Impacted teeth in a turkish orthodontic patient ...

A. Topkara1, Z. Sari2 DDS, PhD, Private Practice, Orthoclinic, Alanya, Antalya, TURKEY 2 DDS, PhD, Professor and Dean, Department of Orthodontics, Faculty of Dentistry, Akdeniz University, Antalya, TURKEY 1

e-mail: [email protected]

Impacted teeth in a turkish orthodontic patient population: prevalence, distribution and relationship with dental arch characteristics abstract Aim Aims of this study are to investigate the prevalence and distribution of impacted permanent teeth (IPT) and also the relationship between impaction and dental arch form and length in a Turkish orthodontic patient population. Materials and Methods Panoramic radiographs, intraoral photographs and dental casts of 1527 patients (947 females, 580 males) aged 13 and above who underwent orthodontic treatment at Selcuk University Department of Orthodontics from 1990 to 2005 were retrospectively reviewed for IPT (except third molars). A comprehensive chart review was conducted in all subjects. Patient and treatment-related data were registered in a computer database for comparative analysis. Results When impacted supernumerary teeth (IST) were excluded, prevalence of IPT was 9.10% with no significant differences between the genders (p=0.897). Prevalence of IPT including IST was 9.69%. Most commonly impacted teeth were maxillary canines (5.24%) followed by mandibular second premolars (2.23%), maxillary second premolars (1.11%) and mandibular canines (0.92%). IST (0.72%) and impacted molars (0.72%) were the least common anomalies after incisor impaction (0.65%). Maxillary to mandibular IPT ratio was 1.88 and majority of IPT were in the anterior

segment with an anterior-posterior ratio of 1.45 in all patients. Conclusion Most commonly affected impacted teeth were maxillary canines, mandibular second premolars, maxillary second premolars and mandibular canines respectively in our population with no predisposition difference between the genders. Arch length deficiency was determined as 14% for patients with maxillary impaction and 10% for patients with mandibular impaction. None of the patients with IPT have shown square arch form. Keywords Arch forms; Arch length deficiency; Impacted teeth; Impaction prevalence; Supernumerary teeth.

Introduction Impaction of a tooth is defined as a tooth that has not erupted yet for various reasons. If a tooth fails to emerge or emerges only partially, it is considered to be impacted. It is a frequent dental anomaly and may lead to many complications. Aetiology consists of local biological factors, such as lack of space in dental arch, trauma, lack of guidance in eruption due to an obstructive formation (odontogenic tumor, retained deciduous tooth, supernumerary tooth etc.); some syndromes and systemic diseases such as cleidocranial dysplasia, Down syndrome, hypothyroidsm and hypopituitarism; and hereditary factors [Zeitler, 2004]. Recent findings from familial cases and molecular researches suggest that non-syndromic disturbances in tooth eruption may have a genetic aetiology as well [Frazier-Bowers et al., 2010; Stellzig-Eisenhauer et al., 2010]. The prevalence of IPT in different ethnic populations was evaluated in several studies. The incidence of IPT excluding third molars has been reported to range from 2.94% to 18.8% [Aktan et al., 2010; Dachi and Howell, 1961; Grover and Lorton, 1985; Kramer and Williams, 1970; Shah et al., 1978; Thilander and Myrberg, 1973]. The main purpose of this study is to investigate the prevalence and distribution of IPT excluding third molars in a large cohort of Turkish orthodontic patient population from a single academic institution. Impacted supernumerary teeth were also evaluated. In addition, some dental arch characteristics such as dental arch form and arch length deficiency were reported for patients with IPT.

Materials and methods Panoramic radiographs, intraoral photographs and

European Journal of Paediatric Dentistry vol. 13/4-2012

311

Topkara A. and Sari Z.

dental casts of 1527 (947 females, 580 males) patients aged 13 and above (mean age 16.4 years) who underwent orthodontic treatment at the Department of Orthodontics at Selcuk University Faculty of Dentistry in Konya from 1990 to 2005 (over 15 years) were retrospectively reviewed. Patients with syndromes such as cleidocranial dysplasia, Down syndrome were excluded from the study. The prevalence of IPT and impacted supernumerary teeth (IST) were calculated based on the chronologic age of the patient and mean eruption times of the teeth. Considering the mean eruption time of second molars as being the last erupting tooth into the oral cavity, 13 years of age was determined as the lower age limit to achieve accurate results. If the tooth was not exposed in the mouth, or in a bad position in the alveolar bone that would not leave it erupting into the oral cavity it was diagnosed as impacted. Records from serial visits were longitudinally evaluated. All records were examined carefully by a single orthodontist. Clinical and radiographic data were cumulatively entered in a custom-designed computer database. IPT assessment was performed separately by including and excluding impacted supernumerary teeth. The data were presented as means and proportions. Groups were compared using Chi-square test for categorical variables respectively, as indicated.

