the survival of restorations. The survival of glass ionomer cement restorations made with hand instruments was comparable with single surface amalgam restorations made with a more conventional technique. Recurrent caries was not associated with any glass ionomer cement restorations made with hand instruments. The retention rate of glass ionomer sealants was low, however one dentist had a sealant retention rate of 81.5 percent that suggests that this procedure can be performed satisfactorily in conjunction with a glass ionomer cement restoration. Operator variances did seem to affect the restorations. Survival of glass ionomer restorations made with both hand and rotary instruments varied for different operators. Similarly, the retention of fissure sealant also varied amongst operators. Operator differences also influenced the extent of tooth substance lost due to cavity preparation. The ART technique is a feasible approach towards the treatment of dental caries especially of one-surface lesions for underserved populations.     

Comparison of two different gingivectomy techniques for gingival cleft treatment

Interdental clefts or invaginations contribute to orthodontic relapse and poor periodontal health in extraction cases. These clefts or invaginations can be removed both by electrosurgical or conventional surgical gingivectomy techniques. This study investigates and compares the efficacy of two different techniques to remove gingival clefts with respect to periodontal health and patient tolerance. Twenty-two patients (mean age, 15.7 years) with bilateral gingival clefts participated in this study. In each patient, the gingival invaginations were removed by gingivectomy using electrosurgery on one side and conventional surgery on the contralateral side. The length and depth of the invaginations, the gingival index of the adjacent teeth, and the changes in visual analogue scale scores were recorded before and after the operation for both groups. Mann-Whitney U-test and Wilcoxon tests were used to analyze the data statistically. The results showed significant improvement in invagination depth and length and gingival index scores for both techniques. There were no statistical differences between the two gingivectomy techniques with respect to gingival health and patient tolerance. Both techniques can be used to remove the gingival invaginations efficiently.     

Microleakage at the cervical margin of composite Class II cavities with different restorative techniques

This study evaluated the microleakage at the cervical margins of Class II composite resin restorations restored with different techniques. Slot cavities were prepared on both proximals of 40 unerupted third molars with one cervical margin located above and the other below the cementoenamel junction. The prepared teeth were randomly assigned to four groups and restored using the following techniques: (I) 3-Sited, (II) Directed-Shrinkage, (III) Resin-Modified Glass-Ionomer Cement or a (IV) Flowable Composite as the gingival increment. All restorations were placed with the same bonding agent and composite resin. The difference among the groups was on the first increment and on its insertion and polymerization techniques. After restoration, the teeth were thermocycled and exposed to a dye. Results showed that all the techniques worked well for enamel, with almost no leakage. However, on cementum, all techniques demonstrated moderate to severe leakage.     

Biomechanical evaluation of different types of rigid internal fixation techniques for subcondylar fractures.

PURPOSE: The aim of this study was to evaluate the biomechanical stability of various internal fixation systems for subcondylar fractures. MATERIALS AND METHODS: Eighteen identical synthetic mandibles were used. Left condylar processes were cut to mimic perpendicular subcondylar fracture and right sides were mimicked oblique subcondylar fracture. The fixation systems used included single 4-hole mini adaptation plate, double fixation with the same plates, single 4-hole mini dynamic compression plate (DCP), Eckelt lag screw system, Wurzburg lag screw plate system and double 4-hole biodegradable miniplates made of poly L-lactide (PLLA). In oblique fractures, one of the screws fixing plates was used bicortically through bone fragments. The loading vector simulated physiologic forces to the condyle on biting with servohydraulic testing machine until failure was reached. Load-displacement curve, maximum load for failure, and stiffness were measured. RESULTS: In perpendicular fracture, double adaptation plate showed the highest level of tolerance load followed by Eckelt lag and double PLLA plate. In stiffness, double adaptation plate and Eckelt lag screw showed higher level of stiffness, whereas double PLLA was almost at the same level of single DCP. In oblique fracture, double adaptation plate showed the highest strength. CONCLUSIONS: In this laboratory setting, double adaptation plates fixation proved to have superior biomechanical stability in both fracture conditions. Eckelt lag screw showed good stability in the perpendicular fracture, however, it was weak in the oblique fracture.     

Custom ocular prosthesis: Comparison of two different techniques

BackgroundLoss of tissue, whether congenital or traumatic or resulting from malignancy or radical surgery, is accompanied by esthetic and psychological effects. Fabrication of an ocular prosthesis is a challenging and time-consuming procedure.Patients and techniquesThis article describes two different techniques of iris customization on two different patients. First technique describes the iris customization with the use of conventional paint on technique while second describes the photographic method of fabricating the eye prosthesis.DiscussionA sequence of steps of construction of ocular prostheses is outlined, and the critical areas of fabrication and artistic techniques employed in the successful prosthetic treatment are described in this article. Conventional iris paint on technique and digital photographic technique to customize the iris are explained along with their advantages, disadvantages and indications.ConclusionIn addition to decrease treatment time and increased simplicity, digital photography technique is particularly advantageous in cases requiring thin acrylic shell type of prosthesis.     

