supernumerary teeth are defined as teeth that exceed the normal dental formula , regardless of their location and morphology . such teeth are relatively common , as reflected by the many studies published in the literature.[13 ] according to literature , the prevalence of supernumerary teeth in permanent dentition is 1 - 14% . around 90 - 98% of supernumerary teeth occur in maxilla , and 90% of these are restricted to pre - maxilla . the most common supernumerary teeth , listed in order of frequency , are the mesiodens , maxillary fourth molars , maxillary paramolars , mandibular premolars , maxillary lateral incisors , mandibular fourth molars , and maxillary premolars . supernumerary teeth are often associated with gardner syndrome , crouzon 's disease , fabry - anderson syndrome , ehler - danlos syndrome , hallermann - steriff syndrome , facial fissures or cleidocranial dysplasia . although multiple supernumerary teeth are very common , the prevalence of 5 or more supernumerary teeth is reported to be less than 1% . many theories have been put forward to explain the anomaly based on developmental interference and heredity . the aim of this paper is to document a rare case of familial occurrence of multiple supernumerary teeth occurring as an isolated non - syndromic trait . we also present the importance of genetic factors as the possible cause of supernumerary teeth . a 28-year - old male reported to our opd with chief complaint of pain in mandibular left first molar . the patient also gave familial history of presence of extra teeth in his grandfather , father , and younger brother . patient also showed presence of 3 supernumerary teeth ; 2 in maxilla , between maxillary right canine and premolar and in place of maxillary left canine and 1 in mandible , in place of extracted right first molar [ figure 1a and b ] . an intra - oral periapical radiograph with respect of mandibular left first molar revealed presence of premolar like tooth in the periapical region of mandibular left second premolar . thus , the patient was subjected to panoramic radiograph , which revealed total of 8 supernumerary teeth along with impacted maxillary left canine [ figure 2 ] . patient was educated about the presence of impacted supernumeraries and then referred to department of conservative dentistry for further treatment . clinical photograph of ( a ) maxillary ; ( b ) mandibular arches showing supernumerary teeth in patient opg of patient showing total 8 supernumerary teeth resembling premolars ( arrows ) and impacted maxillary left canine on the next visit , his father and younger brother were also asked to report for clinical examination . patient 's grandfather was dead , hence we could not get any clinical records , except for the familial history of extra teeth . the father , 60-year - old male , on clinical examination , showed presence of 4 supernumerary teeth ; 1 in maxilla and 3 in mandible . four supernumerary teeth were present in mandible and 2 in maxilla [ figure 3 ] . opg of father showing 5 supernumerary teeth ( arrows ) the younger brother , who was 20-year - old , showed presence of mesiodens clinically . the intra - oral periapical radiograph showed presence of second inverted mesiodens , which was impacted [ figure 4 ] . ( a ) clinical photograph of brother showing mesiodens ; ( b ) iopa showing impacted inverted mesiodens all 3 patients were investigated for presence of any other anomaly , but no significant findings were noted . the dichotomy theory of tooth germs suggests that a tooth bud splits into 2 parts , resulting in 2 teeth of equal or unequal size . another theory suggests that supernumerary teeth are formed as a result of local , independent , or conditioned hyperactivity of dental lamina . a small number of supernumerary teeth may be a common developmental dental anomaly , while multiple supernumerary teeth usually have a genetic component and they are sometimes thought to represent a partial third dentition in humans . nislander and sujaku , in 1963 , proposed that this trait of supernumerary teeth may be associated with autosomal recessive gene with lesser penetrance in females . this was later supported by gallas and garcia in 1999 . according to one theory , mutant genes give rise to supernumerary teeth and this is supported by the finding of increased supernumeraries in patients with facial and dental anomalies such as cleft lip and palate . the development of bilateral supernumeraries also suggests that they may be controlled by a mutant gene . the importance of heredity is emphasized by the increased number of supernumerary teeth found in relatives of those affected . while an autosomal - dominant inheritance with incomplete penetrance has been suggested , the increased incidence in males suggests possibility of sex - linked heredity as stated by bruning et al . as in our cases , this trait was seen in 3 generations of males , which indicates some role of sex - linked heredity [ figure 5 ] . pedigree chart showing sex - linked inheritance of non - syndromic hyperdontia despite advances in the knowledge of tooth morphogenesis and differentiation , relatively little is known about the etiology and molecular mechanisms underlying supernumerary tooth formation . genetic studies mapped cleidocranial dysplasia to chromosomal 6p21 , and heterozygous mutations ( haplo insufficiency ) in runx2 ( cbfa1 ) gene have been identified to be responsible for the development of ccd . apc is located on chromosome 5q21-q22 , and it can be alternatively spliced in multiple coding and non - coding regions . it has also been suggested that inactivation of apc or forced activation of wnt/ ( catenin signaling ) results in multiple supernumerary tooth formation in both humans and in mice , but the key genes in these pathways are not very clear . notably , adult oral tissues , especially young adult tissues , are still responsive to loss of apc or activation of wnt/ ( catenin signaling ) , and are able to form new teeth . homozygous region on chromosome 16q12.2 is thought to be responsible for development of supernumerary incisors by el - toum et al . better understanding of the role of wnt/-catenion , apc , 16q12.2 , and runx2 in the formation of supernumerary teeth , together with detailed analysis of successional tooth formation in various model systems , will allow us to identify the exact genes responsible for supernumerary tooth formation . the occurrence of multiple supernumerary teeth without any associated syndrome has been reported frequently in literature ; however , familial occurrence of non - syndromal multiple supernumerary teeth are very rare . a detailed review of the literature pertaining to case reports of familial non - syndromal supernumerary teeth is given in table 1 . review of literature of case reports showing familial non - syndromic hyperdontia it is seen that most of these case reports have documented presence of non - syndromal supernumerary teeth in 2 generations of the family . however , we report a case where this condition was seen in 3 generations of the family . it is also seen that in most of the cases , the supernumeraries present were mesiodens . to conclude , there may be a definitive group of genes , which plays role in formation of supernumerary teeth . research in recent years has taught us much about the molecular mechanisms underlying tooth morphogenesis and differentiation . however , relatively little is known about the initiation of tooth formation , the genetic control of successional teeth , as well as the mechanisms causing supernumerary tooth formation . further research in stem cell biology and tissue engineering will help us to know the exact etiology of supernumerary tooth formation .
presence of supernumerary teeth is well - recognized clinical phenomenon . 
 however , it is uncommon to find multiple supernumeraries in individuals with no other associated disease or syndrome . 
 presence of multiple supernumerary teeth is thought to have genetic component . 
 we report a rare case where multiple supernumerary teeth were seen without presence of any other syndrome in 3 generations ; father , son , and two grandsons . 
 we also present a review of similar cases published in literature till date . 
 the role of genetics in development of supernumerary teeth is highlighted .