Abstract
Objectives
To evaluate the facial characteristics of edentulous older adults who underwent rehabilitation using complete dentures, and to compare them with dentate individuals.
Background
Edentulism rehabilitation with complete dentures aims to restore occlusion and facial aesthetics.
Materials and Methods
The study included 102 edentulous participants needing prosthodontic rehabilitation with complete dentures and 30 with a natural dentition (aged >65). The 3D facial scans were performed using an Artec optical scanner. Superficial facial landmarks were identified, and 16 parameters were calculated. Regional analysis with the superimposition of two scans was used to calculate the average distances and percentage of non‐matching surfaces in the 11 regions. Paired and independent t‐tests (α = .05) were used to test for group differences, as appropriate.
Results
After rehabilitation with complete dentures, facial changes were most noticeable in the perioral region: wider rima oris, longer upper lip, wider upper vermilion, and more protruded profile. The comparison of facial regions without and with dentures showed fuller and curvier cheeks, with no direct influence of dentures. The edentulous faces with dentures appeared shorter and more retruded than those of dentate individuals. A narrower lower vermilion, retruded upper lip, and more flattened facial profile were observed in females with dentures than in their dentate peers.
Conclusion
Besides the expected positive influence of rehabilitation with complete dentures on facial appearance in the perioral region, there are some unexpected changes, such as fuller cheeks, but there is still deficiency in vertical facial dimensions and a more flattened facial profile.
Keywords: complete dentures, edentulism, facial characteristics, gerodontology, older adults, prosthodontic rehabilitation
1. INTRODUCTION
In humans, aging is a natural and complex process involving the gradual deterioration of various biological functions over time, and it can be seen in facial changes. In the population of developed countries, population ageing is the result of increased life expectancy and a continued decline in fertility rates. The older population has many different health issues, such as cardiovascular diseases, arthritis, osteoporosis, diabetes, cognitive dysfunction, vision and hearing loss, and tooth loss. Edentulism is a concern due to its impacts on both extraoral and intraoral aspects, ultimately affecting oral functions and facial aesthetics. Facial appearance greatly influences psychosocial well‐being and presents the stigma of age discrimination. 1 Older individuals view oral health as essential to their quality of life. Most frequently, oral health impacts eating and comfort, but its influence on facial appearance is also important. 2
Facial ageing represents the transition from youthful facial proportions with an optimal interplay between bone morphology and soft‐tissue volume, to the imbalance between these elements that results in the manifestations of an aged visage. 3 , 4 A prominent contributor to external ageing is tooth loss accompanied by irreversible alveolar ridge resorption in both jaws. The average count of lost teeth increases with advancing age, 5 with dental caries and periodontal disease serving as the primary cause of tooth loss, eventually, if untreated, leading to edentulism. 6 The prevalence of edentulism varies widely among countries and regions. In developed countries, its prevalence has decreased substantially over the past few decades. 7 , 8 According to a study published by the Slovenian National Institute of Public Health in 2019, the prevalence of edentulism among older adults in Slovenia was approximately 12%. 9 Edentulism remains an important public health issue due to population aging and the increasing number of older adults. 10
Several options for rehabilitating edentulous mouths are available, including complete dentures, implant‐supported overdentures and implant‐supported fixed prostheses. Rehabilitation with mucosa‐born removable complete dentures remains the gold standard in many countries. 11 The goal of rehabilitating an edentulous mouth with complete dentures is to replace lost teeth, gingiva and alveolar bone, thereby restoring chewing and speaking skills and facial aesthetics while improving quality of life.
This study aimed to objectively evaluate the facial characteristics of edentulous older adults rehabilitated with complete dentures and to compare them with those of dentate older adults of Caucasian ancestry in Slovenia. A non‐invasive digital three‐dimensional (3D) technology was used. In addition to the standard anthropometric analysis of facial parameters, the study also quantified the matching of scans before and after rehabilitation with complete dentures. The research questions were as follows: (i) how effectively can facial proportions and volumes be restored with complete dentures; and (ii) do the restored facial dimensions differ from those of dentate older people?
2. MATERIALS AND METHODS
This study was approved by the Slovenian National Medical Ethics Committee (MZ 0120‐392/2016‐2, KME 64/08/16). Written informed consent for participation was obtained from all patients, and the study did not influence clinical treatment protocols.
