21 Dental Anthropology 2021 │ Volume 34│ Issue 02 The Prevalence and Possible Causes of Third Molar Agenesis in Post-Medieval Chichester Devyn Caldwell 1* 1 No affiliation Third molars are the last permanent tooth to devel- op, the most variable in size and morphology, and are also the most commonly congenitally absent tooth. According to Sujon et al. (2016), approxi- mately 50% of modern (20th century onwards) hu- man third molars are anomalous, either unerupted, partially erupted or absent. Congenital absence is known as dental agenesis, which results from a developmental anomaly in the dental epithelium or the underlying mesenchyme (Bhutta et al., 2014). Grewal’s (1962) analysis of agenesis in the third molars of mice revealed that congenitally absent teeth begin as tooth germs but growth formation ceases at or before the cap stage of development, at which point the tooth germ resorbs. It may occur unilaterally, bilaterally, in combinations of three teeth, or completely, with all four absent. In their meta-analysis of modern data, Carter & Worthington (2015) found that 22.63% of people worldwide have some degree of third mo- lar agenesis. The samples included in their analysis were gathered from various ethnicities and socio- economic groups, with prevalence ranging from 5.32% - 56.0%. The exact etiology of third molar agenesis is un- known, but a genetic component is well estab- lished (Carter & Worthington, 2015; Frazier- Bowers et al., 2002), and it is thought that delayed growth or a lack of space in the jaw may result in epigenetic absence (Anderson & Popovich, 1981; Kajii et al., 2004; Suri et al., 2004). Disease and nu- trition have also been shown to affect the eruption and formation of third molars (Anderson & Popo- vich, 1981; Garn et al., 1961; Suri et al., 2004), add- ing to the already complex etiology of this trait. Grüneberg’s (1951) experiments with mice indicate that agenesis is the phenotypic result of the ex- treme end of a size continuum. Mice with absent third molars more often displayed small and varia- ble remaining third molars, and as the dental lami- na became smaller, the more likely growth and tooth formation were to cease development and resorb. It has frequently been reported that third molar agenesis occurs more often in modern populations than in the past (Alam et al., 2014; Kajii et al., 2004), ABSTRACT Third molar agenesis is a dental anomaly that occurs in approximately 25% of people worldwide and results in the complete absence of one or more of the third molars. A rise in the preva- lence of congenitally absent third molars has been noted in modern clinical data, and it has been pro- posed as an evolutionary step in the dental reduction of the human dentition. Whilst research has been conducted in extant cohorts, relatively little has been published on third molar agenesis in archaeologi- cal assemblages. A post-medieval assemblage (AD 1550-1850), from Chichester, United Kingdom, was visually and radiographically analyzed to determine the prevalence of this anomaly. Mesiodistal and buccolingual measurements were taken on retained third molars to determine if there was an associa- tion between agenesis and reduced tooth size. Prevalence of agenesis was found to be comparatively high (42.7%) relative to contemporary and modern European samples, and tooth size reduction was documented. Consequently, it can be said that high rates of third molar agenesis are not simply a mod- ern clinical phenomenon, as many prevalence rates in recent populations are lower. Temporal and re- gional patterns are, therefore, unclear. In order to better understand the trajectory and evolution of this anomaly, more archaeological assemblages ought to be examined. *Correspondence to: Devyn Caldwell No current affiliation E-mail: dmcaldwe@ualberta.ca Keywords: Dental Anomalies, Hypodontia, Dental Reduction, Post-Medieval 22 Dental Anthropology 2021 │ Volume 34│ Issue 02 with some claiming the third molar is likely to dis- appear from the human dentition altogether (Raloti et al., 2013). A general reduction in tooth size has taken place throughout hominid evolution, with a rapid reduction in size occurring in the Upper Pal- aeolithic (50,000 – 10,000 YA) and again in the ear- ly Holocene (10,000 - 8,000 YA) (Hillson, 2005). While the impetus behind these changes is unclear, many associate the diminution of teeth with the atrophy of the masticatory complex due to increas- ingly soft diets, advancement of food processing techniques, and the diminished use of the mouth as a tool (Brace et al., 1987; Carlson & Van Gerven, 1977). The agriculturalization that took hold in the early Holocene is thought to have furthered this trend in dental reduction, leading to what may be a further evolutionary step in dental reduction, the congenital loss of the third molar (Sengupta et al., 1999). In this study, the past prevalence of third molar agenesis is examined in a post-medieval assem- blage from Chichester, providing new insights into patterns in agenesis and the role of dental size reduction and its occurrence. This investigation will also test whether this anomaly represents a recent secular trend and will add to our limited understanding of third molar agenesis in archaeo- logical assemblages. Materials The skeletal assemblage under analysis comes from The Litten cemetery at Eastgate Square in Chichester, West Sussex. Chichester has a long his- tory of occupation, with evidence of Roman defen- sive ditches found at The Litten cemetery (Hart, 2012), and continuous settlements recorded from the Anglo-Saxon period onwards (Dhaliwal et al., 2019). In the later medieval period (14th century), Chichester flourished as one of the more important ports in the country, with dominance over the wool trade and a strong agricultural economy (Hart, 2012). A grain-based economy continued in the post-medieval period (1550-1850), although the town’s import declined as the wool trade waned. Chichester also appears to have experienced a pop- ulation surge between 1670-1801, with the number of inhabitants doubling from 2,400 to 4,752 due to increasing trade with London and other domestic markets (Dhaliwal et al., 2019). This assemblage was excavated from a cemetery that seems to have been established in the 12th century with the con- struction of the chapel and altar of St. Michael, which are no longer standing. Interment officially ceased in 1859, although family plots remained active until the end of the 19th century (Hart, 2012). The vast majority (66%) of human remains recov- ered date to the post-medieval period and repre- sent a range of social strata, with the bulk of indi- viduals (1,365), both from the medieval and post- medieval periods, buried in the simple shroud style (Rando, 2016). In the present study, only post- medieval skeletons were analyzed for third molar agenesis. Excavation of the site began in advance of its redevelopment, with 93 burials excavated by Pre- Construct Archaeology Ltd. (PCA) in 2005 and 2006, and the remaining 1637 skeletons excavated by Archaeology South-East (ASE) between August of 2011 and January of 2012 (Hart, 2012). Four hun- dred and thirty skeletons from these excavations that have been retained for analysis at the Univer- sity