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Stability and relapse after orthodontic treatment of deep bite cases - A long-term follow-up study


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The purpose of this long-term follow-up study was twofold-firstly, to assess prevalence of relapse after treatment of deep bite malocclusion and secondly, to identify risk factors that predispose patients with deep bite malocclusion to relapse. Sixty-one former patients with overbite more than 50% incisor overlap before treatment were successfully recalled. Clinical data, morphometrical measurements on plaster casts before treatment, after treatment and at long-term follow-up, as well as cephalometric measurements before and after treatment were collected. The median follow-up period was 11.9 years. Patients were treated by various treatment modalities, and the majority of patients received at least a lower fixed retainer and an upper removable bite plate during retention. Relapse was defined as increase in incisor overlap from below 50% after treatment to equal or more than 50% incisor overlap at long-term follow-up. Ten per cent of the patients showed relapse to equal or larger than 50% incisor overlap, and their amount of overbite increase was low. Among all cases with deep bite at follow-up, gingival contact and palatal impingement were more prevalent in partially corrected noncompliant cases than in relapse cases. In this sample, prevalence and amount of relapse were too low to identify risk factors of relapse.
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European Journal of Orthodontics 36 (2014) 522–530
Advance Access publication 28 November 2012
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Stability and relapse after orthodontic treatment of deep bite
cases—a long-term follow-upstudy
J. C.Danz*, C.Greuter*, l.Sifakakis**, M.Fayed***, N.Pandis* and C.Katsaros*
*Department of Orthodontics and Dentofacial Orthopedics, University of Bern, Switzerland, **Department of
Orthodontics, School of Dentistry, University of Athens, Greece and ***Department of Orthodontics and Dentofacial
Orthopedics, Faculty of Oral and Dental Medicine, Cairo University, Egypt.
Correspondance to: Jan C.Danz, Klinik für Kieferorthopädie, Zahnmedizinische Kliniken der Universität Bern,
Freiburgstrasse 7, CH-3010 Bern, Switzerland. E-mail:
SUMMARY The purpose of this long-term follow-up study was twofold—firstly, to assess prevalence of
relapse after treatment of deep bite malocclusion and secondly, to identify risk factors that predispose
patients with deep bite malocclusion to relapse. Sixty-one former patients with overbite more than 50%
incisor overlap before treatment were successfully recalled. Clinical data, morphometrical measurements
on plaster casts before treatment, after treatment and at long-term follow-up, as well as cephalometric
measurements before and after treatment were collected. The median follow-up period was 11.9 years.
Patients were treated by various treatment modalities, and the majority of patients received at least a
lower fixed retainer and an upper removable bite plate during retention. Relapse was defined as increase
in incisor overlap from below 50% after treatment to equal or more than 50% incisor overlap at long-term
follow-up. Ten per cent of the patients showed relapse to equal or larger than 50% incisor overlap, and
their amount of overbite increase was low. Among all cases with deep bite at follow-up, gingival contact
and palatal impingement were more prevalent in partially corrected noncompliant cases than in relapse
cases. In this sample, prevalence and amount of relapse were too low to identify risk factors of relapse.
Deep bite, by definition increased overbite, is measured
as vertical overlap of the incisors perpendicular to the
occlusal plane absolutely in mm, relatively in percent-
age of incisor overlap or qualitatively by describing the
contact of the lower incisors to the upper arch or palate.
Most commonly, deep bite can be divided into dento-
alveolar origin (overeruption of teeth) and skeletal origin
(decreased lower face height, low mandibular plane angle)
(Nielsen, 1991).
Deep bite prevalence varies from 8.4 to 51.5%, depend-
ing on the threshold values applied, ethnic group and gen-
der (Tausche et al., 2004; Proffit et al., 2007; Lux et al.,
2009; Thilander and Myrberg, 1973). Prevalence of palatal
non-traumatic tooth contact and palatal impingement was
reported to vary from 5.9 to 15.9% (Tausche et al., 2004;
Lux et al., 2009). Angle classification (Angle, 1899) has
been associated with vertical and/or cephalometric patterns.
Class II malocclusion was shown (Lux et al., 2009) to be
significantly associated with increased overbite compared
with class I malocclusion. Class II Division 2, with a preva-
lence of 5.3%, a less frequent malocclusion (Ingervall et al.,
1978), may be associated with a deep bite (Brezniak et al.,
2002). A correlation of increased overbite with retrusive
incisors in Angle class I malocclusions as well as in Angle
class II Division 2 malocclusions was described in the lit-
erature (Simons and Joondeph, 1973).
Treatment of deep bite malocclusion is recommended
in order to reduce or prevent tissue trauma from tooth
contact (Bjørnaas et al., 1994), facilitate possible future
reconstructive dental work and reduce increased tooth wear
(Ritchard et al., 1992; Silness et al., 1993). Reoccurrence
of malocclusion years after the end of treatment may lead
to patients seeking retreatment or questioning the benefit
of their initial therapy. Therefore the long-term stability
seems to be more important than the final result itself.
Relapse is a dento-alveolar and skeletal change after
orthodontic treatment towards the initial malocclusion,
and it is often encountered even in ideally treated cases
(Crum and Andreasen, 1974). These changes are attributed
to a physiologic reestablishment of force equilibrium
(Proffit et al., 2007), periodontal remodeling (Picton and
Moss, 1973; Crum and Andreasen, 1974; Ackerman and
Proffit, 1997), growth or normal/abnormal development
(Bergersen, 1988; Forsberg et al., 1991; Iseri and Solow,
1996). The loss of about one-third of the orthodontic
treatment result during 10 years of follow-up and consistent
relapse of all malocclusion characteristics were reported by
some authors (Al Yami et al., 1999). Therefore, stability
of orthodontic result is one of the biggest challenges in
Increase in overbite after completion of treatment is
regarded as relapse for dental deep bite cases. Several
authors have described deep bite malocclusions as relapse
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prone (Rönnerman and Larsson, 1981; Berg, 1983; Binda
et al., 1994). In a study of Berg (Berg, 1983), relapse
reduced treatment effect by 18.8% on average in 26
patients with deep bite malocclusion after 5–9 years out
of retention. Relapse of deep bite was reported 10 years
after treatment in 23 consecutive patients to almost pre-
treatment levels, although Hawley plates as retention
devices were used in most of the patients (Rönnerman and
Larsson, 1981). Lapatki et al. (2004) investigated a sample
with deep bite and retroclined incisors and found 20% of
vertical relapse on median 2 years post-treatment. Mean
relapse below 1 mm is reported by two investigations 7 or
8.2 years after treatment (Canut and Arias, 1999; Schütz-
Fransson et al., 2006; Al-Buraiki et al., 2005). Several
findings regarding deep bite relapse are reported from
studies investigating samples with other malocclusions.
