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PubMed2003

Comparative in vivo analysis of the sealing ability of three endodontic sealers in post-prepared root canals.

AIM: To compare the sealing ability of the endodontic sealers AH Plus, Sealer 26 and Endofill in premolar teeth of dogs exposed to the oral cavity after post-preparation. METHODOLOGY: Forty teeth with two canals each underwent root canal cleaning and shaping. Before filling, the canals were randomly distributed into three groups according to the sealer to be used: Group 1 - AH Plus; Group 2 - Sealer 26; and Group 3 - Endofill (Dentsply, Indústria e Comércio Ltda.). Immediately after filling, the gutta percha and sealer were partially removed from the canals, leaving material only in the apical third of the root. The teeth were temporarily sealed with glass ionomer sealer for 72 h to ensure setting. The coronal seal was then removed and the canals were exposed to the oral cavity for 45 days. The animals were euthanased and their mandibles and maxillae were removed. After abundant irrigation with distilled water, the canals were dried and filled with India ink. The teeth were sealed again for 96 h before extraction. The roots of the extracted premolars were separated and stored in labelled test tubes. The roots were cleared and the extent of dye penetration was measured with a 20x stereoscopic magnifying lens. RESULTS: Statistical analysis revealed that there were significant differences between the sealers studied (P < 0.001). Means for the extent of dye penetration for AH Plus, Endofill and Sealer 26 were, respectively, 0.13, 2.27 and 3.08 mm. CONCLUSIONS: After 45 days exposure to the oral cavity, none of the sealers was capable of preventing leakage and coronal dye penetration. There were significant differences between the sealers studied, in terms of mean dye penetration.

Analysis of Variance↗

PubMed2004

Comparison of apical transportation between ProFile and ProTaper NiTi rotary instruments.

AIM: To use a newly developed radiographic technique to compare apical transportation and loss of working length (WL) between.06 taper ProFile Series 29 and ProTaper nickel-titanium (NiTi) rotary instruments in vitro. METHODOLOGY: Mesio-buccal canals of 40 extracted mandibular molars were randomly divided into two groups. Group 1 was instrumented with ProFile and group 2 with ProTaper instruments according to the manufacturers' directions. A specially constructed radiographic jig with a Schick digital radiographic system (Schick Technologies Inc., Long Island City, NY, USA) was used to take pre- and postoperative radiographs of the samples at predetermined angulations. Using AutoCAD 2000 (Autodesk Inc., San Rafael, CA, USA), the central axes of initial and final instruments were radiographically superimposed to determine the loss of WL and degree of transportation at D(0), D(1), D(2) and D(4) from the WL. Data were analysed using repeated-measures anova. RESULTS: A statistically significant difference in apical transportation was found at the D(4) level between the two groups (P = 0.05). There was no statistical significance regarding postinstrumentation change in WL between groups. Spearman's Bivariate Correlation analysis indicated no statistically significant relationship between the radius of curvature and transportation. CONCLUSION: The results indicate that both ProTaper and ProFile instruments are comparable to each other in regards to their ability to optimally enlarge root canal with minimal transportation and loss of WL in vitro.

Dental Alloys↗

PubMed2004

Increased width of the apical periodontal membrane space in endodontically treated teeth may represent favourable healing.

AIM: To examine cases showing increased width of the periodontal space (IW) at a long-term follow-up examination and to determine whether this finding could be explained by endodontic or nonendodontic factors. METHODOLOGY: A series of intraoral radiographs was obtained from 131 patients 20-27 years after root canal treatment. The same individuals had been examined 10 years earlier, and radiographs taken immediately after treatment were also available. Fourteen roots (5.6%) demonstrated increased width of the apical periodontal space at the end of the study period. These were subjected to further analysis in an attempt to disclose possible explanatory factors. RESULTS: Two of the 14 cases had reduced marginal bone levels interpreted as the origin of the IW. In three cases, overextended root filling material present 10 years earlier had disappeared and the persistent IW was interpreted as representing a remodelling process. In six cases the findings were explained as being caused by physical and anatomical factors that represented healing without complete re-formation of the apical periodontal structures, or both. Three cases were judged as unfavourable, on the basis of lacking progress in healing, unsatisfactory obturation of the apical portion of the root canal or dentine resorption close to the apical end of the root filling. CONCLUSION: Most of the 14 IW cases examined after 20-27 years could be explained by reduced marginal bone support, or by physical and anatomical factors or they might represent incomplete reformation of the typical apical morphology and were thereby recorded as favourable outcomes.