Comparison of debris removal with three different irrigation techniques

Introduction

The purpose of this study was to compare the effectiveness of debris removal between EndoVac, PiezoFlow, or needle irrigation (Max-i-Probe) in mandibular molars.

Methods

The mesial roots of 30 extracted mandibular molars were mounted in resin by using the K-Kube and then sectioned at 2 and 4 mm from the apex. The specimens were reassembled and instrumented to size 40/0.04. A standard irrigation protocol was used during instrumentation in the PiezoFlow and Max-i-Probe groups. During instrumentation of teeth in the EndoVac group, the manufacturer’s recommendations for irrigation were followed. Images of the canals and isthmuses were taken before final irrigation. The percentage of cleanliness for each canal and isthmus was calculated by using interactive software. The specimens were reassembled for final irrigation with EndoVac, PiezoFlow, and Max-i-Probe by using similar volumes of irrigants. Images were again used to calculate cleanliness. Comparisons of canal and isthmus cleanliness before and after final irrigation were made by using paired t tests, and the groups were compared with repeated-measures analysis of variance (P < .05).

Results

There were no statistically significant differences in canal and isthmus cleanliness among all 3 groups at 2 and 4 mm from working length before or after final irrigation. Canal and isthmus cleanliness significantly improved at all levels after the final irrigation regimen in each group.

Conclusions

Final irrigation by using EndoVac, the PiezoFlow, or Max-i-Probe with similar volumes of irrigants significantly improved canal and isthmus cleanliness.     

Comparison of cold lateral condensation and a warm multiphase gutta-percha technique for obturating curved root canals

AIM: The aim of this project was to evaluate and compare the radiographic quality and sealability of root fillings in extracted human teeth using lateral condensation of gutta-percha or multiphase gutta-percha obturation (Alphaseal). METHODOLOGY: A total of 108 freshly extracted human, mature single-rooted teeth were divided into two identical groups of 54 teeth on the basis of root canal shape. The canals were prepared to a minimum 0.055 taper and enlarged to size 35 at the apex. All root canals were flushed with 17% EDTA solution and 2.5% NaOCl to remove the dentinal smear layer. The canals of one group were obturated using cold lateral condensation of gutta-percha and the canals of the other group were filled using a warm multiphase gutta-percha obturation technique. The extrusion of sealer and/or gutta-percha through the apex of the teeth was recorded using a simple yes/no scheme. The sealability of each technique was assessed by a dye penetration method. The radiographic quality of obturation was determined for each canal using a four-point scale. RESULTS: Root canals filled by multiphase obturation had significantly more extrusion of sealer (P < 0.001) and gutta-percha (P < 0.001) than canals filled by lateral condensation. Canals filled by multiphase gutta-percha obturation had significantly less apical dye leakage than those obturated by lateral condensation (P < 0.05). Lateral condensation achieved significantly better scores for radiographic quality than multiphase obturation from the bucco-lingual view (P < 0.01). CONCLUSIONS: Under laboratory conditions multiphase gutta-percha had better sealability but poorer radiographic quality than lateral condensation.     

Influence of different restorative techniques on microleakage in Class II cavities with gingival wall in cementum

This study compared marginal leakage of Class II cavities with gingival margin in cementum using different techniques. Twenty-four recently extracted third molars were used. Proximal standard box cavities were prepared in both mesial and distal surfaces. The gingival margin was located apical to the cemento-enamel junction. All the preparations and restorations were performed by the same operator. Standard cavities were randomly divided into three groups (n = 16) and restored as follow: Group 1-light-cured composite resin; Group 2-self-cured composite resin + light-cured composite resin and Group 3-amalgam + light-cured composite resin. After polishing, the teeth were thermocycled and their gingival margins exposed to dye. Specimens were sectioned and leakage scores observed in accordance with a standard ranking. Data were subjected to statistical analysis (Kruskal-Wallis). Results showed that the amalgam/resin composite combination demonstrated the least leakage.     

Stress distributions in internal resorption cavities restored with different materials at different root levels: A finite element analysis study

The aim of this study was to evaluate the stresses within simulated roots with internal resorption cavities at the apical, middle and coronal root levels, after obturation with gutta‐percha and/or MTA utilising finite element analysis (FEA). Mandibular premolar teeth with internal resorption cavities at different root levels were modelled. Models were restored with gutta‐percha and/or MTA. An oblique force of 300 N was applied and stress evaluations were carried out. In the MTA‐filled resorption models, the stresses were distributed more homogeneously than the gutta‐percha filled models, and the stress concentrations were lower in the remaining dentinal tissues. If the whole root is considered, the fully gutta‐percha‐filled models generated the highest stress values. Differences between the fully MTA‐filled models and hybrid techniques were present only in the apical resorption models. Both the MTA and combination of MTA and gutta‐percha can be suggested for use in clinical practice, in cases of internal root resorption cavity obturation.     

