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NEED OF PREVENTION STEPS AGAINSTIMPACTION OF MANDIBULAR AND MAXILLARYPREMOLARS

Hristina Arnautska1, Zornica Valcheva1, Tihomir Georgiev2, Tsvetan Tonchev2

1) Department of Prosthetic Dental Medicine and Orthodontics, Faculty of DentalMedicine, Medical University Varna2) Department of Oral and Maxillo-Facial Surgery, Faculty of Dental Medicine,Medical University Varna

Journal of IMAB - Annual Proceeding (Scientific Papers) 2015, vol. 21, issue 4Journal of IMABISSN: 1312-773Xhttp://www.journal-imab-bg.org

ABSTRACT:Lower second premolars, closely followed by upper

premolars, are regarded as the third most common teethprone to impaction, after wisdom teeth and upper canines.

Objective of this article is to show the possibility forspontaneous eruption of impacted premolars upon extrac-tion of deciduous molars and removal of the follicular cystas described in several clinical cases. The present paper re-ports four clinical cases supporting the thesis that regard-less of the reason behind impacted premolars, undertakingpreventive measures significantly improves the position ofthe germ of those teeth.

Conclusions: The early extraction of the deciduousmolar, monitoring the patient and reserving the space forthe succeeding impacted premolar can lead to non-invasiveor relatively short orthodontic treatment (secondaryprevention).If root development is incomplete yet there isa good growth potential which could lead to spontaneouseruption (primary prevention).

Age specifics particular to children such as the greatregenerative abilities of the bone, provide a good progno-sis for spontaneous eruption or significant improvement inthe position of impacted premolars and facilitate the ortho-dontic treatment.

Keywords: lower premolar, second primary molar,impacted premolars, disturbed eruption , prevention

INTRODUCTIONLower second premolars, closely followed by upper

premolars, are regarded as the third most common teethprone to impaction, after wisdom teeth and upper canines.

Impaction of lower second premolars account for 0.1- 0.3% of all impacted teeth [1, 2]. Peck and other authorsclaim that premolar impaction is due to genetically deter-mined factors [3, 4, 5, 6, 7], while Johnsen, Siero and otherauthors consider local factors to be central: namely, the lackof space and ectopic position of the tooth germ [8, 9],ankylosed deciduous molars, odontomas and supernumer-ary teeth [10, 11].

Shear and other authors report that a frequent rea-son for the retention of the premolar germ appears to be thedentigerous or follicular cyst. Follicular cysts are associatedwith the crown of the germ of the developing tooth, enclos-

ing the entire crown along the cervical region, and some-times parts or the whole root of the tooth. [12, 13] Thereare very few instances of large follicular cysts in the max-illa expanding to the maxillary sinus, melting its bone floor.

Follicular cysts are often detected through an en-largement and swelling on the bone, mostly observed amongyounger children. According to Miyawaki and Lukas den-tigerous cysts grow rapidly, are generally painless, and mayresult in destruction of the bone, displacement of adjacentstructures, and resorption of their roots. [14, 15] Thusfollicular cysts lead to displacement of the tooth germ, in-hibiting its growth and causing impaction.

Objective of this article is to show the possibility forspontaneous eruption of impacted premolars upon extrac-tion of deciduous molars and removal of the follicular cystas described in several clinical cases.

Clinical cases:The present paper reports four clinical cases support-

ing the thesis that regardless of the reason behind impactedpremolars, undertaking preventive measures significantlyimproves the position of the germ of those teeth.

Case 1:The first case is of a 13- year-old girl with perma-

nent dentition and persistent deciduous lower second mo-lar due to an impacted lower second premolar on the left.The patient is Class I as per Angle’s classification, withhypodontia of tooth 12 and microdontia of tooth 22. (fig.1a) Family history proved that the mother also hashypodontia, suggesting a congenital predisposition to lackof teeth and impaction of the permanent fifth tooth in themandible. After extraction of the persistent deciduous sec-ond molar there was no need for an orthodontic applianceto facilitate eruption of the second premolar since there wasthere was enough space in the dental arch for it. The childwas followed through check-ups every 3 months in orderto monitor the position of the permanent first molar and thespace available in case preventive measures would becomenecessary. Nine months later a radiographic examinationshowed a visible change in the position of the fifth toothgerm. (fig. 1b) Following the extraction of the persistenttemporary tooth and the growth spurts of the developing

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root of the permanent second premolar, a change in the di-rection of growth and improvement of the tooth positionwere observed. It was decided to conduct orthodontic treat-ment of the hypodontia in the maxilla as well as to restoreaesthetics while waiting for a spontaneous eruption of thesecond premolar. If these results are not achieved within 8months of the beginning of treatment, the premolar will bethen exposed and facilitated into the dental arch.

