Analysis of the gutta-percha filled area in C-shaped mandibular molars obturated with a modified MicroSeal technique

To analyse the gutta-percha filled area of C-shaped molar teeth root filled with the modified MicroSeal technique with reference to the radiographic features and the C-shaped canal configuration. Twenty-three mandibular second molar teeth with C-shaped roots were classified according to their radiographic features as: type I - merging, type II - symmetrical and type III - asymmetrical. The canals were root filled using a modified technique of the MicroSeal system. Horizontal sections at intervals of 600 mu m were made 1 mm from the apex to the subpulpal floor level. The percentage of gutta-percha area from the apical, middle and coronal levels of the radiographic types was analysed using the Kruskal-Wallis test. Complementary analysis of the C-shaped canal configurations (C1, C2 and C3) determined from cross-sections from the apical third was performed in a similar way. No significant differences were found between the radiographic types in terms of the percentage of gutta-percha area at any level (P > 0.05): apical third, type I: 77.04%, II: 70.48% and III: 77.13%, middle third, type I: 95.72%, II: 93.17%, III: 91.13% and coronal level, type I: 98.30%, II: 98.25%, III: 97.14%. Overall, the percentage of the filling material was lower in the apical third (P < 0.05). No significant differences were found between the C-shaped canal configurations apically; C1: 72.64%, C2: 79.62%, C3: 73.51% (P > 0.05). The percentage of area filled with gutta-percha was similar in the three radiographic types and canal configuration categories of C-shaped molars. These results show the difficulty of achieving predictable filling of the root canal system when this anatomical variation exists. In general, the apical third was less completely filled.

Effect of Conventional and Resin-modified Glass-Ionomer Liner on Dentin Adhesive Interface of Class I Cavity Walls After Thermocycling

Objective: The aim of this in vitro study was to analyze the effect of glass-ionomer cement as a liner on the dentin/resin adhesive interface of lateral walls of occlusal restorations after thermocycling. Materials and Methods: Occlusal cavities were prepared in 60 human molars, divided into six groups: no liner (1 and 4); glass-ionomer cement (GIC, Ketac Molar Easymix, 3M ESPE) (2 and 5); and resin-modified glass-ionomer cement (RMGIC, Vitrebond, 3M ESPE) (3 and 6). Resin composite (Filtek Z250, 3M ESPE) was placed after application of an adhesive system (Adper Single Bond 2, 3M ESPE) that was mixed with a fluorescent reagent (Rhodamine B) to allow confocal microscopy analysis. Specimens of groups 4, 5 and 6 were thermocycled (5 degrees C-55 degrees C) with a dwell time of 30 seconds for 5000 cycles. After this period, teeth were sectioned in approximately 0.8-mm slices. One slice of each tooth was randomly selected for confocal microscopy analysis. The other slices were sectioned into 0.8 nun x 0.8 mm beams, which were submitted to microtensile testing (MPa). Data were analyzed using two-way ANOVA and Tukey test (p < 0.05). Results: There was no detectedstatistical difference on bond strength among groups (alpha < 0.05). Confocal microscopy analysis showed a higher mean gap size in group 4(12.5 mu m) and a higher percentage of marginal gaps in the thermocycled groups. The RNIGIC liner groups showed the lowest percentage of marginal gaps. Conclusions: Lining with RMGIC resulted in less gap formation at the dentin/resin adhesive interface after artificial aging. RMGIC or GIC liners did not alter the microtensile bond strength of adhesive system/resin composite to dentin on the lateral walls of Class I restorations.

