Reconsidering the role of nasolabial angle in premolar extraction decision-making: A case-series study.

OBJECTIVES: To evaluate the impact of changes in upper incisor inclination and position on the alteration of the nasolabial angle (NLA) in a series of cases involving the extraction of four first premolars. MATERIALS AND METHODS: The study included 41 patients who underwent orthodontic treatment with premolar extractions. The patients were divided into two groups based on their pretreatment NLA values: Group 1 (NLA ≤ 100°) and Group 2 (NLA > 100°). Measurements of NLA, U1.NA and U1-NA were obtained before and after treatment and U1-Ls pretreatment measure was registered. Statistical analyses were performed to compare the differences in NLA, U1.NA and U1-NA between the two groups and to evaluate the influence of these variables added to U1-Ls (T1) on NLA changes. RESULTS: The results showed that Group 1 exhibited significant changes in NLA, while Group 2 did not. However, both groups showed significant changes in U1.NA and U1-NA. In Group 1, 80% of the individuals presented an increase in NLA and 20% no changes. In Group 2, 10% presented a decrease, 57% no changes and 33% an increase in NLA values. Multiple linear regression analysis indicated that the group factor had a statistically significant influence on NLA variation. Additionally, in Group 2, a negative correlation was observed between changes in U1.NA and NLA. CONCLUSIONS: The findings suggest that individuals with higher pretreatment NLA values tend to maintain their NLA values even after the correction of upper incisor inclination.

Determination of Mouth Width for Facial Reconstruction Based on Statistical Regression Model.

INTRODUCTION: It is important to generate predictable statistical models by increasing the number of variables on the human skeletal and soft tissue structures on the face to increase the accuracy of human facial reconstructions. The purpose of this study was to determine mouth width 3-dimensionally based on statistical regression model. MATERIAL AND METHODS: Cone-beam computed tomography scan data from 130 individuals were used to measure the horizontal and vertical dimensions of orbital and nasal structures and intercanine width. The correlation between these hard tissue variables and the mouth width was evaluated using the statistical regression model. RESULTS: Orbital width, nasal width, and intercanine width were found to be strong predictors of the mouth width determination and were used to generate the regression formulae to find the most approximate position of the mouth. CONCLUSION: These specific variables may contribute to improving the accuracy of mouth width determination for oral and maxillofacial reconstructions.

Correlating Jaw Bone Growth and Nasal Morphology Among Adult Patients With Cleft Lip and Palate: A Retrospective Cephalometric Study.

This retrospective cross-sectional study reviewed adult patients with operated cleft lip and/or palate (CL/P) and normal control, and performed comprehensive craniofacial and nasal morphological analyses based on lateral cephalometric radiographs. Pearson or Spearman correlation coefficient assessed intraclass correlation. Seven hundred fifty-seven operated patients with CL/P, and 165 noncleft normal controls were enrolled. Among the normal and CL/P groups, S-N-A angle registered positive correlations with nasal base prominence (S-N'-Sn, degrees). Upper facial height (N-ANS, mm) had positive correlations with nasal dorsum length (N'-Prn, mm) and nasal bone length (N-Na, mm). Although in patients with bilateral cleft lip and palate, there were moderate negative correlations ( r =-0.541, P <0.05) with soft tissue facial profile angle (FH-N'Pog', degree) and nasolabial angle (Cm-Sn-ULA, degree). Correlation exists between the morphology of jaw bones and external nose among patients with CL/P. Maxillary sagittal insufficiency is associated with concave nasal profile, and maxilla height is associated with nasal length.

Longitudinal changes of the natural craniofacial and dentoalveolar complex in the fourth decade of life.

