Articol Pacurar

METODE  NON-EXTRACŢIONISTE  DE OBŢINERE  A SPAŢIULUI  PE  ARCADĂ  ÎN  TERAPIA  ORTODONTICĂ

Mariana Păcurar1, Ana Maria Jurcă2,  Doru Roman3,  Eugen Bud4, Irina Zetu5, Ioana Vâţă6

 

1 Profesor univ., UMF Tîrgu-Mureş, Fac. de Medicină Dentară, Disciplina de Ortodonţie str. Gh.Marinescu nr.38, 540139 Tîrgu-Mureş

2Asistent univ., UMF Tîrgu-Mureş, Fac. de Medicină Dentară, Disciplina de Ortodonţie str. Gh.Marinescu nr.38, 540139 Tîrgu-Mureş

3Şef de lucrări, UMF Tîrgu-Mureş, Fac. de Medicină Dentară, Disciplina de Ortodonţie str. Gh.Marinescu nr.38, 540139 Tîrgu-Mureş

4Asistent univ., UMF Tîrgu-Mureş, Fac.de Medicină Dentară, Disciplina de Ortodonţie str. Gh.Marinescu nr.38, 540139 Tîrgu-Mureş

5Conferenţiar, UMF Iaşi, Fac. de Medicină Dentară, Disciplina de Ortodonţie

6 Asistent univ., UMF Iaşi, Fac. de Medicină Dentară, Disciplina de Ortodonţie

 

Distalizarea molarului este o metodă de tratament în cazurile de anomalii dento-maxilare, pentru evitarea extracţiei în ocluzie adâncă şi tipar hipodivergent. Literatura de specialitate indică faptul că distalizarea molarului superior este o mişcare tipping  combinată cu rotaţie mezio-bucală şi torc corono-bucal.

Scop: Evaluarea avantajelor distalizării molarului prim superior (durata tratamentului, complianţa pacientului, spaţiul obţinut), prin folosirea diferitelor aparate. Am folosit această metodă în cazul malocluziei clasa II/2 Angle.

Material şi metodă: Analiza statistică pe 435 pacienţi cu vârsta între 11-13 ani, trataţi cu aparate fixe (tehnica straight-wire) între anii 2009-2012. Pacienţii au fost împărţiţi în două grupe: grupa A (83) cu aparate de distalizare şi grupa B (352) cu două subgrupe: B1 (278) trataţi cu alte aparate şi B2 (74) la care s-a efectuat extracţia dentară.

Rezultate: Distalizarea molarului a avut succes în 45 % din cazuri, spaţiul obţinut având valori între 2,13 – 2,33 mm, mişcarea fiind însoţită de tipping. Mişcarea distală corporeală a molarului superior poate fi obţinută când axa de rotaţie este la infinit şi stresul de compresiune este distribuit omogen în ligamentul periodontal. Rata succesului depinde de: erupţia molarului doi, dimensiunea overjetului şi overbitului.          

           Concluzii:  

  1. Distalizarea molarului prim superior/inferior este o provocare în tratamentul ortodontic şi este indicată în malocluzia clasa a II-a Angle cu ocluzie adâncă, profil retrognat şi tipar hipodivergent. În aceste cazuri, extracţia este contraindicată pentru că  înrăutăţeşte profilul.
  2. Distalizarea molarului prim depinde de poziţia molarului doi şi această tehnică nu este singulară, ci se asociază cu aparate fixe.

 

Cuvinte cheie: distalizare, molar doi, clasa II, extracţie, aparate fixe.

  

NONEXTRACTION  METHODS  FOR  SPACE  REGANE  IN  ORTHODONTIC  THERAPY

Mariana Păcurar1, Ana Maria Jurcă2,  Doru Roman3,  Eugen Bud4, Irina Zetu5, Ioana Vâţă6

 

1 Professor, UMF Tîrgu-Mureş, Faculty of Dentistry, Orthodontic Department,

38 Gh. Marinescu st, Tîrgu-Mureş, 540139

2Assistent professor, UMF Tîrgu-Mureş, Faculty of Dentistry, Orthodontic Department, 38 Gh. Marinescu st, Tîrgu-Mureş, 540139

3Lecturer, UMF Tîrgu-Mureş, Faculty of Dentistry, Orthodontic Department,      

38 Gh. Marinescu st, Tîrgu-Mureş, 540139   

4Assistent professor, UMF Tîrgu-Mureş, Faculty of Dentistry, Orthodontic Department,

38 Gh. Marinescu st, Tîrgu-Mureş, 540139

5Lecturer, UMF Iaşi, Faculty of Dentistry, Orthodontic Department

6 Assistent professor, UMF Iaşi, Faculty of Dentistry, Orthodontic Department

 

The molar  distalization is an alternative treatment method in dento-maxilare anomalies, to avoid extraction especialy on low angle cases. Orthodontic literature indicates that upper molar distalization is a tipping movement, combined with mesio-buccal rotation and buccaly-crown torque.     

Aim: To analise the avantages to regane space during upper first molar distalization movement, by using different devices.  We used this method in skeletal class II, dental class II/2  malocclusion Angle  with crowding and low profile.

Material and method:  A retrospective statistical analise on 435 patients aged   11-13 years treated with fixed appliances (straigh wire techique), beetwen 2009-2012. The patients were divided in two groups: group A, (83) who worn  distalization devices  and group B, (352). The group B were divided in: B1(278) with other nonextractions appliances and B2 (74) with extraction during orthodontic treatment.   

