| Sažetak | Istraživanje antropometrijskih mjera TMZ-a provedeno je na 210 lubanja različitih historijskih populacija: iz ranog i kasnog srednjeg vijeka, suvremenog doba s područja Hrvatske, prastanovnika Illinoisa (od 900. – 1500. g.pos.Kr.), Kentuckya (od 500 g. pr. Kr. do 500 g. pos. Kr.) te američkih bijelaca i crnaca 20. stoljeća. Svrha rada bila je odrediti vrijednosti parametara TMZ-a: nagib posteriornog zida zglobne kvržice (NZK) dvjema metodama, visina zglobne kvržice (VZK) i duljina zakrivljene linije (DZL) od najkranijalnije točke zglobne jamice do najkaudalnije točke zglobne kvržice te dobivene rezultate analizirati s obzirom na historijsku populaciju, stranu tijela, spol, dob, ozubljenost (klasifikacija zubnih lukova prema Kennedy-ju i Eichner-u) i stupanj abrazije zuba. Mjerenje je provedeno na rezovima kroz silikonske otiske zglobne kvržice i jamice (klasična metoda), na lateralnim fotografijama te radiografskim snimkama (ortopantomogrami i kefalogrami) lubanja (samo s područja Hrvatske) te na trodimenzionalno optički i laserski skeniranim otiscima zglobne kvržice i jamice, a potom su međusobno uspoređeni i rezultati mjerenja dobiveni različitim tehnikama. Razlike istraživanih parametara TMZ-a obzirom na historijsku populaciju, stranu tijela, spol, dob, stupanj abrazije zuba te klasifikaciju zubnih lukova prema Kennedy-ju i Eichner-u u većini slučajeva nisu bile statistički značajne (p>0,05) što vodi zaključku kako navedene varijable ne utječu na morfologiju TMZ-a. Najveće vrijednosti istraživanih parametara TMZ-a izmjerene su na rezovima kroz središnji dio silikonskih otisaka zglobne kvržice i jamice (p<0,05). Veće vrijednosti NZK-a karakteristika su više zglobne kvržice, a viša zglobna kvržica rezultira pak većom DZL vrijednošću (p<0,05). Uspoređujući rezultate mjerenja parametara TMZ-a na različitim materijalima dobivene su statistički značajno veće vrijednosti na radiografskim snimkama u odnosu na vrijednosti izmjerene na lateralnim fotografijama (p<0,05). Usporedbom rezultata istraživanja na optički i laserski skeniranim uzorcima s rezultatima klasičnog mjerenja, najveća odstupanja vrijednosti dobivena su na optički skeniranim uzorcima (p<0,05) dok se klasična metoda mjerenja na rezovima kroz silikonske otiske zglobne kvržice i jamice može primijeniti kao kontrolna metoda mjerenja zbog svoje velike točnosti. |
| Sažetak (engleski) | Objectives: Skeletal components of the temporomandibular joint (TMJ) are important elements in the biomechanics of the entire masticatory system. The aim of this research was to determine the values of TMJ parameters (AEI - articular eminence inclination, AEH - articular eminence height and AEL - length of curved line from the most superior point of the glenoid fossa to the most inferior point of the articular eminence) among historical populations, and to analyze results with regard to the body side, gender, age, Kennedy and Eichner classification of dental arches and degree of tooth abrasion. Measurements were performed on digitalized sections of silicone impressions of the articular eminence and fossa glenoidalis, lateral photographs, and radiographic images of skulls (panoramic radiograps and cephalograms) in order to compare obtained results and methods. Finally, the aim of this study was also to compare obtained results of TMJ parameters measured on sections through silicone impressions of articular eminence and fossa glenoidalis with values measured on three dimensional - laser and optical scanned silicone impressions.
Materials and methods: The study included 210 skulls grouped according to historical populations: early medieval Croatian population (EMP; 10th-11th century, 30 skulls), late medieval Croatian population (LMP; 12th-15th century, 30 skulls), contemporary Croatian population (CCP; 20th century, 30 skulls), Illinois population (IP; from 900 AD to 1500 AD years, 30 skulls); Kentucky population (KP; from 500 BC to 500 AD years, 30 skulls) and a group of African Americans (AAP; 30 skulls) and American Caucasian (ACP; 30 skulls) of the 20th century.