College London Institute of Archaeology due to high preservation levels or presence of patholog- ical conditions. Of these skeletons, 311 matched the preservation levels required (alveolar bone and dentition present) to warrant examination and only 116 had a minimal level of antemortem tooth loss that allowed for inclusion in this study. Of these 116 skeletons, 89 had complete dentitions without any data missing. The remaining skeletons had missing data in either one (n=18) or two (n=9) of the dental quadrants. These skeletons were incor- porated into the analysis when the lack of data did not affect the results (see below). In total, 46 males, 36 females and 34 skeletons of indeterminate sex were analyzed, comprising 83 adults and 33 subadults. Methods Selection, Visual Assessment, Aging and Sex Estima- tion Skeletons were carefully selected according to a set of criteria designed to minimize the effects of ante- mortem tooth loss. Skeletons with fewer than four teeth lost antemortem were included in the analy- sis. In addition, only skeletons of a maximum age of a pubic symphysis phase 4 (Brooks & Suchey, 1990) and a auricular surface phase 4 (Lovejoy et al., 1985) were incorporated in order to mitigate a greater risk for antemortem tooth loss with increas- ing age. The age at which third molars initiate crown formation varies more than any other tooth (AlQahtani et al., 2010). AlQahtani et al. (2010) re- ported a median dental age of 8.5 years for the ini- tiation of crown development, and Ubelaker (1989) provides a dental age of 10 years +/- 30 months for the initiation of crown mineralisation in both the maxillary and mandibular third molars. In this 23 Dental Anthropology 2021 │ Volume 34│ Issue 02 study, only subadults with a minimum dental age of 12.5 years were included, following the dental age categories established by AlQahtani et al. (2010). According to Garn et al. (1963), 99% of third molars begin their cusp mineralisation by the age of 14 years. However, due to the relatively small number of individuals that fit the criteria for analy- sis in this assemblage, the dental development stage of 12.5 years, defined by AlQahtani et al. (2010), was selected as a minimum in order to max- imize the available data. Mandibles and maxillae were visually observed for the presence or absence of third molars using the following criteria to determine a lack of agene- sis: The tooth is in the alveolus. The tooth was lost post-mortem, with a well- defined alveolus present. The tooth was lost antemortem but the alveo- lus is still in the process of resorbing, and no other pathological or taphonomic pro- cess could be responsible for the feature. The second molar in the particular quadrant has an identifiable distal approximal wear facet (indicating it had once been in contact with a third molar). An unerupted or impacted third molar is visi- ble through radiographic analysis. Third molar agenesis was diagnosed based on the absence of these criteria. If the maxillae or man- dible met these requirements it was x-rayed to en- sure that the third molar was not impacted, devel- oping within the crypt, or had failed to erupt. If radiographic analysis did not reveal a third molar it was therefore determined to be congenitally ab- sent. Impaction was assessed based on abnormal angulation of the tooth in the alveolus or crypt (after Raloti et al., 2013). Sex determination was used to examine differ- ences in size or agenesis prevalence. This was based on a combined assessment of pelvic morpho- logical traits (after Phenice, 1969), including the greater sciatic notch and composite arch (after Bruzek, 2002), as well as measurements of the proximal humeral and femoral heads (maximum diameters after Bass, 1995) and an assessment of the sexually dimorphic features of the skull (after Ubelaker, 1989). The latter two methods were only employed if the features of the pelvis were slightly ambiguous, or if the pelvic bones were missing or too poorly preserved. The dimorphic traits of the pelvis are generally regarded to be more reliable indicators of sex than features of the skull (Bruzek, 2002). The skeletons were assigned sex of male, possible male, indeterminate, possible female, and female. However, due to the small size of the sam- ple possible males and possible females were col- lated with the respective sex. Measurements Measurements of third molars were taken in ac- cordance with the cervical method developed by Hillson et al. (2005) using specialized Paleo-Tech calipers (also developed by Hillson and colleagues, 2005). Cervical measurements are usually not af- fected by the level of crown wear, and as individu- als with an advanced age were not included, tooth wear on third molars was generally not an issue. Individuals with carious lesions affecting the crown could also be included. Mesiodistal measurements were taken by plac- ing the tips of the calipers on the mesial and distal enamel, just occlusal to the cervico-enamel junction (CEJ) and at the midpoint between the buccal and lingual sides of the tooth (see Hillson et al., 2005). Buccolingual measurements were also taken on the buccal and lingual surface at the midpoint of the enamel, slightly occlusal of the CEJ, between the mesial and distal surfaces of the tooth. It is im- portant to note that these measurements were tak- en at the midpoints and are not maximum meas- urements, however, if an enamel extension was present at the midpoint, the tip of the caliper was placed at whichever side of the extension provided the maximum measurement for the midpoint, fol- lowing Hillson et al. (2005). The tips of the calipers that meet end-to-end were used with loose teeth and for the buccolingual measurements of teeth in the alveoli whenever possible. The caliper tips that meet at an angle were most useful for the mesi- odistal measurements of teeth fixed in alveoli, and for the upper third molars, this measurement was approached lingually as these teeth tend to taper lingually, thereby ensuring a precise measurement. Analysis Inter- and intraobserver error tests were performed to ensure reproducibility and accuracy of results. Third molars, especially those in the upper denti- tion, have a variable morphology and can be diffi- cult to measure due to their irregular and oblong crown morphology (Hillson et al., 2005). However, by ensuring the measurements are taken at the midpoint on the CEJ through careful and methodi- cal application of technique, it is possible to achieve consistent results. Two observers unfamil- iar with measurement technique of Hillson et al. (2005) took mesiodistal and buccolingual measure- 24 Dental Anthropology 2021 │ Volume 34│ Issue 02 ments on the same set of ten third molars (five up- per and five lower) following the system described above. The values were then compared using SPSS 21 software to determine mean difference and 95% confidence interval (CI). The buccolingual meas- urements with Observer 2 differed by as much as 0.5 mm, with one measurement revealing a 0.88 mm difference. However, the measurements of Observer 1 closely resembled those of the research- er and therefore these differences were not ex- plored further. In addition, Observer 1 frequently reported slightly