Fidan Alakus Sabuncuoglu

Changes in maxillary incisor dental pulp blood flow during intrusion by mini-implants

Abstract Aim. The aim of this clinical study was to identify changes in pulpal blood flow (PBF) in human central incisors resulting from short- and long-term intrusive orthodontic forces from mini-implants. Materials and methods. A total of 40 sound upper central and lateral incisors in 20 patients scheduled for intrusion for orthodontic reasons were divided into two groups. From each group, 20 teeth were subjected to intrusive force from mini-implants (Group 1 = Light Force: 40 g; Group 2 = Heavy Force: 120 g), whereas the remaining 20 contralateral teeth were not subjected to forces from mini-implants and served as controls. Laser-Doppler flowmetry (LDF) measurements were recorded at baseline and at 3 days and 3 weeks following intrusion. Results. PBF decreased significantly at 3 days (Light Force Group: 7.72 ± 0.50; Heavy Force Group: 7.72 ± 0.52) and then increased towards baseline at 3 weeks (Light Force Group: 10.37 ± 0.58; Heavy Force Group: 10.31 ± 0.45) following intrusion. Conclusions. In other words, despite slight regressive changes in pulpal tissue in the short-term, PBF improved after 3 weeks following intrusion by mini-implants, indicating that the changes observed in PBF is reversible, even following radical incisor intrusion.

Radiological analysis of the relationship between occlusal tooth wear and mandibular alveolar bone density and height.

AIMnThe aim of this study was to examine the relationship between occlusal tooth wear and mandibular alveolar bone density (ABD) and alveolar bone height (ABH) using computer-assisted densitometric image analysis (CADIA) program.nnnMATERIALS AND METHODSnThe study was comprised of 134 mandibular first molar teeth in 90 patients with various degrees of occlusal tooth wear. The degree of tooth wear was classified according to the tooth wear index (TWI). Periodontal examinations were performed on all patients and included plaque index, gingival index, probing depth, and clinical attachment loss measurements. ABD and ABH were measured from intraoral digital periapical radiographs and analyzed using CADIA.nnnRESULTSnNo increases in ABD were observed between TWI 0 and TWI 1 or between TWI 0 and TWI 2 (P > 0.05). However, increases in ABD were observed between TWI 0 and TWI 3 (P < 0.01), TWI 1 and TWI 3 (P < 0.01), TWI 1 and TWI 2 (P < 0.05) and TWI 2 and TWI 3 (P < 0.05). In addition, ABH was found to increase with increase in wear, with the exception of the interval between TWI 0 and TWI 1.nnnCONCLUSIONSnOcclusal tooth wear does not result in any radiologically identifiable changes in the alveolar bone during the initial stages of wear; however, significant increases in both ABD and ABH may be observed as tooth wear progresses.

Effects of magnitude of intrusive force on pulpal blood flow in maxillary molars

INTRODUCTIONnIn this study, we aimed to evaluate and compare blood-flow changes in the pulp tissues of maxillary molars over a 6-month period after orthodontic intrusion using different magnitudes of force.nnnMETHODSnTwenty patients were randomly divided into 2 groups (nxa0= 10) according to the amount of intrusive force applied. An intrusive force of either 125 g (light) or 250 g (heavy) was applied to the overerupted maxillary first molars using mini-implants; no force was applied to the contralateral molars. Laser Doppler flowmetry was used to measure pulpal blood flow (PBF) at baseline and during intrusion at 24 hours, 3 days, 7 days, 3 weeks, 4 weeks, 3 months, and 6 months. The data were analyzed with the Mann-Whitney U and Wilcoxon signed rank tests, with Pxa0<0.05 considered statistically significant.nnnRESULTSnPBF decreased significantly at 3 days and continued to remain suppressed until 3 weeks, after which a gradual trend of recovery was observed until 3 months, when the levels returned to near those measured before intrusion. When the data were analyzed with regard to the amount of applied force, significant differences were observed between the 2 groups only at 3 and 7 days.nnnCONCLUSIONSnThese findings demonstrate that despite slight regressive changes in pulpal tissue over the short term, PBF values tend to return to their initial levels within 3 months, indicating that changes observed in PBF are reversible, even during radical intrusions of molars with 125 and 250 g of forces.