The study included 102 edentulous participants (34 men and 68 women) and 30 dentate adults (13 men and 17 women) older than 65. The participants in the study group had been edentulous for at least 1 year (men 17.6 ± 11.1 years, women 20.6 ± 12.0 years). They were rehabilitated with complete dentures in both jaws at the Department of Prosthodontics at the University Medical Centre, Ljubljana, between 2016 and 2019. Older adults with teeth were included in the dentate comparison group. On average, the male group had 24 ± 4 teeth, and the female group had 23 ± 3 teeth. They had a stable occlusion and repeatable intercuspal position. They had all of their teeth in the inter‐canine region and 3 or more functional dental units of posterior teeth. A premolar in occlusal contact was counted as 1 occlusal unit, and the whole molar crown in the occlusal contact was counted as 2 occlusal units. None of the patients had removable dentures. Excluded from the study were congenital craniofacial anomalies, a history of major facial trauma, plastic or orthognathic surgery, facial palsy and tremors. The information was obtained by meticulously studying the medical history of the participants. Male participants with facial hair were excluded, in order to avoid artefacts. Weight and body mass index (BMI) were assessed to ensure comparability between the study and dentate comparison groups. Due to the sex‐specific nature of facial characteristics, analyses were undertaken separately for men and women.
The 3D facial scans were obtained from all the participants using the 3D optical scanner MHT by Artec with a 3D point accuracy of 0.1 mm and 0.15% 3D accuracy over 100 cm, according to the manufacturer. The 3D camera uses the flying triangulation method for surface scanning, 12 and it is a safe, non‐invasive and repeatable method. 13 During image acquisition, special attention was paid to positioning the participants and relaxing their facial musculature. The participants were seated in a relaxed posture with a natural head position, looking at the front in a relaxed mouth‐closed position (without contractions of the mouth muscles). The instructions were not to swallow and to keep both eyes open while acquiring the image, which took less than 10 seconds. The natural position of the head was achieved by moving it up and down a few times and then stopping the movement and looking at the distance. A relaxed mouth‐closed position was achieved by repeated wide opening and closing of the mouth until light contact with the lips was achieved. In the edentulous group, 3D scans were performed twice on the same day with and without complete dentures, but there were at least 60 minutes in between. The scans were performed at least one week after inserting the new dentures. The dentate comparison group underwent scanning only once.
The 3D surface images were subsequently processed using Artec Studio software to obtain 3D scans in STL format. The scans were pre‐processed to obtain a clean face image, eliminating unnecessary data. The resultant image was delimited superiorly by the border extending beneath the hairline on the forehead, laterally in front of the ears and around the lower jaw angle, and inferiorly by the submental region extending distal to the hyoid bone. Subsequent analyses were conducted using the computer program RapidForm 2006 (INUS Technology Inc.) by only one experienced observer. Before the study, intra‐rater reliability (repeated measures by the same observer at different time points) was verified, showing that the method was accurate and reliable (Table S1). 3D facial analyses of the 37 superficial facial landmarks were performed manually using 3D facial scans (Table 1). The coordinates of the points (x, y, z) were imported into Microsoft Excel to calculate the values of different superficial facial measurements. The distances, lines and angles determined using the superficial facial landmarks are presented in Table 1 and Figure 1A–C. A paired t‐test was used to compare the average values of facial measurements in the study group without and with complete dentures. An independent t‐test was used to compare the average values of the measurements between older adults with complete dentures and the dentate comparison group. The Mann–Whitney U test was used for the variables that had significant values in Shapiro–Wilk's test for normality. Statistical significance was set at p < .05.
TABLE 1.