纸尖法和刮匙法对龈下牙周致病菌检出比较研究

目的：比较纸尖法和刮匙法对慢性牙周炎患者龈下菌斑中牙龈卟啉单胞菌、福赛斯坦纳菌、伴放线菌嗜血菌、具核梭杆菌检出的影响。方法：对30例慢性牙周炎患者分别用纸尖和刮匙法收集4个区域牙周袋探诊最深位点龈下菌斑，采用16SrRNAPCR方法检测两种方法收集到的龈下菌斑样本中的牙龈卟啉单胞菌、福赛斯坦纳菌、伴放线菌嗜血菌、具核梭杆菌。结果：两种方法一致性较好，纸尖法与刮匙法无显著差异（P〉0．05）。结论：纸尖法与刮匙法均为比较准确的取样方法。     

Effect of different root canal obturating materials on push-out bond strength of a fiber dowel

Purpose: During dowel space preparation, the instrumentation forms a thick smear layer along with sealer‐occluded dentinal tubules. The purpose of this study was to evaluate the effect of different obturating materials on push‐out bond strength of a fiber dowel. Materials and Methods: Fifty human uniradicular teeth were decoronated and prepared using the step‐back technique. The specimens were divided into five groups on the basis of obturating materials: group I received no obturation; group II (ZOE) gutta‐percha and zinc oxide eugenol sealer; group III (ZOAH) gutta‐percha and AH plus sealer; group IV (GF) GuttaFlow; and group V (RE) with Resilon Epiphany system. Dowel spaces were made with manufacturer's provided drills, and a fiber dowel was luted. Horizontal slices were obtained from the middle third, and push‐out bond strength (S) was evaluated. Statistical analysis was carried out using one‐way ANOVA and post hoc Tukey's test. Results: The push‐out bond strength values in the control group, ZOE, ZOAH, GF, and RE were 9.303 ± 0.565 MPa, 8.859 ± 0.539 MPa, 8.356 ± 0.618 MPa, 9.635 ± 0.435 MPa, and 8.572 ± 0.256 MPa, respectively. There was no statistically significant difference between the S values of all the groups (p > 0.05). Conclusion: There was no effect of different tested obturating materials on the push‐out bond strength of fiber dowels; however, further studies should be conducted.     

Comparison of lateral condensation and thermomechanically compacted warm alpha-phase gutta-percha with a single cone for obturating curved root canals

OBJECTIVE: To evaluate and compare the sealability and radiographic quality of root fillings in extracted teeth by using lateral condensation of gutta-percha or alpha-phase gutta-percha in conjunction with a single gutta-percha cone. STUDY DESIGN: A total of 108 single-rooted teeth were divided into 2 groups of 54 teeth based on canal shape. Canals were prepared to a minimum 0.055 taper and enlarged to a size 35 at the working distance. Irrigation was done with 17% EDTA and 2.5% sodium hypochlorite (NaOCl) to remove smear layer. One group was obturated by using cold lateral condensation of gutta-percha; the other group was obturated with thermomechanically compacted alpha-phase gutta-percha and a single cone of gutta-percha. Apical extrusion of sealer or gutta-percha was recorded. Sealability of each technique was assessed by dye penetration. The radiographic quality of obturation was also determined. RESULTS: Root canals filled with alpha-phase gutta-percha and a single cone had significantly more extrusion of sealer than canals filled by lateral condensation. Lateral condensation achieved significantly better scores for radiographic quality. There was no significant difference between the 2 filling techniques in terms of apical or coronal leakage. CONCLUSIONS: Thermomechanically condensed alpha-phase gutta-percha used in conjunction with a single gutta-percha cone had poorer radiographic quality than laterally condensed gutta-percha.     

Comparison of postoperative stability of three rigid internal fixation techniques after sagittal split ramus osteotomy for mandibular advancement

IntroductionThe aim of this investigation was to compare the skeletal stability of three different rigid fixation methods after mandibular advancement.Material and methodsFifty-five class II malocclusion patients treated with the use of bilateral sagittal split ramus osteotomy and mandibular advancement were selected for this retrospective study. Group 1 (n = 17) had miniplates with monocortical screws, Group 2 (n = 16) had bicortical screws and Group 3 (n = 22) had the osteotomy fixed by means of the hybrid technique. Cephalograms were taken preoperatively, 1 week within the postoperative care period, and 6 months after the orthognathic surgery. Linear and angular changes of the cephalometric landmarks of the chin region were measured at each period, and the changes at each cephalometric landmark were determined for the time gaps. Postoperative changes in the mandibular shape were analyzed to determine the stability of fixation methods.ResultsThere was minimum difference in the relapse of the mandibular advancement among the three groups. Statistical analysis showed no significant difference in postoperative stability. However, a positive correlation between the amount of advancement and the amount of postoperative relapse was demonstrated by the linear multiple regression test (p < 0.05).ConclusionIt can be concluded that all techniques can be used to obtain stable postoperative results in mandibular advancement after 6 months.