SHEAR BOND STRENGTH OF BRACKETS BONDED TO PORCELAIN SURFACE: IN VITRO STUDY

Purpose: To compare the effects of different porcelain surface treatment methods on the shear bond strength (SBS) and fracture mode of orthodontic brackets. Materials and Methods: Seventy feldspathic porcelain disk samples mounted in acrylic resin blocks were divided into seven groups (n=10) according to type of surface treatment: I, Diamond bur; II, Orthosphoric acid (OPA); III, hydrofluoric acid (HFA); IV, sandblasted with aluminum oxide (SB); V, SB+HFA; VI, Neodymium:yttrium-aluminum-garnet (Nd:YAG) laser; VII, Erbium:yttrium-aluminum-garnet (Er:YAG) laser. Brackets were affixed to treated all-porcelain surfaces with a silane bonding agent and adhesive resin and subjected to SBS testing. Specimens were evaluated according to the adhesive remnant index (ARI), and failure modes were assessed quantitatively under a stereomicroscope and morphologically under a scanning electron microscope (SEM). Statistical analysis was performed using one-way analysis of variance and the post-hoc Tukey test, with the significance level set at 0.05. Results: The highest SBS values were observed for Group V, with no significant difference between Groups V and III. SBS values for Group I were significantly lower than those of all other groups tested. The porcelain/resin interface was the most common site of failure in Group V (40%) and Group III (30%), whereas other groups showed various types of bond failure, with no specific location pre-dominating, but with some of the adhesive left on the porcelain surfaces (ARI scores 2 or 3) in most cases. Conclusion: The current findings indicate that a diamond bur alone is unable to sufficiently etch porcelain surfaces for bracket bonding. Moreover, SB and HFA etching used in combination results in a significantly higher shear-bond strength than HFA or SB alone. Finally, laser etching with either an Nd:YAG or Er:YAG laser was found to be more effective and less time-consuming than both HFA acid and SB for the treatment of deglazed feldspathic porcelain.

EFFECT OF SURFACE TREATMENT ON ENAMEL SURFACE ROUGHNESS

Purpose: To compare the effects of different methods of surface treatment on enamel roughness. Materials and Methods: Ninety human maxillary first premolars were randomly divided into three groups (n=30) according to type of enamel surface treatment: I, acid etching; II, Er:YAG laser; III, Nd:YAG laser. The surface roughness of enamel was measured with a noncontact optical profilometer. For each enamel sample, two readings were taken across the sample—before enamel surface treatment (T1) and after enamel surface treatment (T2). The roughness parameter analyzed was the average roughness (Ra). Statistical analysis was performed using a Paired sample t test and the post-hoc Mann- Whitney U test, with the significance level set at 0.05. Results: The highest Ra (average roughness) values were observed for Group II, with a significant difference with Groups I and III (P<0.001). Ra values for the acid etching group (Group I) were significantly lower than other groups (P<0.001). Conclusion: Surface treatment of enamel with Er:YAG laser and Nd:YAG laser results in significantly higher Ra than acid-etching. Both Er:YAG laser or Nd:YAG laser can be recommended as viable treatment alternatives to acid etching.

THE EFFECT OF DIFFERENT SURFACE TREATMENT TECHNIQUES ON THE SURFACE ROUGHNESS OF FELDSPATHIC PORCELAIN

Purpose: This in vitro study compared the effect of five different techniques on the surface roughness of feldspathic porcelain. Materials and Methods: 100 feldspathic porcelain disk samples mounted in acrylic resin blocks were divided into five groups (n=20) according to type of surface treatment: I, hydrofluoric acid (HFA); II, Deglazed surface porcelain treated with Neodymium:yttrium- aluminum-garnet (Nd:YAG) laser; III, Deglazed porcelain surface treated with Erbium:yttrium-aluminum-garnet (Er:YAG) laser; IV, Glazed porcelain surface treated with Neodymium:yttrium-aluminum-garnet (Nd:YAG) laser, V; Glazed porcelain surface treated with Erbium:yttrium-aluminum-garnet (Er:YAG) laser. The surface roughness of porcelain was measured with a noncontact optical profilometer. For each porcelain sample, two readings were taken across the sample, before porcelain surface treatment (T1) and after porcelain surface treatment (T2). The roughness parameter analyzed was the average roughness (Ra). Statistical analysis was performed using Kolmogorov–Smirnov and Wilcoxon signed rank test. Results: Mean Ra values for each group were as follows: I, 12.64±073; II, 11.91±0.74; III, 11.76±0.59; IV, 3.82±0.65; V, 2.77±0.57. For all porcelain groups, the lowest Ra values were observed in Group V. The highest Ra values were observed for Group I, with a significant difference with the other groups. Kolmogorov–Smirnov showed significant differences among groups (p<0.001). Conclusion: Surface treatment of porcelain with HFA resulted in significantly higher Ra than laser groups. Both Er:YAG laser or Nd:YAG laser on the deglaze porcelain surface can be recommended as viable treatment alternatives to acid etching.

