Dentistry DOI : 10.7860/JCDR/2013/5677.3516
Year : 2013 | Month : Oct | Volume : 7 | Issue : 10 Page : 2326 - 2329

Prevalence and Incidence of Gemination and Fusion in Maxillary Lateral Incisors in Odisha population and Related Case Report

Shashirekha G.1, Amit Jena2

1 Reader, Department of Conservative Dentistry & Endodontics, Institute of Dental Sciences, Siksha ‘O’ Anusandhan University, Bhubaneswar, 751003, Odisha, India.
2 Reader, Department of Conservative Dentistry & Endodontics, Institute of Dental Sciences, Siksha ‘O’ Anusandhan University, Bhubaneswar, 751003 Odisha, India.


NAME, ADDRESS, E-MAIL ID OF THE CORRESPONDING AUTHOR: Dr. Amit Jena, B-122, HIG BDA Duplex, Baramunda, Bhubaneswar, 751003. Odisha, India.
Phone: 9437836499, 9938604876,
E-mail: amitjena@yahoo.com
Abstract

Aim: A survey was conducted to analyze the prevalence and incidence of dental anomalies in relation to maxillary lateral incisors in the Odisha population. A multidisciplinary approach for aesthetic management of a geminated tooth is described.

Material and Methods: A total of 1062 subject, aged between 15-30 years (724 males and 338 Females) were randomly screened at Institute of Dental Sciences, Bhubaneswar, Odisha India. Each subject was examined clinically and radiovisuographically for dental anomalies in relation to maxillary lateral incisors. In the related case described, endodontic management and aesthetic correction of geminated maxillary lateral incisors was done.

Results: Five dental anomalies i.e. gemination, fusion, missing lateral incisors (both unilateral and bilateral), peg shaped incisors (unilateral and bilateral), and dens in dente were observed. Anomalies found were Peg shaped; 2.82%, Missing;1.88%, Gemination;0.28%, Fusion;0.18% and Dens in Dente;0.18%.

Conclusion: Comparison of these results with that of other studies indicated that anomalies in lateral incisors occur at different frequencies among various countries and communities in the world. In the case since maxillary lateral incisors are in the aesthetic zone, recognizing these anomalies will facilitate a successful treatment.

Introduction

Developmental anomalies of the dentition are not frequently observed in clinical practice. However, these anomalies account for a relatively low number of cases as compared to the more common oral disorders such as dental caries and periodontal diseases. Their clinical management is usually complicated, as they present with malocclusions, aesthetic problems and a possible disposition to other oral diseases.

Dental anomalies occur during the embryological and developmental life of the tooth and they usually involve a single tooth germ. The dental anomalies can be classified into different groups: as anomalies which are based on the volume, number, form, position and union of the teeth.

According to Nadal-Valldaura and others [1], fusion is a union of two contiguous dental germs that correspond to normal pieces and which continue together in development, erupting as a fused tooth. A fusion can occur at the level of enamel, cementum and dentin, or it may even involve all extracts of the tooth which involve the pulp. In Gemination, the union takes place between the germ of a normal tooth and that of a supernumerary tooth. Gemination can take place at the same level as that of fusion. Gemination is more frequent in the anterior teeth, although it can also affect molars and bicuspids.

Although the aetiology is not clear, environmental factors, trauma, vitamin deficiencies, systemic diseases as well as certain genetic predispositions have been described as the possible causes [24]. Usually, there is a furrow of variable depth, that may or may not continue throughout the crown and root, indicating the line of adhesion between both tooth germs [3]. Radiographs help in delimiting the layers which are involved in fusion/gemination and to check whether the fusion is total or coronary. Gemination occurs more in primary dentition (0.5% prevalence in children) than in permanent dentition (0.1% prevalence in adults) [4,5]. Predilection is more in maxillary primary incisors and canines [2]. The frequency of a bilateral gemination is 0.02 % in both dentitions and it is found more frequently in Mongolian race (5%) than in Caucasian race(0.5%) [5].

Many epidemiological surveys have been conducted in different parts of the world, to determine the prevalence of various types of dental anomalies [613]. The results have shown that there are regional and ethno racial variations in the prevalence of dental anomalies. This paper has presented the results of a clinical and radiovisuographic survey which was done on anomalies of maxillary lateral incisor tooth number and morphology in Odisha, India, population along with treatment and aesthetic correction of geminated maxillary left–lateral incisor.