lower measurements than those of the researcher, most probably due to measure- ments taken on the CEJ or on the root surface, ra- ther than on the enamel slightly occlusal to the CEJ. Intra-observer tests for mesiodistal measure- ments (MD=-0.098, SD=0.13481) remained close to ±0.2 mm, a range ideal for tooth measurements, but the range for buccolingual measurements was slightly higher (MD=0.027, SD=0.21103). To correct for this, a larger sample size should be used in fu- ture studies in order to determine if the degree of error is acceptable. SPSS 21 Statistics software was used to assess the prevalence of third molar agenesis in the Chichester assemblage and analyze patterns within the sample. The data were divided into three groups: no data missing, one quadrant missing, and two quadrants missing. It is ideal to collect data on complete remains, but information was recorded on all three groups in order to gain as much data as possible. T-tests were performed to determine whether sizes differences exist in the mesiodistal and bucco- lingual measurements of third molars between those with and without third molar agenesis. Dif- ference in sizes between males and females were also compared statistically to determine the impact of sexual dimorphism on the results. Following this test, males and females were analyzed sepa- rately for size differences in third molars. T-tests were also used to determine if significant differ- ences in size existed between the various distribu- tions and patterns of third molar agenesis. Results The total prevalence of third molar agenesis in adult and subadult skeletons in the Chichester co- hort with data present for all dental quadrants is 42.7% (n=38/89). When incorporating those with data missing from one quadrant the prevalence falls to 40.2% (n=43/107) and is slightly higher when including those with missing data in two quadrants at 41.4% (n=48/116) (Table 1). Subadults with complete data yielded a prevalence of 45.8% (n=11/24), and this remained consistent at 45.5% Agenesis N Percent 95% CI Skeletons with no missing data Absent 51 57.3 ± 10.28 Present 38 42.7 ± 10.28 Total 89 100 Including those with data missing from one dental quadrant* Absent 64 59.8 ± 9.29 Present 43 40.2 ± 9.29 Total 107 100 Including those with data missing from one and two dental quadrants* Absent 68 58.6 ± 8.96 Present 48 41.4 ± 8.96 Total 116 100 Table 1. Agenesis prevalence recorded for all skeletons, separated into groups defined on the inclusion of missing data. Agenesis N Percent 95% CI Skeletons with no missing data Absent 13 54.2 ± 19.93 Present 11 45.8 ± 19.93 Total 24 100 Including those with data missing from one dental quadrant Absent 17 56.7 ± 17.73 Present 13 43.3 ± 17.73 Total 30 100 Including those with data missing from one and two dental quadrants Absent 18 58.6 ± 17.60 Present 15 45.5 ± 17.60 Total 33 100 Table 2. Agenesis prevalence recorded for subadult skeletons, separated into groups defined on the inclusion of missing data. *Due to the small number of individuals in the assemblage, the inclusion of individuals with data missing was explored. No significant differences were found between prevalence in any of the groups, and it is therefore acceptable to use individuals with data missing as representative of the assemblage. 25 Dental Anthropology 2021 │ Volume 34│ Issue 02 (n=15/33) when subadult individuals with data missing were included (Table 2). Subadult preva- lence is higher, but not significantly greater, χ2 (1, n=89) = 0.13, p = 0.72, than the 41.5% preva- lence among adults with complete data in this as- semblage (n=27/65) (Table 3). When adults with one (n=30/77) and two (n=33/83) dental quadrants of data missing were included, this lowered the prevalence of agenesis to 39.0% and 39.8%, respec- tively, although the difference between adult and subadult prevalence remained statistically non- significant, χ2 (1, n=107) = 0.17, p = 0.68, and χ2 (1, n=116) = 0.32, p = 0.57. Males in this assemblage show a 38.9% preva- lence of agenesis (n=14/36), whereas females ex- press a prevalence of 39.3% of third molar agenesis (n=11/28). Third molar agenesis in the maxilla was less common than third molar agenesis in the mandible, and the right side was more frequently affected by agenesis than the left (Table 4). The number of teeth missing followed a pattern in fre- quency of two, one, three, four, with agenesis of two molars occurring almost twice as frequent as one, and the absence of three and four was less Agenesis N Percent 95% CI Skeletons with no missing data Absent 38 58.5 ± 11.98 Present 27 41.5 ± 11.98 Total 65 100 Including those with data miss- ing from one dental quadrant Absent 47 61.0 ± 10.89 Present 30 39.0 ± 10.89 Total 77 100 Including those with data miss- ing from one and two dental quadrants Absent 50 60.2 ± 10.53 Present 33 39.8 ± 10.53 Total 83 100 Table 3. Agenesis prevalence recorded for adult skeletons, separated into groups defined on the inclusion of missing data. Males Females Total (Including Indeterminate Sex) Right Left Total Right Left Total Right Left Total Maxilla 9 6 15 6 4 10 21 17 38 (46%) Mandible 7 8 15 7 7 14 23 22 45 (54%) Total 16 14 30 13 11 24 44 39 83 Table 4. The distribution of third molar agenesis between males, females, and the total assemblage, on the right and left sides and in the maxilla and mandible. Figure 1. The frequencies in the number of third molars congenitally absent in individuals with agenesis and all data present in this assemblage. Two third molars absent occur much more often in this assemblage than one third molar absent, and three and four are least common. 26 Dental Anthropology 2021 │ Volume 34│ Issue 02 common (Figure 1). Bilateral agenesis (Figure 2) occurred more frequently than unilateral, or both unilateral and bilateral agenesis in one dentition, for example if unilateral agenesis occurred in the upper arcade and bilateral agenesis in the lower arcade (Table 5). Significant differences in tooth size were found between male and female third molars in this as- semblage. The buccolingual dimensions of the ULM3, URM3, LRM3 and the mesiodistal dimen- sions of URM3, LLM3 and LRM3 (Table 6) pro- duced significant differences between sexes, with mean male measurements being larger. Two significant differences (p < 0.05) were found in the buccolingual dimensions of the ULM3 (p = 0.048, 95% CI [-1.04, -.005]) and URM3 (p = 0.009, 95% CI [-1.15, -.17]), in which those indi- viduals with agenesis showed reduced dimensions compared to individuals without third molar agen- esis (Table 7). When separated by sex, only males with agenesis retained a significant reduction in size (p < 0.05) in the ULM3 buccolingual dimension (Table 8). Third molars visibly reduced in size and complexity, known as “vestigial third molars” as described by Nanda (1954), were noted in seven skeletons that also displayed third molar agenesis. T-tests did not reveal significant differences in the mesiodistal or buccolingual dimensions of third molars between individuals with one or three third molars congenitally absent, bilateral maxil- lary or mandibular agenesis, and those without agenesis. There was a significant difference (p > 0.05) in the mesiodistal dimensions of LLM3 in those