Fracture resistance of Class II glass-ionomer cement restorations

Purpose: To investigate in vitro the effect of retentive grooves, GIC type and insertion method on the fracture resistance of Class II glass-ionomer cement (GIC) restorations. Methods: Premolars were divided into 12 groups (n=10) according to three variables: retentive grooves [presence (PR) or absence AR)], GICs type [Ketac-Molar (KM), Fuji VIII (F8) and RelyX Luting (RX)], and insertion method [syringe injector (SI) or spoon excavator (SE)]. The specimens were subjected to fracture resistance test. Data were submitted to three-way ANOVA and multiple comparisons were performed using a Tukey test (P < 0.05). Results: Mean fracture resistance values (Kgf) +/- standard deviations (SD) were: KM (PR+SI) 65.66 +/- 2.5; KM (PR+SE) = 62.58 +/- 2.1; KM (AR+SI) = 57.11 +/- 1.9; KM (AR+SE) = 51.94 +/- 2.3; F8 (PR+SI) = 63.05 +/- 2.1; F8 (PR+SE) = 60.12 +/- 2.3; F8 (AR+SI) = 55.11 +/- 1.9; F8(AR+SE)=49.20 +/- 1.6; RX (PR+SI)=50.99 +/- 2.4; RX (PR+SE)=48.81 +/- 2.5; RX (AR+SI)=45.53 +/- 2.6; RX (AR+SE)=41.88 +/- 3.0. Statistically significant differences were observed among all the groups tested (P=0.001). There was significant difference when pooled means for GIC type were compared with retentive grooves (P=0.01) and when pooled means for retentive grooves were compared with insertion method (P=0.01).

Clinical Concepts of Dry Socket

Dry socket is one of the most studied complications in dentistry, and a great number of studies have searched for an effective and safe method for its prevention and treatment. One of the great clinical challenges since the first case was reported has been the inconsistency and differences in the various definitions of dry socket and the criteria used for diagnosis. The pathophysiology, etiology, prevention, and treatment of dry socket are very important in the practice of oral surgery. The aim of the present report was to review and discuss each aspect. (C) 2010 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 68:1922-1932, 2010

Orthodontic therapy in patients with pericoronal hamartoma

Pericoronal lesions are undesirable for dental eruption, and they are always associated with unerupted teeth. Pericoronal lesions are common and are usually treated by extraction of the permanent tooth. Pericoronal hamartoma is a special type of pericoronal lesion, and little information about it is available in the orthodontic literature. This report presents a patient with pericoronal hamartoma on the mandibular left permanent first molar who had orthodontic treatment. Because of the similarity of the radiographic radiolucency of pericoronal hamartoma and other lesions, a differential diagnosis must be made to avoid extraction of permanent teeth.

Agenesis of maxillary lateral incisors and associated dental anomalies

Introduction: The objectives of this study were to evaluate the prevalence of dental anomalies in patients with agenesis of maxillary lateral incisors and to compare the findings with the prevalence of these anomalies in the general population. Methods: A sample of 126 patients, aged 7 to 35 years, with agenesis of at least 1 maxillary lateral incisor was selected. Panoramic and periapical radiographs and dental casts were used to analyze other associated dental anomalies, including agenesis of other permanent teeth, ectopia of unerupted permanent teeth, microdontia of maxillary lateral incisors, and supernumerary teeth. The occurrence of these anomalies was compared with prevalence data previously reported for the general population. Statistical testing was performed with the chi-square test (P<0.05) and the odds ratio. Results: Patients with maxillary lateral incisor agenesis had a significantly increased prevalence rate of permanent tooth agenesis (18.2%), excluding the third molars. The occurrence of third-molar agenesis in a subgroup aged 14 years or older (n = 76) was 35.5%. The frequencies of maxillary second premolar agenesis (10.3%), mandibular second premolar agenesis (7.9%), microdontia of maxillary lateral incisors (38.8%), and distoangulation of mandibular second premolars (3.9%) were significantly increased in our sample compared with the general population. In a subgroup of patients aged 10 years or older (n = 115), the prevalence of palatally displaced canines was elevated (5.2%). The prevalences of mesioangulation of mandibular second molars and supernumerary teeth were not higher in the sample. Conclusions: Permanent tooth agenesis, maxillary lateral incisor microdontia, palatally displaced canines, and distoangulation of mandibular second premolars are frequently associated with maxillary lateral incisor agenesis, providing additional evidence of a genetic interrelationship in the causes of these dental anomalies. (Am J Orthod Dentofacial Orthop 2010;137:732.e1-732.e6)

Tooth-wear patterns in subjects with Class II Division 1 malocclusion and normal occlusion

