Volume 4, Issue 4 US $6.00

Editor:Allan G. Farman, BDS, PhD (odont.),DSc (odont.), Diplomate of theAmerican Board of Oral andMaxillofacial Radiology, Professor ofRadiology and Imaging Sciences,Department of Surgical and HospitalDentistry, The University ofLouisville School of Dentistry,Louisville, KY.

Featured Article:Assessing Growth and Developmentwith Panoramic Radiographs andCephalometric Attachments: A criticaltool for dental diagnosis andtreatment planning

In The Recent Literature:Implantology

Lateral cephalograms

Impacted third molars

Calcified stylohyoidal chain

Jaw fracture and third molarimpaction

Learning Objectives:Gain knowledge of the importanceof tooth and skeletal maturitydeterminations as it inputs intodental treatment planning.

Learn the roles of panoramic,cephalometric, and hand-wristradiographic studies in biologicalage determinations.

Learn the factors acting asdeterminants of relative dental andskeletal maturity findings.

It is recommended that radio-graphs be made periodically includingboth during the mixed dentition (8-9year old) and adolescence (12-14 yearold) to evaluate growth and develop-ment, and to look for asymptomaticdental disease [1-3]. Substantialdifferences in the assessed biologicaland the known chronological age canbe indicators of a variety of inheritedand congenital conditions. Further, localfailure in dental eruption within thenormal time range can be evidence ofdental impaction and possibly of apathological process such as a hamar-toma, cyst, or tumor. Failure to removecauses of impaction prior to cessationof the normal eruption time can lead tootherwise unnecessary surgicalorthodontics, a poorer outcomeprognosis, and perhaps to a sequenceof time consuming, expensive, and lessthan ideal replacement strategies [4].

Assessing Growth and Development with PanoramicRadiographs and Cephalometric Attachments: A criticaltool for dental diagnosis and treatment planningBy Dr. Allan G. Farman

indicator of age is that the threepermanent molar teeth in each quad-rant erupt approximately at six-yearintervals. The first permanent molarerupts around 6 years, the secondpermanent molar around 12 years, andthe third molars around 18 years. Rootformation for permanent teeth iscompleted roughly three years followingeruption. The first major attempt atdeveloping a chronology for humantooth development was that of Loganand Kronfeld (1933) and with minormodification is still usable as a roughand ready guide. Using this Table,eruption times for permanent teethusually are within 2 years of the actualchronological age (Table 1; Fig. 1-5) [5].

Demirjian and Levesque (1980)studied dental development of agenetically homogeneous French-Canadian group of children ranging inage from 2.5-19 years using 5,437

TABLE 1: Approximate Dental Maturation Schedule(after Logan & Kronfeld5)

The dental pan-oramic radiographis a quick, simple,and relatively safeway to achieve thegoal of evaluatingthe whole dentitionin a manner that iseasy to explain tothe patient orconcerned parent.

Eruption Sequenceand Timing

There is somecontroversy as tothe precision withwhich tooth devel-opment anderuption predictchronological age;however, mostreports suggest thatthere is a goodcorrelation. One key

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“ Up to 5-6 years of age, no difference was found in the timing of dentaldevelopment between boys and girls, in contrast to the older ages wheregirls were always more developed dentally than boys.”

Fig. 1: The first perma-nent molar commenceseruption at around 6years of age. Note thatthe crown of the secondpermanent molar isdeveloping at this time.

Fig. 2: The first permanent molar is generallyfully erupted by 7 years; however the rootsare still developing. Note that the root apicesare wide open (“blunderbuss” shape). Rootcompletion is approximately 3 yearsfollowing eruption.

panoramic radiographs [6-8]. Thematurity of each mandibular tooth wasevaluated individually. For each stage ofeach tooth, the developmental curves ofboys and girls were compared. Up to 5-6 years of age, no difference was foundin the timing of dental developmentbetween boys and girls, in contrast tothe older ages where girls were alwaysmore developed dentally than boys.Elsewhere, Hegde and Sood (2002)evaluated dental age in 197 children ofknown chronological age (6-13 years)in Belgaum, India [6,9]. When themethod of Demirjian et al. [6-8] wasapplied to Belgaum children, meandifference between true and assessedage for males showed overestimation of0.14 years (51 days) and femalesshowed overestimation of 0.04 years(15 days); hence, the method ofDemirjian et al. showed high accuracyin this population group.