with three third molars missing and bilateral maxillary agenesis; however, the 95% CI for those with agenesis of three molars was not significant due to the small number of individuals with the measurements (Table 9). Discussion To date, the literature on third molar agenesis in past assemblages is extremely sparse, and while it is at times included in the skeletal analysis (Iseri & Uzel, 1993; Munson, 2001; Öhrström et al., 2015; Lieverse et al., 2014), it is not extensively discussed. Only a few studies (Castro, 1989; Henriksson et al., 2019; Nelsen et al., 2001; Sengupta et al., 1999; Vo- danović, 2012) record assemblage-wide data on third molar agenesis as part of broader analyses of dental anomalies. In this study, 116 post-medieval skeletons from The Litten Cemetery in Chichester were analyzed to determine the past prevalence of third molar agenesis and to test any association with reduction in molar size. 42.7% of adult and subadult skele- tons with complete data (n=51/89) demonstrated M3 agenesis. When those with one or two dental quadrants missing are included (to test a larger dataset), this frequency lowered to 40.2% and 41.4%, respectively (see Table 1). While this differ- ence may be attributed to the inclusion of more data, it is also possible that the difference is the result of missing data resulting in undiagnosed agenesis. However, the difference is not statistical- ly significant, and it is therefore acceptable to in- clude the individuals with incomplete data as members of the assemblage. The inclusion of data groups with missing dental quadrants was also explored for subadults and adults separately, and no significant differences in the prevalence of agenesis was found between these groups. In this assemblage, 45.5% (n=18/33) of subadults have third molar agenesis. This indicates that ante- mortem tooth loss is less likely to have an effect on the prevalence of agenesis as subadults are ex- posed for less time to the pathological processes Figure 2. A mandible demonstrating bilateral agenesis of the third molars from the Chichester assemblage (Author’s own 2017). n Percent Unilateral 11 28.9 Bilateral 20 52.6 Both 7 18.4 Table 5. Laterality of third molar agenesis in the Chich- ester assemblage. Bilateral agenesis occurs in over half of those with third molar agenesis. 27 Dental Anthropology 2021 │ Volume 34│ Issue 02 Sex n Mean Sig. (2- tailed)* Mean Difference Std. Error Difference 95% Confidence Inter- val of the Difference Lower Upper ULM3 Buccolingual Male 24 10.3717 0.005 0.82461 0.27705 0.26423 1.38499 Female 17 9.5471 URM3 Buccolingual Male 17 10.2271 0.054 0.51984 0.26034 -0.00984 1.04951 Female 18 9.7072 LLM3 Buccolingual Male 23 8.647 0.064 0.55629 0.29138 -0.03465 1.14723 Female 15 8.0907 LRM3 Buccolingual Male 24 8.5521 0.015 0.60708 0.23828 0.1255 1.08866 Female 18 7.945 ULM3 Mesiodistal Male 24 6.7313 0.164 0.27596 0.19442 -0.1173 0.66921 Female 17 6.4553 URM3 Mesiodistal Male 17 6.7335 0.028 0.49353 0.2147 0.05672 0.93034 Female 18 6.24 LLM3 Mesiodistal Male 24 8.8667 0.024 0.57042 0.24262 0.07926 1.06157 Female 16 8.2963 LRM3 Mesiodistal Male 24 9.0913 0.017 0.64958 0.26195 0.12016 1.17901 Female 18 8.4417 Table 6. Differences between the size of male and female third molars. Male third molars are significantly larger than female third molars (in bold). Agenesis n Mean Sig. (2- tailed)* Mean Difference Std. Error Difference 95% Confidence Interval of the Difference Lower Upper ULM3 Buccolingual Present 14 9.6021 0.048 -0.52331 0.25882 -1.04179 -0.00484 Absent 44 10.1255 URM3 Buccolingual Present 14 9.5486 0.009 -0.66248 0.24341 -1.15138 -0.17358 Absent 38 10.2111 LLM3 Buccolingual Present 9 8.0111 0.129 -0.46178 0.29957 -1.06291 0.13935 Absent 45 8.4729 LRM3 Buccolingual Present 10 8.1040 0.461 -0.20722 0.279 -0.76591 0.35146 Absent 49 8.3112 ULM3 Mesiodistal Present 14 6.4464 0.2 -0.25221 0.19454 -0.64191 0.1375 Absent 44 6.6986 URM3 Mesiodistal Present 14 6.6021 0.817 -0.05207 0.22443 -0.50285 0.39872 Absent 38 6.6542 LLM3 Mesiodistal Present 9 8.3522 0.232 -0.31674 0.26231 -0.84242 0.20895 Absent 48 8.6690 LRM3 Mesiodistal Present 10 8.8960 0.68 0.12682 0.30555 -0.48505 0.73868 Absent 49 8.7692 Table 7. T-test results of size comparison between those with M3 agenesis and those without M3 agenesis. *Significant differences found in the ULM3 buccolingual and the URM3 buccolingual measurements (in bold). All skeletons were used in order to increase the number of individuals analyzed. Separate analyses revealed similar results and therefore data groups were collated. Equal variances are assumed. 28 Dental Anthropology 2021 │ Volume 34│ Issue 02 Agenesis n Mean Sig. (2- tailed) Mean Difference Std. Error Difference 95% Confidence Inter- val of the Difference Lower Upper ULM3 Buccolingual Present 5 8.7980 0.022 -1.15123 0.45548 -2.11680 -0.18566 Absent 13 9.9492 URM3 Buccolingual Present 7 9.2929 0.118 -.62631 0.38043 -1.42894 0.17632 Absent 12 9.9192 LLM3 Buccolingual Present 2 7.4500 0.209 -.81200 0.61855 -2.13040 0.50640 Absent 15 8.2620 LRM3 Buccolingual Present 3 8.0800 0.697 0.16118 0.40688 -0.69365 1.01600 Absent 17 7.9188 ULM3 Mesiodistal Present 5 6.3560 0.779 -0.11785 0.41199 -0.99123 0.75554 Absent 13 6.4738 URM3 Mesiodistal Present 7 6.1900 0.882 -0.05417 0.35974 -.081315 0.70481 Absent 12 6.2442 LLM3 Mesiodistal Present 2 8.3800 0.854 0.08313 0.44391 -0.85792 1.02417 Absent 16 8.2969 LRM3 Mesiodistal Present 3 8.8800 0.438 0.41118 0.51857 -0.67831 1.50066 Absent 17 8.4688 Table 8. T-test results of size comparison between males with M3 agenesis and males without M3 agenesis. Only the ULM3 shows significant differences in size (in bold). Equal variances are assumed. Measurement Type n Mean Sig. (2- tailed) Mean Difference 95% Confidence Inter- val of the Difference Lower Upper LLM3 Mesiodistal Bilateral Maxillary Agenesis 4 8.905 0.02 1.15 0.29535 2. 00465 Agenesis of Three Teeth 2 7.755 0.02 1.15 -3.3154 0.7904 LLM3 Buccolingual Bilateral Maxillary Agenesis 4 8.57 0.149 0.795 -0.44409 2.03409 Agenesis of Three Teeth 2 7.775 0.149 0.795 -1.77698 2.12698 LRM3 Mesiodistal Bilateral Maxillary Agenesis 4 8.907 5 0.145 -1.2625 -3.3154 0.7904 Agenesis of Three Teeth 1 10.17 0.145 -1.2625 -0.44409 2.03409 LRM3 Buccolingual Bilateral Maxillary Agenesis 4 8.575 0.794 0.175 -1.77698 2.12698 Agenesis of Three Teeth 1 8.4 0.794 0.175 -0.44409 2.03409 Table 9. Example of analysis in size patterns between the distributions of agenesis in the dentition. The small number of individuals with measurements available for each tooth dimension in each group made it impossible to determine significant relationships be- tween the variables. 