Fig. 1:a) An orthopantomography prior to treatment

some improvement of the premolar position. Follow-upchecks were carried out every 3 months, making segmentedradiographs. Five months after the extraction of the super-numerary tooth a descent of the second premolar was ob-served. (fig. 2c) A year and three months since treatment aminor bone cover over the second premolar is observed andthe prognosis is for a spontaneous eruption of the secondpremolar.

Fig. 2: a) An OPG showing a supernumerary secondpremolar

b) An orthopantomography after extraction of thedeciduous fifth tooth showing a significant improvementin the position of the permanent premolar

Case 2:A 14-year-old girl was checked in the clinic, being

a Class I patient as per Angle, with impacted upper secondpremolar on the right due to hyperdontia of the premolarand a strong mesial inclination of the first molar on theright. (fig. 2a and b)) . The clinical decision taken was toextract the supernumerary tooth which had an irregularshape. After extraction of the supernumerary tooth segmentbrackets were placed along tooth from right canine to rightpermanent first molar region in order to straighten the heav-ily inclined first molar and provide space for the fifth tootheruption. Due to the deep position of the impacted secondpremolar it was decided not to expose the tooth surgically,but instead to wait for a spontaneous eruption or at least

b) X-ray as per Simpson

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c) eruption path and descent of the second premolar Fig. 3. Deterioration in the position of the firstpremolar due to the increased size of the follicular cyst.

Case 4:A 9-year-old girl with compression in the upper and

lower jaw and lateral deviation to the right. Anorthopantomography revealed a follicular cyst enclosing thegerms of permanent canine and first premolar on the leftin the upper jaw (Fig. 4a). Clinically, a significant swellingand deformation of the bone was observed as a result ofovergrowth of the cyst formation. Following extraction ofthe temporary canine and temporary first and second mo-lar and removal of the cyst sac by draining the fluid, a platewas placed in the maxilla to ease the compression and re-serve the space of the prematurely extracted deciduousteeth, with the attempt to alter the eruption paths of the per-manent canine and first premolar. Six months later a newOPG revealed a change in the eruption paths of both teeth:eruption of the first premolar is pending while the canineis in the desired position and descending to its normal po-sition in the dental arch. (Fig. 4b). Organization of the bonestructure in the region of the removed cyst is also observed.

Fig. 4: a) Prior to extraction of the temporary teeth:presence of a follicular cyst enclosing the canine and thefirst premolar

Case 3:An 11-year-old girl, a Class II patient by Angle, with

compression in the upper and lower jaw. The patient exhib-ited a significant delay in the eruption of permanent teeth.An orthopantomography revealed the presence of afollicular cyst on the lower first premolar on the left and amesial inclination of the premolar towards the canine. (Fig.3a) The patient was referred to for extraction of the tempo-rary canine as well as the temporary first molar. A year anda half later the patient returned for a follow-up check; how-ever, the prescribed teeth extraction had not been performed.Clinically, a swelling of the bone and its crackling towardsthe vestibule in the region of the permanent canine and firstpremolar were observed. A new orthopantomography re-vealed the follicular cyst, significantly increased in size, agreater mesial inclination of the first premolar, which hadinhibited the eruption of the permanent canine. (Fig. 3b)

As seen, at the absence of prevention steps (extrac-tion of the temporary tooth, providing space for the erup-tion of the respective permanent premolar and removal ofthe cyst) the tooth position had worsened and the eruptionof the cyst-associated permanent premolar was inhibited.This can lead to negative impact on adjacent teeth, delay-ing their eruption or even their impaction.

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1. Tsukamoto S, Braham RL.Unerupted second primary molar posi-tioned inferior to the second premolar:clinical report. ASDC J Dent Child.1986 Jan-Feb;53(1):67-69. [PubMed]

2. Borsatt M, Sant’Anna A, NieroH, Soares U, Pardini L. Unerupted sec-ond primary mandibular molar posi-tioned inferior to the second premolar:case report. Pediatr Dent. 1999 May-Jun;21(3):205-208. [PubMed]

3. Peck L, Peck S, Attia Y. Maxil-lary canine-first premolar transposi-tion, associated dental anomalies andgenetic basis. Angle Orthod. 1993Summer;63(2):99-109. [PubMed]

4. Garib DG, Peck S, Gomes SC.Increased occurrence of dental anoma-lies associated with second-premolaragenesis. Angle Orthod. 2009 May;

b) A follow-up panoramic radiograph after 6 months:organized bone structure in the region of the cyst, pendingeruption for P1, improvement in the position of the perma-nent canine

germ root of the permanent premolar is not developed yet,the better the possibility of a spontaneous eruption.