INTRODUCTION: This study aimed to longitudinally examine the changes in craniofacial and dentoalveolar regions during the third and fourth decades of life. METHODS: The data from this study constitute the cephalometric films and plaster models of 8 female and 8 male dental students or dentists. The mean chronological ages of the subjects at the first observation period was 22.09 years for females and 22.64 years for males. The material was collected over 3 intervals: 1985-1989, 1998-2000, and 2016-2017. The observation period was approximately 28 years. Acquired cephalometric recordings and dental models were assessed for subjects in their 20s (baseline), 30s, and 40s. Maxillary, mandibular, maxillomandibular, soft-tissue, and dentoalveolar cephalometric variables were measured with a cephalometric analysis software, and dental cast measurements were made with a digital caliper. Changes in the cephalometric films and dental casts were evaluated statistically. RESULTS: Statistical analysis showed that the length of the midfacial region increased with age. The height of the lower face increased significantly in females and the mandible can be seen mildly rotating to the posterior as it increased in length. The nose moved slightly forward and downward in males and females. Upper lip height was significantly increased in females; however, there was a significant reduction in upper lip thickness for males and females. Soft-tissue pogonion measurements showed a significant forward and downward chin movement in females. Overjet was significantly increased in females, whereas the mandibular arch length was significantly decreased for both sexes, although it was more prominent in females. There was a loss of space in the anterior segments of males and females, resulting in increased crowding. However, the loss of space was only significant in the mandible. CONCLUSIONS: We observed significant changes in skeletal, soft-tissue, and dentoalveolar variables of subjects in their third and fourth decades of life. The fact that many changes have occurred throughout this study demonstrates that the process of maturation and aging is ongoing.

Facial soft-tissue shape changes after fixed edgewise treatment with premolar extraction in individual artificial-intelligence-classified facial profile patterns.

OBJECTIVE: To examine the patterns of pretreatment facial soft tissue shape in orthodontic cases with premolar extraction using artificial intelligence (AI) and to investigate the corresponding changes. METHODS: One hundred and fifty-two patients who underwent orthodontic treatment with premolar extraction were enrolled. Lateral cephalograms were obtained before and after the treatment. For each record, the outlines of the nose-lip-chin profile and corresponding 21 cephalometric variables were extracted. The AI method classified pretreatment records into three subject groups based on the feature variables extracted from the outline. Dentoskeletal and soft tissue facial form changes observed after treatment were compared statistically (P < 0.05) between the groups using ANOVA. Multivariate regression models were used for each group. RESULTS: Group 1 (n = 59) was characterized by Class II high-angle retrognathic mandible with an incompetent lip, group 2 (n = 55) by Class I malocclusion with retruded and thin lips, and group 3 (n = 38) by Class I malocclusion with an everted superior lip before treatment. The ratios of anteroposterior soft tissue to hard tissue movements in Group 1 were 56% (r = 0.64) and 83% (r = 0.75) for the superior and inferior lips, respectively, whereas those in Group 2 were 49% (r = 0.78) and 91% (r = 0.80), and 40% (r = 0.54) and 79% (r = 0.70), respectively, in Group 3. CONCLUSIONS: The modes of facial form changes differed depending on the pre-treatment profile patterns classified by the AI. This indicates that the determination of the pre-treatment profile pattern can help in the selection of soft tissue to hard tissue movement ratios, which helps estimate the post-treatment facial profile with a moderate to high correlation.

Analysis of select esthetic nasal parameters in virtually planned orthognathic patients.

PURPOSE: Bony changes after orthognathic surgery are always followed by changes of the overlying soft tissues. Therefore, morphologic changes of the nose may be expected after procedures involving the maxilla. The purpose of this study was to evaluate the changes in the nasal region due to orthognathic surgery using computed tomography (CT) images of virtually planned patients. METHODS: 35 patients who underwent Le Fort I osteotomy, with or without bilateral sagittal split osteotomy, were included. 3D measurements on preoperative and postoperative images were performed and analyzed. RESULTS: The results revealed that aesthetically acceptable results can be achieved by orthognathic surgery alone. CONCLUSIONS: According to the results of this study, it can be concluded that it is best to reserve decisions on rhinoplasty to the post-orthognathic period.

The Assessment of External Nasal Valve Efficiency After Le Fort I Surgery.