Methodology

A total of 1062 subjects who were aged between 15-30 years (724 males and 338 Females) were randomly screened at the Institute of Dental sciences in Bhubaneswar, Odisha, India. The clinical criteria included subject’s age, gender, number of teeth and shape and size of lateral incisors. History of extraction of lateral incisor was not considered for study. These clinical details were taken by an experienced clinician. Each subject was examined clinically for dental anomalies in relation to maxillary lateral incisors. Pregnant women were excluded from the study.

Radiovisuographic images (RVGs) (Schick Technologies Inc.) were taken in subjects with missing teeth or with abnormal sizes and shapes of maxillary lateral incisors, to detect the nature of the anomaly. Informed consents of subjects were taken for RVGs and all precautions were taken to minimize radiation exposure. The RVG images were analyzed carefully by using an inbuilt image viewing software, by an experienced clinician and by one of the authors. The data was collected and statistically analyzed by using Chi-Square and Fisher Exact tests.

Case Report

During the survey, an interesting case was identified, described below. A 20-year-old female was referred to the Department of Conservative Dentistry and Endodontics for aesthetic correction of her maxillary left lateral incisor. Her medical history was noncontributory. Clinically, the crown of the tooth which was concerned was found to be bifid and a Grade I mobility was noticed [Table/Fig-1].

Pre-operative Photograph

Thermal pulp testing and electric pulp testing (Digitest™ Pulp Tester-Parkell) showed a negative response in central incisor and delayed response in lateral incisor. On probing, a periodontal pocket of 10mm was revealed in between the maxillary left central and lateral incisors. Both teeth were caries free and no missing tooth was detected in the dental arch. An intra-oral periapical radiograph revealed a possible connection between the pulp canals in the lateral incisor and an apical distal curvature in the central incisor [Table/Fig-2]. A vertical bone loss was observed in between the two teeth. The corresponding tooth on the opposite side of the arch appeared clinically and radiographically normal. The tooth was anaesthetized with 2% lidocaine (1:100,000 epinephrine Xylocaine; Astra Zeneca Pharma Ind Ltd, Bangalore, India.), isolated with a rubber dam and access cavities were prepared for maxillary left central and geminated lateral incisor. Two access cavities were prepared on the geminated tooth, pulp was extirpated and pulp chambers were irrigated by using 3% sodium hypochlorite (NaOCl).

Pre-operative Radiograph

Determination of the working length was done by using an apex locator (X-SMART Dual, Dentsply Maillefer) and it was confirmed on RVG. Coronal flaring was done with gates glidden burs/drill (Mani, Inc., Tochigi, Japan), numbers 4 and 5 and cleaning and shaping of root canal was done with K-flex hand files (Dentsply) by a hybrid technique under a copious irrigation of 3% NaOCl. AH Plus resin sealer (Dentsply Maillefer, Ballaigues,Switzerland) was used for obturation with cold lateral compaction, followed by warm vertical compaction. Access cavity was sealed with IRM cement (Dentsply De Trey GmbH, Konstanz, Germany)

In the subsequent appointment, curettage was done and a bioactive synthetic bone graft material (Perioglass, Nova Bone) was used to fill the bony defect [Table/Fig-3a and 3b]. Ceram X Mono (Dentsply) composite restorative material was used for access cavity restoration of the central incisor and aesthetic correction for the Geminated tooth [Table/Fig-4].

Bone graft placement during surgery

4 months after surgery

Post-operative photograph (Lateral view)

Result of Survey

Five dental anomalies such as gemination, fusion, missing lateral incisors, peg shaped incisors and dens in dente were studied in 1062 subjects. A total of 57 subjects were found to have maxillary lateral incisor anomalies. Details of number of subjects and gender distribution of the anomalies are given in [Table/Fig-5].

showing types of anomalies of lateral incisors and their percentage

Types of AnomalyPercentage (%)
1. Peg shaped2.82
a) Unilateral1.12
b) Bilateral1.70
2. Missing1.88
a) Unilateral1.41
b) Bilateral0.47
3. Gemination0.28
4. Fusion0.18
5. Dens in Dente0.18

Discussion

In the survey, a total of 1062 subjects were studied for dental anomalies in maxillary lateral incisors. RVGs were obtained to confirm anomalies of lateral incisors. Dental anomalies can result from many factors like a genetic predisposition, trauma, a vitamin deficit, systemic diseases and environmental causes. Although defects in certain genes are the most influential aetiological events in the prenatal period, post natal periods have also been blamed for anomalies in tooth dimensions, position, and number [2,4,5,14]. Maxillary lateral incisors vary in form more than any other tooth in the mouth, except the third molars [15].