Adult↗

PubMed2004

SEM evaluation of canal wall dentine following use of Mtwo and ProTaper NiTi rotary instruments.

AIM: To compare using scanning electron microscopy (SEM) root canal walls following instrumentation in vitro with two different rotary NiTi instruments. The hypothesis was that no difference should be observable between the experimental groups in terms of debris on canal walls and surface morphology. METHODOLOGY: Twenty-four single-rooted human teeth were selected. Two types of NiTi instruments were used, Mtwo (Sweden & Martina, Padova, Italy) and ProTaper (Dentsply Maillefer, Ballaigues, Switzerland). Irrigation for both groups was performed after each instrument change with 5% NaOCl, 3% H2O2 and 17% EDTA solutions. Three different areas (coronal, middle and apical thirds) of the root canal were evaluated using SEM. The canal wall of each sample was assessed and compared using a predefined scale of four parameters, namely, smear layer, pulpal debris, inorganic dentine debris, surface profile. Data were analysed statistically using the Kruskal-Wallis test (anova). RESULTS: A statistically significant difference (P < 0.01) was found between the apical third and the middle and coronal thirds for both groups. No difference was observable between instrumentation groups. In the apical third canal walls were often contaminated by inorganic debris and by smear layer. In the apical third, the surface profile was affected by uninstrumented regions, comprising dentine depressions and grooves in which predentine was still visible. CONCLUSION: Both instruments produced a clean and debris-free dentine surfaces in the coronal and middle thirds, but were unable to produce a dentine surfaces free from smear layer and debris in the apical third. The presence of deep grooves and depression on dentine walls in the apical third may well explain the presence of less-instrumented areas.

Chelating Agents↗

PubMed2005

The effect of high-frequency electrical pulses on organic tissue in root canals.

AIMS: To evaluate debris and smear layer scores after application of high-frequency electrical pulses produced by the Endox Endodontic System (Lysis Srl, Nova Milanese, Italy) on intact pulp tissue and organic and inorganic residues after endodontic instrumentation. METHODOLOGY: The study comprised 75 teeth planned for extraction. The teeth were randomly divided into two groups (60 teeth) and a control group (15 teeth): group 1 (30 teeth) was not subjected to instrumentation; group 2 (30 teeth) was instrumented by Hero Shaper instruments and apical stops were prepared to size 40. Each group was subdivided into subgroups A and B (15 teeth); two electrical pulses were applied to subgroups 1A and 2A (one in the apical third and one in the middle third, respectively, at 3 and 6 mm from the root apices); four electrical pulses were applied to subgroups 1B and 2B (two in the apical third, two in the middle third). The control group (15 teeth) was prepared with Hero Shapers and irrigated with 5 mL of EDTA (10%) and 5 mL of 5% NaOCl at 50 degrees C but not subjected to the electrical pulse treatment. Roots were split longitudinally and canal walls were examined at 80x, 200x, 750x, 1500x and 15,000x magnifications, using a scanning electron microscope. Smear layer and debris scores were recorded at the 3 and 6 mm levels using a five-step scoring scale and a 200-microm grid. Means were tested for significance using the one-way anova model and the Bonferroni post-hoc test. The differences between groups were considered to be statistically significant when P < 0.05. RESULTS: The mean value for debris scores for the three groups varied from 1.80 (+/-0.77) to 4.50 (+/-0.68). The smear layer scores for group 2 and the control specimens varied from 2.00 (+/-0.91) to 2.33 (+/-0.99). A significant difference was found in mean debris scores at the 3 and 6 mm levels between the three groups (P < 0.001). The Bonferroni post-hoc test confirmed that the difference was due to group 1. In the two subgroups treated with four high-frequency pulses (1B and 2B) a substantial reduction in mean debris scores was found at the 3 and 6 mm level; subgroup 2B was practically free of organic residue. No significant differences for mean smear layer and debris scores were recorded between group 2 and the control group at the two levels; a significant difference was found only for mean smear layer scores at the 3 mm level between subgroup 2B and the control group (P < 0.05). CONCLUSIONS: The Endox device used with four electrical pulses had optimal efficacy when used after mechanical instrumentation. Traditional canal shaping and cleaning was essential to ensure an effective use of high-frequency electrical pulses in eliminating residues of pulp tissue and inorganic debris.