BACKGROUND: The present study investigated how external nasal valve function is affected after Le Fort I osteotomy using external nasal valve efficiency (ENVE) index. MATERIALS AND METHODS: Twenty-one patients who underwent Le Fort I osteotomy with or without mandibular osteotomy were included in the retrospective study. Preoperative and postoperative standardized videos of basal view of the nose during breathing were recorded, and 2 screenshots were taken, 1 in the resting position and the other after deep inspiration. External nasal valve efficiency was calculated at preoperative and postoperative periods for each patient. RESULTS: Of the 21 patients, 12 were women and 9 were men (mean age, 26.63 ± 8.20 years). The mean ENVE index was 0.75 ± 0.16 for the preoperative period and 0.82 ± 0.17 for the postoperative period. There was a significant difference between these values ( P = 0.002). When the correlation of the ENVE with maxillary movements was analyzed, the ENVE was negatively affected by maxillary impaction ( P = 0.011, r = -0.540). CONCLUSIONS: These findings imply that Le Fort I osteotomy positively affects the ENVE index. However, because of the antagonistic relation between maxillary impaction and ENVE, higher maxillary impaction amounts or isolated maxillary impaction should be carefully planned in patients with low ENVE index.

Assessment of the Relation Between Craniofacial Tissue Profile-Morphology and Dermatoglyphics.

This study aims to evaluate the relationship between the convexity angle of facial tissue and fingerprint types by analyzing the connection between dermatoglyphic prints and facial structure. A total of 65 adults (24 females, 41 males) participated in the study. Each participant's fingerprint was analyzed using conventional methods of observation upon the index finger of the dominant hand. Fingerprints were classified into 3 fundamental types: arch, whorl, or loop. Craniofacial profiling was performed with measurements of hard tissue (Gl'-A-Pg') and soft tissue facial convexity (Gl-Sn-Pg) and total facial convexity (Gl-Prn-Pg) angles between 3 anthropological points determined on the lateral direct radiographs of the participants. Soft tissue convexity facial angle (Gl-Sn-Pg) values were found to be an average of 166.83° in females and an average of 162.05° in males. (Gl-Prn-Pg) values were found to be an average of 138.54° in females and 135.27° in males. The soft tissue profile of males showed a significantly convex structure compared with females. Also, the "whorl" type of fingerprint was found to be dominant in both sexes. There is no statistically significant difference in terms of soft tissue profile convexity in individuals belonging to the 3 different fingerprint groups. No statistically significant difference in soft tissue profile angular values between right-hand thumb and index fingerprint type groups were found among and between sexes. However, a comprehensive analysis of the relationships between the nose, lips, mouth, ear, and eyes and fingerprints of the same person may prove to be beneficial.

[Effect of alar base cinch suture based on anatomic landmarks on the morphology of nasolabial region in patients after orthognathic surgery].

OBJECTIVE: To study the effect of a modified alar base cinch suture (ABCS) based on nasal musculature anatomy on the three-dimensional morphology of nasolabial region in patients after Le Fort Ⅰ osteotomy. METHODS: In the study, 30 patients[11 males and 19 females, with an average age of (23.23±2.98) years]with skeletal Class Ⅲ malocclusion underwent orthognathic surgery between August, 2019 and January, 2020 to have the maxilla advanced no more than 4 mm in the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology were involved and were divided into the test and control groups based on the random number table.In the test group, the nasal musculature was identified and labeled before dissection and the ABCS was according to the label, while in the control group, the nasal musculature was directly sutured and knotted in the midline of nose without prepend labeling.All the patients underwent three-dimensional facial photos preoperatively and 6 months postoperatively by using 3dMD face system.On the three dimensional image, soft tissue landmarks of nasolabial region was identified by the same examiner.Fourteen measurements including straight distance, curve distance, angle and ratio were measured.Statistical analysis was done by using SPSS 22.0. RESULTS: There were significant differences between the two groups in cutaneous height of upper lip (P=0.023) and in nasal tip protrusion-alar width (P=0.012).The increase rate of cutaneous height of upper lip and the decrease rate of nasal tip protrusion-alar width in the control group were significantly higher than that in the test group.The alar width and alar base width of the both groups were significantly increased compared with the preoperative level (P < 0.05).The nasolabial angle in the control group was significantly higher compared with the normal value, while there was no significant difference between the test group and the normal value. CONCLUSION: Compared with the conventional suture method, this modified alar base cinch suture is more favorable for the postoperative nasal coordination and nasolabial morphology in patients who need mild to moderate maxillary advancement, and it has certain advantages in operability and objective accuracy.So it could become a modified and accurate method of alar base cinch suture and be widely applied in clinical practice.