In contrast, Teivens et al. (1996)studied the developmental stages of themandibular teeth according to themethod by Demirjian et al. and reporteddiscrepancies in staging where childrenof ages 5 and 12 years were found to fitthe same developmental stage [7,8,10].Their study involved analysis of 197panoramic radiographs of childrenaged 5, 6, 9, and 12 years collected andexamined by each of 13 independentpedodontists, radiologists and forensicodontologists. It was concluded that anymethod for age determination ofchildren with aid of tooth developmentwill suffer from a rather wide range ofuncertainty owing to individual varia-tions. In a separate paper from thesame institution, it was found thatdifferent observers could vary to anextreme degree in age assessmentsmade on the same radiographs, thusbaseline standardization of observersrather than the assessment per se couldwell have contributed to finding a lack ofreliability [11].

Dental age was studied byNykanen et al. in a sample of 261Norwegian children (128 boys and 133girls) by using panoramic radiographswith the same maturity standards [7,12].Reliability was analyzed by repeated

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Fig. 3: At 10 years in the mixeddentition all permanent first molarsand permanent incisors are erupted.The mandibular first premolars are inprocess of eruption. The roots of thefirst permanent molars are complete.This case shows a mesiodens in themaxilla that is displacing the centralincisors and, left unattended, mightcomplicate eruption of the permanentmaxillary canines due to consequentdental crowding.

Fig. 4: At 12 years,the second perma-nent molars erupt. Allpremolars are erupted savefor the mandibular secondpremolars that are still in processof eruption. The permanent maxillarycanines are in process of completion oferuption. The mandibular third molarshave commenced calcification.

assessments of 134 of the radiographs,and the overall mean differencebetween duplicate dental age determi-nations was 0.5 months for intra- and1.8 months for inter-examiner compari-sons. The Norwegian children weregenerally somewhat advanced in dentalmaturity compared with the French-Canadian reference sample. Among theboys the mean difference betweendental age and chronologic age variedin the different age groups from 1.5 to4.0 months. Among the girls thedifference increased with age, varyingfrom 0 to 3.5 months in the younger agegroups (5.5 to 9.0 years) and from 4.5to 7.5 months in the age groups 9.5years and above. The variability inindividual dental age was sometimesmarked and increased with age. For theolder age groups 95% of the individualage estimates were within ± 2 years ofthe real chronological age.

Normal Variations in Eruption TimingGender: As indicated earlier, the

dental development of a geneticallyhomogeneous French-Canadian groupof children ranging in age from 2.5 to 19years was evaluated from 5,437panoramic radiographs by the methodof Demirjian et al. [7,8] Up to 5-6 yearsof age, no difference was found in thetiming of dental development betweenboys and girls, in contrast to the olderages where girls were always moredeveloped than boys. A close relationwas established between the stage offormation of all teeth and their emer-gence.

In a study of dental maturity in 903healthy Chinese children (boys: 465,girls: 438) aged 3-16 years, at 3-5 yearsold, boys had dental maturity slightlyearlier than girls but the genderdifference was not statistically signifi-cant [13]. In the age range of 7-14years, girls were more advanced thanboys (p < 0.05), with girls being onaverage 0.45 years more advancedthan boys. The maximum averagedifference was 0.85 years for thepermanent canine tooth. The time thateach developmental stage took wasshorter in 50% of girls, but longer in

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28% of girls compared to the averagefor boys. There was no differencebetween boys and girls in the remaining22% of cases.

In a study of 929 female and 686male Japanese subjects aged between12 and 30 years, a total of 1,615panoramic radiographs were examined[14]. The mineralization stages of thirdmolars were evaluated on the basis ofthe Demirjian et al. stages, modified inaccordance with Mincer’s model [7,8].No statistically significant differences inthe chronology of third molar mineraliza-tion between maxilla and mandible andbetween sides were observed. Acomparison between genders did notreveal any substantial differences withrespect to third molar development.

Skeletal Pattern: In a Japanesepopulation, Sasaki, et al. (1990)examined variations in dental maturitybetween girls having skeletal Class IIand Class III malocclusions. Usingpanoramic radiographs and lateralcephalograms, they found that thetiming of dental eruption was notsignificantly affected by jaw skeletaltype [15].

In Brazil, Janson et al. carried out adouble blind determination of dentalmaturation, expressed by dental age,for each of 20 subjects (10 male and 10female for each group) selected from400 subjects by virtue of representingthe extremes in open and deep bite.Given the same chronological age, theopen bite group had a mean dental age6 months greater than that determinedfor the deep overbite group [16]. Thisdifference proved to be statisticallysignificant (p <0.05) [16].

Ethnicity: Prabhakar et al. (2002)used the standard Demirjian et al.(1973) dental maturation system for 151healthy Indian children in Davangereand found that this ethnic group was onaverage more dentally advanced thanthe standard by slightly more than oneyear for boys (1.20 ± 1.02 years) andjust less than one year for girls (0.90 ±0.87) [6,17].

