The quality of ultrasonic root-end preparation: a quantitative study

The Effect of Root End Cavity Preparation Using Er,Cr:YSGG Laser, Ultrasonic Retrotip, and Bur on the Apical Microleakage of Retrograde Cavity Filled with MTA Plus

Aim:

The sealing ability of the retrograde material is greatly affected by the technique used for root end preparation. Advances in retrograde preparation techniques such as lasers has shown to provide an efficient outcome. The study was to evaluate and compare the effect of various techniques of retrograde cavity preparation on apical microleakage.

Materials and Methods:

Forty-five single rooted teeth were decoronated. Biomechanical preparation was carried out up to size F2 ProTaper system and obturated. Glass–ionomer cement was used as an access restorative material. The apical root resection was done at 3 mm from the apex at angulation of 90° to the long axis of the root. The allocation of the samples was done into three groups of 15 each. Group A: Retrograde cavities prepared using conventional round bur; Group B: Retrograde cavities prepared using ultrasonic retro preparation diamond tip; and Group C: Retrograde cavities prepared using “Erbium, chromium: yttrium, scandium, gallium, garnet” (Er,Cr:YSGG). The retrograde cavities hence prepared were filled with MTA Plus. Nail varnish was used to coat the samples except at the apical end. Samples were immersed in methylene blue for 24h. Stereomicroscope was used for examination of the sectioned teeth. The data were analyzed using one-way analysis of variance (ANOVA) and post hoc Tukey test.

Results:

Results showed very highly significant difference between laser and bur (P value = 0.001).

Conclusion:

Retrograde preparation with Er,Cr:YSGG showed significantly less microleakage when compared to the use of ultrasonic retrotip and burs.

Effects of Dimensions of Root-End Fillings and Peripheral Root Dentine on the Healing Outcome of Apical Surgery

Objective:

The objective of this study was to assess dimensions of root-end fillings (REFs), as well as peripheral root dentine (PRD) and their effects on the healing outcome of apical surgery.

Methods:

Cone beam computed tomography (CBCT) scans were utilized to measure the REF length and width and the PRD thickness in 61 roots of 53 teeth 1 year after apical surgery. Measurements were taken in the mesio-distal as well as bucco-lingual directions. The REF alignment with respect to the root axis was also evaluated. In addition, the dimensions of REF and PRD were assessed for possible correlations with the healing outcome. Criteria for determining the healing outcome included clinical and radiographic parameters.

Results:

The mean REF length was 2.02±0.52 mm. No significant differences were observed with regard to tooth groups, but one-canal roots had a significantly longer mean REF than two-canal roots (P=0.006). The mean REF widths were 1.14±0.24 mm mesio-distally and 2.61±1.24 mm bucco-lingually. Roots with two canals presented a significantly wider REF (P<0.001) in the bucco-lingual dimension but had a significantly narrower REF in the mesio-distal direction (P<0.001) compared to roots with single canals. PRD measured on average 1.19±0.23 mm at the resection level and 1.44±0.27 mm at the coronal end of the REF. Almost all REFs were perfectly aligned with the longitudinal axis of the roots. With regard to healing outcomes, no correlations were found with REF and PRD values, respectively.

Conclusion:

The mean REF length was 2.02 mm. On average, a thickness >1 mm of peripheral root dentine was maintained. The REF or PRD dimensions had no statistical effect on the healing outcome.

Surgical Endodontics in Dogs: A Review

Surgical endodontic therapy (apical surgery) is a treatment alternative aimed at removing periapical inflammatory tissue followed by apical resection and retro-filling of the root canal. These procedures are performed through a trans-osseous approach. Terminology pertinent to this article include: apical (periapical) curettage – a surgical procedure to remove diseased tissue from the alveolar bone in the apical region of a pulpless tooth; apical cyst – a cyst in bone at the apex of a pulpless tooth. It is believed that such cysts arise after the death of the pulp from noxious physical, chemical, or bacterial stimulation of epithelial rests of Malassez; apicoectomy (apical resection) – amputation of the apical portion of the root and removal of soft tissue in the bone; epithelial rests of Malassez – cords, strands, or clusters of ectodermal cells in the periodontal ligament (or sometimes alveolar bone) derived from remnants of Hertwig's epithelial root sheath. These cells frequently begin proliferating when inflammation occurs in the periodontal ligament and are believed to be responsible for the genesis of the epithelial lining of apical cysts.

Microleakage evaluation around retrograde filling materials prepared using conventional and ultrasonic techniques

INTRODUCTION

The importance of the retrograde cavity preparation and the material used to restore is of utmost importance to achieve successful surgical endodontics.

