Keywords dental implants - impacted teeth - invasive extraction surgery - alternative - therapeutic
option - elderly patients
Introduction
When planning treatments involving dental implants, dentists occasionally come across
patients presenting root remains and/or impacted teeth in the area where an implant
is to be placed. This clinical situation can be solved in various ways. First, impacted
teeth may be moved to a more favorable position by orthodontic traction. This option
has been reported in teenage patients and those aged under 30 years.[1 ] Second, a surgical approach can be planned that avoids infringing the impacted tooth
or root fragment, by inclining the implant or placing it on the vestibular or palatine/lingual
side of the impacted tooth.[2 ] Another option described in the literature is to extract the impacted tooth or root
fragment followed by guided tissue regeneration. This is considered the gold standard
approach to the problem when treating adult patients.[3 ] But this option is more invasive and treatment takes longer. Finally, the use of
short or extra-short implants offers another means of avoiding interference with an
impacted tooth.[4 ]
Ever since Branemark discovered the phenomenon of osteointegration in the 1950s, direct
bone-to-implant surface contact has been considered the principal means of evaluating
healing responses around endosseous implants. Osteointegrated implants are rigidly
connected through intimate contact of bone tissue to the implant suface.[5 ] The entire process involves a complex array of events including the formation of
a provisional fibrin matrix, which is organized by blood vessels, collagen fibers,
and trabecular bone, subsequently maturating into lamellar bone and bone marrow.[6 ]
[7 ]
In 2009, Davarpanah and Szmukler-Moncler[8 ] published the first of a series of articles[9 ]
[10 ]
[11 ]
[12 ] about a paradigmatic change when it comes to drilling and placing implants intentionally
in contact with dental tissues, remaining root fragments or impacted teeth. The protocol
achieved success rates similar to conventional implant placement in the medium term.
Based on this principle, inserting implants through impacted teeth would appear to
offer a potential treatment alternative.[13 ]
This clinical case report describes a geriatric patient with multiple impacted teeth
without any associated syndromes, who was rehabilitated by means of two different
protocols. In the second quadrant, the impacted tooth was dealt with by the classic
approach for middle-aged or elderly patients, which consists of extraction of the
tooth with simultaneous regeneration and implant placement. In the third quadrant,
implants were placed through the impacted teeth for rehabilitation with a fixed denture.
As far as the authors are aware, this is the first case report that describes the
use of this alternative approach in a patient with multiple vertically positioned
impacted teeth.
Case Report
A female patient, aged 78 years came to our clinic in September 2017 for the extraction
of deciduous teeth in the third quadrant (lower deciduous canine and two molars).
The patient classified as ASA I (according to the American Society of Anesthesiologists
Physical Status Classification System) was not taking any medication and was not allergic
to any drug. She did not smoke or have any other addictive habits. Clinical examination
found deciduous teeth remaining in adulthood in the third quadrant with pronounced
mobility ([Fig. 1A ]), which were causing pain. Radiographs showed the presence of multiple impacted
teeth in both jaws with the presence of deciduous teeth in the lower left quadrant
(canine and molars). Impactions were observed of the upper right canine, lower left
canine, as well as the two lower left premolars ([Fig. 1B ]).
Fig. 1 (A ) Clinical image of third quadrant, showing deciduous teeth: canine and first and
second molars. (B ) Panoramic radiograph of patient showing multiple impacted teeth, one canine in the
first quadrant, and one canine and two premolars in the third quadrant. It is also
noted an implant placed in second quadrant.
This patient had attended the clinic 8 years earlier (in April 2009) for the extraction
of a deciduous upper left canine, together with the simultaneous extraction of the
palatally retained canine and corresponding regeneration by means of a fine particulate
xenograft (Apatos, Osteógenos, Madrid, Spain). An implant (external hexagon, 3.8x10
mm Defcon TSH®, Phibo, Barcelona, Spain) was placed in the same surgical session.