Adult↗

PubMed2005

Periapical biomechanics and the role of cyclic biting force in apical retrograde fluid movement.

AIM: To investigate the stress distribution pattern in the periapical region caused by biting forces and to study the role of cyclic biting loads on periapical fluid movement. METHODOLOGY: In the first part, a digital photoelastic experiment was conducted to study stress distribution in the periapical region. In the second, 20 maxillary central incisors were selected and divided into three main groups: normal intact teeth (group 1), tooth specimens in which the root canal was enlarged and maintained wet (group 2), and tooth specimens in which the root canal was enlarged and maintained dry (group 3). The tooth specimens were placed in a polycarbonate support with a cavity filled with a sponge soaked in methylene blue solution to simulate a periapical defect with exudate. During testing, the specimens were placed in a water bath at 37 degrees C, and were loaded cyclically with a load of 20 N, at a rate of 72 cycles min(-1), to a maximum of 20,000 cycles. The specimens were then sectioned and evaluated for retrograde fluid movement using light microscopy. The data were analysed using one-way anova (post hoc tests). RESULTS: Digital photoelastic experiments showed that the compression of teeth produced bending stresses in the periapical region. Testing with cyclic loads demonstrated retrograde fluid movement into the apical portion of the root canal and extraradicular region in all groups. There was a significant difference amongst the apical retrograde fluid movement displayed by different groups (<0.01). Group 2, in which the root canal was enlarged and maintained wet showed maximum retrograde fluid movement, whilst group 3, in which the root canal was enlarged and maintained dry showed the least retrograde fluid movement. CONCLUSIONS: Biting forces would cause bending of the periapical bone and cyclic biting forces would contribute to retrograde fluid movement into the root canal space and extraradicular region.

Alveolar Process↗

PubMed2005

Ex vivo evaluation of the capacity of the Tri Auto ZX to locate the apical foramen during root canal retreatment.

AIM: To evaluate ex vivo the capacity of the Tri Auto ZX to locate the apical foramen during root canal retreatment. METHODOLOGY: The root canals of 62 maxillary and mandibular canines were prepared to a length 1 mm short of the apical foramen, to an apical size 35 using 1% sodium hypochlorite as an irrigant. Once prepared, the length of each tooth was measured directly using a size 15 K-Flexofile introduced in the canal until the tip was visible at the apical foramen. After the file was removed, its length was recorded to a precision of 0.01 mm using a calliper. These direct lengths (DL) became the 'gold standard' for comparison with the electronic lengths (EL) derived from the Tri Auto ZX. After direct measurement, the tooth was measured electronically (EL1) and the canals were filled using lateral condensation of gutta-percha cones and sealer. Seven days later the root filling was removed using solvent, Gates-Glidden burs, and K-files, and new electronic lengths determined (EL2). The electronic lengths (EL1 and EL2) were compared with the DL, and the differences were analysed statistically using the proportions test and Student's t-test. RESULTS: At a tolerance limit of +/-0.5 mm, EL1 coincided with the DL in 76% of cases. Lengths obtained in the presence of remnant of filling material (EL2) coincided in 81% of cases. The proportions test used to compare these percentages showed no statistically significant difference between EL1 and EL2 (P > 0.05). The Student's t-test revealed a statistically significant difference (P < 0.05) between the means of the differences between DL/EL1 (-0.36 mm) and DL/EL2 (-0.04 mm). CONCLUSION: The Tri Auto ZX was accurate to +/-0.5 mm in more than 80% of teeth following removal of root fillings.

Cuspid↗

PubMed2005

Apical extrusion of intracanal bacteria following use of two engine-driven instrumentation techniques.

