Precision of Landmark Positioning on Digitized Models from Patients with Cleft Lip and Palate

Post-treatment Stability in Orthodontic Retention with Twistflex Retainers-Do Patients Benefit from Additional Removable Retainers?

Objectives

To evaluate post-treatment movements of lower anterior teeth during orthodontic retention in patients with fixed twistflex retainers versus those with combined fixed and removable retainers.

Materials and Methods

This study was based on a retrospective data analysis of 57 adult patients during orthodontic retention. They were assigned to two groups: In group 1 (n = 30) the lower jaw was provided with twistflex retainers only and in group 2 (n = 27) with a twistflex combined with a removable retainer for night-time use. Orthodontic study models of the lower jaw were digitalized and superimposed. Tooth movements were analyzed at the retainer bonding (t0) and follow-up appointment ≥ six months later (t1). Rotational tooth movements (°) were measured around the x-axis (mesial/distal direction), the y-axis (buccal/lingual direction) and the z-axis (longitudinal direction, tooth axis). Translational tooth movements (mm) were registered along the x-axis (buccal/lingual direction), the y-axis (mesial/distal direction) and the z-axis (apical/coronal direction).

Results

Canine and incisor position changes during orthodontic retention were more pronounced in group 1 compared to group 2 except for canine rotations around the z-axis. In both groups in most of the cases stable lower incisor alignment could be found, but the proportion was significant higher in group 2 (group 1: 56.7% vs. group 2: 81.5%). Severe misalignment was present in 13.3% of the participants of group 1 and only in 7.4% of group 2. The extent of canine tipping and movements along the x- and y-axis in severe misalignment cases was significantly lower in group 2 compared to 1.

Conclusions

Lower incisor alignment was more stable in patients with combined fixed and removable retainers compared to fixed retainers only.

Clinical Relevance

Based on the present findings, the routinely application of supplementary removable retainers can be recommended to enhance anterior tooth alignment in patients with fixed twistflex retainers.

Anthropometric and Physiologic Parameters in Cleft Neonates: A Hospital-Based Study

The oro-facial morphology is greatly affected in neonates with a cleft lip and palate. The initial evaluation of neonate's body and maxillary arch dimensions is important for treatment planning and predicting growth in cleft patients. The objective of this study was comparative evaluation of the anthropometric and physiologic parameters of cleft and non-cleft neonates in a hospital-based set up. This cross sectional study was conducted on 88 cleft and non-cleft neonates (n = 44 in each group) aged between 0 and 30 days after obtaining approval from the institutional ethics committee and positive written informed consent from their parents. Neonates' body weight, body length, head length, head circumference, and maxillary arch dimensions were measured. Maxillary arch dimensions were measured on dental casts with digital sliding calipers. Statistical analyses performed using the independent t-test and one-way ANOVA analysis were followed by Bonferroni correction for post-hoc comparison. The results showed statistically significant differences in birth weight (p < 0.0001), head length (p < 0.01), head circumference (p < 0.007), and maxillary arch dimensions (p < 0.0001) between cleft and non-cleft neonates. These findings suggest that cleft neonates had significant anthropometric and physiologic variations than non-cleft neonates.

Continuous circular closure in unilateral cleft lip and plate repair in one surgery

The study aims at assessing wound healing and safety of single-stage two-layers continuous closure in patients with unilateral cleft lip and palate (UCLP). In this retrospective, descriptive cohort study, we assessed wound healing without fistula formation at 1, 3, and 6 months after a single-stage two-layer UCLP repair, in which the midline suture is continuously circular all along the oral and nasal sides. We examined lengths of hospital stay and the incidence of intra- and postoperative adverse events. Furthermore, we compared the cleft width at birth and on the day of surgery, after presurgical orthopaedics. Eleven UCLP patients underwent one cleft surgery between July 2016 and June 2018 at the age of 8-9 months. Full primary healing occurred in all patients without fistulas. Median length of post-operative hospital stay was 5 days (range = 4-9 days). No intra- or postoperative adverse events above Grade I (according to ClassIntra and Clavien-Dindo, respectively) occurred. Median and interquartile range (IQR) of the palatal cleft width decreased significantly from birth to surgery, i.e., from 12.0 mm (10.8-13.6 mm) to 5.0 mm (4.0-7.5 mm) anteriorly and from 14.0 mm (11.5-15.0 mm) to 7.3 mm (6.0-8.5 mm) posteriorly (p = 0.0033 in both cases). Given these preliminary results, the concept of single-stage continuous circular closure in UCLP has potential for further investigation. However, it remains to be proven that there are no relevant adverse effects such as inhibition of maxillary growth. Registered in clinicaltrials.gov:NCT04108416.