List of superficial facial landmarks and facial measurements used in the analyses.
| Sign | Name | Profile definition | En face definition |
|---|---|---|---|
| tr | Trichion | Line between scalp and forehead | Midpoint |
| g | Glabella | Most anterior point of the forehead | Midpoint |
| n | Soft‐tissue nasion | Most posterior point on the soft‐tissue contour of the base of the nasal root at the level of the frontonasal suture | Midpoint of the nasal root |
| enL, enR | Endocanthion, left and right | / | Soft‐tissue point located at the inner commissure of each eye fissure |
| exL, exN | Exocanthion, left and right | / | Soft‐tissue point located at the outer commissure of each eye fissure |
| soL, soR | Supraorbitale, left and right | Most anterior point above the orbit | Midpoint between endocanthion and exocanthion |
| ioL, ioR | Infraorbitale, left and right | Prominent rim under the inferior eyelid | Midpoint between endocanthion and exocanthion |
| zyL, zyR | Zygoma, left and right | / | Point above lateral part of corpus ossis zygomatici before it straightens in the AP direction backward |
| zypL, zypR | Zygoma prominence, left and right | / | Intersection of vertical line through exL/R and transverse line through zyL/R |
| prn | Pronasale | Most anterior point of nasal tip | Midpoint of nasal tip |
| alL, alR | Ala nasi, left and right | / | Most lateral point on each alar contour |
| acL, acR | Alare curvature, left and right | / | Point at the facial insertion of each alar base |
| cm | Columella | / | Midpoint of the columella crest at the level of the nostril top points |
| sn | Subnasale | Contact of philtrum and columella | Midpoint |
| a | Subspinale | Most posterior point of the philtrum | Midpoint |
| ls | Labiale superior | Point of the vermilion line of the upper lip | Midpoint |
| St | Stomion | / | Midpoint of the horizontal labial fissure |
| li | Labiale inferior | Point of the vermilion line of the lower lip | Midpoint |
| cphL, cphR | Crista philtri, left and right | / | Point at each crossing of the philtrum and cupids bow |
| chL, chR | Cheilion, left and right | / | Point at each labial commissure |
| b | Sublabiale | Most posterior point on the labiomental soft‐tissue contour that defines the border between the lower lip and the chin | Midpoint |
| pg | Pogonion | Most anterior point of the chin | Midpoint |
| meL, meR | Menton, left and right | / | Point where the vertical point through chL/R reaches the lowest point of the chin |
| gn | Gnathion | Most inferior point on the soft‐tissue contour of the chin | Midpoint |
| goL, goR | Gonion, left and right | Ramus ascendens and corpus mandible tangents intersection | Most prominent point placed lateral and inferior to chL/R point |
| Name | Definition | |
|---|---|---|
| Facial widths | Facial width (mm) | zyL‐zyR |
| Mouth width (mm) | chL‐chR | |
| Facial heights | Total facial height (mm) | g‐pg |
| Middle facial height (mm) | g‐sn | |
| Lower facial height (mm) | sn‐pg | |
| Upper lip height (mm) | sn‐st | |
| Lower lip height (mm) | st‐pg | |
| Upper vermilion height (mm) | ls‐st | |
| Lower vermilion height (mm) | st‐li | |
| Nose height (mm) | n‐prn | |
| Facial distances in profile (depths) | Distance between upper lip and E‐line (mm) | |
| Distance between lower lip and E‐line (mm) | ||
| Facial angles | Facial angle (°) | n‐sn‐pg |
| Soft‐tissue ANB angle (°) | a‐n‐b | |
| Angle of lower facial height (°) | sn‐st‐pg | |
| Nasolabial angle (°) | cm‐sn‐ls |
FIGURE 1.
Facial parameters on facial scans are presented in A, B, and C figures; graphical representations of scans divided into 11 regions are seen in D and E figures, and the superimposition of the scans before and after rehabilitation with the complete denture and the differences along with coloured deviation map is seen in F. The units in the scale of the coloured deviation map are mm (F).
Superimposition of the 3D scans was used to evaluate the degree of deviation between two scans of the same individual in the study group (with and without complete dentures). The scan without denture was imported into the computer program RapidForm 2006 (INUS Technology Inc.) and divided into eleven regions described below. The scan obtained with dentures was then imported into the same workspace as the scan without dentures and registered using a regional iterative closest‐point algorithm. 14 The superimposition reference area was the forehead (region 1), a reliable area for non‐growing patients, 15 and the dentures did not influence it. The shell‐to‐shell difference analysis performed the average and standard deviation distances between the two scans in the regions observed and the percentage of non‐matching surfaces. When calculating the percentage of non‐matching surfaces, the computer program included distances greater than 0.5 mm.