The curve of Spee in a class II Division 1 sample was
reported to gradually relapse over the years or decades
in 21 out of 31 cases (Bernstein et al., 2007). Similarly,
a positive correlation between years out of retention and
overbite relapse was found in another class II Division 2
sample (Canut and Arias, 1999). In 80% of short facial
type patients a post-treatment increase in overbite was
recorded 2 years after treatment completion despite the
use of removable retention for 1 year (Zaher et al., 1994).
Factors that play a role in the development of deep bite
may also play a role in the development of relapse, such
as growth (Björk, 1969; Simons and Joondeph, 1973;
Driscoll-Gilliland et al., 2001; Baccetti et al., 2011),
function (Lapatki et al., 2007; Sciote et al., 2012), inci-
sor overeruption (Burstone, 1977; Lowe et al., 1986)
or hypodontia (Dermaut et al., 1986). Only a few anal-
yses of which factors lead to more stable results or
which are associated with relapse exist. Preston et al.
(2008) did not find a signif icant correlation between
pre-treatment severity of malocclusion and relapse and
no ability to predict relapse by mandibular intercanine
width, overbite, overjet, mandibular incisor irregular-
ity and arch length. Regardless of the treatment modal-
ity the authors found a significant higher prevalence
of relapse for patients in whom the dentitions were not
completely leveled at the end of the treatment. Several
authors (Millett et al., 2006; Preston et al., 2008) did
not show differences in relapse regarding the type of
treatment. One study correlated protrusion of mandibu-
lar incisors during orthodontic treatment with overbite
relapse (Simons and Joondeph, 1973). Neither a sys-
tematic review about retention of deep bite or stability/
relapse of deep bite does exist nor it is possible today
to predict risk of relapse for an individual after therapy
of deep bite.
Therefore the primary purpose of this long-term follow-
up retrospective study was to assess the prevalence of deep
bite relapse in a sample of former orthodontic patients.
The secondary purpose was to identify important factors in
relapse of deep bite to develop hypotheses for a future pro-
spective clinical trial.
Material & Methods
The sample of the present retrospective study consisted
of patients treated at the Department of Orthodontics and
Dentofacial Orthopedics, University of Bern, Switzerland.
No standardized treatment or retention protocols were used
at that time, but an individual treatment and retention plan
was established for each case by different postgraduate stu-
dents and supervisors. Two investigators (D and B) selected
the records, which were stored in the archive during the
years 2000 to 2002. The inclusion criteria were overbite
of 50% or greater as measured as overlap of the incisors
on the initial study models with pencil and ruler (Nanda,
Of a total of 855 former patients, 185 (22%) who met the
inclusion criteria were contacted through mail or electronic
search of the official phone book by name, address or phone
number of the patient himself/herself or the parents by two
investigators (A and B). Due to the long follow-up period,
patients were found to have moved, and contact was lost
with 98 former patients, of whom two had died. With the
agreement of the independent local research ethics commit-
tee Bern, Switzerland (KEK Nr. 036/10, 27.04.2010), we
were able to contact personally 87 patients. Sixty-one (70%)
were willing to participate, whereas 26 (30%) refused to
participate for various reasons. For each of the consenting
patients, tooth cleaning was provided, their retention appli-
ances were examined, and new impressions for dental casts
were taken by three investigators (B, A, D). From the 61
participants, 18 had to be excluded due to the following rea-
sons: 3 had missing models at T1 and/or T2, 7 had OB <
50% at T1, 1 had retreatment during the follow-up period, 7
had partial treatment (T2 and T3 OB > 50%). These seven
patients who discontinued treatment were assigned to the
partial treatment group. The assignment process as well as
drop outs are depicted in a flow chart in Figure 1.
The patient records consisted of three sets of dental casts:
pre-treatment (T1), post-treatment (T2), and end of follow-up
(T3). All complete sets of two lateral cephalograms at T1
and T2 were evaluated.
Measurements of lateral cephalometric radiographs
One investigator (C) evaluated the T1 and T2 cephalometric
radiographs of the patients using cephalometric software
(Viewbox 4, dHAL Software, Kifissia, Greece). The
radiographs were scanned at 300ppi, and the following
angles were measured: SNA, SNB, ANB, SN-GoGn,
PP-MP, Gonial angle, U1-PP, U1-APog, L1-MP, L1-APog
and Interincisal angle. Additionally, the following ratios
were calculated: Lower Face Height / Total Face Height,
Posterior Face Height / Anterior Face Height (S-Go/N-Me).
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524 J. C. DANZ ET AL.
Measurements on dental casts
Measurements on T1-T3 plaster models were carried out
by one investigator (C), using a fine tip digital caliper
(150 mm ISO 9001 electronic caliper, Tesa Technology,
Renens, Switzerland). The following measurements were
made: maxillary and mandibular intercanine width, maxil-
lary and mandibular intermolar width between the central
fossae, incisor overjet, upper incisor overlap (percentage
of the lower incisor overlap by the upper incisor, measured
perpendicular to the occlusal plane).
Statistical Analysis
Descriptive statistics were performed at T1, T2, and T3.
Medians were preferred to the means because of the
higher robustness against outliers with small sample
The initial aim was to divide the sample into a relapse and
a non-relapse group and to identify risk factors predicting
the relapse of deep bite using a logistic regression model as
shown in Figure 2. The threshold value was defined at initi-
ation of the study according to the inclusion criteria as 50%
upper incisor overlap. The outcome variable ‘upper incisor
overlap at T3’ would have been used to test the hypothe-
sis that ‘there is no difference between the relapse and the
non-relapse group’. Given the small number of patients in
the relapse group, a comparison of the groups or a logis-
tic regression analysis was not feasible. Therefore, only
descriptive analysis is presented in this article.
Error of the method
The intracluster correlation coefficient (ICC) was used in
order to assess the method error and specifically intra-exam-
iner agreement. The ICC was calculated for all the variables
measured on 20 randomly selected dental casts and 20 ran-
domly selected cephalometric radiographs using the Stata 12.1
statistical package (Stat Corp, College Station, TX, USA).
The ICC ranged for both dental casts and measurements
ranged from 0.94 to 0.99, indicating very low measurement
error/excellent intra-rater agreement.
Figure 1 Flow chart of patient selection according to inclusion and
exclusion criteria. Inclusion criteria OB > 50% at T1 was applied twice.
The first time with pencil and ruler in the archive and a second time with a
digital sliding caliper. Finally the remaining deep bite cases were assigned
to the relapse group and the stable group.
