The effect of different bonded retainer wires on tooth mobility immediately after orthodontic treatment.

OBJECTIVES: This study aimed to compare the immediate influence of four commonly used retainer wires on tooth mobility following orthodontic treatment with fixed appliances. MATERIALS AND METHODS: Eighty patients after orthodontic treatment were assigned to four study groups (n = 20 in each group). Groups were provided with directly bonded fixed retainers-0.0150″ (group A), 0.0175″ (group B), 0.016 × 0.022″ (group C), and 0.0215″ (group D). Tooth mobility was measured using the Periotest device at two times-after removal of fixed appliance (T1) and after bonding of the retainer (T2). Values of tooth mobility, 'Periotest values', were analysed between groups and compared with the physiologic tooth mobility in a control group of untreated patients (n = 65). Kruskal-Wallis H, Mann-Whitney U, Dunn's test, Fisher's exact test, and binary logistic regression tests were used to analyze the data. RESULTS: Tooth mobility after orthodontic treatment was significantly increased. While canines remained within normal range of tooth mobility, values for incisors increased on average to the first degree of tooth mobility (slight mobility). Logistic regression analysis identified age as a significant predictor for increased tooth mobility (P = 0.032) with odds ratio 1.065 (95% CI 1.005-1.128), with mobility increasing with age. After bonding of the retainer in all four groups, the tooth mobility was reduced to values which were not significantly different form normal physiological values found in the control group (P > 0.05). There were no differences in the amount of change or in tooth mobility values at T2 between the different types of bonded retainers. LIMITATIONS: Age of subjects in the control group was significantly higher than that in the study groups. An alternation method was used instead of randomization to distribute the four different types of retainers. CONCLUSIONS: All of the retainer wires were able to successfully reduce the increased tooth mobility caused by orthodontic treatment to normal levels. The values of tooth mobility after placement of retainers were within the range of physiologic tooth mobility.

The Influence of Powder Milling on Properties of SPS Compacted FeAl.

The Fe-28 at.% Al alloy was studied in this article. The aim was to describe the influence of gas atomized powder pre-milling before SPS (Spark Plasma Sintering) sintering on the structure and properties of the bulk materials. The initial powder was milled for 0.5, 1, and 8 h. It was proven that 1 h milling leads to the change in size and morphology of the particles, B2→A2 phase transformation, and to the contamination with the material from a milling vessel. Powder materials were compacted by the SPS process at 900, 1000, and 1100 °C. The differences between the bulk materials were tested by LM, SEM, and TEM microscopy, XRD, and neutron diffraction methods. It was proven that, although the structures of initial powder (B2) and milled powder (A2) were different, both provide after-sintering material with the same structure (D03) with similar structural parameters. Higher hardness and improved ductility of the material sintered from the milled powder are likely caused by the change in chemical composition during the milling process.

Unexpected complications associated with mandibular fixed retainers: A retrospective study.

INTRODUCTION: The purposes of this retrospective study were to describe the types of unexpected complications associated with mandibular fixed retainers and to assess their prevalences and possible etiologic causes. METHODS: A total of 3500 consecutive patients (1423 male, 2077 female) treated with fixed appliances and a mandibular fixed retainer as a part of the retention protocol were screened during the retention period (2008-2013) for unexpected complications. Thirty-eight subjects (12 male, 26 female; mean age, 20.7 ± 8.9 years) with unexpected complications were identified and assigned to the unexpected complications group and compared with a randomly selected control group of 105 subjects (43 men, 62 women; mean age, 29.5 ± 9.7 years) without unexpected complications. Relationships between unexpected complications and cephalometric and clinical variables were evaluated. RESULTS: An opposite inclination of the contralateral canines (twist effect) was found in 21 subjects. In 89.5%, the left canines were tipped buccally. A torque difference of 2 adjacent incisors (X effect) was identified in 12 patients. In 5 subjects, nonspecific complications were noted. Subjects in the unexpected complications group were significantly younger at debonding (P = 0.03) and had higher mandibular plane angles (P <0.0001) and increased pretreatment ventral positions of the mandibular incisors (P = 0.029). No differences were found between the groups with regard to treatment duration, wire type, failure rate, treatment changes in incisor proclination, or intercanine distance. CONCLUSIONS: Unexpected complications of mandibular fixed retainers are relatively rare. Facial divergence was identified as a possible predictor. However, the etiology is most likely multifactorial. Strong asymmetry among the patients with the twist effect suggests that the mechanical properties of retention wires may play a role and should be examined in the future.