Impact of facial components on the attractiveness of face: A perception-based study.

INTRODUCTION: Magazines and television displays are not merely crammed with faces-they are filled with appealing faces, and both men and women are interested in a suitable partner's appearance. This study investigated what makes a face attractive and whether perception-related differences exist between facial attractiveness and facial components. METHODS: In this descriptive-analytical study, frontal and lateral view photographs of 18 young adults (9 male and 9 female) in Class I, II, and III malocclusions were assessed by 90 orthodontists, dentists, models, and laypeople using a 7-point Likert scale in terms of attractiveness. Based on scores, attractive and unattractive groups were formed. Using image analysis software, a range of defined length, angles, perimeter, and area for lips, nose, and chin were measured for the attractive group. For statistical analysis, each group was compared using a 1-way analysis of variance. Logistic regression was performed to analyze the factors of different parameters to the attractiveness of facial components. RESULTS: Overall full-face width, upper lip angle, lip area, and mentolabial angle was significantly different in all the 3 classes (P ≤0.05). In Class I malocclusion, nasolabial angle among orthodontists, nasofrontal angle among dentists, lower lip among models, and full-face width among laypeople were responsible for facial attractiveness variation. In Class II malocclusion, nose to upper lip among orthodontists, Cupid's bow among dentists, wider face among models, and upper lip among layperson were responsible for variation in facial attractiveness. In Class III malocclusion, lower lip angle among orthodontists and dentists, Cupid's bows among models and layperson was responsible for variation in facial attractiveness. CONCLUSIONS: In Class I faces, lips (Cupid's bows, lower lips, lip areas), nose (nasolabial, nasofrontal, and nasomental angles), and chin (lower lip to chin) contributed to the overall attractiveness of the face, while in Class II faces, lips (upper lip length, interbow distance, lower lip angle), nose (full facial convexity), and chin (mentolabial sulcus), as well as a greater full-face width contributed to the overall attractiveness of the face. In Class III faces, lips (lower lip angle, upper lip length), nose (nose tip angle, full facial convexity), and chin (mentolabial sulcus depth) contributed to the overall attractiveness of the face.

Correlation between cephalometric nasal changes and patients' perception after orthognathic surgery.

INTRODUCTION: The purpose of this study was to evaluate the correlation between cephalometric measurements and patients' perception of nasal changes in those with Class III malocclusion who had undergone orthognathic surgery. METHODS: Eighty-five patients (36 men and 49 women) who received maxillary advancement with (group 1) or without (group 2) maxillary impaction were included in this study. Lateral cephalometric radiographs taken before and at the end of the treatment were analyzed. The patients were given an esthetic evaluation form and asked to evaluate their own noses on the Likert scale (subjective perception), while at the same time, they were asked to evaluate profile silhouettes without knowing that it was their own profile (objective perception). The changes and correlations between the cephalometric measurements and the scores obtained from the esthetic perception questionnaire were evaluated statistically. RESULTS: Postoperative nasal tip inclination and rotation, nasofacial angle, and sagittal position of pronasale had increased significantly (P <0.05), whereas nasal tip protrusion, nasofrontal angle, and vertical position of pronasale had decreased (P <0.05). The change in the nasolabial angle and vertical position of pronasale was statistically different between the 2 surgical groups (P <0.05). In the end, a significant increase was observed in the patients' objective nasal esthetic scores (P <0.05). CONCLUSIONS: Soft tissues are affected by the vertical and sagittal surgical movements of the maxilla. There was a moderate correlation between patients' perception of nasal changes and cephalometric measurements. The subjective evaluation of the nose was similar among patients after surgery, but in the objective assessment, patients found their noses more esthetic.

Clinical Features of Skin Infection After Rhinoplasty with Only Absorbable Thread (Polydioxanone) in Oriental Traditional Medicine: A Case Series Study.

