• Journal of Periodontal and Implant Science
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• v.29 no.1
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• pp.65-80
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• 1999

The purpose of this study was to evaluate the effects of periodontal curet and various rotating instruments on the root surfaces. Thirty-five extracted teeth with advanced periodontal disease were used. They was root planed with periodontal curet, periodontal Perio-Clean bur, periodontal Roto-Perio bur, resin polishing ET bur, and resin polishing diamond fissure bur. To find dentinal tubule orifices on the root surface, tetracycline HCI solution was applied to the one tooth of treated each group. Then, root surfaces were investigated using scanning electron microscope. Amount of loss of cementum was evaluated by loss of tooth substance index. The results were as follows. 1. Groups treated with periodontal curet and Perio-Clean bur showed irregular surface and concavities. Concavities seemed to be lacunae of cementocyte. Other groups treated with Roto-Perio bur, resin polishing ET bur, and resin polishing diamond fissure bur showed partially opened dentinal tubule orifice. 2. Groups treated with periodontal curet and Perio-Clean bur and tetracycline HCl showed irregular surface. No dentinal tubule orifice was seen. Other groups treated with Roto-Perio bur, resin polishing ET bur, and resin polishing diamond fissure bur and tetracycline HCl showed dentinal tubule orifice with various shape and size. 3. Loss of tooth substance indices were compared between groups. There was no statistically difference between periodontal curet and Perio-Clean bur groups. There were statistically differences between periodontal curet and Roto-Perio bur, ET bur, and diamond fissure bur groups. As a result of this study, groups treated with Roto-Perio bur, resin polishing ET bur, and resin polishing diamond fissure bur showed more cementum removed than groups treated with periodontal curet and Perio-Clean bur. Therefore, in a conventional treatment for periodontal disease, it was recommended that periodontal curet or Perio-Clean bur should be used. In a treatment for regeneration of periodontal tissue, it was recommended that Roto-Perio bur, resin polishing ET bur, or resin polishing diamond fissure bur should be used

• Journal of Periodontal and Implant Science
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• v.29 no.2
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• pp.387-400
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• 1999

One of the fundamental causes of periodontal disease is accumulation of bacterial plaque and calculus and most effective method of removing these plaque and calculus are scaling and root planning using hand curet and ultrasonic scaler. Many studies concerning residual degenerated mineral content after periodontal therapies have been carried out, but some problems about these studies were also known. This research studies mineral concents and distribution of residual root surfaces after perfoming hand curet and ultrasonic scaler on root surfaces of single rooted teeth which were extracted for periodontal reasons. EPMA were used to avoid errors from chemical quantative analysis and in addition SEM observation was also performed. The results were as follows. 1. No differences were found between curet group andultrasonic scaler group in Ca, P, Mg and Na level. 2. Concentration level was decreased in the sequence of Ca, P, Mg and Na. 3. Ca and P level were decreased as going to apical portion at curet group and ultrasonic scaler group. 4. More cementum was removed at cervical portion compared to other portion at curet group and ultrasonic scaler group. 5. Ca, P, Mg level was higher in dentin compared to cememtum. There was no difference in mineral level for Ca, P, Mg and Na between root surfaces treated with hand curet and ultrasonic scaler.

• Journal of Periodontal and Implant Science
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• v.30 no.2
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• pp.455-472
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• 2000