Implant site development in the distal region of the mandible: bone formation and its stability over time.

INTRODUCTION: The purpose of this study was to determine the dimensional changes that occur in the alveolar ridge of patients upon distalization of the mandibular first premolars into the place of congenitally missing mandibular second premolars. The amount of bone formation that accompanied orthodontic treatment and the long-term stability of the new bone were assessed. METHODS: Fifty-five patients were included in the study, representing 71 congenitally missing mandibular second premolars. The dimensional changes were evaluated by comparing the dental stone casts and panoramic radiographs taken at treatment initiation (T1) and end (T2) and at follow-ups of 2 years (T3A) and 5 years (T3B). RESULTS: During the treatment period (T1-T2), the alveolar ridge width increased by an average of 28.5%, and the height increased by an average of 1.1 mm. During the retention periods (T2-T3A, T2-T3B), the alveolar ridge decreased by an average of 4.2%, but the height decreased only slightly (by an average of 0.07 mm). CONCLUSIONS: Orthodontic tooth movement created a significant amount of new bone that was stable in both the horizontal and vertical directions.

Comparison of spontaneous eruption and modified closed eruption technique with palatal traction in alignment of impacted maxillary central incisor teeth.

BACKGROUND: Central incisor impaction is a rare condition with potentially severe clinical and psychological implications for the patient. Treatment techniques vary according to the pretreatment situation and individual factors. The aim of this study was to compare the esthetic outcomes and treatment times between two different approaches. MATERIALS AND METHODS: In this retrospective study, thirty-one consecutive patients (13 boys, 18 girls; average age 9.5 ± 2.3 years) with a total of 34 impacted permanent upper central incisors were included in the study. Patients were divided into two groups according to method of treatment. Group A comprised patients in whom spontaneous eruption occurred after space opening (n = 12), and Group B comprised patients in whom teeth showed no eruption and required treatment with a modified closed eruption method with palatally oriented traction (n = 19). Treatment time and esthetic outcomes were assessed and compared between groups. RESULTS: The mean treatment time was 22.0 ± 6.7 months, and all teeth were successfully aligned. No statistically significant difference in average treatment time was found between groups in baseline characteristics (p > 0.05). The amount of attached gingiva was significantly smaller when compared to contralateral reference teeth in the closed eruption group (Group B; p = 0.03). However, no difference in amount of attached gingiva was found between both groups (p = 0.26). Additionally, no difference in the clinical crown length was found between groups (p = 0.27). CONCLUSION: The closed eruption method with palatal traction directed at the peak of the alveolar crest provided results comparable to the physiologic tooth eruption.

Intrusion of overerupted molars with temporary anchorage devices before prosthetic reconstruction: A case report.

Extraction of teeth without adequate prosthetic rehabilitation frequently can lead to overeruption of opposing teeth, which may cause occlusal disturbances and complicate dental restoration. Equilibration with consequent need of endodontic treatment, surgical intrusion or extraction are often indicated as a remedy in such cases. The article proposes a method of orthodontic intrusion with the use of temporary anchorage devices as a predictable and less invasive option. Important clinical aspects of molar intrusion with respect to surrounding anatomical structures are also discussed.

Orthodontic tooth movement: bone formation and its stability over time.

