In Vitro Investigation into the Effect of Cryopreservation on the Mechanical Characteristics of Dental Hard Tissues.

Previous research has reported on hidden damage within the dentin introduced by cryopreservation, but the effect on the mechanical properties of the hard tissues at tooth level remains unclear. The main objective of this study is to investigate the effect of cryopreservation on the mechanical properties of teeth. A matched sample of 234 premolars of 117 children (9 ≤ age ≤ 16 years), bilaterally extracted for orthodontic reasons, were included. For each child, one tooth was randomly allocated to the cryopreservation group and the contralateral tooth was assigned to the control group. Static compression tests were performed to determine load to failure, stiffness, and toughness. In a subgroup of 20 teeth, a cyclic preloading or chewing simulation was performed. Additionally, the fracture mode was determined, and the microstructure of the fractured surfaces was examined using a scanning electron microscope (SEM). Linear mixed model analyses could not detect a statistical difference in the mean load to failure (p = 0.549), mean toughness (p = 0.968), or mean stiffness (p = 0.150) between cryopreserved and non-cryopreserved teeth. No significant difference in load to failure after cyclic preloading was detected between groups (p = 0.734). SEM analysis revealed comparable fracture characteristics between groups. It is concluded that cryopreservation does not affect the mean load to failure, stiffness, or toughness of teeth, indicating that hidden damage in the dentin is not critical at tooth level.

Reliability of the novel cleft lip and palate smile esthetic index (CLP-SEI).

BACKGROUND/OBJECTIVES: The aim of this research was to determine the reliability of a novel index for the assessment of smile esthetics in patients with cleft lip and/or palate (CL ± P) at the end of their multidisciplinary treatment, for use in clinical and academic settings. MATERIALS AND METHODS: Five orthodontists, five periodontologists, five general practitioners, five dental students, and five laypeople rated the smiles of 10 patients with CL ± P twice at a 2 weeks interval. The rating scale consisted of four main categories: 1. nasolabial esthetics, 2. gingival esthetics, 3. dental esthetics, and 4. overall esthetics. A total of 15 parameters were rated. Intra- and inter-rater agreements were calculated using SPSS. RESULTS: The inter-rater agreement varied between good and excellent whereby the orthodontists, periodontists, general practitioners, dental students, and laypeople obtained agreement scores of 0.86, 0.92, 0.84, 0.90, and 0.89, respectively. The intra-rater agreement was good with agreement scores of 0.78, 0.84, 0.84, 0.80, and 0.79, respectively. LIMITATIONS: Smile esthetics were rated on static pictures, not in real life or by video recordings in a young adult population. CONCLUSIONS/IMPLICATIONS: The cleft lip and palate smile esthetic index is a reliable tool for the assessment of smile esthetics in patients with CL ± P.

Rapid maxillary expansion vs slow maxillary expansion in patients with cleft lip and/or palate: a systematic review and meta-analysis.

OBJECTIVES: To compare the dentoalveolar outcomes of slow maxillary expansion (SME) and rapid maxillary expansion (RME) used for maxillary expansion before secondary alveolar bone grafting in patients with cleft lip and/or palate (CL/P). Secondarily, the advantages and disadvantages of SME vs RME were reviewed. MATERIALS AND METHODS: A systematic search was conducted up to November 2021, including Medline (via PubMed), Embase (via Ovid), Web of Science, Cochrane Central, and Google Scholar. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. Risk-of-bias assessment was performed using the Risk of Bias (RoB 2.0) and Risk Of Bias In Non-randomized Studies of Interventions (ROBINS I) tool. Overall quality was assessed using the Grading of Recommendations Assessment, Development, and Evaluation tool. RESULTS: Of 4007 records, five studies met the inclusion criteria. The randomized control trial (RCT) had a low risk of bias, the non-RCTs presented with a moderate risk of bias. Arch width and perimeter increased significantly with both SME and RME treatments. No difference in the increase in palatal depth was found. The meta-analysis showed a greater anterior-to-posterior expansion ratio for the Quad Helix (QH) appliance. The results for dental tipping were not conclusive. CONCLUSIONS: SME and RME promote equal posterior expansion in cleft patients. The anterior differential expansion is greater with SME (QH appliance). No clear evidence exists concerning the amount of dental adverse effects of SME and RME in cleft patients.