Figure 2 The study was planned with the intention to predict relapse
by clinical, cast related or cephalometric variables at T1 or T2 by logistic
regression analysis. Amount and risk of relapse was too low for inferential
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The median age was 12.5 and 11.5 years at T1, 17.1 and
16.7 years at T2, and 29.2 and 26.9 years at T3 for the relapse
and the non-relapse group, respectively. The median active
treatment duration was 3.2 years in the relapse group and
3.6 years in the non-relapse group, while the median long-
term follow-up period was 13.4 years (range 10.7 years to 16.5
years) and 11.7 (range 9.5 to 16.4 years), respectively. The
median long-term follow-up period of all cases was 11.9 years
(range 9.5 years to 16.5 years). Clinical data, cast analysis, and
cephalometric evaluation are summarized in Table 1.
Four out of 43 cases (10.3%) showed relapse of the
incisor overlap of equal to or larger than 50.0% during the
long-term follow-up period. An example of each group is
shown in Figures 3 and 4. The relapse group consisted of
three females and one male, three cases with extractions
or missing teeth, and one case with all teeth present; none
of the patients had an upper fixed retainer at T3, and two
patients had a lower fixed retainer at T3. Sixty-five per
cent of patients had a removable retention appliance after
active treatment for a median period of 1.4 years (range
0.2 to 4.4 years); in the relapse group, one patient received
a removable retention appliance. The incisor overlap at T3
in the relapse group (N = 4) ranged from 55.6 (4.8 mm)
to 50.0% (3.9 mm) and in the non-relapse group (N = 39)
from 48.5 (4.7 mm) to 0.0% (0.0 mm). During the long-
term follow-up period the incisor overlap increased in the
relapse group by 6.7% (median, range 3.2% to 19.8%) and
decreased on average in the non-relapse group by −1.3%
(median, range from 13.8 to −26.3%). The change of the
overjet during the long-term follow-up period was for the
relapse group −1.8 mm (median, range 0.3 to −2.8 mm)
and for the non-relapse group 0.1 mm (median, range
from −1.4mm to 2.0 mm).
The partial treatment group (N = 7) had significantly
increased prevalence of gingival contact or palatal impinge-
ment at T3 compared with the complete treatment group
(relapse and non-relapse pooled, N = 50, Fishers exact test
P < 0.01) as shown in Table 2. Two examples are shown in
Figures 5 and 6.
The prevalence of vertical relapse 12 years after orthodon-
tic treatment of moderate deep bite was found to be low
in the present study. Relapse was defined as an increase
in incisor overlap >50% during follow-up. 10% of the
patients showed relapse with a low median increase of
6.7%, while 90% showed normal vertical relations at long-
term follow-up.
Our findings are in agreement with those of another
study, carried out on a sample with similar inclusion cri-
teria, treatment and retention protocols (Schütz-Fransson
et al., 2006). In the cases with moderate dento-alveolar deep
bite and successful treatment with subsequent retention by
fixed retainers and a temporary removable upper plate, the
prevalence and degree of deep bite relapse were relatively
small and clinically insignificant.
The low prevalence and amount of relapse may be attrib-
uted to the relatively high median age at T2 (17 years) of our
sample (Iseri and Solow, 1996). While it is not scientifically
proven by longitudinal superimpositions, it is plausible that
more remaining growth in addition with anterior growth rota-
tion (Björk and Skieller, 1983) and without retention would
experience increased relapse. A recent study compared facial
types and found a lower relapse tendency for high angle
patients compared with normal or low angle patients (Pollard
et al., 2012). The treatment duration was relatively long, indi-
cating that most of the periodontal remodeling (Crum and
Andreasen, 1974; Kilic et al., 2011) had already taken place
at the time of debonding, and it is not expected that it would
have contributed substantially to the relapse.
Treatment with removable appliances (Hans et al., 1994),
fixed appliances with or without extractions (Parker et al.,
1995) and in severe cases also with maxillofacial surgery
to correct deep bite have been proposed. Various treatment
modalities and combinations were used in this sample,
including one case with maxillofacial surgery (Figure 7).
There are three theoretical ways to orthodontically treat
deep bite malocclusion by leveling of the arch/curve of
Spee: (1) intrusion of lower and/or upper incisors (Burstone,
1977; Nanda, 1981; Ng et al., 2005), (2) labial inclination
of the incisors (pseudo-intrusion) (Burstone, 1977), and
(3) extrusion of posterior teeth possibly associated with a
clockwise rotation of the mandible, which would increase
lower face height (Nanda, 1981). This theoretical clockwise
rotation does not seem to occur in all cases (Bernstein et al.,
2007). No evidence-based recommendations regarding the
effectiveness of treatment of class II Division 2 malocclu-
sion in children can be deducted from the existing literature
(Millett et al., 2006). Stability of deep bite was achieved by
various treatment modalities and combinations.
Three subjects of the relapse group showed spacing in
the upper front (two central diastemae), and the fourth had
increased overjet due to a unilateral distal occlusion. All the
four relapse subjects were missing upper fixed retainers at T3.
It could be that development of spacing in the upper jaw or
persistent overjet with missing dental incisor contact allowed
deepening of the bite in these relapse cases. The influence
of lower lip pressure and height of the lip line was not
investigated in this study. Secondary malocclusion (Williams
et al., 1982; Artun and Urbye, 1988; Lindhe et al., 2003) due
to pathologic tooth migration related to periodontal disease
or pronounced attachment loss is unlikely at the age of this
sample but may become more relevant later in life.
With regard to the four relapse cases and the partial
treatment group, we can speculate that absence of fixed
retainers, relapse of arch form (loss of arch length and
crowding of lower incisors) (Stenvik et al., 2011) or
development of upper spacing may facilitate deepening of the
bite. Without retention, other co-factors like the initial severity
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526 J. C. DANZ ET AL.
Table 1 Descriptive analysis for clinical, dental cast and cephalometric measurements stratified by stable and relapse group.