INTRODUCTION: Orthodontic tooth movement can lead to the creation of bone. The purposes of the study were to investigate the amount of bone formed in orthodontic patients during treatment (maxillary canine distalization) and retention and to assess the long-term stability of the new bone. METHODS: The sample consisted of 80 patients with 128 missing lateral incisors who were treated with distalization of the maxillary canines. They were examined at the beginning of orthodontic treatment (T1), at the end of treatment (T2), 2 years after treatment (T3A), and 5 years after treatment (T3B). The influence of the canine's inclination and its distance from the central incisor at T1 on the amount of bone created and the bone mass stability over time were assessed. Vestibular width of the alveolus was measured on casts at the level of the bone ridge and 5 mm apically from the alveolar ridge. Canine inclination to the alveolar ridge was recorded, as well as the height of the alveolar ridge. RESULTS: During treatment, T1 to T2, the alveolar ridge width was reduced by 4%, and the height decreased by 0.26 mm; during the retention periods (T2-T3A, T2-T3B), the alveolar ridge reduction was 2% on average, with individual variances, and height decreased by 0.38 mm on average. No correlation was found between canine inclination or between the canine distance from the central incisor at T1 and the amount and stability of the bone created by the orthodontic movement. CONCLUSIONS: The bone created through orthodontic tooth movement was stable in both the horizontal and vertical directions. Changes in the width of the alveolus were not related to the amount of bone at the place of agenesis at T1. When the canine erupts next to the central incisor, favorable conditions affect the formation of the bone mass through distalization of the canine at the site of the missing lateral incisor.

Fixed retention: pitfalls and complications.

Long-term stability of orthodontic treatment results is problematic. Long-term or even lifelong retention with bonded retainers is being increasingly used among clinicians. Bonded retainers can provide an efficient and attractive method of retention, particularly because they require minimal compliance from patients. However, the use of bonded retainers is associated with relatively frequent complications, such as detachments of the adhesive layer or wire fractures, as well as unexpected complications with potentially severe consequences with associated periodontal and general health risks. It is imperative that the whole dental team are aware of these pitfalls and complications, and appreciate how to minimise and address these.

Conservative Treatment of Complicated Crown Fracture and Crown-Root Fracture of Young Permanent Incisor-A Case Report with 24-Month Follow-Up.

The complicated crown-root fracture of young permanent teeth is an uncommon traumatic dental injury that is usually treated in a complex way and is demanding not only for the dentist but even for the treated child. In this case report, we present the conservative treatment of a maxillary central incisor in a 10-year-old boy after a traumatic dental injury. Treatment included partial pulpotomy and adhesive fragment reattachment after reflection of the mucoperiosteal flap. The patient was fully asymptomatic at 24-month follow-up, with an aesthetically acceptable outcome. Vital pulp therapy and adhesive fragment reattachment can be a viable treatment option for complicated crown-root fractures, especially when treating immature permanent teeth.

Molar height and dentoalveolar compensation in adult subjects with skeletal open bite.

OBJECTIVE: To evaluate the skeletal and dentoalveolar components in adult subjects with skeletal open bite in the presence or absence of dental compensation. MATERIALS AND METHODS: The study sample included 69 adult female subjects who belonged to three groups according to skeletal vertical relationships and overbite. A total of 15 variables (5 angular, 10 linear) were evaluated. Values in the dentally compensated open bite group (COBG), the dentally noncompensated open bite group (NCOBG), and the control group with normal vertical skeletal relationships and overbite (CG) were compared by means of parametric statistics. RESULTS: The COBG and the NCOBG showed significantly greater incisor and molar heights in both jaws than the CG. No significant difference in upper or lower molar height was found between COBG and NCOBG. Incisor height was significantly greater in COBG than in NCOBG. Elongation in the incisor region was accompanied by significant narrowing of the lower anterior alveolar process in both skeletal open bite groups. Proclination of the upper incisors was significantly smaller in the COBG than in the other groups. CONCLUSIONS: Dentoalveolar components consisting of incisor elongation and inclination play a significant role in compensating for skeletal open bite configuration in adult subjects. Increased molar height is a common finding in adults with skeletal open bite.