Effects of rapid maxillary expansion on facial soft tissues : Deviation analysis on three-dimensional images

Does Differential Maxillary Expansion Prior to Alveolar Cleft Bone Grafting Affect Nasal Width?

OBJECTIVE

Determine the effects of differential maxillary expansion on nasal width in patients with unilateral cleft lip and alveolus with or without cleft of the secondary palate (UCLA ± P).

DESIGN

Retrospective radiographic study.

SETTING

Institutional.

PARTICIPANTS

Forty patients with UCLA ± P who had alveolar bone grafting (ABG) between 2015 and 2020 and available preexpansion and postexpansion cone beam computed tomography (CBCT) scans. Twenty patients with UCLA ± P who underwent ABG without expansion were included as controls.

MAIN OUTCOME MEASURE

Percent change in width at the nasal pyriform, inferior turbinates, and alar base on cleft and noncleft sides.

RESULTS

The study included 40 patients (24 males, mean age 9.6 years) and 20 controls (10 males, mean age 10.1 years). After maxillary expansion, there was an increase in width on the cleft and noncleft sides compared to nonexpanded controls at nasal pyriform (10.9% cleft side, P ≤ 0.001 and 4.3% noncleft side, P ≤ .001), inferior turbinate (8.7%, P ≤ .001 and 4.5%, P = .01), and alar base (6.7%, P = <.001 and 0.8% P = .54). The increase in width was greater on the cleft side than the noncleft side at the nasal pyriform (7.1%, P ≤ .001), inferior turbinate (4.3%, P ≤ .001), and alar base (7.0%, P ≤ 0.001) in the expansion group. There was good to excellent intra-rater and inter-rater agreement for measurements.

CONCLUSION

Patients with UCLA ± P who undergo differential maxillary expansion before ABG exhibit greater nasal widening on the cleft side.

Facial morphology differences in monozygotic twins: a retrospective stereophotogrammetric study

OBJECTIVE

To assess soft tissue differences between monozygotic twins (MZ) for the total face and between facial regions using three-dimensional (3D) stereophotogrammetry and quantitative surface-based 3D deviation analyses.

MATERIALS AND METHODS

The study sample consisted of 14 untreated MZ twins (6 males, 8 females, mean age: 14.75 years) from the archive of Marmara University, Department of Orthodontics. The images were taken by the 3dMDface system, and 3dMDvultus software was used for removal of undesired areas and approximation of the images. Then, stereolithography (.stl) format images were superimposed using the best-fit algorithm using 3-matic software. The face was divided into facial thirds, and upper lip and lower lip + chin regions were created. For the comparison, 3D deviation analyses were performed, and a color map and histogram were created. The data were presented as mean deviation, root mean square (RMS), median, and interquartile range.

RESULTS

Between the facial thirds, there was no significant difference in soft tissue differences for mean deviation. A statistically significant difference was found between the upper and lower face for the RMS value. For the comparison of upper lip and lower lip + chin region, the only significant difference was for the RMS. When the data were presented as median and interquartile range, there were no statistically significant differences between any facial regions.

CONCLUSIONS

Lower facial third and lower lip + chin regions had the greatest differences within MZ twin pairs. The genetic and environmental influences might not be the same for different parts of the face.

Three-dimensional evaluation of social smile asymmetry in patients with unilateral impacted maxillary canine: a 3D stereophotogrammetry study

OBJECTIVE

This study aimed to evaluate social smile asymmetry in patients with unilateral impacted maxillary canine on 3D stereophotogrammetric images.

MATERIAL AND METHODS

The 3D social smile images of participants with unilateral impacted maxillary canine (n:20) and without impaction as a control group (n:20) were included. The images were recorded with a hand-held 3D stereophotogrammetry device (Fuel3D® Scanify®) and Geomagic Essentials 2 reverse engineering software were used for analyses. After the orientation process of the 3D records, the tissues around the smile area were divided into five morphological regions: cheek, upper lip lateral and medial, and lower lip lateral and medial. The deviation margins in the negative and positive directions for the 95% mesh rate and the total percentages of meshes between - 0.5- and + 0.5-mm deviations were calculated. ICC, paired samples t test, independent samples t test, and the Mann-Whitney U test were used for statistical analyses.