Eleven regions of the face were defined with four transverse planes running through the mid‐endocanthion, subnasale, stomion and gnathion. Region 1 was above the horizontal plane running through the mid‐endocanthion, covering the forehead, supraorbital rims, bridge of the nose and the upper half of the eyes with the upper eyelids. Region 2 was located between the horizontal planes running through the mid‐endocanthion and subnasale, including the nose, the upper part of the cheeks with zygoma prominence and the lower half of the eyes with lower eyelids. Region 3 was located between the horizontal planes running through the subnasale and stomion, including the upper lip and middle part of the cheeks. Region 4 was between the horizontal planes running through the stomion and gnathion, including the lower lip, the chin region with the sulcus mentolabialis and the lower part of the cheeks with the mandibular angle. Region 5 was below the horizontal plane running through the gnathion, covering the lower part of the chin and the submental area. Furthermore, the uppermost and lowermost regions were treated as a whole. Two vertical (sagittal) planes running through the mouth's outer corners divided the three middle regions into the centre, left and right sides. Graphical representations of scans divided into 11 regions, superimposition and the differences between regions are presented in Figure 1D–F, along with coloured deviation maps.
3. RESULTS
Table 2 presents the sex, age, weight, BMI and period of edentulism in the study and dentate comparison groups. Figure 2 displays facial scans of participants in different groups.
TABLE 2.
Basic descriptive statistics of the study sample: number, average age in years, weight in kilograms, average body mass index and period of edentulism (brackets contain standard deviations unless otherwise indicated).
| Sex | Study group, n a = 102 | Dentate comparison group, n a = 30 | ||
|---|---|---|---|---|
| Male (n a = 34) | Female (n a = 68) | Male (n a = 13) | Female (n a = 17) | |
| Mean age | 74.4 (7.7) | 77.2 (8.0) | 72.1 (10.0) | 76.5 (10.9) |
| Mean weight | 78.2 (12.2) | 68.0 (13.2) | 84.0 (13.2) | 69.0 (15.2) |
| Mean BMI b | 26.7 (3.7) | 26.5 (4.3) | 27.4 (4.0) | 25.4 (3.3) |
| Mean period of edentulism | 17.6 (11.1) | 20.6 (12.0) | / | / |
Number.
Body mass index.
FIGURE 2.
The facial scan of the female participant before (enface—A, in profile—E) and after rehabilitation with a complete denture (enface—B, in profile—F), the superimposition of both scans (enface—C, in profile—G) and female facial scan of dentate comparison group with natural teeth (enface—D, in profile—H). The units in the scale of the coloured deviation map are mm (C).
In the comparison between edentulous faces without complete dentures and those after their insertion (Table 3), among the 16 parameters, there was a difference observed in 8 linear parameters and all 4 angular parameters in the female group. The difference was observed in 6 linear and all 4 angular parameters in the male group. After the insertion of complete dentures, the mouth was wider in both sexes. There was no difference in the facial heights (total, middle and lower facial heights) in both sexes, except for the total facial height in the female group, where female faces were longer after inserting complete dentures. Dentures influence upper and lower lip heights. The upper lip showed an increase in length (female group—average 1.1 mm, male group—average 1.5 mm), while the lower lip showed a reduction (average 1.6 mm) for both sexes. The upper vermilion height increased in both groups; however, the lower vermilion height experienced an important increase solely in the female group. The data showed an important improvement in the facial profile after the insertion of complete dentures in both sexes; the upper and lower lip distances to the E‐line were reduced; facial angles, angles of lower facial height, and nasolabial angles were smaller, and soft‐tissue ANB angles were larger.
TABLE 3.
Comparison between edentulous faces without complete dentures and with complete dentures separately for females and males (brackets contain standard deviations unless otherwise indicated).