AIM

The aim of the present study is to evaluate the apical micro-leakage of root end cavities filled with Mineral trioxide aggregate, Biodentine and light cure GIC using two different cavity preparation techniques that is conventional bur preparation and ultrasonic tip preparation.

MATERIALS AND METHODS

Eighty extracted single rooted human teeth (except mandibular incisors) with one canal, fully developed apices and without any major carious lesion are collected for the study. The teeth were sectioned at CEJ to standardize the length. Roots are instrumented upto master apical file 40 K size and obturated with gutta percha and AH plus sealer in lateral condensation technique. The teeth were then resected apically at 90° angle axis to the long axis of the root removing 3 mm of the apex. The teeth were divided in to four groups of 20 each- • Group I- samples restored with MTA. • Group II- samples restored with Biodentine. • Group III- (Positive control group)- samples restored with Light activated GIC. • Group IV - (negative control group)- no filling material. Each group is divided into two subgroups (a, b) of ten teeth each 1. Retropreparation done with ultrasonic retrotip. 2. Retropreparation done with conventional bur. The teeth were then immersed in 0.5% Rhodamine B dye for 48 h. The teeth were split longitudinally and the interface between the restored material and the canal wall is observed under Confocal laser scanning microscope. Depth of dye penetration was examined under stereomicroscope.

RESULTS

The statistical analysis was performed by One way ANOVA, t test. Pair wise comparision was done by Newman - Keuls multiple post hoc test. The mean values of Dye penetration for Group Ia (321.23), Group Ib (490.11), Group IIa (1065.14), Group IIb (1170.96), Group IIIa (1888.90), Group IIIb (2025.35). The samples prepared with ultrasonic retrotip showed less microleakage but it is statistically not significant.

CONCLUSION

MTA showed significantly less microleakage when compared to Biodentine and light cure GIC and there is no statistical difference between the ultrasonic retrotip preparation and conventional bur preparation.

Microscope versus endoscope in root-end management: a randomized controlled study

The purpose of this prospective, randomized, clinical study was to monitor the outcome of periradicular surgery, in which either a surgical microscope or an endoscope was used as a magnification device. A total of 113 teeth in 70 patients were included in the study, according to specific selection criteria. The choice of endoscope or surgical microscope was made using a randomized table. One hundred cases were followed for at least 2 years. Of these, 59 root-end management procedures were performed using a microscope and 41 using an endoscope. At the 2-year follow-up they were classified into three groups (success, uncertain healing and failure) according to radiographic and clinical criteria. After a 2-year follow-up, 91 teeth (91%) healed successfully. In the group using an endoscope 90% of successful healing was achieved, while 92% of success was recorded for the group using a microscope. No statistically significant difference was found in the treatment results relating to the type of magnification device. The type of magnification device used did not seem to affect the outcome of endodontic surgery.

SEM analysis of the integrity of resected root apices of cadaver and extracted teeth after ultrasonic root-end preparation at different intensities

AIM

To compare the integrity of root apices of cadaver and extracted teeth after resection, ultrasonic root-end cavity preparation at medium and low ultrasonic power settings and retrieval.

METHODOLOGY

Root canal treatment, perpendicular root-end resection and root-end preparation were performed on single-rooted anterior and premolar teeth (49 teeth in situ in maxillary and mandibular jaws from cadavers and 45 extracted teeth). Apical root-end cavities were prepared with the S12/90 degrees D tip and the Suni-Max ultrasonic unit (Satelec, Merignac, France) at the intensity prescribed by the manufacturer (power 7 at power mode S) (34 cadaver teeth, 30 extracted teeth) and at a lower intensity (power 4 at power mode S) (15 cadaver teeth, 15 extracted teeth). After ultrasonic preparation the cadaver teeth were retrieved from the jaws. Exaflex impressions (GC Corporation, Tokyo, Japan) were made of the root apices after resection, root-end preparation and retrieval. These impressions were processed for SEM analysis, and the recordings evaluated for cracks and marginal chipping.

RESULTS

In general, extracted teeth showed significantly more cracks and chipping than cadaver teeth. Lowering the ultrasonic power from medium to low intensity resulted in equal scores for cracks on extracted teeth and for chipping on cadaver teeth, in higher scores for cracks on cadavers and in lower scores for chipping on extracted teeth. Complete cracks and cracks originating from the root surface occurred only in extracted teeth.