RESULTS

In individuals with impacted canine, the amount of maximum positive deviation in the upper lip medial was 5.64 mm ± 1.46 and maximum negative deviation was - 4.6 mm ± 1.17. In the control group, mean of deviation limits for all parameters was less than 1.19 mm ± 2.62, while in individuals with unilateral impacted maxillary canine, the maximum value was 8.34 mm ± 2.23. The mesh percentage between - 0.5 and 0.5-mm deviations was over 95% in all morphological areas in the control group, while in the impacted canine group, the number of meshes within the specified deviation limits was less than 95%.

CONCLUSION

Individuals with unilateral impacted maxillary canine exhibit greater asymmetry in social smile compared to the control group, with the asymmetry being most prominent near the corners of the mouth and cheeks.

CLINICAL RELEVANCE

Amount of asymmetry was higher in impaction group compared to the control group in social smile. The quantification of a possible smile asymmetry due to the impacted canine is crucial for the diagnosis and treatment planning of orthodontic and/or orthognathic cases for ideal aesthetic results. Hence, smile asymmetry should not be overlooked and should be considered in diagnosis and treatment planning.

Soft tissue evaluation after maxillary protraction with RPE or with the ALT-RAMEC protocol : A controlled 3D study

PURPOSE

To evaluate soft tissue changes following maxillary protraction with different expansion protocols using three-dimensional (3D) stereophotogrammetry.

METHODS

Pretreatment (T0) and postprotraction (T1) stereophotogrammetry and lateral cephalometric images of skeletal class III patients were included in this retrospective study. In all, 32 patients were treated either with a combination of rapid palatal expansion and facemask (RPE/FM; n = 16; mean age: 9.94 ± 0.68 years) or with alternate rapid maxillary expansion and constriction together with a facemask (Alt-RAMEC/FM; n = 16; mean age: 9.74 ± 1.35 years). As a control group 16 untreated patients were recruited (mean age: 9.46 ± 0.8 years). For superimpositioning of the 3D images taken at T0 and T1, the face was divided into defined regions and 3D and differences between the groups were evaluated using 3‑matic software (Materialise Europe, Leuven, Belgium). Cephalometric analyses were also performed.

RESULTS

While the increases in the cephalometric parameters SNA and ANB were significantly greater in the treatment groups, the value for SNB also increased in the control group (p < 0.05). The results of the stereophotogrammetry analyses demonstrated that the mean changes in the RPE/FM and in the Alt-RAMEC/FM groups were significantly different for the midface compared to the control group (0.33 ± 0.26 mm, 0.3 ± 0.31 mm, 0.1 ± 0.18 mm). The maximum positive, negative, and mean changes were also significantly different between the treatment and control groups for the upper lip (p < 0.05). For the lower lip and the chin significant backward movements in the RPE/FM as well as in the Alt-RAMEC/FM group (-1.06 ± 1.26 mm, -0.68 ± 0.45 mm) were observed, while the control group (0.09 ± 0.53 mm) presented changes in the opposite direction. Regarding soft tissue changes, no significant differences were found between the RPE/FM and Alt-RAMEC/FM groups.

CONCLUSION

Both treatment protocols improved the soft tissue profile due to a forward movement of the midface and the upper lip, and a backward movement of the lower lip and chin, compared to the control group.

Slim the face or not: 3D change of facial soft and hard tissues after third molars extraction: a pilot study

BACKGROUND

Whether slim the face or not after removed third molars is the concern of some orthodontic treatment candidates. The aim of this article is to explore the volume changes of facial soft and hard tissues after third molars extraction, as well as develop a reproducible clinical protocol to precisely assess facial soft tissue volume change.

METHODS

A non-randomized, non-blind, self-controlled pilot study was conducted. 24 adults aged 18-30 had ipsilateral third molars extracted. The body weight change was controlled within 2 kg. Structured light scans were taken under a standardized procedure pre-extraction (T0), three (T1), and six (T2) months post-extraction; CBCTs were taken at T0 and T2. The projection method was proposed to measure the soft tissue volume (STV) and the soft tissue volume change (STVC) by the Geomagic software. The hard tissue volume change (HTVC) was measured in the Dragonfly software.