Davidson and Rodd (2001) used across-sectional study to compare dentalage with chronological age in Somali

Fig. 5: At 15 yearsthe roots of the second

permanent molars arecomplete. All permanent

teeth, excepting the third molars,are erupted and completely formed.

children under 16 years of age andage-and-gender-matched whiteCaucasian children, resident inSheffield, England [18]. Dental age wasdetermined for each subject usingexisting panoramic radiographs.Comparisons of the difference betweendental age and chronological age weremade for gender and ethnic group,using independent sample t-tests andsetting significance at p = 0.05. Thesample group comprised 162 subjects:84 Somali and Caucasian boys (meanage 10.6 years) and 78 Somali andCaucasian girls (mean age 11.2 years).The mean difference between dentaland chronological age was 1.01 yearsfor Somali boys, 0.19 years for Cauca-sian boys; 1.22 years for Somali girls,and 0.52 years for Caucasian girls. Thedifference between dental and chrono-logical age was significantly greater inSomali subjects than in Caucasianchildren, and some Somali subjectsshowed a marked discrepancy betweenascribed chronological age and dentalage (range -1.75 to +5.42 years), whichwas most evident in 8- to 12-year-oldchildren. These findings suggest that

there is a need for population-specific dental developmentstandards to improve the accuracyof dental age assessment.

Local Causes of Delayed DentalEruption

Individual or multiple teeth in ajaw segment can fail to erupt in atimely manner due to impactionagainst a “mechanical” obstructioncommonly caused by inappropriatetooth orientation during develop-ment (especially maxillary perma-nent canine or third molar teeth ineither jaw), crowding (impactionagainst a regular tooth or teeth),supernumerary tooth or teeth,retained primary teeth, or toothroots, with or without ankylosis.Primary teeth most likely to beinvolved are those that haveinflamed pulps or periapicallesions, and those that have beentreated by pulpotomy. Other fairlycommon obstructions to dentaleruption are follicular cysts (erup-tion or dentigerous cyst) andhamartomas (complex or com-

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“ Several syndromes are associated with delay or failure indental eruption.”

pound odontomas) [19]. Fortumors or cysts to prevent or delaytooth eruption locally, the lesionneeds to arise in childhood oradolescence. Benign tumors thatcan envelop or overlie a develop-ing tooth include adenomatoidodontogenic tumor, ameloblas-toma (usually unicystic),ameloblastic fibroma, ameloblasticfibro-odontoma, odontogenicmyxoma, and cemento-ossifyingfibroma. Other conditions that canlocally delay tooth eruption includecherubism (usually bilaterally) andfibrous dysplasia (unilateral) [19].Obviously teeth that are absentcannot erupt so hypodontia alsoneeds to be excluded radiographi-cally. Regional odontodysplasiacan also result in failure of eruptionof a segment of teeth, and againrequires radiographic study.Fibromatosis gingivae may eitherdelay eruption or simply hide theteeth from clinical view.

Systemic Conditions DelayingDental Eruption

Low birthweight: Seow(1996) studied the development ofthe permanent dentition in verylow birthweight (< 1500 g)Caucasian children in Australia[20]. 55 very low birthweightchildren (mean age at dentalexamination 7.7 +/- 2.2 years,mean birthweight 1203 +/- 240 g,and mean gestational age 29.8 +/-2.4 weeks) were compared to 55normal birth weight childrenmatched for race, sex, and age.Dental maturity determined frompanoramic radiographs found verylow birthweight children toexperience a delay in dentalmaturation of 0.29 +/- 0.54 yearscompared with normal birthweightchildren (p < 0.02). Very lowbirthweight children < 6 years ofage showed the greatest delay of0.31 +/- 0.68 years (p < 0.001). Incontrast, children aged 9 yearsand older showed no difference indental maturity compared to

controls (p > 0.01), suggesting that“catch-up” growth had occurred.

In a separate study carried out inFinland, comparing dental develop-ment in preterm versus matchedcontrol children, premature birth alsohad no appreciable late effects ontooth-maturation by age 9 years [21].

Second hand smoke: Forevaluation of the effects of secondhand smoke on dental development,panoramic radiographs of 203 childrenbetween the ages of 7-10 years werestudied [22]. Four groups wereseparated: a control group in whichneither parent had smoked during thepregnancy, a group exposed totobacco smoke from the mother only, agroup exposed to smoke from thefather only, and a group exposed totobacco smoke from both parents.Maximum differences betweenchronological and dental ages werefound in children subjected to cigarettesmoke from both parents (35%reduction in dental maturation).

Syndromes: Several syndromesare associated with delay or failure indental eruption. One of the mostcommon of these is cleidocranialdysplasia, in which there are multiplesupernumerary teeth, with delayed orarrested eruption of the permanentteeth (however, the primary dentitionerupts normally) [23,24].