CONCLUSIONS

The number of cracks and degree of chipping caused by ultrasonic root-end preparation was higher on extracted teeth than on cadaver teeth. Lowering the ultrasonic power from medium to low intensity cannot be recommended as it resulted in more cracks and equal chipping on cadaver teeth. Investigation of techniques and materials should be conducted in situ and not on extracted teeth.

Periapical endodontic surgery: a 3-year follow-up study

AIM

To monitor the outcome of periradicular surgery in a group of teeth treated with microsurgical technology and ultrasonic root-end preparation.

METHODOLOGY

One hundred and twenty-eight teeth with failed conventional root canal treatment were included. The surgical procedure was completed using ultrasonic retrotips and a zinc oxide-EBA (Super Seal, Ogna Pharmaceuticals. Milan, Italy)-reinforced material was used to seal the root end cavities. Lesions were examined radiologically at 1. 3. 6. 12, 24 and 36-month intervals. Radiographs were independently analysed according to a previously published classification.

RESULTS

Eight teeth were extracted due to fracture or perforations undetected radiologically: these cases were excluded from the study. Of the 120 teeth examined. the overall success rate was 92.5%; 94 healed with complete bone filling of the surgical cavity, 17 were considered to have healed by apical scar formation, four demonstrated uncertain healing and five were considered failures. Eighty of 120 teeth examined had successfully healed from a radiological point of view within 12 months. No differences in outcome occurred between anterior, premolar and molar teeth. Although all failures occurred in teeth with posts, no statistically significant difference was noted (Mann-Whitney U-test, P = 0.37).

CONCLUSION

Modern surgical endodontic procedures associated and ERA (Super Seal, Ogna Pharmaceuticals, Milan, Italy) root end fillings were successful over 3 years in 92.5% of cases.

Periradicular surgery of molars: a prospective clinical study with a one-year follow-up

AIM

The purpose of this prospective clinical study was to evaluate the outcome of periradicular surgery of molars after one year.

METHODOLOGY

The material consisted of 25 molars with 39 roots demonstrating periradicular lesions of endodontic origin. Surgical treatment included root-end resection, root-end preparation with sonic microtips, and root-end filling with Super-EBA cement. At the one-year follow-up examination, healing was evaluated clinically and radiographically. Healing was assigned to three categories: (i) success (ii) improvement, and (iii) failure using well defined criteria.

RESULTS

Eighty-eight per cent of the surgically treated molars showed successful healing. In 8%, the healing was rated as improved and only 4% were failures.

CONCLUSIONS

The outcome of the present study and data of recently published studies show that periradicular surgery may result in a predictable treatment outcome in molars with persistent periradicular lesions.

Ultrasonic root-end preparation with smooth and diamond-coated tips

The purpose of this study was to compare the effects of smooth and diamond-coated ultrasonic retrotips on the external and internal surfaces of root-end preparations with the aid of a scanning electron microscope (SEM). Forty-four mesial roots of human mandibular molars were selected. The canals were cleaned, shaped and obturated using gutta-percha and sealer. The apical portions were resected at a 45 degrees-angle bevel exposing both mesial canals and the isthmus area. The roots were then divided into two groups according to the type of root-end preparation: Group A--performed with smooth retrotips (S) and Group B--performed with diamond-coated retrotips (DC). The specimens were coded and prepared for SEM evaluation. Observations of the external surface preparation showed that the S and DC retrotips produced very well-centered cavities involving both canals and isthmus area with minimal deviations and no perforative defects. When the internal surface of the root-end preparations was evaluated, it was evident that the use of S retrotips resulted in clean canal walls with little superficial debris and smear layer. Internal canal surfaces done with DC retrotips were irregular showing patent grooves, in contrast with the more uniform, regular and smoother surfaces when S retrotips were employed.

Root deformation during root-end preparation

Ultrasonic root-end preparation techniques have recently been introduced and revolutionized the field of endodontic surgery. However, several reports claimed that there was an increasing incidence of crack formation after ultrasonic root-end preparation. As yet, little work has focused on the root deformation during root-end preparation. Thus, the purpose of this investigation was to measure the amount of root deformation during root-end preparation with the use of microhandpiece and ultrasonic systems by using strain gauge methods, and simultaneously to detect any cracks with the aid of the stereomicroscope, stain, and an image processing system. The results demonstrated the ultrasonic instrumentation produced significantly greater strain on average than that generated with the microhandpiece system. From the viewpoint of fracture, any technique that could diminish the strain on the root would decrease the likelihood of fracture; however, no crack was observed on any resected surface of roots in this study.