Intraoral Digital Impression for Speech Aid/Obturator in Children: Report of 2 Cases

Cleft patients may develop an abnormal opening (fistula) between the oral and the nasal cavities. Surgical repair minimizes the adverse effect on speech and feeding. However, an obturator prosthesis is a nonsurgical approach to help close the communication. The purpose of the case report presented is to show the clinical use of an intraoral digital impression in the fabrication of obturator/speech aid appliances in children with cleft lip and palate deformity. Minimal adjustments were needed, and patients and caregivers responded positively. Prostheses demonstrated good stability and retention at delivery. The use of digital technology seems to have several benefits as an alternative method for capturing impressions, especially in young children with cleft lip and palate deformity.

Three-Dimensional Morphological Changes of the True Cleft under Passive Presurgical Orthopaedics in Unilateral Cleft Lip and Palate: A Retrospective Cohort Study

The aim of this cohort study was to quantify the morphological changes in the palatal cleft and true cleft areas with passive plate therapy using a new analysis method based on three-dimensional standardized reproducible landmarks. Forty-five casts of 15 consecutive patients with complete unilateral cleft lip and palate were laser scanned and investigated retrospectively. The landmarks and the coordinate system were defined, and the interrater and intrarater measurement errors were within 1.0 mm. The morphological changes of the cleft palate area after a period of 8 months of passive plate therapy without prior lip surgery are presented graphically. The median decrease in cleft width was 38.0% for the palatal cleft, whereas it was 44.5% for the true cleft. The width of the true and palatal cleft decreased significantly over a period of 8 months. The true cleft area decreased by 34.7% from a median of 185.4 mm² (interquartile range, IQR = 151.5-220.1) to 121.1 mm² (IQR = 100.2-144.6). The palatal cleft area decreased by 31.5% from a median of 334 mm² (IQR = 294.9-349.8) to 228.8 mm². The most important clinical considerations are the reproducibility and reliability of the anatomical points, as well as the associated morphological changes. We propose using the vomer edge to establish a validated measuring method for the width, area, and height of the true cleft.

Intraoral Digital Impression Technique for a Neonate With Bilateral Cleft Lip and Palate

Objective:

Dental casts are an important aspect in the treatment planning, documentation, and analysis of the dental arch forms of infants with cleft lip and palate (CLP). Impression taking in a neonate is a technique-sensitive procedure, which can result in foreign body dislodgement and carries a small risk of aspiration and airway obstruction. The advent of digital dental technologies and intraoral scanning may facilitate safer, more effective, and accurate impressions for CLP infants.

Design:

A digital intraoral scan of a 3-month-old with bilateral CLP (BCLP) was compared with a conventional alginate impression taken prior to primary lip repair.

Setting:

Princess Margaret Hospital for Children.

Main Outcome Measures:

To test the applicability and accuracy of digital impression taking for a neonate with BCLP and palate using digital morphometrics.

Results:

The average deviation of points ranged above and below the plane of superimposition from +0.78 mm to −0.42 mm with a maximum range of +2.80 mm to −2.80 mm and standard deviation of 0.88 mm. The premaxillary segment showed the greatest degree of variation.

Conclusions:

This is to our knowledge the first report that illustrates the use of a digital impression system to scan the oral structures of a neonate with BCLP. Digital scanning was found to be fast, accurate, and safe, when compared to a conventional alginate impression technique.

Novel 3-D Analysis for the Assessment of Cleft Dimensions on Digital Models of Infants With Unilateral Cleft Lip and Palate

Objective:

To present a 3-D standardized analysis of cleft dimensions.

Materials:

Thirty-one plaster casts of unilateral cleft lip and palate (UCLP) infants were laser scanned. Landmarks and coordinate system were defined. Linear distances and surfaces were measured, and the ratio between cleft and palatal area was calculated (3-D infant cleft severity ratio [3D ICSR]). The digitally measured areas were compared with silicone membranes, adapted to the plaster casts, and analyzed by optic microscopy.