Stable Relapse
Clinical data nMedian Range nMedian Range
Age T1 (years) 39 11.5 9.0–40.8 4 12.5 10.2–14.0
Age T2 (years) 39 16.7 13.2–45.1 4 17.1 15.4–21.2
Age T3 (years) 39 26.9 23.3–56.4 4 29.2 26.4–30.3
Active treatment (years) 39 3.6 0.9–7.9 4 3.2 1.6–4.0
Long-term follow-up (years) 39 11.7 9.5–16.4 4 13.4 10.7–16.5
n% (of 39) n% ( of 4 )
Extracted or missing teeth 18 46 3 75
Upper removeable plate 27 69 1 25
Upper fixed retainer at T3 14 36 0 0
Lower fixed retainer at T3 31 79 2 50
Cast analysis nMedian Range nMedian Range
Overjet T1 (mm) 39 5.7 0.6–11.8 4 4.2 0.9–12.2
Overjet T2 (mm) 39 2.6 1.3–4.8 4 3.9 2.3–5.7
Overjet T3 (mm) 39 2.3 1.2–4.6 4 2.5 1.6–3.2
Overjet T2-T1 (mm) 39 −2.8 −9.7–1.0 4 −1.7 −7.0–4.8
Overjet T3-T2 (mm) 39 0.1 −1.4–2.0 4 −1.8 −2.8–0.3
Incisor overlap T1 (%) 39 64.2 50.7–115.6 4 60.2 50.9–75.1
Incisor overlap T2 (%) 39 28.4 13.6–60.7 4 47.3 30.7–49.6
Incisor overlap T3 (%) 39 28.8 0.0–48.5 4 52.9 50.0–55.6
Incisor overlap T2-T1 (%) 39 −33.7 −89.6–3.2 4 −20.0 −30.2–−1.3
Incisor overlap T3-T2 (%) 39 −1.3 −26.3–13.8 4 6.7 3.2–19.8
T1 mand. ICD (mm) 21 25.5 19.9–28.8 3 26.5 24.2–27.1
T2 mand. ICD (mm) 39 26.8 22.1–29.9 4 25.0 24.2–27.1
T3 mand. ICD (mm) 39 26.5 21.3–29.1 4 24.4 23.6–27.6
T1 max. ICD (mm) 16 32.6 29.4–39.3 1 30.7 30.7–30.7
T2 max. ICD (mm) 39 35.1 29.9–38.4 4 31.3 25.2–36
T3 max. ICD (mm) 39 34.8 29.8–38.4 4 31.0 24.5–35.7
T2-T1 max. ICD (mm) 16 1.5 −5.8–4.9 1 −5.5 −5.5–−5.5
T2-T1 mand. ICD (mm) 21 0.6 −2.7–4.8 3 −1.7 −2.4–0.5
T3-T2 max. ICD (mm) 39 −0.1 −1.3–2.0 4 −0.4 −0.6–−0.2
T3-T2 mand. ICD (mm) 39 −0.2 −5.5–2.1 4 −0.5 −0.9–0.5
Lateral ceph analysis nMedian Range nMedian Range
SNA T1 (°) 29 79.5 73.0–89.1 2 78.5 77.7–79.2
SNA T2 (°) 29 77.5 69.6–88.0 2 76.4 75.2–77.5
SNA T2-T1 (°) 29 −1.4 −4.9–1.7 2 −2.1 −2.5–−1.7
SNB T1 (°) 29 75.4 68.7–82.9 2 75.5 75.2–75.7
SNB T2 (°) 29 75.7 69.7–85.7 2 75.1 74.7–75.6
SNB T2-T1 (°) 29 0.7 −3.2–3.9 2 −0.3 −0.5–−0.1
ANB T1 (°) 29 4.2 −1.5–8.3 2 3.0 2.4–3.5
ANB T2 (°) 29 1.8 −2.6–6.6 2 1.2 0.5–1.9
ANB T2-T1 (°) 29 −1.8 −6.5–0.8 2 −1.8 −1.9–−1.6
GoGn-SN T1 (°) 29 33.7 21.1–44.7 2 32.5 30.6–34.4
GoGn-SN T2 (°) 29 33.0 17.0–44.5 2 33.3 28.4–38.2
GoGn-SN T2-T1 (°) 29 −1.1 −4.1–4.9 2 0.8 −2.2–3.8
MP T1 (°) 29 23.6 9.5–32.5 2 23.0 16.2–29.8
MP T2 (°) 29 22.4 11.0–34.3 2 22.9 14.2–31.5
MP T2-T1 (°) 29 −1.1 −4.8–6.7 2 −0.2 −2.0–1.7
LFH / TFH T1 (%) 29 54.0 50.1–59.3 2 54.7 54.4–55.0
LFH / TFH T2 (%) 29 55.6 52.9–60.6 2 55.2 54.2–56.2
LFH / TFH T2-T1 (%) 29 0.9 −0.8–3.2 2 0.5 −0.2–1.2
PFH / AFH T1 (%) 29 60.3 52.1–73.2 2 63.5 63.3–63.6
PFH / AFH T2 (%) 29 62.4 56.3–79.7 2 63.5 61.4–65.6
PFH / AFH T2-T1 (%) 29 1.7 −5.8–6.9 2 0.1 −1.9–2.0
U1-PP T1 (°) 29 106.9 79.1–127.2 2 98.9 95.5–102.2
U1-PP T2 (°) 29 109.9 100.5–127.7 2 108.6 103.0–114.1
U1-PP T2–T1 (°) 29 3.2 −17.3–38.1 2 9.7 7.5–11.9
L1-MP T1 (°) 29 86.9 78.7–101.2 2 83.3 82.4–84.1
L1-MP T2 (°) 29 92.8 83.4–107.6 2 85.0 83.2–86.8
L1-MP T2-T1 (°) 29 5.7 −8.7–13.7 2 1.8 0.8–2.7
Interincisal angle T1 (°) 29 136.7 109.1–182.3 2 147.9 144.9–150.8
(Continued )
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Figure 3 Long-term stable case. Angle class II Division 2, skeletal
class II, deep bite with palatal impingement, skeletal hypodivergency,
moderate space deficency in the lower arch (left column). Correction with
functional appliance and headgear, Goshgarian, multibracket appliance
segmented arch technique with base arch, upper retention plate, dental
incisor contact (middle column). 10 years long term follow-up (right
Table 1 (Continued)
Stable Relapse
Clinical data nMedian Range nMedian Range
Interincisal angle T2 (°) 29 130.6 102.7–144.1 2 136.5 136.3–136.7
Interincisal angle T2-T1 (°) 29 −7.2 −55.2–12.8 2 −11.4 −14.1–−8.6
Gonial angle T1 (°) 29 122.9 110.0–140.8 2 124.3 121.2–127.4
Gonial angle T2 (°) 29 119.6 109.0–134.8 2 123.9 120.0–127.7
Gonial angle T2-T1 (°) 29 −1.8 −10.9–12.8 2 −0.5 −1.2–0.3
L1-APog T2 (mm) 29 1.5 −2.0–7.8 2 −0.2 −1.8–1.4
L1-APog T1 (mm) 29 −0.6 −9.1–2.7 2 −1.9 −2.9–−0.8
L1-APog T2-T1 (mm) 29 2.6 −0.7–10.5 2 1.7 1.1–2.2
U1-APog T2 (mm) 29 4.4 1.9–10.2 2 2.8 2.0–3.5
U1-APog T1 (mm) 29 5.5 −4.6–10.8 2 1.1 −0.9–3.0
U1-APog T2-T1 (mm) 29 −0.8 −6.0–9.0 2 1.7 0.5–2.9
Differences in numbers (N) are due to missing permanent canines or missing lateral cephalograms.