Instrumentation for periodontal therapy may induce marginal damage which increases plaque accumulation and result in periodontal disease. But there have not been many reports of instrumentations on the artificial crown so far. Therefore this study is conducted to evaluate the effects of various repeated instrumentations on the porcelain crown marginal portion. Of the 10 extracted periodontally diseased maxillary first premolars, were 12 proximal surface used in this study. The finishing line of the preparation was placed on the root surface below CEJ and then the crown was cast and cemented in usual manner. Every 4 surfaces of the 3 instruments-curet, ultrasonic scaler, and ultrasonic curet- is used. and four samples used in each instruments. The relevant procedures and measurements were repeated 3 times in each surfaces. Marginal gap is measured by the microscope and surface roughness, Scannig Probe Microscope. Measurements are made at 5 points in each surfaces, making 20 points in each instrument. The results evaluated statistically were as follows 1. As instrumentation was repeated, both marginal gap and roughness were increased in all group 2. In the hand curet, marginal gap was increased every instrumentation and roughness was increased after second. 3. In the ultrasonic scaler, both marginal gap and roughness were increased every instrumentation. 4. In the ultrasonic curet, marginal gap was increased after third instrumentation and roughness was increased after second. 5. Marginal gap and roughness used by the ultrasonic curet were lower than the others and no difference was seen between the hand curet and ultrasonic scaler From the results of this study, the ultrasonic curet was useful in some aspect, but careful instrumentation was needed. Furthermore it was important to minimize the instrumentation through complete periodontal therapy before setting and adequate plaque control.

• Journal of Periodontal and Implant Science
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• v.38 no.1
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• pp.23-30
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• 2008

Purpose: The purpose of this study was to investigate the incidence of curet fracture and its contributing factors. Material and Methods: Fifty-eight periodontal curets which were broken during periodontal treatment in Kangnung National University Dental Hospital for 1 year were used as study materials. The blade thickness of new curets and broken ones was measured using a digital micrometer. Types of treatment procedures, clinical experience of operators, point of breakage, and method of removal of broken fragments were recorded for each broken curet. Results: The incidence of curet fracture in root planing (16.4 curets per 1,000 procedures) was higher than those in flap surgery (7.5) or supragingival scaling (2.7). No curet was broken during supportive periodontal treatment. The incidence of fracture did not seem to be related with clinical experience of operators. The most frequent breakage point of the curets were upper 1/3 of blades. Fifty-six of 58 broken fragments were removed by non-surgical methods. Two broken tips which could not removed non-surgically were left in the pockets, and proved to be removed spontaneously 1 week later. Conclusion: Root planing showed higher incidence of curet fracture than any other type of periodontal treatment. Most of the fractured fragments were removed by non-surgical method. Further study is needed to develop methods of removal of the fragments which can not be removed non-surgically.

• Journal of Periodontal and Implant Science
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• v.27 no.3
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• pp.585-595
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• 1997

Removal of subgingival calculus is essential for the success in periodontal treatment. Subgingival instrumentation is used for the removal of all bacterial plaque and calculus. In this study, two types of anterior curet were used on ant. teeth to conduct subgingival scaling and root planing. The remaining amount of calculus was evaluated according to type of instrument, depth of pocket, and tooth surface. 24 teeth extracted from patients being treated at Dan Kook University dept. Perio. were used. 4 surfaces per tooth a total of 96 areas were evaluated. 12 teeth treated with Gracey No. 1-2 was used as the control group and 12 teeth treated with Mini-five curet No. 1-2 was the experimental group. The 4 surfaces of the teeth {buccal, mesial, lingual or palatal, distal) were observed under a stereomicroscope and the images were captured 3 times per surfaced with a CCD. The image were observed on the monitor using a $10{\times]10$ grid produced with the Microsoft power point. The amount of calculus remaining was evaluated 3 times per surface. The results were as follows. 1. There was no significant difference in remaining calculus according to the pre-treatment pocket depth, and tooth position{Mx. or Mn). 2. The Mini-five curet showed better results than the Gracey curet but there was no statistically significant difference. 3. In both Gracey curet group and Mini-five curet group the lingual(or palatal) surface showed significant difference compared to the other surfaces(p<0.05). From the results above, it is thought that when treating ant. teeth consideration of the tooth surface is more important than the choice of instrument.