AIM: To evaluate the number of bacteria extruded apically from extracted teeth ex vivo after canal instrumentation using the two engine-driven techniques utilizing nickel-titanium instruments (ProTaper and System GT). METHODOLOGY: Forty extracted single-rooted human mandibular premolar teeth were used. Access cavities were prepared and root canals were then contaminated with a suspension of Enterococcus faecalis and dried. The contaminated roots were divided into two experimental groups of 15 teeth each and one control group of 10 teeth. Group 1, ProTaper group: the root canals were instrumented using ProTaper instruments. Group 2, System GT group: the root canals were instrumented using System GT instruments. Group 3, control group: no instrumentation was attempted. Bacteria extruded from the apical foramen during instrumentation were collected into vials. The microbiological samples from the vials were incubated in culture media for 24 h. Colonies of bacteria were counted and the results were given as number of colony-forming units. The data obtained were analysed using the Kruskal-Wallis one-way analysis of variance and Mann-Whitney U-tests, with alpha = 0.05 as the level for statistical significance. RESULTS: There was no significant difference as to the number of extruded bacteria between the ProTaper and System GT engine-driven systems (P > 0.05). CONCLUSIONS: Both engine-driven nickel-titanium systems extruded bacteria through the apical foramen.

Colony Count, Microbial↗

PubMed2005

Calcium hydroxide dressings using different preparation and application modes: density and dissolution by simulated tissue pressure.

AIM: To study the effect of different apical shapes in prepared simulated root canals on the application of a commercially prepared calcium hydroxide paste by a syringe or lentulo spiral. METHODOLOGY: Three different types of root canal preparation were performed in 90 simulated canals: group A to an apical size 20 and a 0.10 taper using hand and rotary instruments, group B to an apical size 30 and a 0.08 taper using GT rotary instruments and group C to an apical size 40 and a 0.04 taper using ProFile 0.04 instruments. The insertion of calcium hydroxide [Ca(OH)2] paste was accomplished using either a lentulo spiral or a syringe. After 1 week of simulated fluid pressure applied to the apical end of the canal using physiological saline solution, the solution was evaluated for released Ca(OH)2. The specimens were weighed initially, after preparation, after insertion of Ca(OH)2 paste, after temporization with Cavit and after 1 week of simulated fluid pressure. Digital radiographs of the filled canals were taken and canal areas in mm2, gray values of the Ca(OH)2 dressings, total area of voids in mm2, as well as location of voids in the apical, middle or coronal thirds of the root canals were measured. Analyses of variance, with Scheffe's post-hoc tests, as well as chi-square tests were performed. RESULTS: Canals in group C had significantly fewer (P < 0.01) radiographic voids than canals in groups A and B. Using a lentulo spiral resulted in significantly (P < 0.05) fewer voids compared with the injection technique. More voids were detected coronally compared with middle and apical root canal thirds (P < 0.05). CONCLUSIONS: Canal shape and method of application had an impact on the amount and radiodensity of calcium hydroxide dressings in simulated root canals. Canals prepared to an apical size 40 and a taper of 0.04 had the least number of voids; Ca(OH)2 was placed with significantly fewer voids using a lentulo spiral compared with the injection technique.

Calcium Hydroxide↗

PubMed2006

A laboratory analysis of gutta-percha-filled area obtained using Thermafil, System B and lateral condensation.

AIM: To determine the percentage of gutta-percha-filled area (PGFA) in the apical third of root canals when filled with either Thermafil, System B or lateral condensation. METHODOLOGY: Sixty extracted human maxillary central incisor teeth were root filled as following: G1: lateral condensation (n = 20), G2: System B (n = 20) and G3: Thermafil system (n = 20). A horizontal section was cut 2 and 4 mm from the apical foramen of each tooth. The samples were prepared for microscopic analysis and photomicrographs of each apical surface were taken at a magnification of 50x. Through digital image analysis, the cross-sectional area of the canal and the gutta-percha was measured. The PGFA was calculated. The PGFA data obtained in the three groups were analysed using a nonparametric Friedman and Wilcoxon signed-rank tests. RESULTS: Significant differences in PGFA were found between the Thermafil System (G3) and both System B (G2) and lateral condensation (G1) (P < 0.01). The greatest PGFA occurred in the Thermafil group. No significant statistical difference was found between System B and lateral condensation (P > 0.05). CONCLUSIONS: The coated carrier gutta-percha system Thermafil produced significantly higher PGFAs than lateral condensation and System B techniques.

Anatomy, Cross-Sectional↗

PubMed2006

The fundamental operating principles of electronic root canal length measurement devices.