BACKGROUND: Polydioxanone (PDO) is absorbable thread which is usually used for wound closure and face lifting. These days, PDO thread is used increasingly for aesthetic purposes such as correction of facial wrinkles, laxity and even rhinoplasty in many oriental traditional medicine clinics. As rhinoplasty with PDO thread increases, complications also increase. In this study, we will report on the clinical features of patients who got rhinoplasty using PDO thread. METHODS: From August 2018 to July 2019, seven patients (three males and four females) visited our clinic for complications after rhinoplasty with PDO thread. We checked ultrasonography and laboratory findings including wound cultures. We used conservative treatment using antibiotics and performed surgery on three patients. RESULTS: Three patients experienced severe complications with open wounds, abscesses and skin necrosis. Four patients experienced mild complications including redness and thread exposure without open wounds. The location of infection included the nasal tip and inner lining. Six patients had a history of rhinoplasty before. On ultrasonography, abscess formation was seen around the implant inserted before. During the operation, PDO thread cannot be seen except in one patient. CONCLUSIONS: PDO thread cannot be seen in radiologic findings and can cause severe infections like abscess formation with open wounds. In severe infections, massive debridement with the removal of the implant would be required. PDO thread is absorbed usually after six months; mild infection can be controlled by the conservative treatment. The best is not undergoing rhinoplasty with PDO thread for patients who had implants because of potential side effects. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Convergent acoustic field of view in echolocating bats.

Most echolocating bats exhibit a strong correlation between body size and the frequency of maximum energy in their echolocation calls (peak frequency), with smaller species using signals of higher frequency than larger ones. Size-signal allometry or acoustic detection constraints imposed on wavelength by preferred prey size have been used to explain this relationship. Here we propose the hypothesis that smaller bats emit higher frequencies to achieve directional sonar beams, and that variable beam width is critical for bats. Shorter wavelengths relative to the size of the emitter translate into more directional sound beams. Therefore, bats that emit their calls through their mouths should show a relationship between mouth size and wavelength, driving smaller bats to signals of higher frequency. We found that in a flight room mimicking a closed habitat, six aerial hawking vespertilionid species (ranging in size from 4 to 21 g, ref. 5) produced sonar beams of extraordinarily similar shape and volume. Each species had a directivity index of 11 ± 1 dB (a half-amplitude angle of approximately 37°) and an on-axis sound level of 108 ± 4 dB sound pressure level referenced to 20 µPa root mean square at 10 cm. Thus all bats adapted their calls to achieve similar acoustic fields of view. We propose that the necessity for high directionality has been a key constraint on the evolution of echolocation, which explains the relationship between bat size and echolocation call frequency. Our results suggest that echolocation is a dynamic system that allows different species, regardless of their body size, to converge on optimal fields of view in response to habitat and task.

Accuracy of Three-Dimensional Soft Tissue Prediction in Orthognathic Cases Using Dolphin Three-Dimensional Software.

INTRODUCTION: Orthodontists and surgeons have been looking for more accurate methods to plan and predict surgical outcomes in patients with skeletal discrepancies. METHODS: The sample consisted of 20 subjects from the surgical clinic of a graduate orthodontic program who had been treated with Le Fort I maxillary movement, bisagittal split osteotomy, with or without genioplasty. All subjects had to have preoperative (T0) and at least 6 months postoperative (T1) cone-beam computed tomographies that were imported to Dolphin three-dimensional (3D) software version 11.9 in digital imaging and communications in medicine format. Three-dimensional voxel-based superimposition on the cranial base was performed for T0 and T1 to accurately measure the skeletal surgical movements. A virtual orthognathic surgery was performed on T0 to mimic the actual skeletal osteotomies using the treatment simulation tool in Dolphin 3D. A prediction 3D soft tissue image (Tp) was generated based on the Dolphin virtual skeletal planning. The differences between Tp and T1 for all patients were measured using linear and angular measurements visualized by surface mapping. RESULTS: Significant differences were found between Tp and T1 in Nasolabial angle, Soft tissue A point, and Subalar area. CONCLUSIONS: The soft tissue prediction accuracy after double jaw surgery using Dolphin 3D is limited in some areas, especially upper lip and base of the nose.

The Soft Tissue Angular Analysis of Facial Profile in Unoperated Adult Patients with Unilateral Cleft Palate.