A non-cephalometric three-dimensional appraisal of soft tissue changes by functional appliances in orthodontics: a systematic review and meta-analysis.

BACKGROUND: Patients with dental and skeletal Class II growth patterns present typical facial characteristics. Functional appliance (FA) therapy is one of the conventional orthodontic treatment modalities used to harmonize these facial imbalances. OBJECTIVES: The aim of this systematic review was to investigate and summarize the effects of FAs on the facial soft tissues captured in three dimensions. SEARCH METHODS: A systematic search was conducted up to December 2020. Databases Medline (via PubMed), Embase (via Ovid), Web of Science, and Cochrane Central were searched without language restrictions. SELECTION CRITERIA: Randomized clinical trial (RCT)'s investigating the influence of FA therapy on the facial soft tissues in a non-cephalometric and three-dimensional (3D) manner, were included. DATA COLLECTION AND ANALYSIS: Data extraction was independently undertaken by two authors. In case of conflict, a third author was consulted. RoB 2.0 tool was used to assess the risk of bias. A meta-analysis was performed for total facial height, upper lip length, lower lip length, commissural width, and facial depth. The single-step activation versus incremental approach was compared using a random effects model. RESULTS: Five studies were included in the qualitative synthesis of the systematic review. Facial height increased after FA therapy. Three studies met the criteria for the meta-analysis. The mean facial depth increased significantly (P < 0.003) with 1.39 mm (0.46 to 2.32). CONCLUSIONS: Current evidence suggests a positive influence of the FA therapy on the soft tissues in Class II patients. However, conclusions were drawn based on a two-dimensional analysis of 3D images, suggesting that more controlled studies using a comprehensive 3D analysis are necessary to confirm these results. REGISTRATION: PROSPERO registration (CRD 42021224016).

A non-cephalometric two-dimensional appraisal of soft tissue changes by functional therapy in Class II patients: a systematic review and meta-analysis.

BACKGROUND: Facial attractiveness has social, psychological, and economic repercussions. Class II malocclusions are associated with a retroposition of the mandible, facial convexity, protruded upper lip, retruded lower lip, and pronounced mentolabial fold. Functional appliances (FA) try to increase mandibular length and normalize lip position, thereby decreasing the facial profile convexity and aesthetics. OBJECTIVES: The aim of this review and meta-analysis is to investigate the effects of FA on the soft tissues in a non-cephalometric two-dimensional manner. SEARCH METHODS: Medline (via PubMed), Embase (via Ovid), Web of Science, and Cochrane Central were used to identify studies describing the soft tissue results of FA in a non-cephalometric way. The search was conducted up to July 2021. SELECTION CRITERIA: Prospective and retrospective studies investigating the effects of FA appliances on the soft tissues, with non-ionizing, two-dimensional imaging, including an attractiveness assessment based on Visual Analogue Scale or Likert scale, were considered eligible. DATA COLLECTION AND ANALYSIS: Data extraction was performed separately by two authors. Risk of bias was assessed using the ROBINS-I tool. RESULTS: From the eight eligible studies, four were included in the meta-analysis to investigate the influence of assessors on facial attractiveness scores. Age range of the included studies varied from 8 to 21 years old including 313 Caucasian patients whereof 64% females. Six out of eight studies used growing patients as treatment group and only two studies reported follow-up after the end of treatment. Overall facial attractiveness increased after treatment with FA, resulting from a decrease in facial convexity and a normalization of the lip relationship. Orthodontists score higher aesthetic improvements after FA treatment as compared to laypeople. CONCLUSIONS: Current evidence suggests the positive effects of FA on the facial attractiveness in growing and non-growing patients. FA normalize the lip relationship. Furthermore, they tend to decrease facial convexity and advance the chin point. More pleasing results can be expected in growing patients. Orthodontists are more generous when assessing treatment changes as compared to laypeople. REGISTRATION: PROSPERO registration (CRD42021254835).

The orthodontic bonding properties of human enamel after cryopreservation.