It is generally accepted that root canal treatment procedures should be confined within the root canal system. To achieve this objective the canal terminus must be detected accurately during canal preparation and precise control of working length during the process must be maintained. Several techniques have been used for determining the apical canal terminus including electronic methods. However, the fundamental electronic operating principles and classification of the electronic devices used in this method are often unknown and a matter of controversy. The basic assumption with all electronic length measuring devices is that human tissues have certain characteristics that can be modelled by a combination of electrical components. Therefore, by measuring the electrical properties of the model, such as resistance and impedance, it should be possible to detect the canal terminus. The root canal system is surrounded by dentine and cementum that are insulators to electrical current. At the minor apical foramen, however, there is a small hole in which conductive materials within the canal space (tissue, fluid) are electrically connected to the periodontal ligament that is itself a conductor of electric current. Thus, dentine, along with tissue and fluid inside the canal, forms a resistor, the value of which depends on their dimensions, and their inherent resistivity. When an endodontic file penetrates inside the canal and approaches the minor apical foramen, the resistance between the endodontic file and the foramen decreases, because the effective length of the resistive material (dentine, tissue, fluid) decreases. As well as resistive properties, the structure of the tooth root has capacitive characteristics. Therefore, various electronic methods have been developed that use a variety of other principles to detect the canal terminus. Whilst the simplest devices measure resistance, other devices measure impedance using either high frequency, two frequencies, or multiple frequencies. In addition, some systems use low frequency oscillation and/or a voltage gradient method to detect the canal terminus. The aim of this review was to clarify the fundamental operating principles of the different types of electronic systems that claim to measure canal length.

Dental Pulp Cavity↗

PubMed2006

Root canal morphology of mandibular incisors in a Jordanian population.

AIM: To investigate the root canal morphology of mandibular incisors in a Jordanian population using a canal staining and tooth-clearing technique. METHODOLOGY: Four hundred and fifty extracted mandibular incisors were collected from dental clinics within north Jordan. Following pulp tissue removal and staining of the canal systems, the teeth were decalcified with 5% nitric acid, dehydrated with ascending concentrations of alcohol and rendered clear by immersion in methyl salicylate. Cleared teeth were examined by eye and the following features were evaluated: (i) number and type of root canals; (ii) presence and location of lateral canals and intercanal communications; (iii) location of apical foramina; and (iv) frequency of apical deltas. RESULTS: The majority of mandibular incisors had a single canal (73.8% of teeth possessed a Type I canal system). Although 26.2% of the roots possessed two canals, only 8.7% had two separate apical foramina. CONCLUSIONS: The prevalence of two canals in this group of mandibular incisors was 26.2% and is within the range of previous studies performed on populations of different racial origin.

Coloring Agents↗

PubMed2005

Neurosensory disturbances following bone harvesting in the symphysis: a prospective clinical study.

OBJECTIVE: To analyse the occurrence and resolution of neurosensory disturbances following bone harvesting from the symphysis. MATERIAL AND METHODS: In 30 patients, skin sensitivity of the chin/lower lip area and pulp sensitivity of all mandibular anterior teeth were assessed preoperatively, at the time of suture removal, at 6 and 12 months postoperatively. In addition, bone defect dimensions of the donor site were measured intraoperatively, and distances from defect margins to adjacent anatomical structures, such as root apices, mental foramen and inferior border of mandible, were assessed postoperatively on a panoramic radiograph. RESULTS: Pulp sensitivity changes were found in 18.6% of adjacent teeth at the time of suture removal. At the 6-month follow-up, 8.1% of teeth, and at the 12-month re-examination, 0.6% of teeth presented with altered sensitivity. This decrease over time of the number of affected teeth per patients with sensitivity changes was significant (P=2.35e-007). Lower lip hypaesthesia was only observed in one patient postoperatively, with complete resolution at the 6-month follow-up. Radiographic measurements of distances between donor defect and adjacent anatomical structures only reached significant difference for one parameter in patients with sensitivity changes compared with patients without sensitivity changes. CONCLUSIONS: Patients must be informed about possible transient and long-term sensitivity changes of adjacent teeth and soft tissues following bone harvesting from the chin. However, by correctly placing mucoperiosteal incisions and bone cuts, the risk of sensitivity changes can be minimized.

Adolescent↗

PubMed1997

The influence of endodontic treatment upon periodontal wound healing.