Results Excluding the IST data, prevalence of IPT in the overall orthodontic patient population was 9.10% (n=139). Prevalence of IPT was not found to be significantly different in males compared to females (9.31%, n=54 vs. 8.98%, n=85, respectively) (p=0.897) (Fig. 1). IPT data based on gender and anatomical distribution is summarised in Table 1. The most commonly impacted teeth were canines (5.70%, n=87) followed by premolars (3.30%, n=50).

Impacted incisors (0.65%, n=10) and molars (0.72%, n=11) were the least common anomalies (Fig. 1). The most common IPT types were maxillary canines, mandibular second premolars, maxillary second premolars and mandibular canines respectively. Canine impaction was not found to be significantly different between males (5.17%, n= 30) and females (6.02%, n=57) (p=0.563). The number, incidence, location and gender ratio for impacted canines are shown in Table 2. Bilateral canine impaction was seen in 27.6% (n=24) of patients with impacted canines. The prevalence of maxillary canine impaction was 5.24% (n=80) and was not found to be significantly different between males (4.48%, n=26) and females (5.7%, n=54), (p=0.358). Prevalence of bilateral impacted maxillary canines in the overall cohort was 1.38% (n=21), which accounts for 25% of all maxillary canine impaction cases. Mandibular canine impaction was observed in only 14 patients (0.92%). Impaction with transposition was seen in only two patients (0.13%) in the maxillary anterior segment as canine transposition. The second most common IPT were impacted lower second premolars, which was observed in 34 patients (2.23%). There were no significant differences between males (2.76%, n=16) and females (1.90%, n=18, p=0.356). Unilateral impaction of lower second premolars was observed in 26 patients (1.70%), which accounted for 76.5% of all lower second premolar impactions. Maxillary second premolar impaction was seen in 17 patients (1.11%). Impacted molars was seen in 0.72% (n=11) of the population. This percentage was 0.86% for males (n=5) and 0.63% for females (n=6). Second molar impaction was observed in 8 (0.52%), and first molar impaction was seen in only 3 (0.20%) patients. Frequency of molar impaction in the maxilla was 0.52% (n=8), in the mandible was 0.39% (n=6). Prevalence of impacted incisors was 0.65% (n=10) in the overall cohort. This frequency was determined as 1.20% (n=7) for males and 0.32% (n=3) for females. Maxillary impaction was

Prevalence of impacted teeth 12% female

male

total

10% 8% 6% 4% 2% 0% IPT

312

IPT + IST

Canine

Premolar

Molar

IST

Incisor

fig. 1 Prevalance of impacted teeth according to gender groups. IPT: Impacted permanent teeth excluding impacted supernumerary teeth. IPT+IST: Impacted permanent teeth including impacted supernumerary teeth. IST: Impacted supernumerary teeth.


tooth impaction in turkish adolescents

Subjects

Incidence (%) Males

Females

Number of teeth

Right

Left

139

9,10

54

85

225

109

116

Max. Central Incisors

7

0,46

5

2

8

3

5

Max. Lateral Incisors

3

0,20

2

1

4

2

2

80

5,24

26

54

101

48

53

3

0,20

0

3

3

2

1

17

1,11

8

9

20

9

11

All teeth

Max. Canines Max. First Premolars Max. Second Premolars Max. First Molars

1

0,07

1

0

1

0

1

Max. Second Molars

7

0,46

2

5

10

4

6

Mnd. Cental Incisors

1

1,11

1

0

1

1

0

Mnd. Lateral Incisors

0

0

0

0

0

0

0

14

0,92

7

7

19

9

10

5

0,33

1

4

8

3

5

34

2,23

15

19

42

23

19

Mnd. First Molars

2

0,13

1

1

3

2

1

Mnd. Second Molars

4

0,26

2

2

5

3

2

Mnd. Canines Mnd. First Premolars Mnd. Second Premolars

Max.

Mnd.

147

78

tabLE 1 Distribution of impacted teeth in terms of gender and location. Subjects

Incidence (%) Males

Females

Number of teeth

Right

Left

Male/Female Prevalence Rate Ratio

80

5,24

26

54

101

48

53

1/1,3

Mnd. canine imp. 14

0,92

7

7

19

9

10

1,6/1

Total canine imp.

5,70

30

57

120

57

63

1/1,2

Max. canine imp.

87

tabLE 2 Incidence, location and gender ratio for canine impaction. seen in 9 patients (0.59%), while mandibular impaction was seen in only one patient. Impaction of maxillary central incisors was observed in 7 patients (0.46%) in the whole population.