Figure 4 Relapse case with biggest incisor overlap at T3. Angle class II
Division 1, skeletal class II, deep bite with gingival incisor contact, skel-
etal hypodivergency, spacing in the upper front (left column). Treatment
with a removable plate with a frontal bite plateau and headgear. The patient
rejected fixed treatment despite slightly increased overjet, spacing in the
upper front and missing incisor contact. No fixed retainers were used after
treatment (middle column). 10 years later relapse of incisor overlap is appar-
ent but now seemingly stable with frontal dental contact and no complaints.
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528 J. C. DANZ ET AL.
of malocclusion, mandibular growth rotation (Simons and
Joondeph, 1973) and functional influences in combination
with other malocclusions (e.g. lower lip pressure and sagittal
bi- or unilateral relapse), and treatment outcome (e.g. type
of incisor contact, interincisal angle, close interdigitation) or
severe Bolton discrepancy may be clinically significant.
Relapse of the curve of Spee has been shown to be sig-
nificantly increased in patients who were not completely
leveled post-treatment (Preston et al., 2008). These find-
ings may be similar to the comparison between the par-
tial treatment group and complete treatment group in our
study. It seems that patients who had partially corrected
but persistent deep bite, e.g. due to treatment only in the
upper jaw with persistent distal occlusion, or patients who
Table 2 Type of lower incisor contact at T3 in the complete
treatment group (relapse and non-relapse group pooled) and the
partial treatment noncompliance group (excluded cases due to
OB > 50% at T2 and T3) in which overbite has never been treated
Complete Treatment Partial Treatment
Palatal impingement 0 0 1 14
Gingival incisor contact 0 0 4 57
Dental incisor contact 38 88 2 29
No incisor contact 5 12 0 0
Figure 5 Case with partial treatment (OB > 50% at T2). Angle class II
Division 1, skeletal class II, deep bite with gingival incisor contact, skeletal
normodivergency, spacing in the upper and lower front, lack of space in
the lower arch (left column). Initial treatment with upper plate with low
pull headgear and lipbumper. After eruption of all permanent teeth the
patient refused to continue with a multibracket appliance (middle column).
10 years later inflammation at the papilla incisiva is present due to palatal
impingement (right column).
Figure 6 Twelve-year-old boy at T1 with partial treatment (OB > 50% at
T2). Angle class II Division 2, skeletal class II, deep bite with gingival inci-
sor contact, skeletal hypodivergency, unilateral crossbite, moderate frontal
crowding in both arches (left column). The treatment was initiated by cor-
recting the crossbite with a palatal arch and S-elastics. At the same time
a low pull headgear was given to correct class II relationship, but success
was poor due to missing compliance. Fixed appliances including base arch
were used subsequently, but correction of class II relation could neither be
achieved by class II elastics nor fixed class II mechanics. Active treatment
had to be discontinued due to poor oral hygiene without full correction of
deep bite and without establishing incisor contact at T2. At T2, deep bite
was partially corrected. An upper bite plate for daily use and a functional
appliance for night use was given as retention appliances. 13 years later
incisors are in dentogingival contact and deep bite has returned to almost
pre-treatment levels (long-term, right column).
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discontinued treatment or in whom treatment had to be
stopped have a higher prevalence of gingival contact or
palatal impingement at T3. On the other hand, it might be
difficult to predict relapse, because spontaneous reduction
in deep bite was noted in this study as well. An average
decrease in overbite from 4.5 to 3.9 mm was reported in
untreated class II Division 1 cases with deep bite between
adolescence and adulthood (Feldmann et al., 1999), but
this has to be interpreted with caution, because Class II
Division 2 cases, which could be correlated with skeletal
deep bite, were excluded. Similarly, Berg (Berg et al., 2008)
reported a decrease in 9 out of 16 cases between the age 8
and 65 years. Although mandibular growth rotation (Björk,
1969) is difficult to assess without stable implants, the ten-
dency for less relapse in high angle cases (Pollard et al.,
2012) could indicate spontaneous bite opening by back-
ward rotation during growth. It seems that higher variance
of overbite in partially treated cases could be expected over
time than in completely corrected cases. Observation and
retention procedures to avoid relapse of deep bite in par-
tially corrected cases seem therefore to be important unless
backward rotating mandibular growth takes place.
It was not possible to identify factors of importance in
the development of deep bite relapse due to the low preva-
lence and small amount of relapse. The stability rate of
90% in subjects successfully treated for deep bite may be
partly related to selection bias during initial inclusion/
exclusion or from informative loss to follow-up of 30% of
patients. On the other hand, a bigger sample in this study
may not change substantially the outcome because relapse
was rare. In fact, a 6% higher definition of relapse in the
setup protocol would have decreased the number in the
relapse group to zero. Observer bias could not be fully
avoided for timepoints T2 and T3 due to aging of the den-
tal casts.
1. The prevalence of vertical relapse in moderate deep bite
cases after a median post-treatment follow-up of 11.9
years was low (10.3%, relapse group N = 4).
2. The median deepening of incisor overlap in the relapse
group at long-term follow-up (median 13.4 years) was low
(6.7%, with a range from 3.2 to 19.8%).
3. It was not possible to identify important factors to pre-
dict relapse of deep bite malocclusion as prevalence and
the amount of relapses were too low with respect to the
sample, sample size, outcome, and retention procedures.
4. Deep bite at long-term follow-up was more likely due to
partial correction at T2 (OB > 50% at T3, OB > 50% at
T2, N = 7) than due to relapse (OB > 50% T3, OB < 50%
at T2, N = 4).
5. Among all cases with deep bite at T3, gingival contact
and palatal impingement were more prevalent in partially
corrected noncompliant cases than in relapse cases.
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... A deep bite is characterized by excessive vertical overlap of the lower incisors by the upper incisors in maximum intercuspation. A deep bite is a feature of malocclusion that can be dental, skeletal or a combination of both [1]. A deep bite is often associated with a retroclination and extrusion of the upper and lower front teeth, a loss of vertical posterior dimension or a combination of both. ...
Full-text available
Deep bites can be treated by the intrusion of anterior teeth and the extrusion of the posterior teeth, or both, according to the exposure of the incisors in the smile. The aim of this paper is to propose a protocol to improve the effectiveness of deep bite treatments. Orthodontic movements are programmed following the “frog staging” protocol for the anterior teeth, the application of retention attachments and the overengineered final setup. Two case reports described the clinical and radiographic changes with orthodontic treatment using Invisalign clear aligners by applying this protocol.