Trisomy 21 (Down’s syndrome)and juvenile hypothyroidism (cretin-ism) have also been attributed ascauses of delayed eruption. Other, lesscommon, syndromes associated withdelayed or failed dental eruptioninclude: hypopituitarism, osteomatosisintestinal polyposis syndrome(Gardner’s syndrome in which there isa high propensity for development ofintestinal cancer), chondroectodermaldysplasia (Ellis-van Crevald syn-drome), progeria (Hutchinson-Gilford’ssyndrome), osteopetrosis,pyknodysostosis,acrocephalysyndactyly (Apert’ssyndrome), focal dermal hypoplasia(Goltz syndrome), vitamin D deficiencysyndromes, and dystrophic epider-molysis bulosa [25,26]. Drug induced

gingival hyperplasia, such as thatrelated to use of Phenytoin (Dilantin) inprevention of seizures, can either delayeruption, or simply hide the teeth fromclinical view. Radiation therapy fortreating malignancies in childhood hasalso been associated with failed toothdevelopment and either delayed orpremature dental eruption.

Delayed Puberty: Gaethofs et al.(1990) compared the dental age ofboys with constitutional delay in growthand puberty with that of normal healthyboys [27]. The Demirjian et al. methodwas found to be accurate for theBelgium control subjects examined.Boys with delayed puberty hadsignificant delay in dental development(p < 0.01).

Factors in Premature Dental EruptionIndividual teeth can erupt in

advance as a sporadic variant (i.e.natal teeth). Premature eruption of apermanent tooth quite frequentlyoccurs following early loss of its primaryantecedent. More generalized prema-ture eruption has been reported injuvenile rheumatoid arthritis [28],Turner’s syndrome [29,30], hyperthy-roidism, pituitary giantism, hypergo-nadism, Cushing’s syndrome, andadrenogenital syndrome. Localpremature dental eruption has beenfound in association with adjacentbenign vascular (hemangioma) orneural tumors, or due to pressure fromgrowing subjacent jaw neoplasms (e.g.osteogenic sarcoma).

Hass AD, et al. studied 28 subjectsaged 4 to 19 years having Turner’ssyndrome using serial panoramic andcephalometric radiographs. They founddental development to be advanced inall of the subjects and the administra-tion of growth hormone had no effecton this finding [30].

Kotilainen and Pirinen investi-gated dental maturity in 28 Fragile Xaffected boys and 3 girl carriers of thiscondition [31]. The mean relative dentalage was advanced in Fragile X males,based both on formation and onemergence, with more pronouncedadvancement seen in younger

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children. Dental maturity was advancedin heterozygous carrier girls as well.Height and skeletal maturity did notshow a similar trend toward advanceddevelopment.

Assessment of Biologic Age UsingHand-Wrist Radiographs

Skeletal development is animportant maturity indicator duringchildhood [32]. In clinical practice,determination of skeletal age is helpfulfor the diagnosis of disorders of growthand development. Typical disharmonicpatterns in the appearance of bonecenters of hand and wrist have beenfound in certain disorders of develop-ment [32].

Fishman developed a widely-usedsystem of hand-wrist skeletal maturationindicators (SMI), using four stages ofbone maturation (initial ossification,width, capping, and fusion) at sixanatomic sites [33]. Table 2 detailsspecific criteria to be used with theFishman system. The various anatomicfeatures that need to be recognized areannotated in Figure 6 and detailed inexamples in Figures 7 & 8. Using thissystem, it is possible to judge theremaining potential of the jaws, animportant issue for orthodontic treat-ment planning (Figs. 7 & 8). Hand-wristradiographs can be made using astandard cephalometric extension to apanoramic machine.

Assessment of Biologic Age UsingLateral Cephalograms

Lateral cephalometric and lefthand-wrist radiographs from the Bolton-Brush Growth Center at Case WesternReserve University were reviewed todevelop a cervical vertebrae maturationindex [34]. By using the lateral profiles ofthe second, third, and fourth cervicalvertebrae, it was possible to develop areliable ranking of patients in terms ofthe potential for future adolescentgrowth (Table 3, Fig. 9 & 10). A subse-quent study evaluated lateral cephalom-etric and left hand-wrist radiographs of180 untreated subjects (99 girls and 81boys) aged from 8 to 18 [35]. The resultsof this study indicated that cervical

TABLE 2: Hand-Wrist Maturation Schedule(after Fishman33)

Fig. 6:Annotatedhand-wristradiographindicatingthe landmarksneeded toassess skeletalage using theFishmanmethod.

“ Skeletal development is an important maturity indicatorduring childhood.”