29 Dental Anthropology 2021 │ Volume 34│ Issue 02 that stimulate antemortem tooth loss. The prevalence of 42.7% in this assemblage is significantly higher (p < .05) than those reported for British clinical samples in which data was gathered from dental radiographs. Shinn (1976) found that 12.72% (n=318/2500) of patients re- ferred to an orthodontic hospital in Southampton had third molar agenesis, whereas Gravely (1965) found that 25.9% (n=21/81) of patients exhibited third molar agenesis. From the Bristol Dental Hos- pital, Sengupta et al. (1999) found that 22% (n=22/100) of people were found to have third mo- lar agenesis. In other groups of European ancestry prevalences of 28.2% (Krekeler et al., 1974), 28.5% (Trondle, 1973), 29.3% (Weise & Bruntsch, 1965) and 33% (Elomaa & Elomaa, 1973) have been re- ported. In European-derived North American samples, frequencies of 25.7% (Keene, 1965), 22.3% (Thompson et al., 1974) and 31.5% (Harris & Clark, 2008) have been observed. The frequency of M3 agenesis found in this study is comparable to the 44% prevalence reported in extant Asian and Na- tive North American populations (Carter & Worthington, 2015). Clinical accounts of third mo- lar agenesis in Asia appear to be higher than most European groups: 30% in a Malaysian Malay popu- lation (Alam et al., 2014), 33% in a Chinese Malay- sian population (Alam et al., 2014), 50% in Nepal (Upadhyaya et al., 2012), 32.3% in Japan (Endo et al., 2015) and 38.4% in Bangladesh (Sujon et al., 1984). Ren & Kumar (2014) also report a preva- lence of agenesis of 48% of males and 64% of fe- males from southern India, but only 25 individuals of each sex were analyzed, and therefore the small sample size may not be representative. Prevalence rates in archaeological assemblages are also extremely variable, in addition to the way in which data are collected and reported. In the present study, third molar agenesis is reported per individual, but due to preservation requirements or research questions, other studies separate data by the upper and lower dental arcade, the dental quadrant, or as an overall tooth count, making sta- tistical comparisons with such research difficult. The Late Antique (n=117) and early medieval (n=245) assemblages from eastern Croatia exam- ined by Vodanović (2012) produced third molar agenesis prevalences of 30.21% and 15.64% respec- tively, with the change in frequency attributed to population replacement in the early medieval peri- od. Radiographic assessment was not performed, and the frequency of third molar agenesis is pre- sented separately for the upper and lower arcade, rather than for each individual. Without radio- graphic assessment unerupted third molars may be mistaken for agenesis, creating the potential for a slightly higher prevalence than may otherwise be reported. Castro (1989) found comparatively low preva- lences of 7.6% in Gran Canaria, 10.8% in Tenerife, and 9.4% in the Canary Islands in archaeological assemblages dating from the 1st century B.C. – 14th century A.D. In this study, a total of 1,790 maxillae and 1,920 mandibles were visually analyzed for third molar agenesis. Due to the majority of mandi- bles having been separated from their skulls, Cas- tro (1989) calculated the frequency of agenesis sep- arately between the upper and lower dental arches. The author divided the total number of congenital- ly absent third molars by the total number of third molars that would be expected if third molar agen- esis was absent in each individual to determine prevalence. Nelsen et al. (2001) found third molar agenesis to be prevalent in 23.5% of individuals (n=12/51) from the Iron Age cemetery of Noen U-Loke, in Thailand. The authors did not use radiographic analysis. This prevalence is significantly lower, χ2 (1, n=140) = 5.2, p = 0.023, than the prevalence of 42.7% recorded in the present study. The Noen U- Loke assemblage also has a high prevalence of lat- eral incisor agenesis, with 79% of individuals miss- ing at least one lateral incisor. The authors hypoth- esize that endogamy and isolation likely factored in to the high prevalence of lateral incisor hypo- dontia. However, this does not appear to have a marked effect on the prevalence of third molar agenesis, as the modern worldwide average de- scribed by Carter & Worthington (2015) is 22%. In order to understand if endogamy and isolation affected the prevalence of third molar agenesis in this assemblage, analysis of other archaeological assemblages from the time period and the area with more genetic diversity would be necessary in order to confidently assess typical third molar agenesis prevalence. The methods of archaeological analysis em- ployed by Henriksson et al. (2019) in their analysis of medieval and modern Norwegian assemblages align closely with the present study. The authors used both radiographic and visual analysis to de- termine 36 of 130 medieval skeletons had third mo- lar agenesis. A decrease in third molar agenesis from medieval (27.7%) to modern times (17.2%) was detected. The frequency of third molar agene- sis found in the present study (42.7%) is signifi- cantly higher, χ2 (1, n=219) = 5.3, p = 0.021, than the frequency recorded in the medieval Norwegian 30 Dental Anthropology 2021 │ Volume 34│ Issue 02 assemblage. Henriksson et al. (2019) proposes that the higher rate of third molar agenesis in the medi- eval assemblage compared with the modern Nor- wegian sample may be due to the biological rela- tionships present in the cemetery of St. Olav, as opposed to the unrelated sample of modern Nor- wegian 15 year olds. A strong genetic influence could also be present in the Chichester assemblage, and may be a primary factor in the relatively high frequency of 42.7%, although further analysis is required to explore this. Sengupta et al.’s (1999) analysis of Victorian skeletons from the Spitalfields cemetery in London represents the closest archaeological comparison to the present study, both temporally and geograph- ically. The frequency of third molar agenesis was determined by assessing each dental quadrant as a separate specimen, and both visual and radio- graphic analysis were used. The prevalence of third molar agenesis presented here (42.7%) is sig- nificantly higher, χ2 (1, n=140) = 5.2, p = 0.023, than the prevalence of 23.5% recorded at Spitalfields (n=12/51), and is much greater than the frequency of 14% observed in the medieval burials at St. Pe- ter’s Church, Barton-on-Humber, also examined by Sengupta et al. (1999). Due to the proximity and temporal overlap with the Chichester assemblage, it is likely familial genetic predispositions towards third molar agenesis were present in the Chiches- ter assemblage. In addition to a genetic component, diet could have factored in to the rates of third molar agenesis in Chichester. In post-medieval Britain, the diet was heavily impacted by the industrial revolution of the 17th century, with food becoming sweeter and increasingly processed (Rando et al., 2014). Refined flour and white bread became pop- ular, and in 18th – early 19th century London, pota- toes, bread, and tea were a dietary staple (Mant, 2015). Increasingly processed diets reduce dental wear on the occlusal and interproximal surfaces of teeth. As teeth wear down more space becomes available in the jaw due to the mesial drift of teeth, and without this wear, dental crowding and im- paction are more likely to occur (Sengupta et al., 1999). Rando et al. (2014) compared the mandibu- lar morphology of medieval and post-medieval Londoners and found a decrease in the robusticity of bone associated with masticatory muscles in post-medieval skeletons. The strong association between the hardness of diet, cranio-facial devel- opment, and the resulting formation of dental anomalies has been demonstrated in the literature, and likely contributed