... Orthodontic treatment is mandatory for correction of malocclusion but relapse of malocclusion happens if any aberrant muscle activity is ignored (Danz et al.,2012). Retraining the abnormal muscle tone and function, along with correction of the dento -alveolar system is necessary, to evade the risk of relapse and to achieve stable orthodontic results (Ramirez and Farrell,2005). ...
Full-text available
Aims: One of the biggest problems globally is malocclusion. The action of orofacial muscles is affected by tenacious oral habits. The quick diagnosis and subsequent treatment of orofacial disorders render countless welfares by reducing both related malocclusion and opportunity of relapse subsequently to orthodontic treatment. Pre-orthodontic trainers are innovative types of prefabricated removable functional appliances claimed to train the orofacial musculature; thus correcting malocclusion. This review aimed to search the literature for studies and case reports on the effectiveness of pre-orthodontic trainers on early correction of developing malocclusion and highlight particularly on its structural characteristics and its mechanism of action. Current literature provides sufficient evidence that these appliances are effective in treating Class II malocclusions especially those caused by mandibular retrusion. Case reports on Class I malocclusion have reported relief of anterior crowding, the alignment of incisors, and correction of deep bite with pre-orthodontic trainers. Promising results with pre-orthodontic trainers are realized in improved nasal breathing, improved swallowing pattern, and removal of habits like tongue thrusting and mouth breathing.
... Este resultado é superior ao encontrado por Karaiskos et al. (2005), que verificaram uma prevalência de 5,31%, mas inferior ao relatado por Brito et al. (2009a), que detectaram essa alteração oclusal em 19,2% entre crianças de 9 a 12 anos. Cavalcanti et al. (2008) A MP dento-alveolar é relacionada às condições de extrusão de incisivos e intrusão de molares ou a combinação de ambos e esquelética quando associada a alterações de crescimento na mandíbula e/ou maxila (DANZ et al., 2014;NIELSEN, 1991 ...
... Anomalias craniofaciais 33 ( A MP dento-alveolar é relacionada às condições de extrusão de incisivos e intrusão de molares ou a combinação de ambos e esquelética quando associada a alterações de crescimento na mandíbula e/ou maxila (DANZ et al., 2014;NIELSEN, 1991 ...
... Anomalias craniofaciais 33 ( A MP dento-alveolar é relacionada às condições de extrusão de incisivos e intrusão de molares ou a combinação de ambos e esquelética quando associada a alterações de crescimento na mandíbula e/ou maxila (DANZ et al., 2014;NIELSEN, 1991 ...
... Deep bite features are constituted by a mix of dental and skeletal conditions that can influence the severity of the malocclusion (Danz et al., 2014;Nielsen, 1991). Dental conditions are represented by over-eruption of maxillary and mandibular incisors, vertical inclination of both incisors on respective basal bone and loss of posterior vertical dimension, while skeletal conditions are represented by growth pattern and gonial angle. ...
Full-text available
Objective To review a series of clinical studies demonstrating the clinical efficiency of aligners with bite ramps in the treatment of severe deep bite. Materials and Methods In order to predictably manage the correction of deep bite with aligners, precision bite ramps on maxillary incisors have been used while posterior extrusion and anterior intrusion in the lower jaw with lateral attachments and proper levelling of the curve of Spee have been planned. Transverse correction and controlled upper and lower incisors proclination completed the treatment plan. Results Full deep bite correction with normal overbite was obtained in nine months of treatment by a combination of anterior intrusion and posterior torque correction, distal tipping and relative extrusion. Conclusion The use of bite ramps represents a valid option for the successful treatment of deep bite with aligners creating proper space for lateral sector extrusion and supporting lower anterior intrusion and controlled proclination.
... 36 In a long-term study on deep bite patients, in which relapse was defined as an increase in incisor overlap to 50% or greater, only 10% of the study population displayed relapse when followed for an average of 11.9 years. 37 Although there is little data regarding methods of retention in deep bite cases, extraction does not seem to be a key factor in the stability of the results. According to a Cochrane review conducted in 2017, there is little evidence-based literature regarding the efficacy of extraction versus non-extraction orthodontic treatment in resolving deep bite malocclusion in class II division 2 cases. ...
Retention may be particularly challenging after the correction of specific malocclusion features, such as tooth rotations, open bite and expansion, which are all inherently unstable. In this article, some indications for active retention are reviewed by highlighting a variety of clinical techniques and appliances. Active retention is discussed in relation to preservation of tooth alignment and in the three planes of space: sagittal, vertical and transverse. In some situations, an active retention regimen may be helpful to minimise or counteract relapse after orthodontic treatment and to improve patient satisfaction during the typically lengthy post-treatment period.
... Danz et al. found that with successful treatment followed by the placement of a fixed retainer and a temporary removable upper plate, the degree of relapse is relatively small and clinically insignificant. 22 However, fixed retainers can increase the accumulation of calculus, which in turn can increase the marginal recession of the gingiva. 23,24 Therefore, the use of a fixed retainer for our patient, who had fair oral hygiene, was not deemed beneficial. ...
Objective This case report emphasizes the importance of controlling vertical movement of posterior teeth for a non-growing Class II malocclusion with a complete deep overbite and large overjet. The intrusion of incisors without molar extrusion is one of the key factors for the aesthetics and stability of treatment outcomes. Case A 19-year-old woman had a chief complaint of excessive incisor display while smiling. She was diagnosed with an Angle Class II malocclusion with a complete deep overbite and large overjet caused by the improper interposition of her lower lip and overerupted incisors. To achieve satisfactory results, the vertical movements of posterior teeth needed to be controlled. Two orthodontic miniscrews were used in her maxillary arch to intrude the incisors and control the movement of molars. Concurrently, a utility intrusion arch was used to intrude and labially incline the lower incisors. Treatment result Her upper and lower incisors had been intruded by 4 mm and 3 mm, respectively, without the extrusion of posterior teeth. The-lip-to-incisor relationship at rest position had been improved and she was pleased with the results. Conclusion These mechanics were effective for a complete deep overbite correction without undesirable effects.