If the cyst is sized and destroys much of the bone,its marsupialization should be initiated in order to reducethe pressure in the cyst formation and its size to ease thebone recovery. Thus complications can be avoided, but stillthere is a risk of recurrence [16].

K. Thoma, S. Marks and other authors likewise re-port in their studies that if removal of the cyst and extrac-tion of the temporary tooth is done at an age when the toothis still actively growing (in early mixed dentition or earlystage of late mixed dentition), the change in the eruptionpath of the impacted tooth is happening fast, which is re-lated to the degree of formation of the tooth root, which inturn is a major factor in the eruption of permanent teeth [17,18]. Quite often though, apart from an early extraction oftemporary molars and removal of the cyst, orthodontic treat-ment to assist straightening of the premolar germ may benecessary [19, 20]

The following conclusions can be drawn from thediscussion above:

CONCLUSIONS:1. The early extraction of the deciduous molar, moni-

toring the patient and reserving the space for the succeed-ing impacted premolar can lead to non-invasive or relativelyshort orthodontic treatment (secondary prevention).

2. If root development is incomplete yet there is agood growth potential which could lead to spontaneouseruption (primary prevention).

3. Age specifics particular to children such as thegreat regenerative abilities of the bone, provide a good prog-nosis for spontaneous eruption or significant improvementin the position of impacted premolars and facilitate the or-thodontic treatment.

DISCUSSION:The clinical cases demonstrate that even an unfavour-

able and deep position of an impacted premolar can bemodified by extracting the preceding temporary molar andremoving the follicular cyst, if any. In certain cases wherethere is sufficient space only extraction of the deciduousteeth and monitoring the patient may be appropriate. In thecases of unfavourable inclination of the premolar it is ad-visable to reserve the space for eruption of the premolar orif there is insufficient space and some orthodontic deform-ity, treatment should be initiated. Even if spontaneousstraightening and eruption of premolars is not achieved, theextraction of temporary molars as early as mixed dentitionor permanent dentition (with incomplete root growth) cre-ates favourable conditions for improved position of im-pacted premolars. This shortens and facilitates an orthodon-tic treatment at a later stage and avoids surgical interven-tion on exposing and continuous withdrawal of the premo-lar. The earlier temporary molars are extracted when the

79(3):436-441. [PubMed] [CrossRef]5. Baccetti T, Leonardi M, Giuntini

V. Distally displaced premolars: a den-tal anomaly associated with palatallydisplaced canines. Am J OrthodDentofacial Orthop. 2010 Sept;138(3):318-322. [PubMed] [CrossRef]

6. Shalish M, Peck S, WassersteinA, Peck L. Malposition of uneruptedmandibular second premolar associatedwith agenesis of its antimere. Am JOrthod Dentofacial Orthop. 2002 Jan;121(1):53–56. [PubMed] [CrossRef]

7. Daugaard S, Christensen IJ,Kjaer I. Delayed dental maturity indentitions with agenesis of mandibularsecond premolars. Orthod CraniofacRes. 2010 Nov;13(4):191–196.[PubMed] [CrossRef]

8. Kudo M, Konta H, Oguchi H.

Clinical Observation of Unerupted Pri-mary Molars in the Patients ofHokkaido University Pediatric DentalClinic. Jpn J Ped Dent. 1996; 34:824-34.

9. Bhasker SN. Orban’s Oral His-tology and Embryology. Mosby, St.Louis; 1986:372-373pp.

10. Andreasen JO. The impactedpremolar. In: Andreasen JO, PetersenJK, Laskin DM, eds. Textbook andcolor atlas of tooth impactions. Diag-nosis, treatment and prevention. Co-penhagen: Munksgaard,1997:177-195pp.

11. Shalish M, Peck S, WasserteinA, Peck L. Increased occurrence ofdental anomalies associated withinfraocclusion of deciduous molars.Angle Orthod. 2010 May;80(3):440-

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Address for correspondence: Dr. Hristina Arnautska,Department of Prosthetic Dental Medicine and Orthodontics, Faculty of DentalMedicine, Medical University - Varna,84, Tsar Osvoboditel Str., Varna, Bulgaria.Mobile: +359/877 599 675E-mail: tineia@yahoo.com

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Please cite this article as: Arnautska H, Valcheva Z, Georgiev T, Tonchev Tsv. Need of prevention steps against impactionof mandibular and maxillary premolars. J of IMAB. 2015 Oct-Dec;21(4):959-963.DOI: http://dx.doi.org/10.5272/jimab.2015214.959

Received: 22/09/2015; Published online: 25/11/2015