to third molar agenesis in the Chichester assemblage (Corruccini et al., 1983; Corruccini & Lee, 1984; John et al., 2012; Yamada and Kimmel, 1991). However, the Spitalfields as- semblage (Sengupta et al., 1999) was also exposed to these influences and has a much lower preva- lence (23%) of third molar agenesis. Therefore, die- tary influences alone cannot account for the high prevalence rates found in the Chichester assem- blage. It is also relevant to consider the how the biocul- tural environment, the relationship between bio- logical and cultural elements, may have impacted growth in post-medieval Chichester. Despite the resistance of tooth formation to growth disruptions (Hillson, 2005), delayed dental eruption is often reported in individuals with systemic disease, in the absence of essential nutrients, or in individuals living in a low socioeconomic setting (Cardoso, 2007; Suri et al., 2004). Delayed formation and eruption has also been correlated with increased frequency of third molar agenesis, and reduced morphological complexity in first and second mo- lars (Anderson and Popovich, 1981). Research has shown that the pre-natal environment and the quality of breastfeeding during tooth development also affect the size of the third molars (Garn et al., 1980; Grüneberg, 1951; Grüneberg, 1963; Lumey and Stein, 1985). In Chichester in the early 17th cen- tury and again in 1665, the plague was present, and smallpox peaked in 1722, 1740, 1759 and 1775 (Morgan, 1992). In the 19th century, “the health of Chichester often lagged behind the rest of the country” (Morgan, 1991:23), with epidemics linked to water and sewage, such as cholera and typhoid fever, occurring at regular interval. Statistics from 1871-1880 put Chichester amongst the highest number of cases of consumption and typhoid fever in the country, and historical records detail poor sanitation and a lack of the necessary infrastructure for clean water supply and sewage drainage (Morgan, 1992). Such adverse conditions would certainly have disrupted growth, and may have also had an impact on the development of third molars. Size Reduction and Agenesis Third molars highly reduced in size, both in mesi- odistal and buccolingual dimensions, and/or sim- plified in morphology, are often referred to as ves- tigial molars (Nanda, 1954), a term that implies an evolutionary trend towards dental reduction. These third molars are easily recognized upon vis- ual assessment. In Nanda’s (1954) analysis of ves- tigial third molars, all individuals with diminution also had third molar agenesis in other dental quad- rants. Size reduction has also been demonstrated in 31 Dental Anthropology 2021 │ Volume 34│ Issue 02 dentitions with agenesis of other tooth types (Baum & Cohen, 1971). Grüneburg (1951) proposed that agenesis is the most severe expression of a size continuum, in which the tooth germ falls below a critical threshold and formation ceases. From this evidence it might be expected that individuals in the Chichester assemblage who demonstrate third molar agenesis would have other third molars re- duced in size and would be smaller upon compari- son with those that do not have third molar agene- sis. In this assemblage, all individuals demonstrat- ing vestigial third molars (n=7) (Figure 3) had third molar agenesis, except for one skeleton that was missing data on the URM3. It is likely the number of vestigial third molars in this assemblage would have been higher had post-mortem loss not been a factor, and if third molars in alveolar tooth crypts had been measured radiographically. Buccolingual measurements of the maxillary third molars in individuals with agenesis were sig- nificantly smaller (p < 0.05) than those without agenesis in this study (Table 7). Maxillary third molars are more frequently reported congenitally absent than mandibular third molars in the litera- ture (Carter & Worthington, 2015). Given that the buccolingual dimensions of maxillary third molars in this assemblage were smaller in those with agen- esis, it is possible to infer maxillary molars are more vulnerable not only to agenesis, but to dimi- nution as well; however, mandibular agenesis was found to be slightly more common in this assem- blage (54% vs 46%, Table 4), though this difference was not statistically significant, χ2 (1, n=166) =1.18, p = 0.278. Baum & Cohen (1971) collected buccolingual and mesiodistal measurements of all teeth, except third molars, from a clinical sample of European- derived ancestry in the Northeastern United States. They analyzed size reduction in the presence of dental agenesis in tooth types other than the third molar. In contrast to the present study, the authors found that mesiodistal dimensions demonstrated a statistically significant association with size reduc- tion and agenesis in 70% of tooth types, excluding third molars. Buccolingual dimensions were, how- ever, only reliable indicators of the association be- tween size reduction and agenesis in measure- ments of the canines. Garn et al. (1968) investigated the relationship between buccolingual and mesi- odistal dimensions. While the two are correlated, the results reveal more autonomy than commonali- ty governing morphological expression, although the further distal in the dental arcade the tooth, the higher the correlation between the two dimen- sions. Therefore, it might be expected that both the mesiodistal and buccolingual dimensions of third molars would demonstrate an association with size reduction and agenesis. The fact mesiodistal meas- urements did not show a statistically significant association between size reduction and agenesis in this study may be due the small number of indi- viduals in this cohort, the highly variable morphol- ogy of third molars, or it could be an indication that the relationship between buccolingual and mesiodistal dimensions is both population depend- ent and complex. Another factor complicating results is the signif- icant differences (p < 0.05) in size between the third molars of males and females (see Table 6). To ex- plore this further, an analysis of the relationship between size and agenesis was conducted sepa- rately. Removing indeterminate sex from the pool of measurements eliminated 29% of the assem- blage. Males (n=46) continued to present signifi- cantly smaller third molars in the presence of third molar agenesis compared to those without agene- sis in the buccolingual dimension of the upper left third molar. The smaller female sample size (n=36) made testing the correlation between agenesis with smaller tooth size more difficult. The final question of analysis in this study fo- cused on detecting patterns in size reduction amongst those with third molar agenesis. Khalaf (2016) analyzed the relationship between size re- duction and agenesis in all tooth types in individu- Figure 3. Left portion of a mandible demon- strating a third molar reduced in size and mor- phology (Author’s own 2017). The remaining third molars are congenitally absent. 