Objective: Orthodontic bite turbos are used to separate the maxillary and mandibular arch when disocclusion is needed for brackets placement or extrusion of teeth. Bite turbos should have adequate wear resistance to maintain disocclusion but also avoid abrasion of the opposing enamel. The objective of this study was to measure the wear of three materials used as bite turbos and opposing enamel wear. Materials and methods: 10mm×8mm×4mm specimens (n=8) of Transbond™LR (3M™) Transbond™ Plus (3M™) and Triad®gel (Dentsply) were prepared in silicone molds. Cusps of extracted premolars were prepared to a standard cone shape. Extracted maxillary incisors were used as reference for flat enamel surfaces. The experiments were performed on the modified UAB wear testing device at 20N for 200,000 cycles at 1Hz. All surfaces were scanned with a non-contact profilometer at 10micron resolution. Volumetric wear was measured with superimposition software and data analysed with one-way ANOVA and Tukey post-hoc. Results: Significant differences were seen in the wear of materials and opposing enamels (P<.01). Material wear ranked: Triad®gel (.878±.196mm3)>Transbond™ Plus (.317±.062mm3)>Transbond™ LR (.136±.027mm3)>Enamel (.053±.04mm3). Opposing enamel ranked: Transbond™ LR (.158±.086mm3)=Enamel (.128±.035mm3)=Transbond™ Plus (.126±.025mm3)>Triad®gel (.039±.008mm3). Conclusions: All bite turbo materials wore more than natural enamel but caused equal or less wear to opposing enamel than tooth-tooth contact. Triad®gel underwent 2.5× and 6× the wear of Transbond™ Plus and Transbond™ LR respectively. The bite turbo material used may be selected based on preference for longevity.
Early interceptive treatment for the elimination of factors inhibiting dental arch development and mandibular and maxillary growth is applied varyingly by orthodontists, possibly because there is little scientific evidence that such interventions are of actual benefit. The aim of this study was to determine specific factors for treatment need in the early mixed dentition period in order to obtain basic data to support early intervention. The study was part of a larger survey of 8768 children aged between 6 and 17 years. From this sample, 1975 children aged between 6 and 8 years were used to estimate the prevalence of malocclusions using the Index of Orthodontic Treatment Need (IOTN) during the early mixed dentition period. The results showed that deep overbite and overjet, both more than 3.5 mm, were the most frequent discrepancies, affecting 46.2 and 37.5 per cent of patients, respectively. An anterior open bite was registered in 17.7 per cent, crossbite in 8.2 per cent, and a reverse overjet in 3.2 per cent. A tooth width to arch length discrepancy was recorded in 12 per cent of teeth in the upper arch and in 14.3 per cent in the lower arch. The proportion of children estimated using the Dental Health Component of the IOTN to have a great or very great treatment need (grades 4 and 5) was 26.2 per cent. The higher values of treatment need during the mixed dentition period may account for temporary changes in the dentition and for the discrepancy in overjet and overbite. These discrepancies will be compensated in part during mandibular growth and development of the dental arch. Nevertheless, the findings indicate the early development of progressive malocclusion symptoms which are evidenced in the IOTN and concur with the acronym 'MOCDO' hierarchy (missing, overjet, crossbite, displacement, overbite). This early formation of progressive symptoms inhibiting or disturbing mandibular or maxillary growth or the development of the normal dental arch, i.e. crossbite, reverse overjet and increased overjet with myofunctional disorders, should be treated at an early stage.
A common orthodontic problem is a deep overbite malocclusion. Because of its high relapse tendency, it is also one of the most challenging problems to treat. To minimize relapse, the morphologic characteristics of patients need to be considered. The aim of this study was to compare deepbite relapse in 3 groups of patients categorized by vertical growth type. The total sample included 60 patients treated at the University of Washington in Seattle, all with initial overbites greater than 50%. Data were collected from casts and cephalometric radiographs at 3 time points: pretreatment, posttreatment, and 10 years postretention. A mixed-effects model (analysis of variance) and post-hoc t tests were used for the statistical evaluations. The high-angle subjects showed the least deepbite relapse (0.1 ± 1.1 mm), whereas the low-angle (1.2 ± 0.9 mm) and the normal-angle (1.4 ± 1.3 mm) subjects had statistically significant relapses P <0.001. This overbite relapse might be partially due to changes in the mandibular and interincisal angles, which were also observed in these 2 groups. High-angle subjects tend to relapse less in overbite than do low-angle and normal-angle subjects in the long term.
We identified masseter muscle fiber type property differences in subjects with dentofacial deformities. Samples of masseter muscle were collected from 139 young adults during mandibular osteotomy procedures to assess mean fiber areas and percent tissue occupancies for the 4 fiber types that comprise the muscle. Subjects were classified into 1 of 6 malocclusion groups based on the presence of a skeletal Class II or III sagittal dimension malocclusion and either a skeletal open, deep, or normal bite vertical dimension malocclusion. In a subpopulation, relative quantities of the muscle growth factors IGF-I and GDF-8 gene expression were quantified by real-time polymerase chain reaction. Fiber properties were not different in the sagittal malocclusion groups, but were very different in the vertical malocclusion groups (P ≤ .0004). There were significant mean fiber area differences for type II (P ≤ .0004) and type neonatal-atrial (P = .001) fiber types and for fiber percent occupancy differences for both type I-II hybrid fibers and type II fibers (P ≤ .0004). Growth factor expression differed by gender for IGF-I (P = .02) and GDF-8 (P < .01). The ratio of IGF-I:GDF-8 expression associates with type I and II mean fiber areas. Fiber type properties are very closely associated with variations in vertical growth of the face, with statistical significance for overall comparisons at P ≤ .0004. An increase in masseter muscle type II fiber mean fiber areas and percent tissue occupancies is inversely related to increases in vertical facial dimension.
This study was a cephalometric evaluation of the growth changes in untreated subjects with deepbite at 4 time points during their developmental ages (from the early mixed dentition to the permanent dentition, and from the prepubertal phase to young adulthood). A sample of 29 subjects with deepbite (overbite >4.5 mm) was followed longitudinally from about 9 through about 18 years of age. Dentofacial changes at 4 times, defined by the cervical vertebral maturation method, were analyzed on lateral cephalograms. Nonparametric statistical analysis was used for comparisons. Overbite improved on average by 1.3 mm between the first and last measurements; it worsened significantly during the prepubertal period, but it improved significantly at the pubertal growth spurt. From the prepubertal ages through young adulthood, overbite improved in 83% of the subjects and self-corrected in 62% of the subjects. Improvements in overbite were related to the initial amount of maxillary incisor proclination. The significant improvement in overbite during the adolescent growth spurt depended on the amount of vertical growth of the mandibular ramus and the eruption of the mandibular molars. Subjects with deepbite showed worsened occlusal conditions during the prepubertal and mixed dentition phases, but had significant improvements thereafter. Improvements in overbite cannot be predicted on the basis of skeletal vertical relationships. These results provide useful indications for appropriate orthodontic treatment timing for an increased overbite.