• Journal of Periodontal and Implant Science
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• v.31 no.1
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• pp.257-269
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• 2001

Removal of subgingival calculus is essential for the success in periodontal treatment. Subgingival instrumentation is used for the removal of all bacterial plaque and calculus. In this study, Gracey curet and Ultrasonic curet were used on single rooted teeth to conduct subgingval scaling and root planning. The remaining amount of calculus was evaluated according to type of instrument, depth of pocket, and tooth surface. 24 teeth were extracted from 14 patients being treated at department Periodontology Seoul Advantist dental hospital were used. Total 96 area(4 surface per teeth) were evaluated. 12 teeth treated with Gracey curet were used as the control group and the other 12 teeth treated with Ultrasonic curet were examined for experimental group. The 4 surface of the teeth(buccal, mesial, lingual or palatal, distal) were observed through the stereomicroscope and the images of the surface were captured and saved in CCD. The images were displayed on the monitor and the amount of calculus remained was evaluated by overlapping $10{\times}10$ grid pixel screen produced by Microsoft power point. The results evaluated were as follows 1. There was no statistically significant difference in residual calculus and tooth position following scaling and root planning of all group, but statistically significant correlation with residual calculus, probing depth, instruments and tooth surface. 2. There was statistically significant correlation between residual calculus and probing depth, but no statistically significant difference in residual calculus, tooth surface and tooth position on experimental(Ultrasonic curet) group. 3. There was no statistically significant difference in residual calculus according to the pre-treatment pocket depth and tooth position, but statistically significant correlation with tooth surface. The amount of residual calculus increase with mesial, distal, buccal and lingual(or palatal) surface on control(Gracey curet) group. 4. The Gracey showed better results than ultrasonic curet in mesial and distal surface, and there is significant difference. The results demonstrate that ultrasonic curet alone is inadequate for thorough subgingival debridement and suggest that Ultrasonic curet with Gracey curet should be more effective.

• Journal of Periodontal and Implant Science
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• v.27 no.3
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• pp.575-584
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• 1997

The quality of periodontal instrument cutting edge is a basic element of effective root planing procedure. Using instruments, the sharp edge is changed into blunt or beveled edge. With the blunt instrument, the periodontal treatment can't be carried into accuracy and effective. The study on the wear of periodontal curet is insufficient, there are few publications about the change of sharpness of cutting egde after using instrument and a certen reports were published on the study of scanning electron microscope(SEM) examination. In this study, to declare the number of strokes for sharpening of instruments, the changes of cutting edge is measured by the clinical methods, tactile sensitivity examination and refraction light-white line test after scaling strokes and root planing strokes. SEM test was added for defined the changes of cutting edges. The 7/8 Gracey curets that have been never used was tested. Maxillary molars which were extracted from the School of Dental Medicine, Dankook University was used. Subjected teeth had attachment loss more than 6 mm in bucca-lingual surface and sufficient calculus of a band type in cervical area. The strokes of curet were executed 3, 5, 7, 9, 11, 13 times on scaling stroke and 10, 15, 20, 25, 30, 35 times on root planing stroke. A resident has periodontal experience over 3 years carried out the clinical examinations those tactile sensitivity examination and refraction light-white line test 5 times. The case there being tactile sensitivity certenly is 2, the case being felt tactile sensitivity is 1, and the case there not being tactile sensitivity is 0. The visual examination was recorded as following. The case that refracted white line is not recognised is 2, the case that uncerten is 1, and the case that acknowledged is 0. The results were obtained as follows. 1. After scaling strokes, the tactile sensitivity was reduced after 11 strokes and disappeared in 13 strokes. 2. In tactile sensitivity after root planing procedures, sensitivity was reduced after 25 strokes and disappeared in 35 strokes. 3. In case of visual examination, the detection of refracted white line was increased after 9 strokes of scaling procedures and the accuracy of wear wasn't showed after root planing procedures. 4. In SEM, metal projection was observed on new periodontal curet cutting edge and it was disappeared after scaling procedures. 5. In SEM, the cutting edge was showed changing linear into an aspect of the surface after 5 strokes of scaling procedures and 10 strokes of root planing procedures and showed beveled edge in 11 strokes of scaling procedures, 25 strokes of root planing procedures. The results of 3-type examination indicated that the sharpening of curet should be performed after 11 strokes of scaling procedures and 25 strokes of root planing procedures.

