JCO, Miniscrew Loosening, Prof B.Melsen

Prof. B. Melsen talks in simple words  about miniscrews and the reasons behind failure.
First of all the failure of miniscrews can be seen immediately (in the first couple of weeks) or later.


A summary of some of the points given in this article:


Early Failure:

• Insufficient primary stability (wrong site selection, due to insufficient bone quality, or quantity)
• Iatrogenic failures (jiggling during the insertion, over-screwing)
• Magnitude and direction of the force loading (high magnitude of force, it is advised to start with around 50cN and increase the force gradually, also unscrewing moments should be avoided)

Later Failure:

• Change of the local environment (inflammation due to root proximity, or change of the local bone turn over, e.g. in relation to resorption of the root of a deciduous tooth)
• Systemic factors (such as smoking, alcoholism, and medication that influences bone turnover have been proven risk factors for implant failure in general)

In any case when a miniscrew fails, the new insertion site has to further away from the old one, at least twice the diameter of the screw. In addition choosing to change the site and use the screw with an indirect loading instead of direct could be advised if a screw fails more than once at the same patient.

This is the link of Prof B. Melsen's article at the current issue of the JCO.


References:
Clinical Guide
Clinical Applications

D.G.

Bone Anchored Maxillary Protraction of Growing Class III Patients, EuJO

The traditional protocol for maxillary protraction of growing class III pre-pubertal patients would be expansion and loosening of the mid-palatal suture with the means of a Hyrax appliance. That will be followed with 5-7months (more depending on the severity and patient compliance) of protraction with a facemask, with a force of 300-400gr elastics (8-14oz). The optimal use of the facemask would be 14-16h/day.

Meta analysis, of stability of anterior open bites, Feb AmJO 2011

G. M. Greelee et al, performed an interesting meta analysis on a topic that is quite hot, for the orthodontic world. Anterior open bite patients and the stability of closure treatments wether this is a surgical or a non surgical approach. This meta analysis is published at the current issue of the American Journal of Orthodontics and Dentofacial Orthopedics


The initial search was done at PubMed, EMBASE, Cochrane Library, gray zone literature and hand searching. It was performed using the abstracts of 105 articles initially.


From those 21 articles met the criteria. The articles that were excluded did not have:

Pediatric Reuhmatology International Trial Organization, PRINTO

PRINTO organization started in 1996 by Alberto Martini, and Nicollino Ruperto. Initially it consisted of rheumatoid arthritis centers in 14 countries. Today it numbers 50 countries and more than 350 centers. 

It is a non profit, non governmental, International organization. Its' aim is the collaboration of different centers around the world to the better understanding, treatment and of-course research in the field of  pediatric rheumatoid diseases. More information can be found here. 

Two of the ongoing projects of the organization:

• Juvenile Dermatomyositis Trial
• Autoinflamatory Diseases Working Group

A list of prior trials and projects of the organization can be found here.

There is a large database of all basic information related to Juvenile Idiopathic Arthritis (poly-, oligo-arthritis, extended or not, and systemic arthritis), Skleroderma, Bechet, Lupus, and other relevant pediatric rheumatoid diseases. This is the link and it is a database translated in more than 15 languages.

Mandibular deviation and canted maxillary occlusal plane treated with miniscrews and intraoral vertical ramus osteotomy

In the American Journal of Orthodontics and Dentofacial Orthopedics of December 2009, there is an interesting suggestion of treating patients with mandibular deviation (unilateral mandibular displacement) and canted maxillary occlusal plane.


The traditional method of choice would be, a BSSO and setback of the mandible with rotation on the z axis, followed with a 3-piece LeForte I on the maxilla with differentiated intrusion to correct the cant of the upper jaw. 
However the authors suggest a less invasive approach with an intraoral vertical ramus osteotomy and setback-rotation on the mandible, and an approach with miniscrews and intrusion on the maxilla to correct the canting on the upper.