t`•. Acta Med Kinki Univ •

Vol. 36, No. 1 37-40, 2011

A case study in

odontologica

estimating age based

1 findings in skeletal

on forensic

remains

Nobutaka

Department

Okusa, Hitoshi Nishio, Hiroshi Noda and Shinji

of Legal Medicine, Kinki University Faculty of

Osakasayama, Osaka, 589-8511, Japan

Tatsumi

Medicine,

Abstract

A method for estimating age based on oc-

clusal wear of the teeth and palatine suture

morphology has been widely used. This allows us

to estimating age based on macroscopic findings. However, even if the living status and jaw

growth are taken into consideration, the accu-racy of this method is not sufficient. In this

case, a marked difference was observed in esti-

mated age between two methods based on the degree of occlusal wear and palatine sutures.

To avoid this discrepancy, a number of

approaches, including radiography, a comparison

of the morphology of teeth using a study model, and data preparation employing dental charts

are necessary. Some factors, such as distortion,

growth and developmental disorders of the jaw-

bone, diet, occlusal relationship, and habits often

influence age estimation especially when the

dental attrition degree of the tooth is used.

When there is a discrepancy in the estimated

age, caution should be exercised. There is an

individual difference in the status of the syne-

chia. We observed a case that misled us into

presuming younger age. It is rare that estimated age is higher than a real age. Age estimation is

performed from both sides of dental attrition and

palatal suture in this time. This case demon-strated a large discrepancy in age estimation

between dental attrition and sutures of the

palatine bone.

Key words : forensic odontology, dental attri-

tion, age estimation, palatine suture

Introduction

In skeletal or charred remains lacking the soft

tissue, hard tissues such as the teeth, bone, nails,

and hair provide important information. In

particular, the teeth are important because the influences of external physical and chemical

factors are slight. Many methods for estimating

age from skeletal remains have been reported.

Ogata et al. evaluated part of the skull based on

radiographs and the palatine sutures, and esti-

mated the age.' Kimura et al. estimated age

based on the degree of occlusal wear by employ-

ing Takei's method for personal identification.2

Tomaru et al. estimated age based on the

degree of occlusal wear of the mandibular inci-

sors, and reported a correlation between the

occlusal wear index and age.' In our depart-

ment, we have also made an identification by

superimposition using dental films in a previous

case, as well as for suspect identification.4'5 In

this paper we report a case in which there was a

marked difference between the age estimated

based on the degree of occlusal wear and that

based on the palatal sutures of skeletal remains.

Case

In April in a previous year, a primary school

student playing in the mountains discovered a

skeletonized femur, and reported it with his

mother to the police. During a search of the

vicinity, the right femur, right tibia, mandible,

and skull were discovered. Since the sites of

discovery differed among these bones, we anal-

yzed to determine whether the bones belonged to

Received September 15, 2009 ; Accepted January 24, 2011

37

N. Okusa et al.

the same person and estimated age.

Forensic odontological findings

The autopsied cadaver had 2 mandibular and 7 maxillary remaining teeth (total, 9 teeth). The

postmortem missing teeth were the left central incisor, left lateral incisor, left canine, left first and second premolars, left first and second molars, and the right central incisor (8 teeth) in the maxilla and the left canine, left first and second premolars, and the right first and second

premolars (5 teeth) in the mandible (total, 13 teeth) (Figs. 1, 2, 3). There was a maxillary fracture with a border between the hard and soft

palates ; almost all horizontal plates of palatine bone is lacked. Alveolar bone of maxillary right

Fig. 1

• y4 , •

• , .-.;

4T

E

.. , • . .-. • • e .

sk A. ;,::.

i1 •-:-., . v , ' ' t-.,?..:1 .

1

: . . t:-tf- •-.,,

•.,

LI

Occlusal surface of maxillary dentition. Breakage is

seen in the boundary of the hard and soft palate. All

almost horizontal plate of palatine bone is lacked.

Showing missing tooth was right second molar, right

first molar, right first and second premolars, right

central incisor, left central incisor, left lateral incisor,

left canine, left first and second premolars, left first

and second molars. There is no treatment the remain-

ing teeth.