| Males without CD a /with CD a | Females without CD a /with CD a | |||||
|---|---|---|---|---|---|---|
| Em b (n c = 34) | Pm d (n c = 34) | t‐Test, sig. | Ef e (n c = 68) | Pf f (n c = 68) | t‐Test, sig. | |
| Facial width (mm) | 126.4 (7.7) | 125.3 (8.4) | .625 | 119.8 (7.7) | 119.8 (7.9) | .978 |
| Mouth width (mm) | 48.4 (6.4) | 52.5 (6.0) | .000* | 44.2 (5.2) | 48.1 (4.7) | .000* |
| Total facial height (mm) | 123.2 (7.1) | 123.7 (6.7) | .479 | 111.7 (6.1) | 112.5 (6.4) | .040 |
| Middle facial height (mm) | 71.4 (3.9) | 71.4 (3.9) | .839 | 64.1 (4.1) | 64.5 (4.2) | .191 |
| Lower facial height (mm) | 52.2 (5.0) | 52.9 (4.5) | .204 | 48.0 (4.4) | 48.4 (4.6) | .182 |
| Upper lip height (mm) | 22.4 (3.6) | 23.9 (3.2) | .000* | 20.5 (3.2) | 21.6 (2.7) | .000* |
| Lower lip height (mm) | 31.0 (3.0) | 29.4 (2.5) | .002* | 28.9 (3.5) | 27.3 (3.3) | .000* |
| Upper vermilion height (mm) | 4.2 (1.2) | 6.2 (1.5) | .000* | 4.5 (1.5) | 6.4 (1.5) | .000* |
| Lower vermilion height (mm) | 5.6 (2.5) | 5.8 (2.1) | .669 | 5.0 (2.2) | 6.0 (1.7) | .000* |
| Nose height (mm) | 50.3 (4.0) | 50.4 (3.9) | .726 | 44.8 (3.6) | 44.8 (3.7) | .932 |
| Distance upper lip to E‐line (mm) | 13.4 (4.5) | 8.6 (3.0) | .000* | 13.6 (3.1) | 9.0 (2.3) | .000* |
| Distance lower lip to E‐line (mm) | 9.8 (4.2) | 6.1 (3.1) | .000* | 10.5 (3.9) | 6.8 (2.4) | .000* |
| Facial angle (°) | 171.3 (5.6) | 168.8 (6.3) | .000* | 173.0 (4.8) | 170.9 (5.0) | .000* |
| Soft‐tissue ANB angle (°) | 2.9 (1.6) | 3.8 (2.3) | .007 | 2.4 (1.6) | 3.1 (1.9) | .008 |
| Angle of lower facial height (°) | 202.6 (12.2) | 190.5 (6.1) | .000* | 205.7 (11.7) | 194.0 (7.2) | .000* |
| Nasolabial angle (°) | 117.2 (9.6) | 106.4 (8.6) | .000* | 115.4 (11.6) | 105.8 (9.2) | .000* |
Note: Due to multiple pairwise comparison, we adjusted the level of significance with applying Bonferroni correction. Due to 16 test, the new significant level was set below .003.
Complete dentures.
Edentulous males.
Number.
Males with complete dentures.
Edentulous females.
Females with complete dentures.
Statistically significant difference.
The comparison of edentulous faces with complete dentures and their dentate peers showed few differences between the sexes (Table 4). Significant differences were observed in 6 linear and 3 angular parameters in the female group and 4 linear and 1 angular parameters in the male group. Both sexes with complete dentures had shorter faces than those in the dentate older adults. The total facial height was reduced by 10 mm, and the middle and lower facial heights were reduced by 5 mm in both sexes. The lower lip was shorter (p < .0001) in the group with complete dentures in both sexes. The lower vermilion height was found to be, on average, 1 mm shorter in females with complete dentures than the male group. The upper lip in the female group with complete dentures appeared more retruded, and the distance to the E‐line was longer (average of 1.4 mm) than that in the dentate comparison group. Conversely, it was not seen in males. The facial angle and angle of the lower facial height were larger in the female study group (p = .006 and p = .008, respectively), and the soft‐tissue ANB angle was smaller than that in the dentate comparison group. In the male group among the angles, a significant difference (p = .032) was observed only in the angle of lower facial height, which was larger in the study group with complete dentures.
TABLE 4.