The incidences of gemination and fusion in this study were 0.28% and 0.18% respectively. These values were lower as compared to those of other studies [5]. Traditional terminologies such as concrescence, fusion and gemination should be considered as potential embryologic causes of the anomalies and not as the exact diagnoses [6,12]. Fusion or gemination are developmental anomalies with inherently bizarre anatomies. In order to distinguish between fusion and gemination, it has been suggested that the teeth in the arch be counted, with the anomalous crown being counted as one. A full complement of teeth indicates gemination, whereas one tooth less than normal indicates fusion. This rule is compromised if a normal tooth fuses with a supernumerary tooth [13].

The incidence of peg shaped maxillary lateral incisors (2.82%) in our study was in accordance with those in other studies [1619]. It was also noted, as in other studies, that unilateral pegs were mainly present on left side of maxilla [20].

Missing maxillary lateral incisors accounted for 1.6% subjects in this study. An earlier study which was done by Pinho [7] reported a prevalence of 1.3% for such an anomaly. Nordgarden reported a prevalence of 0.9% for this anomaly in Norway [9].

The prevalence of dens in dente ranged from 0.04%–10% [21, 22]. The teeth which were most affected were permanent maxillary lateral incisors and a bilateral occurrence was not uncommon. It occurred in 43% of all cases [23,24].

Cakici et al., reported that dens in dente was detected in only maxillary lateral incisors, with no gender difference [25]. The permanent maxillary lateral incisor appeared to be the most frequently affected tooth, with the posterior teeth being less likely to be affected [26]. A primary dentition involvement was reported in another study [27].Hamasha and Al-Omari [28], in 2004, conducted 1660 full-mouth surveys and found the frequency of dens in dente to be 2.95% in patients and 0.65% in teeth.

Incidence of dens in dente was found to be 0.18% in our study and unilateral only. General features of teeth with dens in dente included peg shaped formations, incisal notching, increased labio-lingual and mesio-distal diameters, a conical morphology and the presence of an enlarged palatal cingulum or a cusp [29].

In this case report, the number of teeth was normal and a differentiation from gemination was difficult or impossible. Concerning the treatment, an exact differentiation between fusion and gemination may not be critically important.

An access preparation was done as two separate coronal entries, to preserve as much tooth structure as possible and a communication was discovered between the two pulp canals in the apical third of the tooth.

As periodontal defect involved both the central incisor and the geminated lateral incisor, an endodontic treatment and subsequently, a periodontal treatment were done. The bioactive bone graft material which was used was Perioglass, due to its easy availability and simpler application. Except for a mesial overlapping of the geminated lateral incisor on central incisor, all teeth were arranged symmetrically in the arch. In order to enhance the aesthetics, reduction of the mesiodistal size of the maxillary lateral incisor was done, which provided the required space for composite restoration.

Other common treatment alternatives for treating geminated tooth include extraction, hemisection, reshaping after the endodontic treatment and just leveling of the dental arch without any intervention.

Conclusion

A careful clinical and radiographic examination is essential to decide the fate of the tooth. Even if mid-root connections between the pulp chamber become evident, a proper multidisciplinary approach helps in treating any anomaly of the tooth.

The present case report indicates that Geminated tooth may present aesthetic and functional problems, which may require endodontic treatment, bone grafting and composite restoration. In the present study, incidences of germination, fusion and dens in dente were found to be low.

Limitations of The Study

Although panoramic radiographic examinations of individuals would have allowed more accurate data regarding other dental anomalies and morphologies, this was not feasible in the current study

Potential Conflicts of Interest: None

References

[1]Nadal-Valldaura A, Patología dentaria 1993 BarcelonaEd. Rondas:55-8.  [Google Scholar]

[2]Croll TP, Rains NJ, Chen E, Fusion and gemination in one dental arch: report of a case J Dent Child 1981 48:297-9.  [Google Scholar]

[3]Levitas TC, Gemination, fusion, twining and concrescence J Dent Child 1965 32:93-100.  [Google Scholar]

[4]Stewart RE, Prescott GH, Oral facial genetics 1976 St LouisMosby Ed:138-42.  [Google Scholar]

[5]Favalli O, Webb M, Culp J, Bilateral twinnig: report of case ASDC J Dent Child 1998 65:268-71.  [Google Scholar]

[6]Goren S, Tsoizner R, Dinbar A, Levin L, Brezniak N, Prevalence of congenitally missing teeth in Israeli recruits Refuat Hapeh Vehashinayim 2005 22:49-53.:87  [Google Scholar]