Although the clinical outcome of the implant-supported crown after 8 years was acceptable
and had never caused any problems ([Fig. 2A ]
[2B ]), the patient had been traumatized by the surgery and postoperative period and refused
to undergo similar surgery in the mandible.
Fig. 2 (A ) Clinical image shows acceptable clinical outcome of the implant-supported crown
in the upper left quadrant in position of the canine 8 years after implant placement.
(B ) Periapical radiograph of the implant–crown complex in canine position in second
quadrant, exhibiting no bone loss.
For this reason, it was proposed to place implants anchored in the impacted teeth.
The treatment protocol planned fulfilled Declaration of Helsinki guidelines for experimentation
involving human subjects. The procedure was explained to the patient, as well as the
risks and possible complications involved, and she gave her informed consent to proceed.
It should be noted that no change in the positions of the impacted teeth was observed
since the first time the patient had attended the clinic 8 years earlier ([Fig. 3 ]).
Fig. 3 Panoramic radiograph of the patient 8 years before. No significant changes in the
positions of impacted teeth have taken place up to the present.
Following extraction of the deciduous teeth, two external hex implants (S.I.N. Implant
system, Sao Paulo, Brazil) of 10 mm length were placed in position of the canine (3.75
mm diameter) and second premolar (4.1 mm diameter). The procedure was performed under
local anesthetic; the implants were inserted through the impacted teeth at the canine
and second premolar positions. It was necessary to follow the complete drilling sequence
with abundant irrigation because of the hardness of the dental tissues ([Fig. 4A ]). A single dehiscence defect and the exposed threads of the implant were grafted
with fine grain xenograft (Apatos, Osteógenos) ([Fig. 4B ]) without any membrane; the surgical sites were sutured with 5/0 polyamide multifilament
suture (Supramid, Aragó, Barcelona, Spain).
Fig. 4 (A ) Clinical image after extracting deciduous teeth, finishing drilling sequence through
impacted teeth. (B ) Clinical image of implants anchored through impacted teeth after regenerating the
gap with particulate xenograft. (C ) Postsurgical periapical radiograph showing implants placed through impacted teeth.
The postsurgical periapical radiograph showed implant placement in the second premolar
position completely passing through the tooth, while the implant in canine position
penetrated the coronal part of the impacted tooth ([Fig. 4C ]). No postoperative pain was recorded and both implants placed through the impacted
teeth healed uneventfully. Sutures were removed 10 days after surgery and rigorous
follow-up of the patient continued throughout the healing period, with follow-up visits
scheduled after 1 month and 2 months.
Four months after surgery the second phase commenced, connecting healing abutments.
Fifteen days later, the restoration phase began, consisting of an implant-supported
metal ceramic denture. To improve the prosthetic crown emergence, individualized screw-retained
abutments were used to support the prosthesis ([Fig. 5A ]
[B ]). The restoration was cemented onto the abutments ([Fig. 6A ]
[6B ]) using zinc oxide-based provisional cement with eugenol (Temp-Bond Original; Kerr
Dental, Detroit, United States).
Fig. 5 (A ) Clinical image of individualized abutments screwed to implants; image shows good
gingival health. (B ) Periapical radiograph verifying correct fit of individualized abutments.
Fig. 6 (A ) Clinical image: checking metal prosthesis on individualized abutments. (B ) Occlusal view of fixed partial denture.
At follow-up visits, the case evolved satisfactorily, fulfilling the success criteria
established by Buser et al[14 ] and Cochran et al.[15 ] No radiolucent images around the implants were observed in radiographs taken during
the follow-up, nor were any abnormal reactions at the bone-to-implant or impacted
tooth-to-implant interfaces. The patient was recalled every 6 months after delivery
of the definitive restoration, undergoing clinical and radiographic examination ([Fig. 7 ]), and to date (a follow-up period of 24 months), no signs or symptoms of failure
have occurred, or any complication at any stage.
Fig. 7 Periapical radiograph after 24 months follow-up. Neither impacted teeth nor implants
have undergone any changes.
The patient found treatment acceptable and was pleased to have avoided the trauma
of extraction.