Comparison of edentulous faces with complete dentures and dentate comparison group separately for females and males (brackets contain standard deviations unless otherwise indicated).
| Males with CD a /DCG b | Females with CD a /DCG b | |||||
|---|---|---|---|---|---|---|
| Pm d (n c = 34) | Cm e (n c = 13) | t‐Test, sig. | Pf f (n c = 68) | Cf g (n c = 17) | t‐Test, sig. | |
| Facial width (mm) | 125.3 (8.4) | 126.8 (4.5) | .945 | 119.8 (7.9) | 120.3 (7.2) | .862 |
| Mouth width (mm) | 52.5 (6.0) | 49.9 (5.9) | .200 | 48.1 (4.7) | 48.0 (5.0) | .934 |
| Total facial height (mm) | 123.7 (6.7) | 133.5 (6.4) | .000* | 112.5 (6.4) | 121.1 (6.5) | .000* |
| Middle facial height (mm) | 71.4 (3.9) | 76.3 (5.5) | .001* | 64.5 (4.2) | 68.9 (4.1) | .000* |
| Lower facial height (mm) | 52.9 (4.5) | 57.5 (3.8) | .002* | 48.4 (4.6) | 53.0 (5.5) | .001* |
| Upper lip height (mm) | 23.9 (3.2) | 24.0 (2.3) | .201 | 21.6 (2.7) | 21.8 (2.8) | .731 |
| Lower lip height (mm) | 29.4 (2.5) | 33.7 (2.9) | .000* | 27.3 (3.3) | 31.4 (4.0) | .000 h , * |
| Upper vermilion height (mm) | 6.2 (1.5) | 6.0 (1.9) | .651 | 6.4 (1.5) | 5.8 (1.4) | .129 h |
| Lower vermilion height (mm) | 5.8 (2.1) | 6.1 (1.7) | .572 | 6.0 (1.7) | 7.0 (2.0) | .053 h |
| Nose height (mm) | 50.4 (3.9) | 52.2 (4.5) | .201 | 44.8 (3.7) | 46.8 (4.3) | .067 |
| Distance upper lip to E‐line (mm) | 8.6 (3.0) | 9.2 (2.6) | .487 | 9.0 (2.3) | 7.6 (2.9) | .043* |
| Distance lower lip to E‐line (mm) | 6.1 (3.1) | 6.9 (2.6) | .435 | 6.8 (2.4) | 5.8 (2.9) | .134 |
| Facial angle (°) | 168.8 (6.3) | 171.2 (4.9) | .228 | 170.9 (5.0) | 167.2 (4.5) | .006* |
| Soft‐tissue ANB angle (°) | 3.8 (2.3) | 3.4 (1.5) | .924 h | 3.1 (1.9) | 4.4 (1.6) | .007 h , * |
| Angle of lower facial height (°) | 190.5 (6.1) | 186.0 (6.1) | .010 h , * | 194.0 (7.2) | 188.8 (6.6) | .011 h , * |
| Nasolabial angle (°) | 106.4 (8.6) | 102.1 (11.5) | .601 h | 105.8 (9.2) | 105.6 (8.7) | .938 |
Complete dentures.
Dentate comparison group.
Number.
Males with complete dentures.
Dentate males.
Females with complete dentures.
Dentate females.
Mann–Whitney U test.
Statistically significant difference.
Facial scans taken before and after the placement of complete dentures were superimposed to compare the surfaces. Average scan‐to‐scan distances and percentage of non‐matching surfaces, considering distances larger than 0.5 mm, were evaluated and are presented in Table 5. Overall, scans of the entire face did not match in 44% and 42% of the surfaces among females and males, respectively, and the average distance between the two scans was 0.8 mm in both sexes. In region 2, the percentage of non‐matching surfaces was 31% and 35% in the female and the male groups, respectively. The data showed us the largest differences between scans in regions 3, 4 and 5, particularly in the centre of regions 3 and 4, where non‐matching surfaces were over 80%. The mean distance between scans in region C3 was 2.9 and 3.1 mm among the female and male groups, respectively.
TABLE 5.
Mean distances (mm) and percentages of non‐matching surfaces in observed facial regions between scans of subjects with and without complete dentures separately for females and males (brackets contain standard deviations unless otherwise indicated).