Introduction: The aim of this study was to investigate the prevalence of tooth wear in adolescents with Class II malocclusion, compared with those with normal occlusion. Methods: The sample consisted of dental casts obtained from 310 subjects, divided into 3 groups: group 1, 110 subjects with normal occlusion (mean age, 13.51 years); group 2, 100 complete Class II Division 1 patients (mean age, 13.44 years); and group 3, 100 half-cusp Class II Division 1 patients (mean age, 13.17 years). Dental wear was assessed by using a modified version of the tooth-wear index. The 3 groups were compared by means of the Kruskal-Wallis and Dunn tests, considering the frequency and the severity of wear on each surface of each group of teeth. The level of statistical significance was set at 5%. Results: The normal occlusion group had statistically greater tooth wear on the palatal surfaces of the maxillary central incisors and the incisal surfaces of the maxillary canines than the corresponding surfaces in both Class II malocclusion groups. The complete and half-cusp Class II Division 1 malocclusion groups had statistically greater tooth wear on the occlusal surfaces of the maxillary second premolar and first molar, the occlusal surfaces of the mandibular premolars, and the buccal surfaces of the mandibular posterior teeth compared with the normal occlusion group. The half-cusp Class II Division 1 malocclusion group had significantly greater tooth wear on the incisal surfaces of the mandibular incisors compared with the complete Class II Division 1 malocclusion group. Conclusions: Subjects with normal occlusion and complete or half-cusp Class II Division 1 malocclusions have different tooth-wear patterns. Tooth wear on the malocclusion subjects should not be considered pathologic but rather consequent to the different interocclusal tooth arrangement. (Am J Orthod Dentofacial Orthop 2010; 137: 14. e1-14.e7)

Effects of the pendulum appliance, cervical headgear, and 2 premolar extractions followed by fixed appliances in patients with Class II malocclusion

Introduction: In this retrospective study, we compared the cephalometric effects, the dental-arch changes, and the efficiency of Class II treatment with the pendulum appliance, cervical headgear, or extraction of 2 maxillary premolars, all associated with fixed appliance therapy. Methods: The sample of 82 patients with Class II malocclusion was divided into 3 groups: group 1 patients (n = 22; treatment time, 3.8 years) were treated with the pendulum appliance and fixed orthodontic appliances. Group 2 patients (n = 30; treatment time, 3.2 years) were treated with cervical headgear followed by fixed appliances; group 3 patients (n = 30; treatment time, 2.1 years) were treated with 2 maxillary premolar extractions and fixed appliances. The average starting ages of the groups ranged from 13.2 to 13.8 years. Data were obtained from serial cephalometric measurements and dental casts. The dental casts were analyzed with the treatment priority index. The treatment efficiency index was also used. Results: The 3 treatment protocols produced similar cephalometric effects, especially skeletally. Comparisons among the 2 distalizing appliances (pendulum and cervical headgear) and extraction of 2 maxillary premolars for Class II treatment showed changes primarily in the maxillary dentoalveolar component and dental relationships. The facial profile was similar after treatment, except for slightly more retrusion of the upper lip in the extraction patients. The treatment priority index demonstrated that occlusal outcomes also were similar among the groups. The treatment efficiency index had higher values for the extraction group. Conclusions: The effects of treatment with the pendulum appliance or cervical headgear and extraction of 2 maxillary premolars associated with fixed appliances were similar from both occlusal and cephalometric standpoints. Class II treatment with extraction of maxillary teeth was more efficient because of the shorter treatment time. Differences in maxillary incisor retraction should be noted, but these differences might have been due to greater maxillary dentoalveolar protrusion in the extraction group before treatment. (Am J Orthod Dentofacial Orthop 2009;136:833-42)

Nonextraction treatment of a skeletal Class III malocclusion

This case report describes the nonsurgical, nonextraction therapy of a 16-year-old boy with a skeletal Class III malocclusion, a prognathic mandible, and a retrusive maxilla. He was initially classified as needing orthognathic surgery, but he and his parents wanted to avoid that. The Class III malocclusion was corrected with a rapid palatal expander and a maxillary protraction mask followed by nonextraction orthodontic treatment with fixed appliances, combined with short Class III and vertical elastics in the anterior area. The height of the maxillary alveolar process and the vertical face height were slightly increased with treatment. Class I molar and canine relationships were achieved, and the facial profile improved substantially. (Am J Orthod Dentofacial Orthop 2009; 136: 736-45)