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vertebral maturation and hand-wristskeletal maturation were significantlyrelated. A study in Italy by Franchi et al.concurred that cervical vertebralmaturation is an appropriate method forthe appraisal of mandibular skeletalmaturity in individual patients on thebasis of a single cephalometric obser-vation [36]. They concluded that theaccuracy of the cervical vertebralmethod in the detection of the onset ofthe pubertal spurt in mandibular growthprovides helpful indications for orth-odontic treatment timing of patientshaving mandibular deficiencies. Theaccuracy of cervical vertebral matura-tion in determining skeletal age duringthe circum-pubertal period was found tobe valid and reliable in children ofChinese ethnicity [37]. Minars M et al.(2003) used repeated evaluations of 30randomly selected, pretreatment lateralcephalometric radiographs and foundthe accuracy of determining skeletalmaturity and growth potential withlateral cephalograms to be R=0.98(highly accurate) [38].

Biological Age and OrthodonticIntervention

In Australia, Grave et al. con-structed velocity curves for stature andmandibular growth for 47 boys and 27girls, and plotted maturation events onthe curves [39]. For the majority ofchildren, peak velocity in mandibulargrowth coincided with peak velocity instature increments. Particular radiologicmaturation events occurred consistentlybefore, during, or after the adolescentgrowth spurt, contributing to a positive,purposeful, and more confidentapproach to the management oforthodontic patients, particularly thosewith a Class II malocclusion.

Kopecky GR et al. (1993) treated41 patients with clinically diagnosedClass II, Division I malocclusions withmidface prognathism using Kloehn-typecervical headgear [40]. All casesincluded longitudinal series both oflateral cephalometric radiographs andof hand-wrist films made before, during,and after treatment. Skeletal and dentalchanges were related to specific

Pre-Pubertal(Note: Adductor sesamoid not ossified.)

Post-Pubertal(Note: Adductor sesamoid is ossified.)

Fig. 8: Comparison of hand-wristradiographs from pre-pubertal patienthaving significant growth potential(left), and of post-pubertal individualwith little growth potential (right).

Fig. 7: Details of epiphyseal “width,” “capping”and “fusion” at phalynx base, and of ossifica-tion of the adductor bone. These are keyindicators of skeletal age.

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maturational periods and comparedwith their related chronologic age toevaluate optimum timing for maximumtreatment response. This study foundtiming of cervical headgear treatmenton the basis of skeletal maturation ispreferable to use of chronologic age.The most favorable results weredemonstrated during maturationalperiods associated with a high degreeof incremental growth velocity.

Baccetti et al. (2001) evaluated theshort-term and long-term treatmenteffects of rapid maxillary expansion intwo groups of subjects treated with theHaas appliance [41]. Treatment out-comes were evaluated before and afterthe peak in skeletal maturation, asassessed by the cervical vertebralmaturation method, in a sample of 42patients compared to a control sampleof 20 subjects. The group receivingearly treatment had not passed thepubertal peak in skeletal growth whentreatment commenced, whereas the latetreatment subjects had (See Table 3).Rapid maxillary expansion treatmentbefore the peak in skeletal growthvelocity was able to induce morepronounced transverse craniofacialchanges at the skeletal level. Biologicalage determination is important intreatment planning effective rapidpalatal expansion.

Age and IdentityIn Belgium, Van Erum et al. evalu-

ated 48 patients aged 2-32 years withshort stature of prenatal origin. Theyobserved tooth development andcraniofacial growth using panoramicand cephalometric radiographs [42].While craniofacial growth was closelyrelated to general growth and skeletalage, dental maturation closely corre-lated with chronologic age.

In the United States, an immigrant’sage can be critical to his or her effort togain entry to and residence in thecountry. Minors who enter the UnitedStates illegally are, unlike adults, exemptfrom immediate deportation. Minors arepermitted to remain in the United Statesif they are granted political asylum or“special immigrant juvenile status,”

Fig. 9: Schematic of maturationsequence of third cervical vertebra(C3) after Hassel & Farman34

TABLE 3: Cervical Vertebral MaturationSchedule (after Hassel & Farman34)

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Fig. 10: Maturation sequence forcervical vertebra (C2-4) used forskeletal growth potential determina-tion after Hassel & Farman34.

given when a child is the victim ofabuse or neglect. If denied asylum,minors cannot be sent home untilrelatives in their home country arecontacted. In the view of thefederal immigration authorities,dental and bone radiographs areone of the most reliable ways ofdetermining age [43]. Trager, a USdentist with a dental office directlyabove Customs and Immigrationat Kennedy Airport, NY, andanother office in LaGuardia, notedthat the eruption of third molarsand the fusion of bones in thewrist usually signify that a personis over 18 years of age [43].Detainee’s challenges to thismeans of age determination haveapparently been dismissed infederal court [44]. Nevertheless,there can be no precision incorrelation of biological (skeletal

or dental) age and the chronologicalage that is so important in law. One canonly specify the likelihood of age givena population sample, not the exact ageof a specific individual. Biological age isimportant for dental treatment planningand can be assessed with some utilityusing dental, cephalometric and hand-wrist radiographs. Precise chronologicalage correlations can never be guaran-teed. The most accurate determinant ofbeing over 18 years of age, however,according to Friedrich et al. is thepresence of filled wisdom teeth. Thecorrelation was reported as being 100%[44].

