Upper molar distalization: a critical analysis.

Traditional upper molar distalization techniques require patient co-operation with the headgear or elastics. Recently, several different intraoral procedures have been introduced to minimize the need for patient co-operation. This article reviews the appliances currently available for maxillary molar distalization and critically analyses their dentoalveolar and skeletal effects.

Effects of conventional and high-intensity light-curing on enamel shear bond strength of composite resin and resin-modified glass-ionomer.

The purpose of this study was to evaluate the shear bond strengths of a composite resin (Transbond XT; 3M/Unitek, Monrovia, Calif) and a resin-modified glass ionomer (Fuji Ortho LC; GC America Inc, Alsip, Ill) cured with 2 different light-curing units: a conventional visible light unit (Ortholux XT; 3M Dental Products, St Paul, Minn) and a xenon arc light unit (Plasma Arc Curing [PAC] System; American Dental Technologies, Corpus Christi, Texas). One hundred twenty freshly extracted bovine permanent mandibular incisors were randomly divided into 1 of 8 groups; each group consisted of 15 specimens. Two groups (1 group for each type of adhesive) were exposed to the visible light for 20 seconds (Transbond XT) and 40 seconds (Fuji Ortho LC), respectively, and used as control groups. The remaining 6 groups (3 for each adhesive) were cured with the xenon arc light for 2, 5, and 10 seconds. After bonding, all samples were stored in distilled water at room temperature for 24 hours and subsequently tested in a shear mode on an Instron universal testing machine (Instron Corp, Canton, Mass). For the groups bonded with Transbond XT, no statistically significant differences (P =.868) were found between the shear bond strength of the control group cured with Ortholux XT and those of the groups cured with the PAC System for 2, 5, or 10 seconds. When the shear bond strengths of the groups bonded with Fuji Ortho LC were evaluated, no statistically significant differences (P =.087) were found between the control group that was cured with Ortholux XT and those cured with the PAC System. The bond strength of the composite resin was significantly higher than that of the resin-modified glass ionomer in all the groups tested (P <.0001). The present findings indicate that, compared with visible light-curing, the xenon arc light enables the clinician to significantly reduce the curing time of both bonding agents, without affecting their shear bond strengths. Therefore, xenon arc light sources can be recommended as an advantageous alternative for curing both composite resins and resin-modified glass ionomers.

Effects of five-day versus one-day infusion of iloprost on the peripheral microcirculation in patients with systemic sclerosis.

OBJECTIVE: To evaluate the effects of iloprost infusion on the microcirculation in patients suffering from severe Raynaud's phenomenon secondary to systemic sclerosis. METHODS: Eight patients received a 7-hour infusion of iloprost for five consecutive days and then for one day 3 months later. The effects on vascular distensibility were evaluated by piezoelectric plethysmography before and after the treatment and at 2, 4 and 6 weeks. RESULTS: The beneficial effects on the peripheral microcirculation were statistically significant after five days of infusion (distensibility index: 0.18 +/- 0.01 vs 0.23 +/- 0.01, p < 0.002) and lasted for less than four weeks, whereas no difference (0.22 +/- 0.04 vs 0.24 +/- 0.02, p: ns) was seen after one day of treatment. One patient suffered from typical angina pectoris with electrocardiographic changes of the ST wave detected during the infusion. CONCLUSION: Our results show that a five-day infusion of iloprost has an effect which lasts from two to four weeks; after four weeks the distensibility index returned to the baseline value. The one-day infusion had no effect on the vascular bed, studied by the piezoelectric pletysmographic method. Treatment with five consecutive days of infusion every four weeks is an impracticable scheme to adopt, however. We have therefore instituted a treatment schedule of a single daily infusion every four weeks with the aim of maintaining the effects induced by the initial five-day infusion. The preliminary results obtained with this schedule are reported.

Adaptations of masticatory muscles to a hyperpropulsive appliance in the rat.

The plasticity of masticatory muscles was studied by comparing rats that were wearing a protrusive appliance and were kept on a liquid diet with two control groups: (1) pair-fed rats and (2) rats that had free access to ordinary pelleted food. The animals were 45 days old at the beginning of the experiment and were studied for a period of 20 days. Three jaw muscles with different functions were examined: masseter, temporalis, and digastric. Muscle fiber composition was determined (1) by fiber counting after staining with four monoclonal antibodies, which were able to recognize the four major myosin heavy chain (MHC) isoforms and therefore four fiber types (I, IIA, IIX, IIB) and (2) by electrophoresis on 6% polyacrylamide gels. The comparison between free-diet rats and pair-fed rats showed that the change from a hard pelleted diet to a liquid diet caused a shift in fiber type and MHC distribution, characterized by an increase of IIB MHC in temporalis and digastric muscles but not in the masseter muscle. The comparison between pair-fed rats and rats wearing appliances showed on the contrary a decrease in IIB MHC and an increase in IIA and IIX MHC. The results support the conclusions that (1) rat jaw muscles can quickly adapt to functional demand changing their fiber type composition, (2) the changes appear restricted inside the fast fiber population, and (3) fiber-type changes caused by dietary variation are not less than those caused by orthodontic intervention and must be taken into account to assess the effect of the appliance correctly.