Investigated TMJ parameters were: articular eminence inclination (AEI) measured by two methods and expressed in degrees (method 1 - M1 - the angle between the line connecting the most superior point of the glenoid fossa and the most inferior point of the articular eminence with the Frankfurt horizontal plane; method 2 - M2 - the angle between the best fitting line to the posterior wall of the articular eminence and the Frankfurt horizontal plane), articular eminence height (AEH) - vertical distance (mm) from the most superior to the most inferior point of the articular eminence, and the length (mm) of curved line (AEL) between the most superior point of the glenoid fossa and the most inferior point of the articular eminence. All skulls were without any damage in the measured area (articular eminence, fossa articularis, meatus acusticus externus, and orbitae). AEI, AEH and AEL were measured on the lateral digital photographs of skulls and radiographs (only for Croatian skulls) - panoramic radiographs and cephalograms using appropriate computer software, as well as on the sections through the right/left silicone impressions of the articular eminence and fossa glenoidalis made for each skull ("classic" method). The base of silicone impressions was parallel to the Frankfurt horizontal plane. Silicone impressions were sliced from lateral to medial side into 5 sections (between each section was a distance of 4 mm). The sections were digitalized and AEI, AEH and AEL were measured using appropriate computer software. Thirty right and thirty left silicone impressions were randomly selected from the total number of silicone impressions. Selected silicone impressions were three-dimensionally digitalized by laser and optical scanner. Applied methods of three-dimensional digitalization of silicone impressions also allow simulation of sections (from lateral to medial side) through the virtual impressions of the articular eminence and fossa glenoidalis with distance of 4 mm between each section. TMJ parameters were measured using appropriate computer software. AEI, AEH and AEL values measured on three-dimensionally digitalized impressions were compared with the results of "classic" measurements. AEI, AEH and AEL were analyzed according to the certain historical population, body side, gender, age (three age groups: skulls under 30 years of age at the time of death; skulls from 31 to 45 years of age at the time of death, and skulls with 46 years of age or older at the time of death), Kennedy and Eichner classification of dental arches, and degree of tooth abrasion (abrasion 1 – occlusal surfaces covered by enamel; abrasion 2 – occlusal surfaces with denuded dentin surrounded by enamel; abrasion 3 - no enamel on the occlusal surfaces). AEI, AEH and AEL values measured by different methods (sections through silicone impressions of articular eminence and fossa glenoidalis, lateral photographs, radiographs, laser and optically scanned silicone impressions) were also compared.
Statistical analysis was performed using the computer software IBM SPSS Statistics 19 (SPSS Inc., Chicago, Illinois, USA). Obtained data were analyzed by method of descriptive statistics and by following statistical tests: independent students T test, one-way analysis of variance ANOVA and Scheffe post hoc test, univariate statistical analysis, Pearson's correlation coefficient and non parametric Friedman test. The results were analyzed at the significance level of p<0.05.
Results: Mean values of TMJ parameters measured on EMP silicone impressions: right AEI M1 was 35.43°, and left AEI M1 was 36.58°; right AEI M2 was 53.35°, and left AEI M2 was 54.35°; right AEH value was 6.47 mm, and left AEH value was 6.69 mm; right AEL value was 12.10 mm, and left AEL value was 12.30 mm.
Mean values of TMJ parameters measured on LMP silicone impressions: right AEI M1 was 37.91°, and left AEI M1 was 38.26°; right AEI M2 was 60.13°, and left AEI M2 was 61.42°; right AEH value was 6.74 mm, and left AEH value was 6.93 mm; right AEL value was 12.15 mm, and left AEL value was 12.40 mm.
Mean values of TMJ parameters measured on CCP silicone impressions: right AEI M1 was 34.72°, and left AEI M1 was 34.59°; right AEI M2 was 53.49°, and left AEI M2 was 54.34°; right AEH value was 6.20 mm, and left AEH value was 6.43 mm; right AEL value was 11.76 mm, and left AEL value was 12.30 mm.
Mean values of TMJ parameters measured on IP silicone impressions : right AEI M1 was 31.56°, and left AEI M1 was 36.62°; right AEI M2 was 44.14°, and left AEI M2 was 52.67°; right AEH value was 5.82 mm, and left AEH value was 6.32 mm; right AEL value was 11.99 mm, and left AEL value was 11.55 mm.