Discussion
Dental impaction has been reported to affect as much as 25 to 50% of the population.[16 ] Multiple impacted teeth not associated with craniofacial syndromes are a rare condition
and present a therapeutic challenge to the dentist.[17 ] The first option for teenagers and young adults is a combination of surgery and
orthodontic traction to move the impacted teeth into position. In this context, Becker
and Chaushu[1 ] made a study of palatally impacted canines, concluding that the prognosis for successful
orthodontic resolution of an impacted canine in an adult is poorer than in a younger
patient and that prognosis worsens with age. Furthermore, when this treatment is performed
in older patients, a successful outcome may be expected to take considerably longer.
For this reason, cases of impacted teeth are often approached through surgery and
subsequent restoration. In this sense, extraction of an impacted tooth with simultaneous
implant placement and regeneration are considered the “gold standard” treatment.[3 ] But this approach is more invasive and prolongs treatment, particularly in cases
where cortical bone is not adequately preserved, and so it may not be possible to
place implants during the same surgical session. Consequently, this option is often
refused by patients.
Notwithstanding as a rule, clinicians tend to prefer to place implants in pristine
and/or regenerated bone. As affirmed by Melcher,[18 ] the characteristics of wound healing are determined by the type of cells that repopulate
the lesioned area. When drilling bone, the cells that occupy the lesion comprise bone
cells, bone marrow, and blood cells, which will determine the healing pattern and
the formation of direct bone apposition over the titanium implant surface. However,
diverse experimental histological animal studies have suggested the possibility of
achieving implant anchorage within or encroaching on ankylosed root remains or impacted
teeth with periodontium simulating that found around natural teeth.[19 ]
[20 ]
[21 ] Microscope studies have affirmed the appearance of periodontal ligament with a layer
of cementum over the implant surface occupying a space containing the collagen fibers
and blood vessels characteristic of periodontal ligament.[20 ]
[21 ]
On the basis of these findings, Davarpanah and Szmukler-Moncler[8 ]
[9 ]
[10 ]
[11 ]
[12 ] published a series of articles (the first in 2009) describing a case series in which
implants were placed through ankylosed impacted root remains or impacted teeth. The
authors suggested that this alternative to the conventional bone-to-implant interface
would not interfere with the implants or their mid- to long-term survival.
Nevertheless, recent articles by Nevins et al[22 ] and Langer et al[23 ] reported belated implant failures when placed through impacted root remains. Scanning
electron microscopic evaluation revealed that the failed implant surfaces were infiltrated
by bacterial deposits and calculus. The authors recommend caution when placing implants
through retained root fragments, as this involves long-term risk. But the case series
published by Amato et al[24 ] and Davarpanah et al,[9 ]
[12 ] who placed implants through impacted teeth, obtained satisfactory results in the
medium term. This difference in prognosis could be due to the fact that root remains
were in contact with the buccal medium for a long time, involving foreseeable bacterial
penetration, which could lead to failed implant osteointegration. Besides the impacted
teeth are not related with infection issue, whereas the retained roots might be.
These procedures aim to shorten restorative treatment time and are more acceptable
to the patient. As they maintain the integrity of the vestibular table, they also
optimize esthetic outcomes as remaining crown fragments provide greater support for
soft tissues.[25 ]
The protocol described in this case report is unconventional and not extensively documented.
Nevertheless, it offers a useful treatment option that avoids the trauma of extraction
and reduced treatment time in cases in which the outcomes may in any case be unpredictable.
Conclusion
Within the limitations of this case report, placing dental implants through impacted
teeth would appear to offer a possible therapeutic option for implant-supported restorations
in middle-aged or elderly patients, for whom surgery and orthodontic traction are
not possible, and/or patients who refuse to undergo more invasive extraction surgery.
Further studies are needed with longer follow-ups, larger sample sizes, and standardized
clinical protocols to confirm the outcomes of the present case report, before this
protocol can be introduced into routine clinical therapeutic practice.