• Journal of Periodontal and Implant Science
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• v.30 no.2
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• pp.443-455
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• 2000

The aim of periodontal therapy is a removal of a bacterial plaque butthe instrumentation for plaque control has two nature : removal of a bacterial plaque and increase of surface roughness. Complication of instrumentation is enable to damage to the root surface and artificial crown. Therefore this study was conducted to evaluate the effects of repeated instrumentation on the marginal portion of artificial crown. Fifteen proximal surfaces of ten extracted periodontally diseased maxillary first molars were used. The finish line was placed on the root surface, and then the crown was casted and cemented in usual manner. Three kinds of instruments: hand curet, ultrasonic scaler, and ultrasonic curet were used. After instrumentation, final polishing was done with rubber cup and pumice. And surface changes were evaluated by stereomicroscope and scannig probe microscope. Roughness was increased after instrumentation in all groups, and was decreased after polishing except ultrasonic scaler group. Roughness in the ultrasonic scaler group was lower than others, and roughness after polishing in the hand curet group was lower than others. These results indicate that polishing procedure is recommended, because periodontalinstruments increase the surface roughness and induce the irreversible damage to the marginal portion.

• Journal of Periodontal and Implant Science
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• v.29 no.3
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• pp.703-715
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• 1999

The purpose of this study was to evaluate the degree of wear of periodontal curet's cutting edges made by three different manufacturers. In the first case of the experiment, this study was done with each new curett in the following three experiment. Twelve new double-ended No. 11/12 Gracy curettes from three different manufacturers (A, B and C) was randomly selected from our stock at first test. They were weared by wear tester with fixed pressure and limited distance. This study measured the width of worn curettes'cutting edge. The results were as follows ; 1)In 50 times experiment, this study discoverd that each manufacturer's curette was appeared with different degree of wear (p<0.01) 2)In 100 times experiment, this study result similarly to the 50 times experiment(p<0.01). 3)In 150 times experiment, the result of this study were alike as the X50 experiment and X100 experiment. In the second case of the experiment, the study was done with a curett of a manufacturer in the following three experiment. Two double-ended No. 11/12 Gracy curette from three different manufactures (A, B and C) was randomly selected from our stock at second test. 1)In 50 times experiment, this study discovered that each manufacturer's curette was appeared with different degree of wear (p<0.05). 2)In 100 times experiment, the result was same, compared with the 50 times experiment. 3)In 150 times experiment, this study also discovered that the result was same with the result of the upper two cases. In conclusion, this study discovered that the two cases of experimental were shown with a same result.

• Journal of Dental Rehabilitation and Applied Science
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• v.30 no.2
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• pp.131-137
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• 2014

Purpose: This study examined the efficiency and wear of periodontal instrument sharpening using aluminum oxide stones with different levels of roughness. Materials and Methods: Thirty new No. 9-10 Gracey curets were used in this study. All curets had become dull after scaling and root planing. After similar blunting, the instruments were divided randomly into three groups (240, 600, 800 grit) containing 10 curets each. The stones were applied correctly to the lateral surface of each curet to maintain the $70-80^{\circ}$ angle. After resharpening, sharpness of the curets was examined by an optical microscope. After 20, 40, 60, and 80 strokes, the wear was measured at 1 mm and 2 mm from the tip of the cutting edge using a digital caliper. The data was analyzed statistically using analysis of variance (ANOVA) with repeated measures, 2-way ANOVA, and a Fisher's exact test. Results: The degree of sharpness increased significantly (P < 0.001) as the number of sharpening strokes grew for all stones. A comparison of the degree of sharpness on the same number of strokes showed that the 240 grit group significantly excelled the other groups on 5 and 10 strokes, respectively (P < 0.001). The mean wear showed no statistically significant difference among the groups (P > 0.05). Conclusion: The efficiency of Gracey curet resharpening was enhanced with more coarse stones, though we should consider the wear of the instrument during resharpening.