Extractions as a form of interception in the developing dentition: a randomized controlled trial.

OBJECTIVE: To determine if the extractions of lower primary canines are an effective procedure to relieve crowding of the labial segment. STUDY DESIGN: randomized controlled trial. Subject sample: 83 cases were collected in clinics in Italy, Germany and Wales. The groups were followed over a 2-year period. METHODS: Subjects were randomly allocated to a primary canine non-extraction or extraction group. Dental casts of the patients were collected at the start and at the recall period of the trial. The outcome measures recorded were lower incisor crowding, arch length, intermolar width, overbite, overjet, lower clinical crown heights and lower incisor inclinations. STATISTICS: The Mann-Whitney test was used to compare the differences between the extraction and non-extraction groups. RESULTS: In both groups, crowding reduced 1.27 mm in the non-extraction group and 6.03 mm in the extraction group. The difference between the 2 groups was 4.76 mm (P<0.05). The arch perimeter decreased more in the extraction group by 2.73 mm (P<0.05). As the incisor inclination stayed essentially the same, the loss in arch length was attributed to the molars moving forward. The net gain from extracting deciduous canines was 2.03 mm. CONCLUSIONS: There was a reduction in lower incisor crowding as a result of lower primary canine extraction. However, arch perimeter decreased more in the extraction group leaving less space for the eruption of the lower secondary canines.

Bone response to orthodontic loading of endosseous implants in the rabbit calvaria: early continuous distalizing forces.

The purpose of this experimental study was to evaluate the effect of early orthodontic loading on the stability and bone-implant interface of titanium implants in a rabbit model. Twenty-four short threaded titanium fixtures were inserted in the calvarial mid-sagittal suture of 10 rabbits. Two weeks following insertion, 20 implants (test group) were subjected to continuous distalization forces of 150 g for a period of 8 weeks. The remaining four implants (control group) were left unloaded for the same follow-up interval. Clinically, all implants except for one test fixture were stable, and exhibited no mobility or displacement throughout the experimental loading period. Histologically, all stable implants were well-integrated into bone. No differences could be found between the pressure and tension surfaces of the test implants relative to bone quality and density within a range of 1000 microns from the fixture surface. Similarly, qualitative differences were not observed between the apical and coronal portions of test fixtures. Morphometrically, a mean percentage bone-to-implant contact of 76.00 +/- 18.73 per cent was found at the test pressure sides, 75.00 +/- 11.54 per cent at the test tension sides, and 68.00 +/- 15.55 per cent at the control unloaded surfaces. No statistically significant differences in the percentage of bone-to-metal contact length fraction were found between test pressure surfaces, test tension surfaces, and unloaded control surfaces. Marginal bone resorption around the implant collar or immediately beneath it was found in roughly the same percentage of analysed sites in the test and control fixtures. In contrast, slight bone apposition was demonstrated at the implant collar of the test pressure surfaces, while no apposition or resorption were observed in the test tension zones. This study suggests that short endosseous implants can be used as anchoring units for orthodontic tooth movement early in the post-insertion healing period.

[Epidemiological study and orthodontics]. / Indagine epidemiologica e ortognatodonzia.

Prevention is now playing a major role in all fields. An epidemiological survey of malocclusions has evaluated 6 years old children in one district in the Regione Veneto (Northern Italy). Some indications are provided as regards preventive and interceptive orthodontics (including treatment aimed to reducing the severity of problems) in the therapy of the most frequent malocclusions in this age group.

[Prevention in dentistry: evaluation after one year]. / Prevenzione in odontostomatologia: valutazione a distanza di un anno.

The Authors planned an after one year revision of a sample of no. 138 children of a ULSS 8 (VI) District, involved in a odontoiatric prevention program.

[Progression of DMF index--DMF from 3 to 12 years: need for preventive intervention]. / Andamento indice DMF--DMF fra i 3 e i 12 anni: necessità di intervento preventivo.

To evaluate the prevalence of soft deposits and the trend of dmf/DMF index, a group of children between 3 and 12 years of age has been examined. A DMF Index of 5.74 at 12 proves the need to promote educational and prevention programmes in the Ulss 34 area since the WHO program "Health for all in the year 2000" sets a target of a DMF Index below 3 at 12.

[Epidemiological study of the prevalence of caries, periodontal diseases and malocclusion in a school population]. / Indagine epidemiologica sulla prevalenza di carie, parodontopatie e malocclusioni in una populazione scolastica.

A randomized stratified sample of children 3 to 12 years of age has been examined, DMFT, CPITN, soft deposits and malocclusion have been analyzed. The prevalence of caries, periodontal involvement and malocclusion has been observed to be rather high, thus requiring the organizing of detailed preventive programs to reach the W H O target set for the year 2000.

[Water absorption and resistance to wear of 2 newly invented composite resins]. / Assorbimento d'acqua e resistenza all'usura di due resine composite di nuova concezione.

Two recently built composites, one for posterior teeth, and the other for general employ, were evaluated in relation to their water absorption and resistance to wear by means of the "scratch test". Critical loads and attrition of the two materials were also evaluated, with statistical analysis. The results supported the good qualities of the two composites, which are to be considered very advanced in the field of esthetic reconstruction materials.

["On line" processing using a microcomputer of bioelectric signals of gnathological significance]. / Elaborazione "on line" mediante microcomputer di segnali bioelettrici di interesse gnatologico.

EMG during diagnosis and treatment monitoring in orthodontics and gnatology has become widely used. The Authors describe the linking of a PC to an amplifier of EMG signals. The program is then reported and commented on.

[A proposed method for analysis of the correlation between electromyographic and cephalometric parameters]. / Proposta di una metodica per l'analisi della correlazione tra parametri elettromiografici e cefalometrici.

This work reports on a method of analysis and statistical correlation of electromyographic and cephalometric parameters. Has been employed a computer as oscilloscop with digital memory.