DEBONDING OF CERAMIC BRACKETS BY ER:YAG LASER

Purpose: The objective of the present study is to evaluate the effects of Er:YAG laser debonding of ceramic brackets on the bond strength and the amount of adhesive resin remnant. Materials and Methods: Twenty human mandibular incisors were randomly divided into two groups of 10 and polycrystalline ceramic brackets (Transcend series 6000, 3M Unitek, Monrovia, CA, USA) were bonded on enamel surfaces. Group 1 was the control group in which no laser application was performed prior to the shear bond strength (SBS) testing. In Group 2, Er:YAG was applied in 3W power for 6 seconds using the scanning method. The brackets were tested for SBS with an Instron universal testing machine and results were expressed in megapascals (MPa). The amount of adhesive remnant was evaluated with Adhesive Remnant Index (ARI). One-way analysis of variance and Tukey’s post-hoc tests were used for statistical analysis. Results: Mean ± standard deviation of SBS values in the control group was 13.42 ±1.23 MPa and 8.47 ±0.71 MPa in the Er:YAG group and this difference was statistically significant (p<0.05). The evaluation of ARI scores demonstrated more adhesive was left on the enamel surface with Er:YAG group. Conclusion: 3W power Er:YAG laser application with the scanning method to polycrystalline ceramic brackets demonstrated lower bond strengths and higher ARI scores during the debonding procedure.

Changes in human pulp blood flow during canine retraction.

Abstract Aim: To evaluate the effects of maxillary canine retraction on pulpal blood flow (PBF) in humans as recorded by laser Doppler flowmetry (LDF). Methods: Maxillary canines of 24 participants were divided into two groups (nu2009=u200912 each). Teeth in the study group underwent maxillary canine retraction using mini-implants as anchorage for approximately 4 months, with 100u2009g of force applied via coil springs. Subjects in the control group received no orthodontic treatment. LDF measurements were recorded at baseline (T0); during retraction, at 24u2009hours (T1), 3 days (T2), 7 days (T3) and 1 month (T4); and at the end of retraction (T5) in the study group and at similar time-points in control subjects. Data were analyzed using the Friedman, Wilcoxon signed rank and Mann–Whitney U tests, with the significance level set at 0.05. Results: No significant changes in PBF perfusion units (PU) were observed in the control group over the course of the study. However, PBF in the study group increased significantly from T0 (3.6u2009±u20090.2 PU) to T1 (3.7u2009±u20090.2 PU, pu2009<u20090.001) and decreased severely from T1 to T2 (3.3u2009±u20090.1, pu2009<u20090.001). PBF in the study group was still significantly lower at T3 (3.4u2009±u20090.1 PU, pu2009<u20090.001) in comparison to T0; however, at T4 and T5, PBF was found to have returned to pre-retraction levels. Conclusion: The fact that PBF values returned to initial levels within one month of the initiation of retraction despite short-term, hyperaemic, regressive changes demonstrates that the changes observed in PBF during canine retraction are reversible.

Management of Class III Malocclusion with Missing a Maxillary Central Incisor (A Case Report)

Aim: The present case report describes the orthodontic treatment of a patient with a missing maxillary right central incisor and a skeletal Class III jaw relationship due to a retrognathic maxilla. Materials and nMethods: Treatment was conducted in two phases, with a removable appliance and Delaire’s facemask used in the first phase and a fixed appliance used in the second phase. Mesial movement of the maxillary canine, first premolar, second premolar and first molar was achieved sequentially over the two phases of treatment. After 36 months, the anterior space was closed, and good intercuspation and interproximal contacts and satisfactory root parallelism were achieved. Finally, interproximal spaces were closed orthodontically, the crown of the upper right lateral incisor was anatomically modified to imitate a central incisor, the right maxillary canine was reshaped slightly along the incisal edge, and a gingivectomy was performed in the maxillary canine area to achieve normal vertical crown proportions. nResults: Post-treatment intraoral photographs show satisfactory dental alignment and acceptable overjet and overbite. The patient was satisfied with her teeth and profile. nConclusion: The combination of maxillary protractor and fixed appliance successfully corrected the skeletal Class III malocclusion and achieved forward mesial movement of the maxillary posterior teeth.