# Mandibular Premolar Impaction

Authors: Vimal Kalia; Manmeet Aneja
Journal: Scholarly Research Exchange
 (2009)

---

## Abstract

Literature specific to impacted premolars is not extensive despite the fact that mandibular 2nd premolars alone account for 2.4% of dental impactions.
The purpose of this paper is to describe the radical approach (extraction) of a transversally impacted 2nd premolar in the mandible through a lingual approach due to its peculiar position presuming it will contribute toward the literature regarding impacted mandible premolars.


---

## Body

## 1. Introduction

Impacted teeth are
those which are prevented from erupting by some physical barrier, in the
eruption path. Lack of space, due to the crowding of the dental arches or to
premature loss of primary  teeth with subsequent partial closure of their area,
is a common factor in the etiology of partially or completely impacted teeth.
Genetic and environmental factors are included in the multifactorial nature of
tooth eruption, which may be disturbed at any stage of tooth development [1]. By definition,  an  impacted tooth is one that is embedded in the alveolus so
that its eruption is prevented or the tooth is locked in position by bone or
the adjacent tooth/teeth [2]. Mandibular second premolars rank third after third
permanent molars and maxillary permanent canines, in frequency of impactions [3]. The
prevalence of impacted premolars has been found to vary according to age [4]. The
overall prevalence in adults has been reported to be 0.5% the range being 0.2
to 0.3% for mandibular premolars [4, 5]. Premolar impactions may be due to local
factors such as mesial drift of teeth arising from premature loss of primary
molars; ectopic positioning of the developing premolar tooth buds; or pathology
such as inflammatory or dentigerous cyst. They may also be associated with over
retained or infraocclusal ankylosed primary molars or with syndromes such as
cleidocranial dysostosis [6–11]. In the anterior mandible, the
mandibular premolars erupt after the mandibular first molar and mandibular
canine. Thus if the room for eruption is inadequate, one of the premolars
usually the second premolar remains unerrupted and becomes impacted [12]. Literature
specific to impacted premolars is not extensive despite the fact that
mandibular second premolars alone account for approximately 24% of all dental
impactions [3, 13]. Various treatment methods have been suggested including
observation, intervention, relocation, and extraction depending on the tooth’s
position, depth of the impacted tooth, relationship with adjacent teeth, and
orthodontic treatment. This case report describes the radical approach
(extraction) of a transversally impacted 2nd premolar in the mandible in an
unusual position with the crown lying lingual to the root apices of 1st molar
tooth through a lingual approach presuming it will contribute toward the
literature available regarding impacted 2nd premolars. The unusual orientation
of the crown and root of this impacted 2nd PM makes this case report rare.


## 2. Case Report

An 18-year-old girl
was referred after orthodontic intervention for the removal of an impacted left
2nd premolar tooth  35 which was not visible in the oral cavity. An adequate edentulous space was
present instead of tooth  35, and there was a history of extraction of over retained deciduous predecessor during
the orthodontic treatment. The present plan was to extract the impacted tooth,
place an implant, and rehabilitate the patient. The patient had no significant
medical history with no apparent systemic problems. She did not report any history
of trauma to the jaws. Intraoral examination revealed the presence of 34 and 36
teeth with an adequate space between them for a 35 to erupt (see Figure1), but
the alveolar bone density in the region was diminished. The occlusion was
satisfactory with no trismus, and oral hygiene was good. On palpation, a little
bulge could be felt on the lingual aspect of 36, at the level of the mylohyoid
ridge (see Figure 2). The intraoral periapical X-ray and OPG (see Figure 3)
revealed the presence of a severely impacted 2nd premolar tooth 35 which was
lying almost horizontal with the crown facing distally and was overshadowed by
the roots of tooth  36.
The roots of the impacted tooth were mesially directed but appeared short and
stunted. The deep impacted mandibular second premolar was extracted from the
lingual approach in a surgical procedure under local anesthesia. An incision
was given in the lingual gingival crevice extending from 2nd molar to canine
tooth; with a mucoperiosteal elevator, a lingual flap was raised to expose the
lingual aspect of 36. A slight bulge on the bone was visible (see Figure 4). A
sterile high speed handpiece cooled with sterile saline solution was used for
osteotomy and crown sectioning. The crown was removed and then the root was
delivered (see Figures 5, 6). The wound was irrigated, homeostasis was achieved,
and the wound was closed with 3-0 silk sutures. Sutures were removed on the
seventh postoperative day. The patient healed uneventfully and clinical and
radiographic followups were  satisfactory (see Figure 7). Once the bone healing was optimum, an implant was
placed in the area of tooth  35 (see Figure 8).Figure 1
Showing adequate space for 35 to erupt.Figure 2
Showing a little bulge on lingual aspect of 36.Figure 3
OPG showing the impacted 35.Figure 4
Showing slight bulge on the bone and surgical exposure.Figure 5
Odontotomy of 35.Figure 6
Extracted premolar.Figure 7
OPG showing uneventful healing.Figure 8
OPG showing implant in position.


## 3. Discussion

Treatment options for
impacted teeth include observation, intervention, relocation, and extraction.
On occasions, there may be some interaction between these treatment options [14].
Literature specific to impacted premolar is not extensive despite the fact that
mandibular  2nd
premolars alone account for approximately 24% of all the dental impactions [13].  In selecting an appropriate treatment option, the underlying etiological  factors,
space requirements, need for extractions of primary molars, degree of impaction,
and root formation of the impacted premolar should be considered. Factors such
as patients medical history, dental status, oral hygiene, functional and
occlusal relationship and attitude toward and compliance with treatment will
influence choice of treatment options [15, 16]. In this particular case, the degree
of impaction, unusual placement of the impacted tooth, that is, transverse
position and crown present lingual to the root apices of the first permanent
molar, the complete root formation, and the reduced level of available
dentoalveolar bone made monitoring a bad choice of treatment as at 18
years of age growth potential had ceased. The position of the transversely
impacted second premolar was so unfavorable that no orthodontic treatment of
this tooth was envisaged, and hence extraction was planned.
Andreasen [4] suggests
that surgical exposure should be confined to cases, both maxillary and
mandibular with no more than 45°
tilting and limited deviation from the normal position, and
hence this case definitely required removal of the impacted tooth. As the crown
was on the lingual aspect, the lingual approach and splitting of the tooth,
that is, odontectomy  with odontotomy was the logical choice. The lingual approach was taken due to
the tooth position. Besides, the buccal flap would have jeopardized the mental
nerve emerging from the mental foramen and the apices of the first permanent
molar tooth. But lingual approach comes with the inherent risk of infection in
the sublingual space. Careful irrigation of the surgical area and not allowing
the bone and tooth dust to remain in that area
prevent  any delayed healing and infection. Correct
knowledge of regional anatomy, careful manipulation of tissues, and correct
application of mechanical principles involved in tooth extractions allow
surgical success. This peculiar and rare case will contribute toward the minimal
literature available regarding impacted second premolar tooth and offers
lingual approach as an alternative in such situations.



---

*Source: 821857-2009-03-11.xml*