A scanning electron microscopy comparison of enamel polishing methods after air-rotor stripping.

In the last few years, orthodontic literature has shown particular interest in the interproximal enamel reduction technique described as stripping or slenderizing. Most researchers have shown, by scanning electron microscopy (SEM) studies, the difficulties encountered while attempting to remove coarse abrasions left after stripping with the first instrument. The objective of this SEM study was to compare the different polishing methods proposed in the literature and to assess the efficiency of our own procedure. For this purpose, 48 healthy human teeth (premolars and molars) were used after removal for orthodontic or periodontal reasons. The teeth were divided into eight groups of six teeth each (two molars and four premolars), and mounted on a typodont to simulate a clinical situation. Each group underwent stripping according to one of the following techniques: 16-blade tungsten carbide bur and fine and ultrafine diamond burs; coarse diamond bur and fine and ultrafine diamond burs; coarse diamond disk and Sof-Lex disks (Dental products/3M, St. Paul, Minn.); 16-blade tungsten carbide bur and phosphoric acid on finishing strip; and 8-straight blade tungsten carbide diamond bur and Sof-Lex disks. The SEM investigations demonstrated that it is not possible to eliminate, with normal polishing and cleaning methods, the furrows left on the enamel both by the diamond burs and the diamond disks and the 16-blade tungsten carbide burs. Mechanical and chemical stripping as well did not prove to be effective. By contrast, with the use of a 8-straight blade tungsten carbide bur followed by Sof-Lex disks for polishing the enamel, it is possible to obtain well-polished surfaces that many times appear smoother than the intact or untreated enamel.

[Electromyographic and electrognathographic analysis of patients with juvenile rheumatoid arthritis]. / Analisi electtromiografica ed elettrognatografica in soggetti affetti da artrite reumatoide giovanile.

Seven patients, affected by JRA, underwent an examination by electromyography and electrognathography, to judge variations in the activity of some masticatory muscles and in the movements of the jaw. The muscular activity and masticatory mechanics show a reduction in the freedom of movement. The system cannot work in all the positions allowed by the physiological mobility of the TMJ.

[TMJ in subjects with juvenile rheumatoid arthritis: functional and cephalometric analysis]. / L'ATM in soggetti affetti da artrite reumatoide giovanile: analisi funzionale e cefalometrica.

The Authors studied 21 patients affected by Juvenilis Rheumatoid Arthritis. The TMJ compromission was evaluated by un objective, clinical and radiographic examination. A teleradiographic with cephalometric analysis was also performed to all subjects. The results show a greater TMJ compromission in earlier arisen disease subjects.

[Oro-facial-digital syndrome type II: clinical and cephalometric study of a case]. / La sindrome oro-deigito-facciale tipo II: studio clinico e cefalometrico di un caso.

The Authors report a case of Oral-Facial-Digital syndrome type II (Mohr syndrome); three cephalometric tracings and a clinical study were carried out, in order to evaluate the oro-facial abnormalities. A complete cephalometric study has never been performed in this syndrome before.

[Rapid palatal expansion. Monitoring of orthopedic effects with C.A.T]. / Espansione rapida del palato: controllo degli effetti ortopedici con la T.A.C.

It has been made a check with TAC on 10 subjects, submitted to Rapid Expansion Palatal. The technique provided a direct and careful vision of the disiuntion, allowing to prove with scientific exactitude for the first time the diastase of ptherigoideis processes.

[Histological evaluation of tooth movement using immunocytochemical research]. / Valutazione istologica degli spostamenti dentari mediante indagine immunocitochimica.

A new immunocytochemical methodology has been applied to value the proliferation in the periodontal tissue following experimental tooth movement. Orthodontic tooth movement has been obtained in Guinea pigs by a coil sporing, and a proliferation marker administrated "in vivo"; the proliferation marker used is Bromodeoxyuridine, a thimidine analogue which is taken up by DNA synthesizing nuclei, and afterwards intensified by two monoclonal antibodies, where the second is FITC coniugated. Instead of some technical difficulties, the results are encouraging for further development.

[Clinico-histological evaluation of surgical orthodontic treatment for fused teeth]. / Valutazione clinico-istologica del trattamento chirurgico-ortodontico dei denti fusi.

Seeking an evaluation pattern for periodontal wounds following the surgical section of two fused teeth healing, the authors caused in an animal a similar lesion. After that, they valued the undergoing to pressure or traction periodontal re-organizing and the histological-clinical data showed a tissues favourable repair.

[Oral hygiene motivation in orthodontic patients]. / Andamento dell'igiene orale nel paziente ortodontico.

The task of the present study has been to verify experimentally if prolonged motivation may produce better oral hygienic conditions in orthodontic patients. Applying oral hygienic index modified, gingival index and saliva lactobacilli's concentration count, the A.A. obtained encouraging data evaluating the motivated subjects situation versus control group.

[Dental age and skeletal age: correlation study]. / Eta'dentale ed eta'scheletrica: ricerca di correlazioni.

Authors looked for a correlation between dental and skeletal age, to simplify diagnosis, considering 116 subject's panoramic and carpal radiography. Results unfortunately show that is impossible to estimate skeletal maturation by dental analysis only.