Mean values of TMJ parameters measured on KP silicone impressions: right AEI M1 was 34.36°, and left AEI M1 was 34.54°; right AEI M2 was 46.44°, and left AEI M2 was 50.25°; right AEH value was 5.98 mm, and left AEH value was 5.85 mm; right AEL value was 12.09 mm, and left AEL value was 11.57 mm.
Mean values of TMJ parameters measured on AAP silicone impressions: right AEI M1 was 36.48°, and left AEI M1 was 36.42°; right AEI M2 was 50.24°, and left AEI M2 was 52.50°; right AEH value was 6.72 mm, and left AEH value was 6.60 mm; right AEL value was 12.66 mm, and left AEL value was 12.48 mm.
Mean values of TMJ parameters measured on ACP silicone impressions: right AEI M1 was 36.26°, and left AEI M1 was 38.72°; right AEI M2 was 52.85°, and left AEI M2 was 58.37°; right AEH value was 6.60 mm, and left AEH value was 6.86 mm; right AEL value was 12.73 mm, and left AEL value was 12.52 mm.
Mean AEI values measured by method M1 on lateral skull photographs ranged from 29.59° to 37.65°, and mean AEI values measured by method M2 ranged from 45.25° to 58.60°. Mean AEH values measured on lateral skull photographs ranged from 5.88 mm to 9.78 mm, and mean AEL values ranged from 11.12 mm to 13.33 mm.
Mean AEI values measured by method M1 on cephalograms ranged from 36.54° to 39.84°, while mean AEI values measured by method M2 ranged from 56.53° to 59.98°. Mean AEH values measured on cephalograms ranged from 6.69 mm to 9.63 mm, while mean AEL values measured on cephalograms ranged from 12.78 mm to 13.56 mm.
Mean AEI values measured by method M1 on panoramic radiographs ranged from 32.21° to 40.58°, while mean AEI values measured by method M2 on panoramic radiographs ranged from 53.86° to 60.81°.
AEI, AEH, AEL values didn't differ significantly between historical populations (p>0.05) regardless of the performed measurement technique. AEI, AEH, AEL values didn't differ significantly according to the body side, gender, age and tooth abrasion (p>0.05). Also, the combination of certain historical population and some other variable (age, gender, tooth abrasion, Kennedy and Eichner classification of dental arches) didn’t significantly affect measured TMJ parameters (p>0.05).
AEI, AEH and AEL values increased from lateral to medial sections through the silicone impressions of the articular eminence and fossa glenoidalis. The highest AEI, AEH and AEL right side value was measured on the second or third section, and the lowest value was measured on the fifth, most medial section (p<0.05). On the left side, the highest AEI, AEH and AEL values were measured on the third section through the silicone impressions of the articular eminence and fossa glenoidalis while lower values were measured on the fifth section (p<0.05) except AEI M1 with highest value on the fifth section (p<0.05).
In most cases, positive, medium or strong correlation existed between AEI M1 and AEH; AEI M2 and AEH, as well as between AEH and AEL values (p<0.05). Between AEI and AEL values was found positive but weak correlation (p<0.05).
AEI M1 and AEI M2 values measured on panoramic radiographs and cephalograms were statistically significantly higher than values measured on lateral photographs (p<0.05).
If we compare results obtained by “classic method” with values measured on three-dimensionally scanned silicone impressions (laser and optical), from a total of 16 (100%) statistically significant differences, the smallest difference between values measured by „classic method“ and values measured on laser scans existed in 13 cases (81.3%) whereas the results measured on optical scans showed the highest variation (p<0.05). For the remaining 3 (18.7%) cases, the smallest difference was obtained between values measured on the laser and optical scans with highest variation of results measured by classic method (p<0.05).
Conclusion: AEI, AEH and AEL values didn't differ among historical populations and according to the body side, gender, age, Kennedy and Eichner classification of dental arches and tooth abrasion. The lowest TMJ values on sections through the silicone impressions of the articular eminence were medial and lateral, and higher values on the central sections. Higher AEI value follows higher AEH, and higher AEH results in greater AEL value. Different measurement techniques give consequently different values of TMJ parameters (higher values measured on radiographic images), therefore, it is of great importance to state which technique was used when expressing AEI, AEH, and AEL data. Among values measured on optical and laser scanned impressions and by „classic“ method, the greatest variations were mostly obtained for values measured on optical scans, while the „classic method“ can still be used as a method with very high accuracy. |