Results: Upper molar distalization is succesed in 45% cases, the values of the space beeing : 2,13- 2,33 mm, these mouvement is by tipping. Bodily distal upper molar movement could be obtained only when rotational axis is at infinite and the compressive stress is homogeneously distributed in the periodontal ligament

The succes rate is depending on some factors: eruption of second molar, overjet and overbite size.

Conclusions:

  1. Molar distalisation is a challenge in orthodontic treatment and is indicated for class II Angle, crowding and low angle (extraction makes the prophile worse).
  2. Molar distalization is depending on second molar position and this tehnique is not singular, but associated with multibracket appliance .

 Key words: distalisation, second molar, class II, extraction, fixed appliances.

Modern orthodontic therapy attempts, whenever possible, a nonextractional treatment, with convenient means for the patient, which would allow current activities and especially to not affect facial harmony. (1)

In this context, molar distalization is an useful treatment method in obtaining arcade space, especially in anomalies Class II/2 Angle with accentuated  retrognatic profile and hipodivergent growth pattern, cases where extraction would obviously create aesthetic facial damage. (2)

The authors have proposed in this paper an assessment of molar distalization method in comparison with other nonextraction therapy methods (expansion, frontal protrusion and stripping).

            Material and methods.

 We conducted a retrospective statistical study on a sample of 435 patients, aged between 11-13, who were treated at the Orthodontic Department of the Faculty of Dentistry in Tirgu Mures and Iasi in the period 2009-2012, for various malocclusions.

The initial sample was divided into two subgroups: group A – 83 patients with  upper or lower molar distalization. The following parameters were evaluated:
            – duration of  treatment
            – type of distalization
            – type of used appliance
            – obtained results.

Group B – represented by the rest of the patients, were divided into two subgroups: B1 – cases of permanent teeth extractions and B2 – nonextractional cases, treated with other methods than distalization.  

            Results.

The distribution of cases by gender demonstrated a predominance of female patients, representing 64% of the studied group (Figure 1).

Analysis of cases depending on the type of anomaly revealed a higher frequency of class I Angle malocclusion (56,09%), class II represented by 35%, of which 20,69% class II/1, 14,71% class II/2, and class III Angle malocclusion only 8,51% of the studied group (Table 1).

In group A, represented by patients with molar distalization, the distribution on the arches was the following: the upper jaw 11,26%, lower jaw  4,83% and bimaxilarry: 2.99% of cases (Table 2).

The distribution of cases from B2 subgroup includes:

  • upper expansion plate 34%
  • lower expansion plate 8%
  • maxillary disjunction (rapid palatal expander)  4%
  • functional therapy 2,5%
  • class II elastics 37%
  • lee-way-space maintenance 1,5%
  • stripping (interproximal reduction)  13%                 
  • Correlation betwen owerjet and distalization

Correlational analysis of the type of extractional/nonextractional treatment related to overjet shows that: for the overjet values between 0-2 mm, the most frequent is nonextractional therapy (other than distalization) in 60% of cases, followed by dental extraction in 28% of cases and molar distalization in 12% of cases. The frequency with which it was used distalization decreases with the growth of overjet value. (Figure 2)

Correlational analysis of the type of extractional/nonextractional treatment related to overbite shows that in open bite cases is more frequent extraction treatment and in deep bite cases the most frequent treatment is nonextraction  . (expander or stripping), folowed by distalization cases.  (Figure  3)

Our study showed an increased incidence of therapy with molar distalization in class II/2 anomalies (28,13%), followed by class I Angle (11,07%) and class II/1  (4,44%) (Figure 4).

Regarding the type of dentition, we found that the difference in the incidence of upper molar distalization is not significant, between permanent (10,81%) and mixed dentition (11,57%), as opposed to the lower jaw, with a frequency of 7,02% in the mixed dentition and 2,16% in the permanent dentition (Figure 5).

In our study the most frequent type of appliance used for molar distalization was the palatal plate with one way screw in 43,37% of cases, followed by fixed appliances in 27,71% of cases.

A major issue in this kind of therapy is the  timeing of treatment initiation. In  group A  the average age of the patients was 10 years and in group B 9 years. The highest chances of molar distalization success are in situation when second molar is not errupted.

The updated data from the literature indicate that during molar distalization we obtain a distal tipping,  less corporal displacement, because the force application point is at distance from the resistance center of the tooth. (6, 7)

 For bodily movement, the moment/force ratio at the molar centre of resistance must be zero, so it is necessary to reduce the moment on the molar bond using a counterbalancing couple (CBC) with effects in vertical plane (9, 10)

Conclusions

  1. The molar distalization shows a 45% success rate with the following order: Class II/2 –  28%; class I – 11%; Class II/1 – 4,4%.
  2. The average treatment period  for molar distalization was 9 months.
  3. In 25% of patients with molar distalization the expected results were not achived. This outcome  was attributed to the type of used appliance.
  4. Molar distalization has a greater chance of  succes  in patients in whom  the second molar hasn’t erupted.
  5. Treatment with molar distalization was associated with increased values of overjet. As the value of the overjet increses, the succes rate of treatment decreases. The success of treatment was also correlated with increased values of overbite.

Bibliography

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  2. Antonarakis Gregory Stylianos, Stavros Kiliaridis: Maxillary molar Noncompliance  Intramaxillary Appliances in Class II Malocclusion. A Systematic Review. Angle Orthodontist, vol.78. no-6, 2008.
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