The aims of this study were to investigate the effects of 2 force levels on the amount of relapse and to determine whether there is a relationship between the rates of tooth movement and relapse. Approximately 20-g (group I) and 60-g (group II) forces were applied to the maxillary central incisors of 25 young adult (14 weeks of age) New Zealand female rabbits. Active tooth movement lasted 20 days. Then, the appliances were removed, and the incisors were released. The distance between the incisors was measured daily from the midlevels of the crowns by using a digital caliper during the active phase of tooth movement for 20 days, and then relapse was measured at the same level for 37 days. Analysis of variance and the Bonferroni multiple range test were used for statistical analyses. After active tooth movement, the mean total opening amounts were 3.98 ± 0.59 mm in group I and 4.82 ± 0.82 mm in group II, and the mean difference was approximately 0.8 mm. A rapid relapse was observed on the initial days in both groups, and its rate decreased with time. Significant relapse was observed in the first 5 and 8 days of the experiment in 20-g and 60-g force groups, respectively. The relapse in group II was significantly greater than in group I only on the first day of experiment. Statistically significant correlations were found between total tooth movement and relapse (R = 0.896, P <0.001). These results showed a close relationship between the amount of relapse and orthodontic force magnitude. Greater relapse occurred during the initial days after appliance removal, and this indicates that retention appliances are needed immediately after the removal of orthodontic appliances.
Very few studies have addressed long-term development and risks associated with untreated malocclusion. The purpose of this study was to examine changes in occlusion in a lifelong perspective and to compare oral health and attitudes toward teeth among persons with malocclusion with those having normal occlusion. In 1950 an epidemiologic survey of 2349 8-year-olds was conducted and included 4 intraoral photographs. Three selected samples with different malocclusions (deep bite, crossbite, or irregular teeth) and 1 sample with normal occlusion (a total of 183 subjects) were, 57 years later, invited for examination and an extensive interview about dental experiences and attitudes. Sixty-nine responded (38%) and constitute the subjects studied. Malocclusion remained the same or worsened except in subjects having deep bite in childhood, which in some improved and in others became worse. Crowding generally increased. Sixteen persons reported moderate or severe temporomandular joint (TMJ) problems, and of these 7 belonged to the group with crossbite in childhood. With few exceptions, the subjects in all samples had good oral hygiene, visited the dentist regularly, and had well-preserved dentitions. Mean number of missing teeth was significantly lower among those with normal occlusion compared with the malocclusion groups. Individuals with normal occlusion responded favorably to all questions related to attitudes and experiences about their teeth, while responses in the malocclusion groups varied. Persons with the particular malocclusions examined experienced more problems related to teeth later in life compared with those having normal occlusion in childhood.
The aim of this study was to provide detailed information concerning clinically relevant occlusal traits and the prevalence of occlusal anomalies in an orthodontically relevant period of dental development. Four hundred and ninety-four German schoolchildren (237 males and 257 females), median age 9 years, were orthodontically examined. Overjet and overbite were measured to the nearest 0.5 mm, and sagittal molar relationships were registered clinically to the nearest quarter unit. In addition, crossbites, scissor bites, and midline displacements were evaluated. Descriptive statistics was complemented by testing gender differences and differences between groups with Class I and Class II anomalies (Mann–Whitney U-test) as well as a statistical evaluation of differences between the three dental stages (Kruskal–Wallis test). Overjet exhibited an extreme range between −2 and 12 mm (median values 3–3.5 mm). An increased overjet was more prevalent than a reduced or reverse overjet, and a severely increased overjet greater than 6 mm was a common finding affecting around 5–10 per cent of the children. Similarly, overbite showed considerable variations of between −1 and 9 mm (medians 3–3.5 mm) and males exhibited a significantly larger overbite than females. In Class II malocclusion subjects, overbite was significantly enlarged (on average between 0.5 and 1 mm) when compared with those with a Class I malocclusion. Traumatic contact of the gingiva affected every 14th child. A Class II molar relationship of three-quarter units or more was a frequent finding affecting more than one child in five. In addition, at 9 years of age, 3 per cent of the children exhibited a Class III molar relationship of at least a half unit. The wide range of orthodontically relevant occlusal traits found in the present study underlines the need for orthodontic screening at 9 years of age (or earlier).
To analyze changes in occlusion between the ages of 8 and 65 years in persons with a deep overbite at the age of 8 who did not receive orthodontic treatment. To describe their experiences regarding their own dentition as well as their opinions on dental esthetics and oral health. To compare these findings with those of the Normal Occlusion (N-Group) described in Part 1. With one exception, the 20 persons in our cohort had not undergone orthodontic therapy. Our documentation was based on intraoral photographs taken at the two time points in addition to an interview and facial photos at the age of 65. The overbite could be evaluated in 16 persons. In four persons various degrees of mucosal indentations in connection with the overbite had been registered. The average number of missing teeth was 3.4, compared to 1.6 in the N-group. All participants reported their oral health to be good or excellent and, similar to the N-group, nearly all considered dental esthetics to be important. The overbite had decreased during the observation period in nine, increased in five, and remained stable in two persons.
Not all patients with deep overbite should be treated with the same mechanics. Some patients require intrusion of the anterior teeth, while others require primarily extrusion. This article has discussed the principles of incisor and canine intrusion and has demonstrated the use of intrusion springs that are capable of intruding incisors with minimal side effects on the posterior teeth. Six principles must be considered in incisor or canine intrusion: (1) the use of optimal magnitudes of force and the delivery of this force constantly with low-load-deflection springs; (2) the use of a single point contact in the anterior region; (3) the careful selection of the point of force application with respect to the center of resistance of the teeth to be intruded; (4) selective intrusion based on anterior tooth geometry; (5) control over the reactive units by formation of a posterior anchorage unit; and (6) inhibition of eruption of the posterior teeth and avoidance of undesirable eruptive mechanics.
Previous orthodontic treatment, the awareness of malocclusion, the demand for orthodontic treatment and the prevalence of malocclusion were studied in 389 Swedish men, aged 21-54 years (mean age 32 years). Nine percent had been treated with an orthodontic appliance and 15% reported that permanent teeth had been extracted on orthodontic indications. Malposition of teeth was found in 75%, with rotation as the most common type of malposition. Crowding was recorded in 43% and spacing in 18%. Fifty-seven percent had some occlusal anomaly. The need for orthodontic treatment was rated on a four-point scale. It was found that 76% were in need of treatment. The need for treatment was only slight in half of the men but moderate to urgent in 25% of the sample. About a quarter of the men were aware of malposition of front teeth, equally often for maxillary and mandibular teeth, but only about 1% were aware of malposition of posterior teeth. Only a few percent thought they were in need of orthodontic treatment. The presence of malocclusion was correlated to age, place of birth and educational level. This might perhaps be a consequence of tooth loss.