| Females | Males | |||
|---|---|---|---|---|
| Mean (mm) | Percentage | Mean (mm) | Percentage | |
| Whole face | 0.8 (0.9) | 44 | 0.8 (0.9) | 42 |
| Region 1 | 0.3 (0.3) | 13 | 0.3 (0.4) | 16 |
| Region 2 | 0.5 (0.4) | 31 | 0.5 (0.5) | 35 |
| Region R2 | 0.4 (0.4) | 30 | 0.5 (0.5) | 36 |
| Region L2 | 0.4 (0.4) | 29 | 0.5 (0.4) | 30 |
| Region C2 | 0.5 (0.5) | 34 | 0.6 (0.6) | 41 |
| Region 3 | 2.1 (1.2) | 64 | 1.4 (1.3) | 66 |
| Region R3 | 1 (0.9) | 58 | 1.1 (1) | 63 |
| Region L3 | 1 (0.9) | 57 | 1 (0.9) | 56 |
| Region C3 | 2.9 (1) | 96 | 3.1 (1.1) | 96 |
| Region 4 | 1.1 (0.9) | 67 | 1.2 (0.9) | 69 |
| Region R4 | 1 (0.8) | 63 | 1.1 (0.8) | 62 |
| Region L4 | 1 (0.7) | 63 | 1.1 (0.8) | 67 |
| Region C4 | 1.6 (1) | 80 | 1.8 (0.9) | 82 |
| Region 5 | 1.4 (0.8) | 78 | 1.4 (0.8) | 72 |
4. DISCUSSION
Rehabilitating edentulism aims to restore essential oral functions, such as chewing, eating and speaking, while reinstating a natural facial appearance harmonising with the denture teeth. The study confirmed the positive impact of prosthodontic rehabilitation with complete dentures on the facial appearance of edentulous individuals with the 3D stereophotometrical method. As expected, changes were most prominent in the perioral region and facial profile; surprisingly, there were no differences in facial height. Despite the absence of direct influence of the dentures in the upper cheek area, they become fuller and curvier. Relative to individuals with natural teeth, prosthodontically rehabilitated faces were shorter, and perioral tissues in profile had a more retruded appearance. Furthermore, sexual dimorphism was observed in the narrower lower vermilion, retruded upper lip and flattened facial profile among females.
Stereophotogrammetry and superficial facial analysis of 3D facial scans are now well‐established and proven methods. However, some rules must be followed. The most important aspect is to position the subject's head in the natural head position and to achieve the mandibular rest position. 16 Demirekin et al. 17 did a study with a similar method evaluating the impact of prosthodontic rehabilitation of edentulous faces but with no comparison group with natural teeth and younger participants. In our study, a sex‐based comparison of the groups was performed. 18 Similar studies found in the literature did not appreciate sexual dimorphism in their analyses and did not divide participants by sex. 17 , 19 , 20 , 21 , 22 Another challenging issue is comparing facial features among individuals with varying BMIs because BMI significantly affects facial proportions. In our study, the BMIs of the participants were slightly higher than those of the general population, which is characteristic of older adults. 23 Still, no differences were observed between the groups. Limitations of the present study were the inclusion of the measurements made only for one ethnic group, Caucasian individuals, and a small dentate comparison group sample size. Another weakness of the study is a relatively short period between the new prostheses' first insertion and scanning (from 1 to 3 weeks), which could disable continuing soft tissue adaptation to a new situation.
As expected, changes around the mouth are consequences of tooth loss and denture placement, and the aim is to compensate for alveolar bone resorption and replace the missing teeth to support soft tissues. Dentures resulted in wider rima oris and longer upper lip for both sexes, as described in a previous study. 21 However, in our study, the lower lip was shorter for both sexes. The lengthening of the upper lip and shortening of the lower lip indicate changes in the position of the mouth and musculus orbicularis oris, adapting to the new underlying support, but as already described as a consequence of facial aging. 24 Upper and lower lip vermilions become narrower with age, as described in a previous study. 3 A study by Pucciarelli et al. 20 reported similar findings regarding mouth width and upper and lower vermilion heights but with no influence of complete dentures on lip height.
All parameters in the profile view were influenced by the complete dentures and improved after placement, with no discernible gender‐based differences. As previously described, the loss of incisors and canines results in retruded lips and a concave facial profile, 25 the aesthetics of which improve with the replacement of these teeth. The facial angle, depicting the face contour in profile, becomes less obtuse, indicating a less concave appearance. The main factors affecting the nasolabial angle are the skeletal angle ANB, the inclination of the incisors and canines supporting the upper lip, and ptosis of the nose tip. 26 In our study, a greater nasolabial angle was observed in the group with complete dentures, which underscores the impact of lip support, as previously described. 19 Bidra et al. 27 showed that the influence of labial flanges of complete dentures on a nasolabial angle is clinically unimportant.