RESULTS

The final sample size is 23, including 5 males (age 26.6 ± 2.5 years) and 18 females (age 27.3 ± 2.5 years). The HTVC was - 2.33 ± 0.46ml on the extraction side. On the extraction side, the STV decreased by 1.396 (95% CI: 0.323-2.470) ml (P < 0.05) at T1, and increased by 1.753 (95% CI: -0.01-3.507) ml (P = 0.05) at T2. T2 and T0 had no difference (P > 0.05). The inter and intra-raters ICC of the projection method was 0.959 and 0.974. There was no correlation between the STVC and HTVC (P > 0.05).

CONCLUSIONS

After ipsilateral wisdom teeth extraction, the volume of hard tissue on the extraction side reduces, and the volume of facial soft tissue does not change evidently. However, further research with large sample size is still needed. The STV measurement has excellent repeatability. It can be extended to other interested areas, including forehead, nose, paranasal, upper lip, lower lip and chin, which is meaningful in the field of orthodontics and orthopedics.

TRIAL REGISTRATION

ChiCTR, ChiCTR1800018305 (11/09/2018), http://www.chictr.org.cn/showproj.aspx?proj=28868 .

Evaluation by 3D stereophotogrammetry of facial changes in edentulous patients after rehabilitation

OBJECTIVE

To assess facial changes after oral rehabilitation with complete dentures (CDs) by 3D technology allows understanding the results of a treatment that changes facial proportions. Precise outcome parameters can improve decision making. This descriptive observational research aimed to assess facial changes in completely edentulous patients after oral rehabilitation with a CD by a 3D stereophotogrammetry system.

METHODOLOGY

30 edentulous patients (7 men and 23 women), aged 50 to 75, were analyzed with stereophotogrammetry at 28 previously determined anthropometric landmarks, at 2 different times: T1, before treatment, and T2, after inserting the CDs. Images were analyzed with a specific software for linear and angular measurements. The paired t-test was used to compare timestamps (α=0.05).

RESULTS

Major changes were observed in 7 of the 13 linear measures and 7 of the 9 angular measures. The following linear measurements had an increase: Sn-Gn (lower third of the face), Ls-Li (height of the vermilion lip), and ChL-ChR (mouth width). Sn-Ls (nasal philtrum height) decreased. For angular measurements, Sn-St-Pg (lower facial convexity) angles increased, and the Prn-Sn-Ls (nasolabial angle) and GoR-Pg-GoL (mandible convexity) angles decreased.

CONCLUSIONS

Major facial changes in newly rehabilitated edentulous patients with CDs included an increase of the lower third of the face, of the vermilion lip, of mouth width, and of the lower facial convexity, and a decrease of the nasolabial angle and mandible convexity.

Morphologic reproducibility in 6 regions of the 3-dimensional facial models acquired by a standardized procedure: An in vivo study

INTRODUCTION

A standardized procedure was proposed to control involuntary motion and other factors during the capture of structural light scanning that could influence the morphology of 3-dimensional facial models; interoperator reproducibility was evaluated.

METHODS

Twenty subjects volunteered for facial scanning. Three researchers scanned each volunteer 3 times on the same day using the FaceScan structural light scanning system (Isravision, Darmstadt, Germany) and after the proposed procedure. Captures were done at 5-minute intervals. The 3 facial scans acquired by the same researcher were compared by reverse engineering software (Geomagic; 3D Systems, Rock Hill, SC). Six facial regions, including forehead, nose, paranasal, upper lip, lower lip and chin, and cheek, were divided. With the first scan as a reference, the other 2 scans were registered, and surface-to-surface distance maps were acquired to calculate the mean, standard deviation, and root mean squares (RMS) between 2 surfaces. The reproducibility between 3 researchers was then evaluated by a 1-way analysis of variance.

RESULTS

The mean of 6 facial regions was close to 0. The RMS of lip regions were largest (0.48-0.53 mm), the forehead was smallest (0.21 mm), and the others ranged 0.37 mm to 0.42 mm. The standard deviation was slightly smaller than RMS and had the same trend of change. There was no significant difference in RMS among the 3 researchers (P >0.05).