)

Fig. 2 Front of maxillary dentition

molar is lacked. And it is unknown whether the

maxillary right second molar was present. Con-

cerning the palatine sutures, since there were clear incisor sutures on the left and right sides

and the left transverse palatal suture, the age was

estimated to be about 20-30 years. However,

occlusal wear was marked in the anterior area of the mandible, and the cusps and edges had large-

ly disappeared (Figs. 3, 4). The exposure of

dentin was seen observed in zonal patterns. In addition, when the method of Takei was used, it

was calculated with 60.4 years old, suggesting an

age of more than 60 years. No treatment scars

were noted in the remaining teeth.

Discussion

In living bodies and cadavers for analysis,

worn, treated, and carious teeth are often mixed.

In this case, the degree of occlusal wear is

examined. In skeletal remains, the palatine

sutures are also examined. We found that, the

YL

%. •

r'

• 17

. -••••

Obit. Pfleidt - '

Fig. 3 Occlusal surface of mandib exposed in the front tooth.

The front tooth overlaps

Showing missing tooth w,

premolars, left canine, premolars. There is no tre

teeth.

•

Fig. 4 Front

cusp is

"jc.

of mandibular dentition. Dentin is

tps because of crowding.

as left first and second

right first and second

treatment on the remaining

if 04-

N,. yr F1

of mandibular dentition.

dental attrition.

Incisal edge and

38

A case study in estimating age based on forensic odontological findings in skeletal remains

estimated age based on the degree of occlusal wear (young age) markedly differed from that based on the palatal sutures (advanced age). The age difference was about 30 years, which may be associated with jaw growth, the ingested types of food, occlusal relationship, and habits. Among

jaw deformities and growth abnormalities, man-dibular protrusion due to maxillary hyperplasia or mandibular hyperplasia is often observed, as well as maxillary protrusion, cross bite, and open bite. Cases of maxillary undergrowth due to the

prevention of maxillary sinus enlargement by chronic sinusitis during the growth period have been reported. Thus, a more careful and detailed interpretation of findings is important. This case showed no mandibular overgrowth due to the mandible deformity. Excluding the mandibular

protrusion, the crowding of the mandibular anterior teeth could be suspected. Therefore, we speculate that insufficient growth space during infancy induced occlusal abnormality, and exces-sive tooth contact in the crowding area during mastication caused occlusal wear abnormality. However, Abe et al. classified malocclusion into

superoinferior, anteroposterior, horizontal, crowding, and spaced dental arches, and perfor-med mastication experiments using various types of food. These experiments demonstrated that it was difficult to eat many types of food with superoinferior or anteroposterior malocclusion.6 Miyatani et al. measured the mean occlusal force during mastication in patients with maloc-clusion, and reported that the patients had a lower occlusal force than normal occlusion. In addition, compared with females, males show no significant correlation between masticatory abil-ity and maxillofacial or dental arch morphol-ogy.' Therefore, mild crowding except greater number of teeth does not markedly affect the masticatory muscle strength or masticatory abil-ity.8 In this case, we speculate that the mas-ticatory muscle or ability had not been affected, but excessive occlusal wear due to crowding in addition to physiological occlusal wear was the reason for the estimation of more than 60 years of age.

Concerning the palatal sutures, the closure state markedly varies among individuals, and the age estimated based on sutures is lower than the chronological age. As Sakaue et al. showed, estimation of the minimal age based on macro-scopic findings alone, tends to cause errors even if attention is paid to the occlusal relationship.9

In addition to macroscopic findings, radiogra-

phy is sometimes used. X-ray films provide information on the degree of tooth calcification,

the presence or absence of the pulp, and treat-

ment states. The possibility of locating antemor-

tem films is high, and these films can be useful

data for comparison. In addition, the morphol-

ogy and state of crowns can be evaluated in a

study model, and dental charts can be produced.

Therefore, radiography in addition to macro-

scopic findings provides data to support dental

charts and is also useful for comparison with a

study model. These methods are indispensable

for the accurate estimation of age and subsequent

rapid identification. This rare case, which

showed a large discrepancy in age estimation

between dental attrition and sutures of the

palatine bone, led us to reconsider not only the accuracy of the usual estimation methods but

also various factors of aging from anatomi-

physiological findings and the roentgenological

point of view. In conclusion, it is necessary to combine several findings derived from alveolar

bone degree without depending on one estimate

alone both sides of the dental attrition degree

and the suture to improve the reliability of the

age estimation. Forensic age estimation from

skeletal remains is still important. We should

take occlusal growth into consideration if the

estimated age shows inconsistency.

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39

N. Okusa et al.

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