IPT prevalence based on impacted tooth counts As shown in Table 1, 225 permanent teeth were impacted in 139 patients with a mean of 1.62 teeth per patient. This figure was 1.58 (134/85) for females compared to 1.69 (91/54) for males. Ratio of maxillary to mandibular IPT was found to be 2.19 in females (92/42) compared to 1.53 (55/36) in males, and 1.88 in all subjects. The number of IPT in the anterior segment was higher than the number of IPT in the posterior segment with an anterior-posterior ratio of 1.53 in females (81/53), 1.33 in males (52/39) and 1.45 in the overall population (133/92).

IPT prevalence including supernumerary teeth (IST)

impacted

The prevalence of IPT including IST was 9.69%


(n=148), and not significantly different between males (10%, n=58) and females (9.5%, n=90), (p=0.819), (Fig. 1). The prevalence of IST was 0.72% (n=11), consequently IST and impacted molars were the least common anomalies after incisor impaction. There was no significant difference between male (1.03%, n=6) and female patients (0.53%, n=5) (p=0.410) (Fig. 1). Table 3 summarises the distribution of 11 patients with IST. Their mean age is 15 years between the ranges of 13-25 years, and the median age was 14 years. When the number of IST per patient was investigated, we found that 9 patients (0.59%) had only one IST, 2 patients (0.13%) had two IST. Only one impacted mesiodens was found in one patient. The number, incidence, location and gender ratio for IST are shown in Table 3. The most frequent IST were found in mandibular posterior, maxillary anterior, maxillary posterior and mandibular anterior regions respectively. We observed that 8 patients had IST alone (without concomitant IPT), whereas the remaining 3 patients had IST in combination with another impacted tooth

313


Impacted Supernumerary teeth

Subjects

Incidence (%)

Males

Females

Number of teeth

Total

11 (0,72%)

100

6

5

13

0,1

1

0

1

Mesiodens

1 (0,07%)

Max. anterior segment

3

27,3

3

0

4

Max. posterior segment

3

27,3

0

3

3

Mnd. anterior segment

1

0,1

0

1

1

Mnd. posterior segment

4

36,4

3

1

5

type. There were only four patients with IPT related to impacted or emerged adjacent supernumerary teeth.

Relationship between impaction dental arch characteristics

and

Of all 105 patients who exhibited IPT in the maxilla, ovoid and tapered upper arch forms were observed in 84 and 21 patients respectively with 4/1 ratio; and of all 52 patients who have IPT in the mandible, ovoid and tapered lower arch forms were observed in 48 and 4 patients respectively with 12/1 ratio (Fig. 2). None of the patients showed a square arch form. Maxillary arch length deficiency was determined in 15 patients who have IPT in the maxilla (14%) and mandibular arch length deficiency was found in 5 patients (10%) who had IPT in the mandible (Fig. 3).

Distribution of arch forms 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0%

Discussion Our study demonstrated that the prevalence of impaction in a large Turkish orthodontic population was 9.10% which falls within the range of 0.49%-18.8% reported in the literature [Dachi and Howell, 1961; Grover and Lorton, 1985; Jena et al., 2010; Kramer and Williams, 1970; Shah et al., 1978; Thilander and Myrberg, 1973]. In the only previous Turkish study that investigated IPT prevalence this was 2.94%, which was much lower than our results [Aktan et al., 2010]. Studies in the literature represent patients from different genetic background and have unique patient selection criteria. In addition, differences in methodology like definition of the impaction and the age range of subjects should consider when comparing the prevalence found in this study with other percentages. In our cohort, the incidence of IPT did not differ significantly between the genders, which is in agreement with some previous reports [Aktan et al., 2010; Fardi et al., 2011]. Most frequently, IPT in our population were canines followed by premolars. Although this finding was in agreement with the literature, when considering each tooth type there were slight differences between the studies. In our study the most frequently IPT type was maxillary canines, followed by mandibular second premolars, maxillary second premolars and mandibular canines. Fardi et al. [2011] indicated the same order,

314

tabLE 3 Distribution of impacted supernumerary teeth in terms of gender and location.

92% 80%

fig. 2 Distribution of arch 20% forms of the 8% patients 0% 0% with Ovoid Tapered Square maxillary and/or maxillary arch mandibular arch mandibular impaction. Distribution of arch lenght

100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0%

90%

86%

fig. 3

arch lenght Prevalance deficiency

14%

10%

maxillary mandibular arch arch

of arch length defficiency in patients sufficient arch lenght with maxillary and/or mandibular impaction.