The interrelationship between periodontal and endodontic disease has aroused much speculation, confusion, and controversy. Pulpal and periodontal problems are responsible for more than 50% of tooth mortality today. Diagnosis is often difficult since these diseases have been studied primarily as separate entities. The toxic substances of the pulp may initiate periodontal defects through canal ramifications and patent dentinal tubules, thus impairing wound healing in regenerative procedures. Although no studies exist addressing the direct effect of pulpal infection on the outcome of guided tissue regeneration (GTR) procedures, several studies do indicate that pulpal status may play a significant role toward the end results of GTR. This review article discusses the potential influence of endodontic treatment on the long-term outcomes of GTR. Potential pathways between the pulp and periodontal ligament, which may be responsible for the failure of the regeneration of new periodontal attachment apparatus, are explored. Examination and review of the clinical and research findings in the literature relating to perio-endo lesions are made to demonstrate that a negative influence may exist between GTR outcomes and the status of the pulp.

Bacterial Infections↗

PubMed1996

Scanning electron microscopic observations of apical root surfaces of teeth with apical periodontitis.

The aim of this study was to observe apical root surfaces of teeth with chronic periapical lesions. Five premolars and three molars with radiographically demonstrable periapical lesions were extracted and fixed in 2.5% phosphate-buffered glutaraldehyde solution for 9 days. The apical 3-mm portion of 17 roots was removed and prepared for scanning electron microscope. Lacunar resorption zones were frequently observed on the root surfaces. Bacteria and yeast cells were detected in some of the lacunae. Periapical bacterial plaque with a smooth structure was present mostly around the main apical foramen. Cementum-like tissue deposits indicative of repair were seen adjacent to some resorption areas. Clastic cells tightly attached to crater-like depressions with finger-like projections were observed laterally on the specimens. Current research should be focused on new procedures to eliminate extraradicular microrganisms and periapical bacterial plaque in persistent periapical infections.

Chronic Disease↗

PubMed1997

Experimental apexigenesis in baboons.

Apexification with calcium hydroxide is a routine procedure. However, some clinical reports suggest that root completion can occur by controlling the infection without use of a catalyst. The present study investigated the use of tetracycline treatment (in root canals) on root growth in immature teeth, rendered non-vital experimentally. Incisors in 3 young baboons were exposed and canals were left open. After 2 months all canals were cleaned and treated with either tetracycline or formocresol. Some canals in each group were filed. Animals were sacrificed after 6 months. Bacterial evaluations were done before placing medications, one week later and six months after that. The number of bacteria were reduced in all treatment groups. Root growth almost near completion was observed in more teeth treated with tetracycline than in the formocresol group.

Animals↗

PubMed1997

Effect of laser treatment on the root canal of human teeth.

The purpose of this study was to examine the morphological and temperature changes of the apical portion of human extracted teeth treated by Nd: YAG, CO2 and Argon-lasers. Seventy-two single-rooted human teeth were studied. The root canals were prepared conventionally. Laser treatment of the apical portion of the canal was carried out by means of an optic fiber or metal tip. Temperatures were recorded thermographically. Two-thirds of the specimens were stained with black India ink and 36% silver ammonium fluoride solution. All specimens were irradiated by the three types of lasers at several intensities and the temperatures were recorded. Half of the specimens were prepared for the telescopic light microscope and for scanning electron microscopic observation, and the rest for histopathological examination by light microscope. The scanning electron microscopic evaluation showed that the laser energy vaporized the deposited debris, producing a glaze-like surface. The histopathological investigation revealed a tapered, enlarged apical lased area. All three laser devices were capable of vaporizing the debris in this way but the degree of morphological change was highly dependent on energy level and duration. The Argon-laser produced the highest temperatures.

Argon↗

PubMed1998

Prospective study of two retrograde endodontic apical preparations with and without the use of CO2 laser.

This article covers a 4-year study that reports 320 cases in which endodontic surgery was performed for residual apical lesions or lesions that could not be treated in a conventional way. Four groups of 80 teeth each were formed and they were followed up after a 12-month interval. The first group comprised cases treated with a micro bur, retrograde filling and IRM; the second, cases treated at the apical and radicular portions with a CO2 laser; the third, cases in which the retrograde cavity was prepared with an ultrasonic device instead of a micro bur; and the fourth group comprised cases treated in a similar way to the second group, i.e., cases treated at the apical and radicular portions, but with a CO2 laser instead of a micro bur. After 12 months, the results showed a better prognosis with ultrasonic treatment. Regardless of technique, the CO2 laser did not improve the healing process.

Adolescent↗