Concluding RemarksThe literature points to there being

close correlation between growthpotential and skeletal maturity asdemonstrated from morphologicalevaluation of the cervical spine on

lateral cephalograms, or of the bonesof the hand and wrist. It is this skeletalgrowth potential that is important fororthodontic assessment. As the lateralcephalogram is standard for orthodon-tic assessment presently, evaluation ofthe spine obviates an additionalradiograph being made of the handand wrist. Even when a thyroid shieldis worn by the patient, C3 is usuallyincluded in the cephalogram.

There seems to be a closerassociation between dental develop-ment as viewed on a panoramicradiograph and chronological age,than between chronological age andskeletal maturity. This is particularly thecase if ethnic variability is taken intoaccount. Nevertheless, populationstandards are not precise when itcomes to evaluation of the individual.Kjaer et al. found that while skeletalmaturation was delayed by more thanfour years in four siblings with Seckelsyndrome, tooth maturity progressednormally [45]. While there are manylocal and systemic causes of delayedand premature dental eruption, toothdevelopment is perhaps the bestradiographic indicator of chronologicalage during childhood and adoles-cence.

It may be necessary to makeadjustments over time to any referencechart as it appears that the rate ofdental maturation might be accelerat-ing. Nadler (1998) compared 1970 and1990 Caucasian patient samples, age8.5-14.5 years old, and demonstrateddental age reductions of 1.2 years formales and 1.5 years for females, givinga combined mean reduction of 1.4years [46]. Further, it has been estab-lished that there is a variation of ± 15months at the 95% confidence intervalusing dental age to estimate chrono-logical age among Chinese children[47]. Perhaps like in aging horses, theuse of dental aging for humans is tobest be considered as being a“respected imprecise science” [48].

Knowledge of the normal se-quence and timing of dental eruptionprovides useful information regardingthe selection of radiographic proce-

“ There seems to be a closer association between dental development asviewed on a panoramic radiograph and chronological age, than betweenchronological age and skeletal maturity.”

1 01 01 01 01 0

“ When there is a local cause of failed eruption, early intervention can savemuch time, effort, cost, and discomfort with respect to the patient.”

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dures to evaluate the patient who fallsoutside the normal range, or whoshows asymmetry in tooth eruptionpatterns. When there is a local cause offailed eruption, early intervention cansave much time, effort, cost, anddiscomfort with respect to the patient. Amost comprehensive overview of thedentition, providing ready bilateralcomparisons, is the panoramic radio-graph. Diligent use of the panoramicradiography at key stages of growthand development is advocated as abasic standard of care.

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30. Midtbo M, Halse A. Skeletal maturity,dental maturity, and eruption in youngpatients with Turner syndrome. ActaOdontol Scand 1992;50:303-12.

31. Kotilainen J, Pirinen S. Dental maturityis advanced in Fragile X syndrome. AmJ Med Genet 1999;83:298-301.

32. Heinrich UE. Significance of radiologicskeletal age determination in clinicalpractice. Radiologe 1986;26:212-215.

33. Fishman LS. Maturational patterns andprediction during adolescence. AngleOrthod 1987;57:178-193.

34. Hassel B, Farman AG. Skeletalmaturation evaluation using cervicalvertebrae. Am J Orthod DentofacialOrthop 1995;107:58-66.

35. Kucukkeles N, Acar A, Biren S, Arun T.Comparisons between cervicalvertebrae and hand-wrist maturationfor the assessment of skeletal maturity.J Clin Pediatr Dent1999;24:47-52.

36. Franchi L, Baccetti T, McNamara JA Jr.Mandibular growth as related tocervical vertebral maturation and bodyheight. Am J Orthod DentofacialOrthop 2000;118:335-340.

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37. Chang HP, Liao CH, Yang YH,Chang HF, Chen KC. Correlation ofcervical vertebra maturation withhand-wrist maturation in children.Kaohsiung J Med Sci 2001;17:29-35.

38. Minars M, Burch J, Masella R,Meister M. Predicting skeletalmaturation using cervicalvertebrae. Today’s FDA2003;15:17-19.