Cephalometric evaluation in different phases of Jasper jumper therapy

Introduction: The aim of this study was to evaluate the dentoskeletal and soft-tissue effects of Class II malocclusion treatment with the Jasper jumper followed by Class II elastics at the different stages of therapy. Methods: The sample comprised 24 patients of both sexes (11 boys, 13 girls) with an initial age of 12.58 years, treated for a mean period of 2.15 years. Four lateral cephalograms were obtained of each patient in these stages of orthodontic treatment: at pretreatment (T1), after leveling and alignment (T2), after the use of the Jasper jumper appliance and before the use of Class II intermaxillary elastics (T3), and at posttreatment (T4). Thus, 3 treatment phases could be evaluated: leveling and alignment (T1-T2), use of the Jasper jumper (T2-T3), and use of Class II elastics (T3-T4). Dependent analysis of variance (ANOVA) and Tukey tests were used to compare the durations of the 3 treatment phases and for intragroup comparisons of the 4 treatment stages. Results: The alignment phase showed correction of the anteroposterior relationship, protrusion and labial inclination of the maxillary incisors, and reduction of overbite. The Jasper jumper phase demonstrated labial inclination, protrusion and intrusion of the mandibular incisors, mesialization and extrusion of the mandibular molars, reduction of overjet and overbite, molar relationship improvement, and reduction in facial convexity. The Class II elastics phase showed labial inclination of the maxillary incisors; retrusion, uprighting, and extrusion of the mandibular incisors; and overjet and overbite increases. Conclusions: The greatest amount of the Class II malocclusion anteroposterior discrepancy was corrected with the Jasper jumper appliance. Part of the correction was lost during Class II intermaxillary elastics use after use of the Jasper jumper appliance. (Am J Orthod Dentofacial Orthop 2011;140:e77-e84)

Pulpotomy of human primary molars with MTA and Portland cement: a randomised controlled trial

Objective This study compared the clinical and radiographic effectiveness of mineral trioxide aggregate (MTA) and Portland cement (PC) as pulp dressing agents in carious primary teeth. Methodology Thirty carious primary mandibular molars of children aged 5-9 years old were randomly assigned to MTA or PC groups, and treated by a conventional pulpotomy technique. The teeth were restored with resin modified glass ionomer cement. Clinical and radiographic successes and failures were recorded at 6, 12, 18 and 24-month follow-up. Results All pulpotomised teeth were clinically and radiographically successful at all follow-up appointments. Six out of 15 teeth in the PC group and five out of 14 teeth in the MTA group exfoliated throughout the follow-up period. No statistically significant difference regarding dentine bridge formation was found between both groups throughout the follow-up period. As far as pulp canal obliteration is concerned, a statistically significant difference was detected at 6-month follow-up (p < 0.05), since the beginning of mineralised material deposition could be radiographically detected in 100% and 57.14% of the teeth treated with PC and MTA, respectively. Conclusions PC may serve as an effective and less expensive MTA substitute in primary molar pulpotomies. Further studies and longer follow-up assessments are needed.

Long-term stability of Class II malocclusion treated with 2-and 4-premolar extraction protocols

Introduction: The objective of this study was to cephalometrically compare the stability of complete Class II malocclusion treatment with 2 or 4 premolar extractions after a mean period of 9.35 years. Methods: A sample of 57 records from patients with complete Class II malocclusion was selected and divided into 2 groups. Group 1 consisted of 30 patients with an initial mean age of 12.87 years treated with extraction of 2 maxillary premolars. Group 2 consisted of 27 patients with an initial mean age of 13.72 years treated with extraction of 4 premolars. T tests were used to compare the groups` initial cephalometric characteristics and posttreatment changes. Pearson correlation coefficients were calculated to determine the correlation between treatment and posttreatment dental-relationship changes. Results: During the posttreatment period, both groups had similar behavior, except that group 1 had a statistically greater maxillary forward displacement and a greater increase in the apical-base relationship than group 2. On the other hand, group 2 had a statistically greater molar-relationship relapse toward Class II. There were significant positive correlations between the amounts of treatment and posttreatment dentoalveolar-relationship changes. Conclusions: Treatment of complete Class II malocclusions with 2 maxillary premolar extractions or 4 premolar extractions had similar long-term posttreatment stability. (Am J Orthod Dentofacial Orthop 2009;136:154.e1-154.e10)