32 Dental Anthropology 2021 │ Volume 34│ Issue 02 als with mild (≤2 teeth congenitally missing), mod- erate (3-5 teeth congenitally missing) and severe (≥6 teeth congenitally missing) hypodontia. They found that size reduction in the remaining teeth increased with the severity of hypodontia. With this research in mind and Grewal’s (1951) evidence of third molar diminution in mice, it was hypothe- sized that individuals in the Chichester assemblage with three third molars congenitally absent might have a smaller remaining third molar than those with less third molars congenitally absent. In addi- tion to relationships in size within third molar agenesis, any differences that existed between cer- tain groups of third molar agenesis and those with- out agenesis, for example those with three congeni- tally absent third molars and those without third molar agenesis, were tested to determine if size differences in third molars could be found between these groups. Unfortunately, this reduced the num- ber of individuals in each measurement category and it was not possible to reach statistical signifi- cance (see Table 9). Size patterns within third mo- lar agenesis have yet to be explored in modern or archaeological data, and therefore further testing is required. Conclusions Rates of third molar agenesis recorded in modern clinical data are often interpreted as a secular trend in which the third molar, now deemed redundant due to decreased dental wear, low masticatory stress and soft diets, will eventually cease develop- ment and potentially disappear from the human dentition. Although there is an established genetic component, the etiology is far from clear. Research on archaeological assemblages is vital in order to better understand the trajectory and origin of this phenomenon, and this study provides a valuable contribution to the relatively little that is known about third molar agenesis prevalence in the past. In post-medieval Chichester, third molar agenesis occurred in 42.7% of individuals. This result is higher than any reported for a clinical British sam- ple, and it is also significantly higher than the prevalence reported from the Victorian Spitalfields assemblage (Sengupta et al., 1999), indicating that an inheritance pattern may be present amongst the skeletons from the post-medieval assemblage of the Litten cemetery in Chichester. While reduced dental wear and masticatory stimulation may con- tribute to the frequency of agenesis in this assem- blage, a strong genetic influence combined with the adverse community health conditions may prove to be important etiological components of third molar agenesis and avenues for future re- search. Significant differences in the size of third molars between those with third molar agenesis and those without were found, although only two of the eight measurements analyzed were found to be significant. If third molars are indeed vestigial, more studies with larger sample sizes will be need- ed to further test any temporal trend. This includes the examination of archaeological as well as clini- cal samples. Acknowledgements I thank Dr. Carolyn Rando and Dr. Simon Hillson, University College of London, Institute of Archae- ology, for their teaching and guidance during my Master’s thesis, from which this project derives. I would also like to offer my gratitude to four anon- ymous reviewers for their work on earlier drafts, and to Dr. Anita Sengupta, University of Manches- ter, Division of Dentistry, for her assistance in my data collection. Finally, I would like to sincerely thank Emma Phillips and Dannielle Croucher for their much appreciated participation in my IO er- ror study. REFERENCES Alam, M.K., Muhammad, A.H., Muhammad, A.K., Shaifulizan, A.R., Ramizu, S., & Hassan, A. (2014). Multivariate analysis of factors affecting presence and/or agenesis of third molar Tooth. PLoS ONE, 9(6), E101157. AlQahtani, S.J., Hector, M.P. & Liversidge, H.M., (2010). Brief communication: The London Atlas of human tooth development and erup- tion. American Journal of Physical Anthropology, 142(3), 481–490. Anderson, D., & Popovich, F. (1981). Association of relatively delayed emergence of mandibular molars with molar reduction and molar posi- tion. American Journal of Physical Anthropology, 54, 369-376. Baum, B.J. & Cohen, M. (1971). Studies on agenesis in the permanent dentition. American Journal of Physical Anthropology, 35(1), 125–128. Bhutta, N., Sadozai, S.R.K., & Chatha, M. (2014). Correlation of third molar agenesis with hypo- dontia in an orthodontic population. Pakistan Oral & Dental Journal, 34(4), n/a. Brace, C.L., Rosenberg, K.R. and Hunt, K.D., (1987). Gradual change in human tooth size in the late Pleistocene and Post‐ Pleistocene. Evolution, 41(4), 705–720. 33 Dental Anthropology 2021 │ Volume 34│ Issue 02 Brooks, S. & Suchey, J.M. (1990). Skeletal age deter- mination based on the os pubis: A comparison of the Acsádi-Nemeskéri and Suchey-Brooks methods. Human Evolution, 5(3), 227-238. Bruzek, J. (2002). A method for visual determina- tion of sex using the human hip bone. American Journal of Physical Anthropology, 117, 157-168. Cardoso, H.F.V. (2007). Environmental effects on skeletal versus dental development: Using a documented subadult skeletal sample to test a basic assumption in human osteological re- search. American Journal of Physical Anthropology, 132(2), 223–233. Carlson, D.S., & Van Gerven, D.P. (1977). Mastica- tory function and Post-Pleistocene evolution in Nubia. American Journal of Physical Anthropology, 46, 495-506. Carter, K., & Worthington, S. (2015). Morphologic and demographic predictors of third molar agenesis: A systematic review and meta- analysis. Journal of Dental Research, 94(7), 886- 894. Castro, J.M.B. (1989). Third molar agenesis in hu- man prehistoric populations of the Canary Is- lands. American Journal of Physical Anthropology, 79(2), 207–215. Corruccini, R.S., Potter, R.H.Y. & Dahlberg, A.A. (1983). Changing occlusal variation in Pima Amerinds. American Journal of Physical Anthro- pology, 62(3), 317–324. Corruccini, R.S., & Lee, G.T.R. (1984). Occlusal var- iation in Chinese immigrants to the United Kingdom and their off-spring. Archives of Oral Biology, 29(10), 779–782. Dhaliwal, K., Rando, C., Reade, H., Jourdan, A., & Stevens, R.E., (2019). Socioeconomic differences in diet: An Isotopic examination of Post- Medieval Chichester, West Sussex. American Journal of Physical Anthropology, 171(4), 584-597. Elomaa, M. & Elomaa, E. (1973). Third molar apla- sia and formation in orthodontic patients. Proce- edings of the Finnish Dental Society, 69, 141–146. Endo, S., Sanpei, S., Ishida, R., Sanpei, S., Abe, R., & Endo, T. (2015). Association between Tthird molar agenesis patterns and agenesis of other teeth in a Japanese orthodontic popula- tion. Odontology, 103(1), 89–96. Frazier-Bowers, S., Guo, D., Cavender, A., Xue, L., Evans, B., King, T., Milewicz, D., & D'Souza, R. (2002). A novel mutation in human PAX9 caus- es molar oligodontia. Journal of Dental Re- search, 81(2), 129-133. Garn, S.M., Lewis, A.B. & Bonne, B. (1961). Third molar polymorphism and the timing of tooth formation. Nature, 192, 989. Garn, S.M., Lewis, A.B. & Kerewsky, R.S. (1963). Third molar agenesis and size reduction of the remaining teeth. Nature, 200, 488–9. Garn, S.M., Lewis, A.B. & Kerewsky, R.S. (1968). Relationship between buccolingual and mesi- odistal tooth diameters. Journal of Dental Re- search, 47(3), 495. Garn, S.M., Osborne, R.H., Alvesalo, L., & Horo- witz, S.L. (1980.) Maternal