One of the main challenges in prosthodontics is establishing the vertical dimension of occlusion (VDO), which greatly influences facial aesthetics. Determining VDO is an essential part of complete denture fabrication. From an aesthetic point of view, it implies achieving an appropriate lower facial height and ensuring a pleasing appearance of the lips, teeth and gums. 28 Clinicians can choose and combine pre‐extraction and post‐extraction methods to determine VDO. 29 Similar studies have found that facial height, especially lower facial height, increased after inserting complete dentures. 17 , 19 , 20 , 21 Surprisingly, our study showed no changes in the middle and lower facial heights. The outcome is likely attributed to the relaxed mouth‐closed position that was opted for the scans in our study. Most of the previously mentioned studies favoured the use of for their scans, 19 , 20 despite the study of Toyoshima et al., 21 where the position of the mandible during the scanning was not defined. This indicates that the relaxation method for determining the VDO is reproducible in an individual edentulous patient, regardless of whether the patient has dentures.
Unexpected findings, such as shorter faces with complete dentures than dentate ones, have not been described before. 20 , 22 Surprisingly, they were shorter in both the middle and lower thirds, and this was consistent for both sexes. This suggests that complete dentures did not completely compensate for the loss of alveolar bone. A study by Tang et al. 19 demonstrated the impact of alveolar ridge atrophy on facial height and consequently on facial aesthetic. Additionally, our study displayed a smaller angle in the lower facial third in participants with complete dentures, indicating more retruded perioral tissue. Interestingly, sexual dimorphism was observed in some facial characteristics. Females with prostheses had a narrower lower vermilion, less protruded upper lip and flatter facial profiles than females with preserved natural teeth. This means that prostheses in females did not fully compensate for the loss of tissues, making it a gender‐specific characteristic.
A more comprehensive and illustrative approach to describe changes in the entire face as a whole unit 30 after complete denture insertion involves a regional analysis with superimposition on the forehead, facilitating the visualisation of alterations in all three planes and has not been described in literature yet. Significant changes occurred across all facial regions following the insertion of complete dentures. In the superimposition reference area forehead region, two scans aligned well in almost 90% (Table 5) since the prosthetics did not influence this region. The small percentage of non‐matching surfaces is probably a consequence of the eyebrows and surrounding hair. As expected, most changes were noticed in the lower facial third, especially in the perioral and chin regions, where almost 100% of the surface exhibited changes following prosthodontic rehabilitation. The cheeks became fuller and curvier, resulting in a healthier and youthful appearance, as can be achieved with dermal fillers, although this was no direct influence of the prostheses. This phenomenon of the face acting as a unified soft‐tissue mask has previously been documented following bone changes in orthognathic patients. 31
Turning to the clinical implications, understanding facial characteristics of edentulous faces rehabilitated with complete dentures and dentate patients of the same age may help to improve rehabilitation outcomes. Besides standard diagnostic procedures and clinical evaluation, the 3D stereophotogrammetry could be a new diagnostic and research procedure involved in clinical practice to understand better and consider soft‐tissue response on prosthodontic rehabilitation with complete dentures, and 3D regional analysis offers more data on facial changes. To observe the soft tissue adaptation on complete dentures, the same study, but with a 3 to 6‐month time gap between denture insertion and scanning, should be done. 22 It would also be valuable for clinical work to differentiate facial characteristics in the early stage of edentulism (after the first complete dentures) and after a longer period of edentulism (after the following complete dentures).
5. CONCLUSIONS
Our study confirmed the positive impact of complete denture rehabilitation on the facial appearance of edentulous individuals; significant changes of the entire face followed, especially in the perioral region and facial profile, but did not influence facial height. With the 3D regional analysis, alterations in the upper cheek area were seen, which became fuller and curvier despite the absence of direct influence from the dentures. However, when compared to individuals with natural teeth, prosthodontically rehabilitated faces were shorter.
Supporting information
Table S1.
Skomina Z, Kuhar M, Verdenik M, Ihan Hren N. Stereophotometric facial changes in edentulous older adults after rehabilitation with complete dentures. Gerodontology. 2025;42:100‐109. doi: 10.1111/ger.12774
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Supplementary Materials
Table S1.