OBJECTIVE: The purpose of this study was to investigate the differences in facial profile development between unoperated adult cleft palate (UACP) patients and normal controls and to analyse the reasons for the differences. MATERIALS AND METHODS: A total of 50 individuals with a unilateral cleft palate and 20 normal controls were selected to undergo angular measurement of their facial profiles. Data with significant differences between the two groups were analysed. RESULTS: Seven angle measurements of the facial profile showed that the mid-facial protrusion of the UACP patients had no significant differences from the control group (p > 0.05). But their angle of the medium face (N'-Trg-Sn) was significantly lower than the non-cleft controls (p < 0.05), suggesting a worse vertical development of the middle face. A significantly larger nasal tip angle (Cm-Sn/N'-Prn) for UACP patients suggested they had a rounder and blunter nasal tip (p < 0.05). The soft tissue facial angle and chin-lip angle of UACP patients had significant differences from non-cleft controls (p < 0.05), but the head position angle (Sn-Sm-THP) had no significant difference between two groups (p > 0.05), which suggested a steep mandibular plane for UACP patients but without severe retraction of the chin. CONCLUSION: The development of facial protrusions in UACP patients is similar to that in normal adults, but the vertical development in the middle face is insufficient. Such hypoplasia may be related to the intrinsic deficiency of the maxilla. There is a tendency for flat nasal growth and insufficient development of the chin in UACP patients. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Upper airway in children with unilateral cleft lip and palate evaluated with computational fluid dynamics.

INTRODUCTION: Children with unilateral cleft lip and palate (UCLP) exhibit snoring and mouth breathing. They are also reported to show obstructive sleep apnea syndrome. However, their upper airway ventilation condition is not clearly understood. Therefore, this study was performed to evaluate upper airway ventilation condition in children with UCLP with the use of computational fluid dynamics. METHODS: Twenty-one children (12 boys, 9 girls; mean age 9.1 years) with UCLP and 25 children (13 boys, 12 girls; mean age 9.2 years) without UCLP who required orthodontic treatment underwent cone-beam computed tomography (CBCT). Nasal resistance and upper airway ventilation condition were evaluated with the use of computational fluid dynamics from CBCT data. The groups were compared with the use of Mann-Whitney U tests and Student t tests. RESULTS: Nasal resistance of the UCLP group (0.97 Pa/cm3/s) was significantly higher than that of the control group (0.26 Pa/cm3/s; P < 0.001). Maximal pressure of the upper airway (335.02 Pa) was significantly higher in the UCLP group than in the control group (67.57 Pa; P < 0.001). Pharyngeal airway (from choanae to base of epiglottis) pressure in the UCLP group (140.46 Pa) was significantly higher than in the control group (15.92 Pa; P < 0.02). CONCLUSIONS: Upper airway obstruction in children with UCLP resulted from both nasal and pharyngeal airway effects.

Gain of exposure provided by extended incision in lateral rhinotomy approach: A cadaveric study.

OBJECTIVE: To assess the gain of exposure provided by extensions of the lateral rhinotomy (LR) incision, including subciliary extension, lip-splitting extension, or both (Weber-Fergusson incision), by comparing the surgical field obtained with every incision. The final goal is to better delineate the indications of each approach. MATERIALS AND METHODS: Prospective study on fresh frozen specimens. A LR incision was first performed, and then extended by subciliary and/or lip-splitting incisions. The exposure of the anterior facial skeleton and of the deep retromaxillar spaces (pterygopalatine fossa and infratemporal fossa) were assessed. The distance between the nasal bone and the most lateral part of the exposure was measured. RESULTS: Dissection was performed on 4 specimens, with 7 LR. Three LR incisions were extended with subciliary incision, 3 with lip-splitting incision, and 4 with Weber-Fergusson incision. LR incision alone gave only limited access to the lateral orbital rim, the zygomatic arch and the maxillary tuberosity. Both subciliary and lip-splitting incisions gave access to the lateral orbital rim and to the zygomatic arch, but only upper lip incision provided a good access to the maxillary tuberosity. Weber-Fergusson did not significantly increase the surgical field obtained with lip-splitting extension alone. The exposure of the deep retromaxillar spaces was the same in all cases. CONCLUSION: LR incision with lip-splitting extension provided an optimal access to the anterior facial skeleton and to the maxillary tuberosity. In terms of exposure, it was equivalent to Weber-Fergusson approach. The exposure of deep spaces was the same regardless of the incision.