and gestational influ- ences on deciduous and permanent tooth size. Journal of Dental Research, 59, 142-143. Gravely, J.F. (1965). A radiographic survey of third molar development. British Dental Jour- nal, 119, 397-401. Grewal, M.S. (1962). The development of an inher- ited tooth defect in the mouse. Development, 10 (2), 202-211. Grüneberg, H. (1951). The genetics of a tooth defect in the mouse. Proceedings of the Royal Society of London. Series B, Biological Sciences (1934-1990), 138(892), 437–451. Grüneberg, H.M.N. (1963). The pathology of develop- ment: a study of inherited skeletal disorders in ani- mals, Blackwell Scientific. Harris, E.F., & Clark, L.L. (2008). Hypodontia: An epidemiologic study of American Black and White people. American Journal of Orthodontic Dentofacial Orthopedics, 134, 761–7. Hart D. (2012). A post-excavation assessment and up- dated project design for Excavations at Eastgate Square, Chichester, West Sussex, ASE (Report No: 2012060). Archaeology South-East. East Sussex. Henriksson C.H., Andersson M.E.M., & Moystad, A. (2019). Hypodontia and retention of third molars in Norwegian Medieval skeletons: Den- tal radiography in osteoarchaeology. Acta Odon- tologica Scandinavica, 77(4), 310-314. Hillson, S. (2005). Teeth, 2nd ed. Cambridge: Cam- bridge University Press. Hillson, S., FitzGerald, C. & Flinn, H. (2005). Alter- native dental measurements: Proposals and re- lationships with other measurements. American Journal of Physical Anthropology, 126(4), 413–426. Iseri, H., & Uzel, I. (1993). Impaction of maxillary canines and congenitally missing third molars: Description of an ancient skull (7250-6700 bc). European Journal of Orthodontics, 15(1), 1-5. John, J., Nambiar, P., Mani, S.A., Mohamed, N.H., Ahmad, N.F., & Murad, N.A. (2012). Third mo- lar agenesis among children and youths from 34 Dental Anthropology 2021 │ Volume 34│ Issue 02 three major races of Malaysians. Journal of Den- tal Sciences, 7(3), 211-217. Kajii, T.S., Sato, Y., Kajii, S., Sugawara, Y., & Iida, J. (2004). Agenesis of third molar germs depends on sagittal maxillary jaw dimensions in ortho- dontic patients in Japan. Angle Orthodontics, 74 (3), 337–342. Keene, H. (1964). Third molar agenesis, spacing and crowding of teeth, and tooth size in caries- resistant Naval recruits. American Journal of Or- thodontics, 50(6), 445-451. Khalaf, K. (2016). Tooth size in patients with mild, moderate and severe hypodontia and a control group. Open Dentistry Journal, 10, 382–389. Krekeler, B., Scharf, F., & Tröndle, D. (1974). Rönt- genstatistische untersuchungen über Nichtanla- ge und Dystopien der Weisheitszähne. Deutsche Zahnarztliche Zeitschrift, 29, 591–593. Lieverse, A.R., Pratt, I.V., Schulting, R.J., Cooper, D.M.L., Bazaliiskii, V.I., & Weber, A.W. (2014). Point taken: An unusual case of incisor agenesis and mandibular trauma in Early Bronze Age Siberia. International Journal of Paleopathology, 6, 53-59. Lovejoy, C.O., Meindl, R.S., Pryzbeck, T.R., & Mensforth R.P. (1985). Chronological metamor- phosis of the auricular surface of the ilium: A new method for the determination of adult skel- etal age at death. American Journal of Physical Anthropology, 68, 15-28. Lumey, L.H., & Stein, Z.A. (1985). Famine and birthweight in the second generation: Maternal transmission of an environmental experience. In: Abstract IV Congress of Auxology, Montreal. Philadelphia: Taylor & Francis. Mant, M., & Roberts, C. (2015). Diet and dental car- ies in Post-Medieval London. International Jour- nal of Historical Archaeology, 19(1), 188–207. Morgan, R. (1992). Chichester: A documentary history. 1st ed, Chichester, Sussex: Phillmore & Co Ltd. Munson, C. (2001). Residential mortuary practices and skeletal biology at the Late Mississippian Hovey Lake Site, Posey County, Indi- ana. Midcontinental Journal of Archaeology, MCJA, 26(1), 1-52. Nanda, R.S. (1954). Agenesis of the third molar in man. American Journal of Orthodontics, 40(9), 698 –706. Nelsen, K., Tayles, N., & Domett, K. (2001). Miss- ing lateral incisors in Iron Age South-East Asians as possible Indicators of Dental agenesis. Archives of Oral Biology, 46, 963-971. Öhrström, L., Seiler, R., Böni, T., Aali, A., Stöllner, T., & Rühli, F. (2015). Radiological findings in an ancient Iranian salt mummy (Chehrabad ca. 410-350 BC). Skeletal Radiology, 44(6), 811–821. Phenice, T.W. (1969). A newly developed visual method of sexing the os pubis. American Journal of Physical Anthropology, 30(2), 297–301. Raloti, S., Mori, R., Makwana, S., Patel, V., Menat, A. & Chaudhari, N. (2013). Study of a relation- ship between agenesis and impacted third mo- lar (wisdom) teeth. International Journal of Re- search Medicine, 2(1), 38-41. Rando, C. (2016). The human remains Collections at the UCL Institute of Archaeology: Recent ac- quisitions from Eastgate Square, Chichester, Sussex. Archaeology International, 19(3), 79–83. Rando, C., Hillson, S., & Antoine, D. (2014). Chang- es in mandibular dimensions during the Medi- aeval to Post-Mediaeval transition in London: A possible response to decreased masticatory load. Archives of Oral Biology, 59(1), 73–81. Ren, CG, Kumar, B.S. (2014). Prevalence of erup- tion of third molar tooth among South Indians and Malaysians. Journal of Academic Dental Edu- cation, 1(1), 32–35. Sengupta, A., Whittaker, D.K., Barber, G., Rogers, J., & Musgrave, J.H. (1999). The effects of dental wear on third molar eruption and on the Curve of Spee in human archaeological denti- tions. Archives of Oral Biology, 44(11), 925–934. Shinn, D.L. (1976). Congenitally missing third mo- lars in a British population. Journal of Dentistry, 4(1), 42–44. Sujon, M.K.K., Alam, M.K.A. & Rahman, S.A. (2016). Prevalence of third molar agenesis: As- sociated dental anomalies in non-syndromic 5923 patients. PLoS ONE, 11(8), 1-9. Suri, L., Gagari, E., & Vastardis, H. (2004). Delayed tooth eruption: Pathogenesis, diagnosis, and treatment. A literature review. American Journal of Orthodontics & Dentofacial Orthopedics, 126(4), 432–445. Thompson, G.W., Popovich, F. & Anderson, D.L. (1974). Third molar agenesis in the Burlington Growth Centre in Toronto. Community Dentistry and Oral Epidemiology, 2(4), 187–192. Tröndle, D. (1973). Röntgenologische Unter- suchungen Zum Nachweis der Nichtanlage und Dystopie der Weisheitszähne. Med. Diss., Frei- burg. Ubelaker, D.H.M.N. (1989). Human skeletal remains: excavation, analysis, interpretation. 2nd ed., Wash- ington: Taraxacum. Upadhyaya, C., Adhikari, B.R., Kafle, D., & Humagain, M. (2012). Agenesis of third molars 35 Dental Anthropology 2021 │ Volume 34│ Issue 02 in orthodontic patients attending Dhulikhel Hospital. Orthodontic Journal Nepal, 2(1), 32–35. Vodanović, M., Galić, I., Strujićc, M., Peroš, K., Šlause, M., & Brkića, H. (2012) Orthodontic anomalies and malocclusions in Late Antique and Early Mediaeval Period in Croatia. Archives of Oral Biology, 57, 401-412. Weise, W., & Bruntsch, E. (1965). Rőntgenologische Untersuchungen zum Nachweis und zur Entwicklung des Weisheitszahnes. Zahnärztl Rdsch, 74, 245–249. Yamada, K., & Kimmel, D.B. (1991). The effect of dietary consistency on bone mass and turnover in the growing rat mandible. Archives of Oral Biology, 36(2), 129–138.