CONCLUSIONS

With the constraint of the standardized procedure, the morphologic reproducibility of facial models in 6 regions was satisfying.

Superimposition of serial 3-dimensional facial photographs to assess changes over time: A systematic review

INTRODUCTION

Superimpositions of 3-dimensional photographs enable a thorough and risk-free assessment of facial changes over time. However, the available methods and the evidence supporting them have not been assessed systematically. The paper summarizes and assesses the current evidence on superimposition methods of serial 3-dimensional facial photographs available in the literature.

METHODS

The following databases were searched without time restriction (last updated December 2020): MEDLINE via PubMed, EMBASE, Cochrane Library, and Google Scholar. Unpublished literature was searched on Open Grey and Grey Literature Report. Authors were contacted if necessary, and reference lists of relevant papers were screened. All studies with sample size ≥6 that tested the accuracy or precision of a superimposition technique, or agreement between different techniques regarding facial surface changes, were considered. The 2 authors performed data extraction independently using predefined forms. The risk of bias was assessed through the Quality Assessment and Diagnostic Accuracy Tool 2 tool.

RESULTS

Eight studies fulfilled the inclusion criteria. The total risk of bias of 7 studies was high and of 1 low. Seven studies had high total applicability concerns, and 1 was unclear. There was high heterogeneity among studies, which tested constructed planes through manually selected landmarks, a configuration of 9 landmarks, various surface areas, and the entire facial surface as superimposition references. A small rectangular area on the forehead combined with one on the middle part of the nose and the lower wall of the orbital foramen showed promising results.

CONCLUSIONS

The limited available evidence suggests that surface-based registration is superior to landmark-based registration. Further research in the field is mandatory.

Valid 3D surface superimposition references to assess facial changes during growth

Currently, the primary techniques applied for the assessment of facial changes over time utilize 2D images. However, this approach has important limitations related to the dimensional reduction and the accuracy of the used data. 3D facial photography has been recently introduced as a risk-free alternative that overcomes these limitations. However, the proper reference areas that should be used to superimpose serial 3D facial images of growing individuals are not yet known. Here, we tested various 3D facial photo superimposition reference areas and compared their outcomes to those of a standard anterior cranial base superimposition technique. We found that a small rectangular area on the forehead plus an area including the middle part of the nose and the lower wall of the orbital foramen provided comparable results to the standard technique and showed adequate reproducibility. Other reference areas that have been used so far in the literature were less reliable. Within the limitations of the study, a valid superimposition reference area for serial 3D facial images of growing individuals is suggested. The method has potential to greatly expand the possibilities of this highly informative, risk free, and easily obtained 3D tool for the assessment of facial changes in growing individuals.

Evaluation of the Soft Tissue Changes after Rapid Maxillary Expansion Using a Handheld Three-Dimensional Scanner: A Prospective Study

Facial soft tissue esthetics is a priority in orthodontic treatment, and emerging of the digital technologies can offer new methods to help the orthodontist toward an esthetic outcome. This prospective study aimed to assess the soft tissue changes of the face after six months of retention following Rapid Maxillary Expansion (RME). The sample consisted of 25 patients (13 females, 12 males, mean age: 11.6 years) who presented with unilateral or bilateral posterior crossbite requiring RME, which was performed with a Hyrax expander. 3D facial images were obtained before treatment (T₀) and at the end of a six-month retention period after the treatment (T₁) using a structured-light 3D handheld scanner. Linear and angular measurements were performed and 3D deviation analyses were done for six morphological regions of the face. Significant changes in various areas of the nasal and the upper lip regions were observed. Based on the results of the study and within the limitations of the study, RME with a Hyrax expander results in significant morphological changes of the face after a six-month retention period.