Main Outcome Measures:

Repeatability, reproducibility, and validity.

Results:

Bland-Altman plots showed minor bias for anterior cleft width (0.16 mm), arch length (0.23 mm), and palatal surface (−9.18 mm2). The random error was maximum 0.78 mm for linear measurements and 12.1 mm2 for area measurements, reliability of 3D ICSR was 0.99 (intraclass correlation coefficient), differences between measurements on digital and plaster models were less than 2%.

Conclusions:

The method offers valid and reproducible 3-D assessment of cleft size and morphology. 3-D infant cleft severity ratio can be used as baseline value for surgical planning and may have a role in predicting dentofacial development.

Automated detection of alveolar arches for nasoalveolar molding in cleft lip and palate treatment

Nasoalveolar moulding (NAM) has become a widely accepted and evidence-based treatment strategy for newborns with cleft lip and palate (CLP), attempting to reduce the cleft gap and to form an appropriately shaped alveolar arch by an intraoral patient-specific NAM plate and to erect the usually flattened nostrils towards a natural nose wing occurrence. The generation of such an appropriately shaped NAM plate requires, besides 3d information of the patient’s initially cleft lip and palate, an estimated target model of the maxilla. Previous studies showed the applicability of curve-based approaches to describe the maxilla during early infancy. We have developed an automated algorithm implemented with the programming language Python, describing the alveolar arch by an approximated ellipse. Therefore, the digitalized data sets of human maxillae were aligned to a global coordinate system with a total least square method and subsequently analyzed with the curvature-based algebraic point set surfaces (APSS) algorithm. The gathered information of height ratio and curvature allows the detection of points on the alveolar segments and therewith the fit of an ellipse describing the human maxilla. In 84.5% of 193 maxilla impressions of healthy newborns the fitted ellipses described the course of the maxilla within defined margins. Applying the algorithm to 38 newborns suffering from unilateral cleft lip and palate in 76.3% the fitted ellipses bridge the CLP alveolar segments, so that a harmonic alveolar arch can be deduced. Describing the alveolar arch by one or multiple ellipses allows (i) to automatically measure the dimensions of the maxilla, (ii) to derive a growth model during early infancy, (iii) to derive a healthy harmonic arch from CLP alveolar segments and (iv) to automatically generate a basic NAM device on the basis of the virtually modified maxilla.

Effect of lip closure on early maxillary growth in patients with cleft lip and palate

IMPORTANCE

Debate continues about the cause of midfacial growth disturbance in patients with facial clefts.

OBJECTIVE

To evaluate the functional effect of surgical closure of the lip before palatal closure according to the technique by Delaire on early maxillary growth in patients with complete unilateral cleft lip and palate.

DESIGN, SETTING, AND PARTICIPANTS

Twenty-two patients with unilateral cleft lip and palate were studied using plaster casts obtained at the time of cheilorhinoplasty and 6 months later before palatal closure. The interrupted lateral muscles were anatomically repositioned using the surgical technique by Delaire. No patients had received preoperative orthodontic treatment or a passive palatal plate. Cast analyses were performed using a digital caliper.

MAIN OUTCOMES AND MEASURES

Landmark positioning was performed 3 times by 2 different examiners to define intraobserver and interobserver differences. The final maxilla dimensions were recorded as the distances between the mean landmark positions. Using the t test, dimensions obtained before palatal closure were compared with dimensions obtained before lip closure.

RESULTS

The method allowed good reproducibility. Functional closure of the lip significantly narrowed the transverse anterior cleft areas by -2.36 mm (P < .05). Sagittal variables were increased by 1.68 mm on the nonaffected side and by 1.48 mm on the affected side (P < .05 for both).

CONCLUSIONS AND RELEVANCE

Functional closure according to the technique by Delaire narrows the transverse dimensions of the maxilla, while simultaneously preserving initial sagittal growth.

LEVEL OF EVIDENCE

4.

Evaluation of the intercanine distance in newborns with cleft lip and palate using 3D digital casts

OBJECTIVE

The purpose of this present study was to compare, by means of 3D digital casts, the anterior transverse dimension of the dental arch of newborns with and without cleft lip and palate.

