Missing upper incisors: a retrospective study of orthodontic space closure versus implant

This retrospective observational study was carried out in accordance with the ethical
standards set forth in the 1964 Declaration of Helsinki. Informed written consent
was obtained from each patient and a parent or guardian.

Twenty-six patients with missing maxillary incisors, who were treated by one orthodontist
between 2004 and 2006 in two centers, were all invited to a follow-up examination.
One of the patients was omitted from the study because she could have only been treated
by means of implant insertion. Five of the patients refused to attend. Out of the
20 remaining patients, 10 were treated by implant insertion and 10 by orthodontic
space closure.

The selection criteria included patients who had the following:

Congenital absence of the maxillary central and/or lateral incisor.

Patients treated with orthodontic space closure and/or implant.

Patients who could have been treated by either space closure or implant insertion.

Patients not treated with autotransplantation or crown bridge.

No periodontal breakdown or history of periodontal disease.

The implant group (IG) consisted of ten patients (five males, five females, mean age
20?±?1.4 years at the time of implant insertion). All the implants were of the same
type and were inserted by the same surgeon. Fourteen teeth including four lateral
and ten central maxillary incisors were totally missing in the implant group. The
average treatment time of these patients was 18?±?4 months. The orthodontic space
closure (OSC) group consisted of ten patients (six males, four females, mean age 19?±?2.1 years
at the completion of treatment). Seventeen teeth including seven lateral and ten central
maxillary incisors were totally missing in the OSC group. The average treatment time
of these patients was 29?±?7 months (Table 1). For retention, upper and lower Hawley retainers were worn by all the patients for
1 year.

Table 1. Distribution of age, sex, and left or right missing teeth in the OSC and implant groups

The follow-up records were taken 5 years or more after the completion of treatment
(mean interval was 5.6?±?0.4 years).

Tooth mobility (TM) 11], plaque index (PI) 12],13], probing depth (PD), infraocclusion (I), open gingival embrasure (black triangle)
14], and temporomandibular joint dysfunction (TMD) of the patients were recorded at the
follow-up examinations (Table 2).

Table 2. Clinical records of periodontal states

Probing depth was recorded at four sites for each upper central and lateral incisor
with a periodontal probe. Identical intra-oral radiographs, taken with the ‘parallel
technique’, were used for assessment of infraocclusion. Evaluation of the image distortion
was done by measuring the length of the implant (L) as it appears on the radiography
and comparing it to the real length of the implant (Figure 1). In order to evaluate infraocclusion, a reference point (p) was selected on the
intersection between the incisal and mesial borders of the tooth adjacent to the implant.
Afterwards, a line was drawn from this point perpendicular to the longitudinal axis
of the implant creating the projection of p. The distance between the projection of
p and the apex of the implant was measured, and the difference between this distance
after the completion of treatment and follow-up examination was recorded as infraocclusion
(X2 ? X1) (Figure 1). The distance of the alveolar crest to the contact point of the teeth was used to
evaluate the presence of an open embrasure (black triangle). A distance of more than
5 mm was considered as black triangle 14].

Figure 1. Method of measuring infraocclusion.

The prevalence of signs and symptoms of TMD was assessed by means of an anamnestic
questionnaire 15] (Table 3). A score ‘0’ indicated the absence of symptoms, whereas ‘1’ was given for a report
of an occasional occurrence. Grade 2 indicated the presence of symptoms, and a score
of ‘3’ was used to indicate severe pain or bilateral symptoms. The sum of the scores
was used to classify the sample into four categories: (1) from 0 to 3, TMD free; (2)
from 4 to 8, mild TMD; (3) from 9 to 14, moderate TMD; and (4) from 15 to 23, severe
TMD. Plaque was measured by the plaque index developed by Quigley and Hein 12] and modified by Turesky et al. 13]. The scoring system is as follows: 0?=?no plaque, 1?=?separate flecks of plaque at
the cervical margin of the tooth, 2?=?a thin continuous band of plaque at the cervical
margin, 3?=?a band of plaque wider than 1 mm but covering less than one third of the
crown, 4?=?plaque covering at least one third but less than two thirds of the crown,
5?=?plaque covering two thirds or more of the crown. None of the patients had systemic
diseases or long-term pharmacological treatment until the end of follow-up studies.

Table 3. Questionnaire for assessing TMD

Patient satisfaction was assessed using the visual analog scale (VAS) 16],17]. The subjects were asked to record their happiness with their dental and facial appearance
on a 10-cm VAS having phrases ‘very dissatisfied’ (score 0) on the left end and ‘very
satisfied’ (score 10) on the right end.

Each patient was examined by two examiners in two sessions with an interval of 1 week.
The inter-examiner agreement was calculated through kappa analysis. A kappa value
of 0.96 showed perfect agreement. T-test was used to evaluate the data of the study.