Directionality of nose-emitted echolocation calls from bats without a nose leaf (Plecotus auritus).

All echolocating bats and whales measured to date emit a directional bio-sonar beam that affords them a number of advantages over an omni-directional beam, i.e. reduced clutter, increased source level and inherent directional information. In this study, we investigated the importance of directional sound emission for navigation through echolocation by measuring the sonar beam of brown long-eared bats, Plecotus auritusPlecotus auritus emits sound through the nostrils but has no external appendages to readily facilitate a directional sound emission as found in most nose emitters. The study shows that P. auritus, despite lacking an external focusing apparatus, emits a directional echolocation beam (directivity index=13 dB) and that the beam is more directional vertically (-6 dB angle at 22 deg) than horizontally (-6 dB angle at 35 deg). Using a simple numerical model, we found that the recorded emission pattern is achievable if P. auritus emits sound through the nostrils as well as the mouth. The study thus supports the hypothesis that a directional echolocation beam is important for perception through echolocation and we propose that animals with similarly non-directional emitter characteristics may facilitate a directional sound emission by emitting sound through both the nostrils and the mouth.

Nose profile morphology and accuracy study of nose profile estimation method in Scottish subadult and Indonesian adult populations.

This study investigated nose profile morphology and its relationship to the skull in Scottish subadult and Indonesian adult populations, with the aim of improving the accuracy of forensic craniofacial reconstruction. Samples of 86 lateral head cephalograms from Dundee Dental School (mean age, 11.8 years) and 335 lateral head cephalograms from the Universitas Padjadjaran Dental Hospital, Bandung, Indonesia (mean age 24.2 years), were measured. The method of nose profile estimation based on skull morphology previously proposed by Rynn and colleagues in 2010 (FSMP 6:20-34) was tested in this study. Following this method, three nasal aperture-related craniometrics and six nose profile dimensions were measured from the cephalograms. To assess the accuracy of the method, six nose profile dimensions were estimated from the three craniometric parameters using the published method and then compared to the actual nose profile dimensions.In the Scottish subadult population, no sexual dimorphism was evident in the measured dimensions. In contrast, sexual dimorphism of the Indonesian adult population was evident in all craniometric and nose profile dimensions; notably, males exhibited statistically significant larger values than females. The published method by Rynn and colleagues (FSMP 6:20-34, 2010) performed better in the Scottish subadult population (mean difference of maximum, 2.35 mm) compared to the Indonesian adult population (mean difference of maximum, 5.42 mm in males and 4.89 mm in females).In addition, regression formulae were derived to estimate nose profile dimensions based on the craniometric measurements for the Indonesian adult population. The published method is not sufficiently accurate for use on the Indonesian population, so the derived method should be used. The accuracy of the published method by Rynn and colleagues (FSMP 6:20-34, 2010) was sufficiently reliable to be applied in Scottish subadult population.

Soft tissue changes following extraction vs. nonextraction orthodontic fixed appliance treatment: a systematic review and meta-analysis.

The aim of this systematic review was to assess the effect of systematic extraction protocols during orthodontic fixed appliance treatment on the soft tissue profile of human patients. Nine databases were searched until December 2016 for controlled clinical studies including premolar extraction or nonextraction treatment. After elimination of duplicate studies, data extraction, and risk-of-bias assessment according to the Cochrane guidelines, random-effects meta-analyses of mean differences (MD) or standardized mean differences (SMD) and their 95% CIs were performed, followed by subgroup, meta-regression, and sensitivity analyses. Extraction treatment was associated with increased lower lip retraction (24 studies; 1,456 patients; MD = 1.96 mm), upper lip retraction (21 studies; 1,149 patients; MD = 1.26 mm), nasolabial angle (21 studies; 1,089 patients; MD = 4.21°), soft-tissue profile convexity (six studies; 408 patients; MD = 1.24°), and profile pleasantness (three studies; 249 patients; SMD = 0.41). Patient age, extraction protocol, and amount of upper incisor retraction during treatment were significantly associated with the observed extraction effects, while the quality of evidence was very low in all cases due to risk of bias, baseline confounding, inconsistency, and imprecision. Although tooth extractions seem to affect patient profile, existing studies are heterogenous and no consistent predictions of profile response can be made.