MATERIAL AND METHODS

The sample was composed of ninety-four children aged from 3 to 9 months divided into three study groups: Group I - children without craniofacial deformities (control group); Group II - children with unilateral cleft lip and palate; Group III - children with bilateral cleft lip and palate. Impressions were executed before lip and palate repair in patients with clefts. Dental casts were digitized using a 3D scanner linked to a computer. Measurements of the intercanine distance were measured on the digital casts. Intergroup comparisons were performed using ANOVA (p<0.05).

RESULTS

The results showed a mean of 36.5 mm for unilateral cleft lip and palate group, 34.8 mm for bilateral cleft lip and palate group and 27.52 mm for the control group. There was a statistically significant difference between the control group and both groups of patients with cleft lip and palate. There was no statistically significant difference between complete unilateral and bilateral cleft lip and palate groups.

CONCLUSIONS

Patients with complete cleft lip and palate were born with an increased anterior dimension of the maxillary dental arch compared to non cleft patients.

Evaluation of tip and torque on virtual study models: a validation study

BACKGROUND

The objectives of this study were to develop and validate a novel analysis protocol to measure linear and angular measurements of tip and torque of each tooth in the dental arches of virtual study models.

METHODS

Maxillary and mandibular dental casts of 25 subjects with a full permanent dentition were scanned using a three-dimensional model scanner. Sixty points per arch were digitized on each model, five points on each tooth. A custom analysis to measure linear distances and angles of tip and torque was developed using a new reference plane passing as a best-fit among all of the lingual gingival points, with the intermolar lingual distance set as the reference X-axis. The linear distances measured included buccal, lingual, and centroid transverse widths at the level of canines, premolars, and molars as well as arch depth and arch perimeter.

RESULTS

There was no systematic error associated with the methodology used. Intraclass correlation coefficient values were higher than 0.70 on every measure. The average random error in the maxilla was 1.5°±0.4° for torque, 1.8°±0.5° for tip, and 0.4±0.2 mm for linear measurements. The average random error in the mandible was 1.2°±0.3° for torque, 2.0°±0.8° for tip, and 0.1±0.1 mm for the linear measurements.

CONCLUSIONS

A custom digital analysis protocol to measure traditional linear measurements as well as tip and torque angulation on virtual dental casts was presented. This validation study demonstrated that the digital analysis used in this study has adequate reproducibility, providing additional information and more accurate intra-arch measurements for clinical diagnosis and dentofacial research.

Early effect of vomerine flap closure of the hard palate at the time of lip repair on the alveolar gap and other maxillary dimensions

OBJECTIVE

Comparison of the effects of vomerine flap (VF) closure of the hard palate at the time of lip repair with non-closure of the hard palate in subjects with unilateral cleft lip and palate (UCLP).

DESIGN

Retrospective, single-blinded, cohort study.

SETTING

Study model sets of 40 consecutive, non-syndromic, infants with complete UCLP operated on between 1988 and 1998.

PATIENTS

All subjects were operated on by a single consultant plastic surgeon immediately before and after the unit's change of protocol (1993), when VF closure of the hard palate was incorporated at the time of lip repair. Subjects were divided into two groups: VF ( n = 18) and non-VF (n = 22), which acted as a control group. Each subject had maxillary impressions taken before lip repair at 3 months (VF mean age = 11.7 weeks; non-VF mean age = 13.4 weeks) and before palate repair at 6 months (VF mean age = 22.8 weeks; non-VF mean age = 24.0 weeks).

MAIN OUTCOME MEASURES

Seven predetermined landmarks and four maxillary dimensions were computed following single-blinded analysis using a reflex microscope.

RESULTS

Repeatability tests showed good measurement precision. The operator measurement errors were 0.00018 mm in a horizontal plane (X and Y) and 0.00028 in the vertical plane (Z). The VF group showed significant changes in the alveolar cleft width. There were no statistically significant changes in any arch-form variable between the VF and non-VF groups.

CONCLUSION

The decrease of alveolar arch gap width at palate repair (6 months) in the VF group was significantly more than the decrease observed in the non-VF group, and there was no significant decrease in the, anterior and posterior arch width or anteroposterior length of the hard palate in the VF group compared with the non-VF group.