Comparative efficiency of Class II malocclusion treatment with the pendulum appliance or two maxillary premolar extractions and edgewire appliances

The objective of this study was to compare, on study models and initial cephalograms, the efficiency of Class II malocclusion treatment with the pendulum appliance, and with two maxillary premolar extraction protocol. The sample consisted of 48 treated Class II malocclusion patients: group 1 comprised 22 patients (7 males, 15 females) treated with the pendulum appliance, with an initial mean age of 14.44 years and group 2, 26 patients (14 males, 12 females) treated with two maxillary premolar extractions at an initial mean age of 13.66 years. To compare the efficiency of each treatment protocol, the occlusal outcomes were evaluated on dental casts using the Peer Assessment Rating (PAR) Index and the treatment time (TT) of each group was calculated on clinical charts. The degree of treatment efficiency was calculated as the ratio between the percentage of occlusal improvement, evaluated through the PAR index, and TT. Statistical analysis was undertaken by means of t-tests. The findings demonstrated that the two maxillary premolar extraction protocol provided the occlusal outcomes in a shorter time (group 1: 45.7 months, group 2: 23.01 months) and, therefore, demonstrated greater treatment efficiency than the pendulum appliance.

Comparative distalization effects of Jones jig and pendulum appliances

Introduction: In this study, we compared the dentoalveolar changes of Class II patients treated with Jones jig and pendulum appliances. Methods: The experimental group comprised 40 Class II malocclusion subjects, divided into 2 groups: group 1 consisted of 20 patients (11 boys, 9 girls) at a mean pretreatment age of 13.17 years, treated with the Jones jig appliance for 0.91 years; group 2 comprised 20 patients (8 boys, 12 grls) at a mean pretreatment age of 13.98 years, treated with the pendulum appliance for 1.18 years. Only active treatment time of molar distalization was evaluated in the predistalization and postdistalization lateral cephalograms. Molar, second premolar, and incisor angular and linear variables were obtained. The intergroup treatment changes in these variables were compared with independent t tests. Results: The maxillary second premolars showed greater mesial tipping and extrusion in the Jones jig group, indicating more anchorage loss during molar distalization with this appliance. The amounts and the monthly rates of molar distalization were similar in both groups. Conclusions: The Jones jig group showed greater mesial tipping and extrusion of the maxillary second premolars. The mean amounts and the monthly rates of first molar distalization were similar in both groups. (Am J Orthod Dentofacial Orthop 2009;135:336-42)

Relationship between malocclusion severity and treatment success rate in Class II nonextraction therapy

Introduction: The purpose of this study was to evaluate the treatment success rate of Class II malocclusion without extractions, according to initial severity. Methods: Class II subjects (n = 276) were divided into 2 groups according to the severity of the malocclusion. Group 1 comprised 144 patients with bilateral half Class II malocclusion at the initial mean age of 12.27 years. Group 2 comprised 132 patients who initially had bilateral complete Class II malocclusion at the initial mean age of 12.32 years. The patients` initial and final study models were evaluated with Grainger`s treatment priority index. Chi-square tests were used to test for differences between the 2 groups for categorical variables. Variables regarding occlusal results were compared with independent t tests. Results: Group 1 had a significantly better final occlusal result, a shorter treatment time, and a higher treatment efficiency index. Conclusions: Based on these results, it was concluded that bilateral half Class II malocclusion has a better treatment success rate than bilateral complete Class II malocclusion when treatment is conducted without extractions. (Am J Orthod Dentofacial Orthop 2009; 135: 274.e1-274.e8)