Interlabial gap behavior with time, JWFO

An interesting article is in press at the Journal of the World Federation of Orthodontists JWFO

The article aims to clarify wether the interlabial gap (shown as number 2 on the tracing to the left) reduction over time can be associated with the treatment therapy that was chosen.

62 Class I and Class II patients (with lip incompetence) were treated with or without extractions, and the gap was measured before, after and at the long term follow up.

What was found is that the interlabial gap decreases significantly more at the extraction therapy group compared to the non-extraction one. This happens during treatment.

During retention however, non-extraction group has a greater decrease of the gap, when compared to the extraction therapy group.

Also the authors show that variables such as lip length are associated with the amount of interlabial gap but NOT the decrease during treatment and over-time. The later has to do with the treatment chosen, and of course normal aging.

In plain words the decrease of interlabial gap during treatment at the extraction therapy group happens faster, and that is why during retention there is a smaller decrease when compared to the non-extraction therapy. "Aging faster?!"

The article can be found here: http://www.jwfo.org/article/S2212-4438(13)00056-8/abstract

DG

Comparison of Untreated and Treated Subjects, Occlusal Changes.

Post-Treatment and Physiologic Occlusal Changes Comparison. TheAngleOrthodontist, early online access.

The article compares the occlusal changes during retention of (PAR and Little indexes):

1. 97 cases 4 premolar extraction cases and 
2. 58 non extraction cases, versus 
3. 114 untreated subjects.

What was found is that:

• The treated groups showed more changes according to PAR and Little maxillary indexes than the untreated group in the observation period.
• The post-treatment change of the mandibular anterior crowding of the treated extraction group was greater than the mandibular crowding caused by physiologic changes in the untreated group.

An article is published at the European Journal of Orthodontics, from a Finish group, "Dental arch width, overbite, and overjet in a Finnish population with normal occlusion between the ages of 7 and 32 years"

In this article there is a series of dental casts of Class I, Untreated Subjects, been analyzed:

1. 18 women and 15 men
2. at age 7, 10, 12, 15 and 32 years old

What was found is that:

• Both arches at canine and molar region increase from 7-15 and decrease from 15-32 years of age.
• Overjet and overbite changes are also noted from 15-32 years, as well as attrition and tooth wear that plays a role to the above mentioned occlusal changes.

Discussion:

Physiological changes in the occlusion is a major subject, that even though there are some very important studies been published in the past, we still do not know that much about.

It should be mentioned strongly to our patients that your dentition and your soft tissue for that matter WILL deteriorate with age, and whenever it is possible the orthodontist should be in doubt of what he/she sees and how it is explained to the patient. 

An example could be of course secondary mandibular crowding and the role of wisdom teeth eruption which is so effortlessly blamed by the orthodontist to be the cause of this crowding development. When we know or should know that canine width DOES decrease with age, especially in the lower jaw and that the contact points become surfaces (are worn out) and teeth tend to slowly migrate mesial with age...

Suggested previous literature:

1. Sinclair PM, Little RM. Maturation of untreated normal occlusions. Am J Orthod. 1983;83:114–         123.
2. Thilander B. Orthodontic relapse versus natural develop- ment. Am J Orthod Dentofacial Orthop. 2000;117:562–563.
3. Al Yami EA, Kuijpers-Jagtman AM, van’t Hof MA. Stability of orthodontic treatment outcome: follow-up until 10 years postretention. Am J Orthod Dentofacial Orthop. 1999;115: 300–304.
4. Bishara S E, Jakobsen J R, Treder J, Nowak A 1997 Arch width changes from 6 weeks to 45 years of age. American Journal of Orthodontics and and Dentofacial Orthopedics 111: 401–409
5. Henrikson J, Persson M, Thilander B 2001 Long-term stability of dental arch form in Norman occlusion from 13 to 31 years of age. European Journal of Orthodontics 23: 51–61
6. Thilander B 2009 Dentoalveolar development in subjects with normal occlusion. A longitudinal study between the ages of 5 and 31 years. European Journal of orthodontics 31: 109–120

D.G.

Upper bonded retainer failures, AngO ahead of print

The Angle Orthodontist, at it's online ahead of print, has published an interesting retrospective study of Dr Sabine Ruf of Giessen University, Germany.

466 consecutive upper bonded retainers were checked and surprisingly a 58.2% of the patients experienced failures of their retainer.

Click to enlarge

Now that's plain a lot. Looking at the graph above:

• The retainers that fail at the first 6 months are due to detachments. The incidents of detachment reduce over-time.
• The complete loss of the retainer has more or less the same probability of happening over-time.
• Lastly the fracture of the retainer, as expected is something that happens more often after a year or two.

Abstract link

D.G.

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:

Angle Classification Today, and Post-treatment Stability.

Edward Angle is considered the father of modern orthodontics. He classified malocclusions by the relationship of the mesio-buccal cusp of the upper first molar and the mesio-buccal groove of the lower first molar.

• Class I: When the mesio-buccal cusp of the upper molar sits in the mesio-buccal groove of the lower first molar.
• Class II: When the upper molar cusp is placed anteriorly and there is an overjet (div1) or there is a compensatory retroclination of the upper incisors (div 2)
• Class III When the lower molar is anteriorly displaced, with or without a negative overjet (mandibular prognathy or maxillary retrognathism)

An alternative to space retention, for agenesia patients.

Case presentation:

 

Patient L.R. 15y.o. after active treatment, agenesia of 22, space created for an implant on that region. The patient is in adolescence and the implant will be placed after growth has ceased completely at the age of 19-20. The temporary prosthetic rehabilitation of an agenesia space is an important issue especially in cases of lateral(s) missing

Postorthodontic root approximation after opening space for maxillary lateral incisor implants

This is one of the most common implications - problem after successfully treating a lateral incisor(s) agenesia patient. Treatments are usually quite lengthy but also carried out sometimes a bit earlier in the patients life.