[7]Pinho T, Tavares P, Maciel P, Pollmann C, Developmental absence of maxillary lateral incisors in the Portuguese population Eur J Orthod 2005 27:443-449.  [Google Scholar]

[8]Maatouk F, Baaziz A, Ghnima S, Masmoudi F, Ghedira H, Survey on hypodontia in Sayada, Tunisia Quintessence Int 2008 39:115-120.  [Google Scholar]

[9]Nordgarden H, Jensen JL, Storhaug K, Reported prevalence of congenitally missing teeth in two Norwegian counties Community Dent Health 2002 19:258-261.  [Google Scholar]

[10]Albashaireh ZS, Khader YS, The prevalence and pattern of hypodontia of the permanent teeth and crown size and shape deformity affecting upper lateral incisors in a sample of Jordanian dental patients Community Dent Health 2006 23:239-243.  [Google Scholar]

[11]Thongudomporn U, Freer TJ, Prevalence of dental anomalies in orthodontic patients Aust Dent J 1998 43:395-398.  [Google Scholar]

[12]Calikshan MK, Traumatic gemination – Triple teeth. Survey of the literature and report of a case Endod Dent Traumatol 1992 8:130-3.  [Google Scholar]

[13]Antonio José de Azevedo, Maxillary Lateral Incisor with Two Root Canals: Fusion, Gemination or Dens invaginatus? Braz Dent J 2000 11(2):141-146.  [Google Scholar]

[14]Uslu O, Akcam MO, Evirgen S, Cebeci L, Prevalence of dental anomalies in various malocclusions Am J Orthod Dentofacial Orthop 2009 135:328-35.  [Google Scholar]

[15]Major M, Stanley Ash, Nelson J, The permanent maxillary incisors Dental Anatomy   [Google Scholar]

[16]Peck S, Peck L, Kataja M, Prevalence of tooth agenesis and peg shaped maxillary lateral incisors associated with palatally displaced canine (PDC) anomaly AJODO 1996 110:441-43.  [Google Scholar]

[17]Meskin LH, Gorlin RJ, Agenesis and peg shaped permanent maxillary lateral incisors J Dent Res 1969 27:563-73.  [Google Scholar]

[18]Alvesal L, Portin P, The inheritance pattern of missing, peg shaped and strongly mesiodistally reduced upper lateral incisors Acta Odontol Scand 1969 27:563-75.  [Google Scholar]

[19]Basdra Efthimia K, Kiopasoglou Magdalini N, Komposch Congenital teeth anomalies and malocclusion: a genetic link? EUO 2001 23:145-51.  [Google Scholar]

[20]Peck S, Peck L, Kataja M, Prevalence of tooth agenesis and peg shaped maxillary lateral incisors associated with palatally displaced canine (PDC) anomaly AJODO 1996 110:441-43.  [Google Scholar]

[21]Reddy YP, Karpagavinayagam K, Subbarao CV, Management of Dens invaginatus diagnosed by spiral computed tomography J Endod 2008 34:1138-1142.  [Google Scholar]

[22]Er K, Kustarci A, Ozan U, Tasdemir T, Non surgical endodontic treatment of Dens invaginatus in a Mandibular premolar with large Peri-radicular lesion: A case report J Endod 2007 33:322-324.  [Google Scholar]

[23]Hulsmann M, Dens invaginatus: aetiology, classification, prevalence, diagnosis and treatment considerations Int Endod J 1997 30:79-90.  [Google Scholar]

[24]Steffen H, Splieth C, Conventional treatment of dens invaginatus in maxillary lateral incisor with sinus tract: one year follow-up J Endod 2005 31:130-3.  [Google Scholar]

[25]Cakici F, Celiekoglu M, Arslan H, Topcuoglu HS, Erdogan AS, Assessment of the prevalence and characteristics of dens invaginatus in a sample of Turkish Anatolian population Med Oral Patol Oral Cir Bucal 2010 15(6):e855-8.  [Google Scholar]

[26]Conklin WW, Bilateral dens invaginatus in the mandibular incisor region Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1978 45:905-8.  [Google Scholar]

[27]Eden EK, Koca H, Sen BH, Dens invaginatus in a Primary molar ASDC Journal of Dentistry for Children 2002 69:49-53.  [Google Scholar]

[28]Hamasha AA, Al-Omari QD, Prevalence of dens invaginatus in Jordanian adults Int Endod J 2004 37:307-10.  [Google Scholar]

[29]Alani A, Dens invaginatus; a problem from the outside in Int Dent J 2009 59(6):343-8.  [Google Scholar]