39. Grave K, Townsend G. Hand-wristand cervical vertebral maturationindicators: how can these eventsbe used to time Class II treat-ments? Aust Orthod J 2003;19:33-45.

40. Kopecky GR, Fishman LS. Timingof cervical headgear treatmentbased on skeletal maturation. Am JOrthod Dentofacial Orthop1993;104:162-169.

41. Baccetti T, Franchi L, CameronCG, McNamara JA Jr. Treatmenttiming for rapid maxillary expan-sion. Angle Orthod 2001;71:343-350.

42. Van Erum R, Mulier M, Carels C, deZegher F. Short stature of prenatalorigin: craniofacial growth anddental maturation. Eur J Orthod.1998;20:417-425.

43. Hedges C. Airport dentist crucial toINS gatekeeping. NY Times on theweb, July 22, 2000.

44. Friedrich RE, Ulbricht C, vonMaydell LA. Dental caries andfillings in wisdom teeth as an aid inforensic dentistry for determiningchronologic age over 18.Radiologic studies oforthopantomography images ofchildren and adolescents ArchKriminol 2003;212:74.

45. Kjaer I, Hansen N, Becktor KB,Birkebaek N, Balslev T. Craniofa-cial morphology, dentition, andskeletal maturity in four siblingswith Seckel syndrome. Cleft PalateCraniofac J 200138:645-651.

46. Nadler GL. Earlier dental matura-tion: fact or fiction? Angle Orthod1998;68:535-538.

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In The Recent Literature:Implantology: Panoramic radiographywas proven to be equal to intraoralradiography for the assessment ofperi-implant bone loss in the anteriormandible.Zechner W, Watzak G, Gahleitner A,Busenlechner D, Tepper G, Watzek G.Rotational panoramic versus intraoralrectangular radiographs for evalua-tion of peri-implant bone loss in theanterior atrophic mandible. Int J OralMaxillofac Implants 2003;18:873-878.[From the Department of Oral Surgery,University of Vienna, Austria.]

In patients with atrophic mandibles,elevation of the floor of the mouth oftenprevents intraoral rectangular radiogra-phy for longitudinal follow-up studies,while extraoral techniques such aspanoramic radiographs have beenperceived to produce distorted views ofthe interforaminal region. In this study,intraoral and panoramic radiographswere compared for their accuracy inevaluating peri-implant bone loss. In arecall program, 22 patients with 88screw-type implants (44 MKII and 44Frios) were followed. Interforaminalmarginal bone loss was evaluated bypanoramic radiography and by usingintraoral radiographs. In addition,pocket depth, Periotest readings, andbleeding on probing were recorded. Forstatistical analysis, the Spearmancoefficient of correlation was used. Theeffects on bone loss and clinicalvariables were computed with a mixedmodel and the Bland and Altmanmethod. Computed as least squaremeans, the mean difference betweenpanoramic radiographs (2.4 +/- 0.2 mmfor MKII implants and 1.6 +/- 0.2 mm forFrios implants) and intraoral radio-graphs (2.6 +/- 0.2 mm and 1.4 +/- 0.2mm, respectively) was 0.2 mm (range,0.1 to 0.8 mm). In this study, the twoimaging techniques were comparableclinically in terms of the precision withwhich they could be used to measuremarginal bone loss. Hence, for highlyatrophic mandibles with unfavorableimaging conditions, rotational pan-oramic radiographs can be a usefulalternative to intraoral radiographs forevaluating peri-implant bone loss.

Lateral cephalograms: Cervicalvertebral morphology can be usedto accurately assess skeletalmaturity.San Roman P, Palma JC, Oteo MD,Nevado E. Skeletal maturationdetermined by cervical vertebraedevelopment. Eur J Orthod2002;24:303-311. [From the Depart-ment of Orthodontics, ComplutenseUniversity, Madrid, Spain.]

This study investigated the validity ofusing cervical vertebral radiographicassessment to predict skeletalmaturation. Left hand-wrist and lateralcephalometric radiographs of 958Spanish children from 5 to 18 years ofage were studied. The classification ofGrave and Brown was used to assessskeletal maturation from the hand-wrist radiograph. Cervical vertebraematuration was evaluated with lateralcephalometric radiographs using thestages described by Hassel andFarman and by Lamparski. A newmethod to evaluate the cervicalmaturation by studying the changes inthe concavity of the lower border,height, and shape of the vertebralbody was created. Correlationcoefficients were calculated toestablish the relationship betweenskeletal maturation values obtained bythe three classifications of vertebraland skeletal maturation measured atthe wrist. All correlation valuesobtained were statistically significant(p < 0.001). In the population investi-gated, the new method was asaccurate as the Hassel and Farmanclassification and superior to theLamparski classification.