Distraction Therapy to Correct Trismus Following Noma

Trismus is a frequent complication of healed Noma infection and is caused by soft tissue and muscle contraction. Free-flap surgery is recommended to replace the missing oral mucosa and soft tissue. However, significant complications can occur if this surgery is performed in places like Africa, where conditions are usually less than optimal. In 2007, the authors started to treat patients with trismus in Niamey, Niger by distracting the soft tissue and muscle constriction between the jaws with a bone distractor continuously for 1 month with the aim of achieving a mouth opening of 3 cm. The distraction was limited to 1 mm/d. performed under local anesthesia with some sedation. Minor complications such as infection in the pin holes were easily managed. In 2009, 2 patients with trismus after Noma with a follow-up of 2 years were reported. Till date, the authors have successfully performed trismus release in more than 69 patients in Niamey and Guinea Bissau. The present study analyses the results of distraction therapy in 40 patients with follow-ups until 60 months. At the end of distraction, the mean interincisal distance was 2.7 ± 0.5 cm. Mouth opening 6 months after distraction had not reverted. However, 3 to 5 years after treatment, some signs of relapse were detected, with an average mouth opening of 1.5 ± 1.9 cm. Physiotherapy was unfortunately not feasible. The presented results strongly support the efficacy of distraction therapy to correct trismus in Noma patients.

Three-dimensional stereophotogrammetric analysis of nasolabial soft tissue effects of rapid maxillary expansion: a systematic review of clinical trials

The aim of this systematic review is to analyse the quality and clinical evidence in the literature analysing, through 3D stereophotogrammetry, the nasolabial soft tissue modifications that may occur after rapid maxillary expansion (RME). This systematic literature review was based on the PRISMA-P statement and was registered in the PROSPERO database with the following protocol ID: CRD42017079875. Pubmed, Cochrane, EBSCO, Scopus, Web of Science databases were searched with no restriction of year or publication status. Selection criteria were: randomised clinical trials, controlled clinical trials, cohort studies, cross-sectional studies, case-control studies on patients with unilateral/bilateral crossbite, transverse maxillary deficiency and crowding, treated with RME and monitored by 3D stereophotogrammetry. 652 articles were retrieved in the initial search. After the review process, 11 full-text articles met inclusion criteria. After the evaluation process, 4 publications were included for the present literature review. Due to the heterogeneous methodology meta-analysis was not possible; consequently, a systematic assessment of the studies and summary of the findings from the available evidence were used to answer the research question. The maximum widening of the alar cartilage is 1.41 ± 0.95 mm, whose clinical significance is open to question. The effect of RME on the mouth width remains controversial. In Altindis et al., the difference between pre-treatment and post-treatment mouth width (1.80 mm increment in the banded RME group) was statistically significant, while in Baysal 1.86 mm was considered a non-significant value. Inconsistencies and limitations in the study population and measurement protocols were detected between studies. These data underline the necessity for updated guidelines that allow to standardise, for this type of study, sample selection, measurement methods and collection of results.

Transverse Skeletal Effects of Rapid Maxillary Expansion in Pre and Post Pubertal Subjects: A Systematic Review

OBJECTIVE

The aim of this systematic review was to assess the transverse skeletal effects of rapid maxillary expansion (RME) in pre and post-pubertal subjects.

MATERIAL AND METHODS

Five databases were searched till May 2018; Pubmed, Cochrane, Scopus, Lilacs and Web of science in addition to the manual search of other sources. There were no language restrictions. Methodological Index for Non-Randomized Studies MINORS was used to assess the quality and risk of bias of the trials included.

RESULTS

Six studies were finally included in the qualitative analysis. A meta-analysis wasn't performed due to the heterogeneity of methodologies and outcomes. All of the included studies showed drawbacks in their structure yielding weak evidence. On the short term, RME caused an increase in the maxillary and lateral-nasal widths in pre-pubertal subjects by 3.4 mm and 3.3 mm, and by 2.8 and 2.2 mm respectively in post-pubertal subjects. Although statistically insignificant, the maxillary width increase was more than that of the post-pubertal subjects by 0.6 mm. Over the long term, expansion produced permanent increases in the transverse dimensions of both the dento-alveolar and skeletal components of the maxilla and circum-maxillary structures in pre-pubertal subjects. The post-pubertal subjects presented with a statistically significant increase only in the later-nasal width by 1.3 mm than the untreated controls with no permanent increase in the skeletal maxillary width.

CONCLUSION

The literature is very deficient regarding the use of skeletal age as a reference in the treatment of skeletal crossbites using RME. Only weak evidence exists supporting the increased maxillary and lateral-nasal widths after tooth-tissue borne RME in pre-pubertal subjects, with these effects being less in the post-pubertal ones.