whereas Aktan et al. [2010] implied a different order after maxillary canines as mandibular canines, mandibular premolars and maxillary premolars. Canine impaction was found as 5.7%, which falls within a range of 2.2%-8.8% indicated in literature [Aktan et al., 2010; Fardi et al., 2011; Rozsa et al., 2003]. Maxillary canine impaction was 5.24% and this agrees with the range of 0.8%-8.4% indicated in previous studies in different populations [Celikoglu et al., 2010;


tooth impaction in turkish adolescents

Fardi et al., 2011; Grover and Lorton, 1985; Kramer and Williams, 1970]. Male to female prevalence ratio was 1/1.3, indicating a higher prevalence for females. This result was within the range 1/1.3-1/3.2 indicated in previous reports [Jacobs, 1996]. In our investigation mandibular canine impaction was very rare (0.92%) and in the range between 0.1%-1.29%, as indicated by other researchers [Shah et al., 1978; Yavuz et al., 2007]. Prevalence of maxillary canine impaction was 5.7-fold higher than mandibular canine impaction. This difference was calculated as between 3.8-16.8-fold in recent population investigations which concluded the rarity of mandibular canine impaction. [Aktan et al., 2010; Aydin et al., 2004; Celikoglu et al., 2010; Chu et al., 2003; Fardi et al., 2011; Grover and Lorton, 1985; Saglam and Tuzum, 2003]. Maxillary bilateral canine impaction was observed in 25% of all maxillary canine impactions which falls within the range of 17-45% reported by Jacobs [1996]. There is limited number of studies on premolar impaction and the prevalence was indicated between 1.03%-2.7% [Fardi et al., 2011; Grover and Lorton, 1985; Simsek-Kaya et al., 2011]. Our result was slightly over this range (3.3%). As indicated in the most of the related literature, the lower second premolar was the most frequently impacted premolar type (2.23%), followed by the upper second premolar [Fardi et al., 2011; Simsek-Kaya et al., 2011]. In our research molar impaction was 0.72% and second molar impaction was more common than first molar impaction, which is consistent with other studies. Grover and Lorton [1985] and Bacetti [2000] reported that the most frequently impacted molars were the second molars. Fardi et al. [2011] indicated molar impaction prevalence as 1%. There are some different results on prominent gender in the literature [Baccetti, 2000; Fardi et al., 2011] which suggest a genetic component. In the present study increased prevalence for males (male/female prevalence ratio is 1.4/1) was observed. Incisor impaction is a rare phenomenon. Its prevalence was indicated as 0.16% by Aktan et al. [2010]. Fardi et al. [2011] indicated that none of the patients presented with impacted incisor. We found it as 0.65% in our patient population with a higher prevalence for males to females (male/female prevalence ratio is 3.8/1). This ratio difference for genders together with the molar impaction ratio difference suggests a possible involvement of sexual chromosomes in the cause of tooth eruption disturbances.

Prevalence of IPT including supernumerary teeth (IST)

impacted

When IST information was incorporated, prevalence of impaction in our study was found to be 9.69% without any gender predisposition and prevalence of IST was found to be 0.72%. Although our prevalence


of IST was not significantly different between the genders, male to female prevalence ratio was 1.9/1, consistent with the 2/1 ratio between males and females reported for supernumerary teeth in Caucasians [Luten, 1967]. There are several investigations on prevalence of supernumerary teeth that indicated the occurrence as between 0.1%-3.8% in population [Bäckman and Wahlin, 2001; Luten, 1967; Salem, 1989]. Nevermore, there is not much data on prevalence of IST and IPT including IST. A recent study by Fardi et al. [2011] investigated prevalence of impaction including IST data, however this study differ significantly with regards to age and group of patients studied. They indicated the prevalence of impaction (including IST) as 13.7% and prevalence of IST as 1.8%. One might consider that we should have determined a low age limit due to the inclusion of patients with IST which are typically diagnosed in younger age. However, the primary aim of this study was to investigate the prevalence of impacted teeth in a Turkish orthodontic population. In our study the most frequent IST were found in mandibular posterior, maxillary anterior, maxillary posterior and mandibular anterior regions respectively. Only one impacted mesiodens was found in one patient. Nevertheless, different order patterns were published in the literature on supernumerary teeth suggesting higher prevalences for maxillary anterior region and mesiodens [Esenlik et al., 2009; Fardi et al., 2011; Luten, 1967].

Conclusion Prevalence of IPT was found to be 9.69% including IST and 9.10% excluding IST in a large Turkish orthodontic population, which agrees with other studies from Caucasian populations. Although some regional differences exist in terms of prevalence and distribution of impaction in various populations, the main impaction types remain very similar. Most frequently impacted tooth was maxillary canine followed by mandibular second premolar, maxillary second premolar and mandibular canine. Prevalence of IPT was similar in both gender groups. Low prevalence of arch length deficiency was determined for both arches in the patients with IPT. Ovoid arch form was the most frequently seen arch form for both maxillary and mandibular arches, while none of the patients with IPT showed square arch form.

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