Impacted third molars: An intimateassociation between the tooth andthe inferior alveolar canal oftenresulted in a darkening of the root ofthe affected tooth when viewed withpanoramic radiography.Bell GW. Use of dental panoramictomographs to predict the relationbetween mandibular third molarteeth and the inferior alveolar nerve.Radiological and surgical findings,

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and clinical outcome. Br J OralMaxillofac Surg 2004;42:21-27. [Fromthe Oral and Maxillofacial Surgery,Dumfries and Galloway Royal Infir-mary, Dumfries, United Kingdom]

Preoperative radiological observationsfrom dental panoramic tomographswere compared with surgical findings atremoval of third molars with respect torelationship of the tooth to the inferioralveolar nerve. One surgeon viewed theradiographs of 219 patients andrecorded the radiological observationsof the mandibular third molar tooth andthe inferior alveolar nerve. The samesurgeon removed the teeth and madedetailed records of morphology of theroot and its relation to the inferioralveolar nerve. Patients were reviewedpostoperatively. A total of 300 teethwere removed and the neurovascularbundle observed during surgery. Theroots were grooved or deflected due totheir proximity to the neurovascularbundle in 12% of the cases (n=35).There was an intimate relation betweenthe mandibular third molar tooth and theinferior alveolar nerve in 51% of caseswhen darkening of the root wasobserved (n=12), but only in 11% ofcases (n=11) when there appeared tobe interuption of the radiopaque outlineof the inferior alveolar canal radio-graphically.

Calcified stylohyoidal chain:Stylohyoidal ossifications show age-related increases in prevalence,length, and topographical location inpanoramic radiographs.Krennmair G, Piehslinger E. Variantsof ossification in the stylohyoid chain.Cranio 2003;21:31-37. [From theDental Clinic, Department of Remov-able and Fixed Prosthodontics,University of Vienna, Austria]

This study evaluated the age-relateddifferences in the incidence, length, andtopographic location in ossifications ofthe stylohyoid chain. Panoramicradiographs of 420 patients (795reviewed stylohyoid-chains), subdi-vided into four age groups (< 20 y, 21-40 y, 41-60 y, > 60 y) were examined forthe incidence, length, and topographiclocation of stylohyoidal ossification. Twohundred forty-five (30.8%) out of 795stylohyoidal chains showed radiologicalvariabilities (elongation of the styloidprocess or ossification of the stylohyoidligament). With increasing age, therewas an increase in prevalence andlength of stylohyoidal ossifications (p<0.01). A significant linear correlationbetween the length of the stylohyoidalossifications and age was only found inthe young age group (< 20 y., p <0.01).There was also a higher prevalence ofisolated locations in the superiorstylohyoidal segment in this age group(< 20 yrs). With increasing age, therewas a pronounced presence of ossifica-tions in the middle and inferior stylohy-oid segments and combinations ofossified variabilities. Stylohyoidalossifications show age-related in-creases in prevalence, length, andtopographical location.

Jaw fracture and third molar impac-tion: This study did provide evidencethat patients with retained or im-pacted third molars are significantlymore susceptible to angle fracturethan those without third molars.Meisami T, Sojat A, Sandor GK,Lawrence HP, Clokie CM. Impactedthird molars and risk of angle frac-ture. Int J Oral Maxillofac Surg2002;31:140-144. [From the Depart-ment of Oral and Maxillofacial Sur-gery, The University of Toronto Facultyof Dentistry, Ontario, Canada.]

This investigation assessed theinfluence of the presence, position,and severity of impaction of themandibular third molars on theincidence of mandibular anglefractures. A retrospective cohortstudy was designed for patientspresenting to the Division of Oraland Maxillofacial Surgery, TorontoGeneral Hospital, Canada, fortreatment of mandibular fracturesfrom January 1995 through June2000. The study sample comprised413 mandibular fractures in 214patients. Demographic data collectedincluded age, sex, mechanism ofinjury, and number of mandibularfractures. Independent variablesstudied were the presence, position,and severity of impaction of thirdmolars; the outcome variable was theincidence of mandibular anglefractures. Panoramic radiographsand hospital records were used todetermine and classify thesevariables. The incidence of anglefractures was found to be signifi-cantly higher in the male populationand was most commonly seen in thethird decade of life. Assault was themost frequent causative factor. Thisstudy did provide evidence thatpatients with retained or impactedthird molars are significantly moresusceptible to angle fracture thanthose without third molars. Patientswith third molars had a three timesincreased risk of angle fractureswhen compared to patients without(p <0.001), and impaction of thirdmolars significantly increased theincidence of mandibular anglefractures (p <0.001). The severity andangulation of third molar impactionsdid not prove to be significantlyassociated with angle fractures.

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