The aim was to investigate the effect of cryopreservation on the enamel bonding properties of orthodontic brackets. Sixty-six human premolars were randomly allocated to a control group or a cryopreserved group. Conventional stainless-steel orthodontic brackets were bonded with a light cure adhesive on the buccal side of the premolars. The shear bond strength (SBS) was determined at a crosshead speed of 1 mm/min. The SBS and adhesive remnant index (ARI) were evaluated respectively by an independent samples t test and Fisher's exact test (α≤0.05). The mean failure load was lower in the cryopreserved group. However, this difference in SBS was not significant (p=0.443). In both groups, the ARI mostly indicated a failure at the enamel-adhesive interface. The mean ARI scores for both groups were not significantly different (p=0.099). Within the limitations of this macro bond strength testing, it can be concluded that cryopreservation does not significantly affect the bonding properties of enamel.

The Effect of Autologous Alveolar Bone Grafting on Nasolabial Asymmetry in Unilateral Cleft Lip and Palate.

The objective of this study was to examine whether an autologous alveolar bone graft has an effect on the nasolabial asymmetry in unilateral cleft lip, alveolus, and palate. Fifteen children (mean age 7.5 ±â€Š2.4 years) with non-syndromic unilateral cleft lip and palate (CLP) were included. Non-ionizing three-dimensional images were acquired prior to and three months after the alveolar bone grafting procedure. A 2D and a landmark-independent 3D asymmetry assessment were used to detect changes of asymmetry in the nasolabial area. For the 2D assessment, a cleft and non-cleft side ratio for 4 linear nasal and 2 linear labial distances was expressed as a Coefficient of Asymmetry (CA). The 3D asymmetry assessment comprised a robust superimposition of the face with its mirror image, expressed as a root-mean-square-error (RSME) in mm. A significant decrease in the CA for the labial distance from the facial midline to the labial commissure was observed (P = 0.036). Also, the CA for the labial distance from the facial midline to the highest point of Cupid's bow increased significantly (P = 0.028). Non-significant changes were observed for the CA for the 2 nasal distances and the 2 other labial distances. No significant changes in 3D nasal asymmetry were detected (P = 0.820). Alveolar bone grafting completes the alveolar ridge but has only little to no clinical effect on the asymmetry of the secondary cleft lip nasal deformity.

The evaluation of the transport medium for extracted premolars prior to cryopreservation: an in vitro study.

Autotransplantation is a versatile technique for the replacement of a missing tooth and cryopreservation can expand its scope. The aim of this in vitro study is to compare the antimicrobial effect of different transport protocols on procured teeth prior to cryopreservation. Streptococcus oralis biofilms were grown on ten sterile premolars, incubated for 48 h and subjected to the following transport procedures: an untreated (contaminated) control group, a group rinsed with phosphate buffered saline (PBS), a group transported in PBS, a group transported in Dulbecco's Modified Eagle's medium (DMEM) supplemented with fetal calf serum (FCS), and a group transported in DMEM supplemented with FCS and antibiotics (AB). The effect of cryopreservation as such, as well as the combination with a transport medium (DMEM + FCS + AB) on the contamination was also tested. The surviving bacteria were harvested, and determined by plate counting. There was no significant reduction in contamination after rinsing the tooth, after transport in PBS or after transport in DMEM with FCS. Significant reductions were observed for transport in DMEM with AB when compared to the control group (p = 0.003). Cryopreservation as such reduced the biofilm significantly (p < 0.001). No cumulative effect could be found when transport in DMEM + FCS + AB was followed by cryopreservation. Within the limitations of this laboratory set-up, DMEM + FCS + AB was the most effective transport medium in S. oralis biofilm elimination. It could not be concluded that rinsing of the tooth gives an additional reduction. Cryopreservation as such decontaminated the teeth more effectively than any tested transport procedure.

Quantifying Soft Tissue Changes in Cleft Lip and Palate Using Nonionizing Three-Dimensional Imaging: A Systematic Review.

PURPOSE: The use of nonionizing 3-dimensional (3D) imaging in cleft lip and palate (CLP) research is well-established; however, general guidelines concerning the assessment of these images are lacking. The aim of the present study was to review the methods for quantification of soft tissue changes on 3D surface images acquired before and after an orthopedic or surgical intervention in CLP patients. MATERIALS AND METHODS: A systematic literature search was performed using the databases MEDLINE (through PubMed), CENTRAL, Web of Science, and EMBASE. The literature search and eligibility assessment were performed by 2 independent reviewers in a nonblinded standardized manner. Only longitudinal studies reporting the assessment of pre- and postoperative 3D surface images and at least 10 CLP patients were considered eligible. RESULTS: Fifteen unique studies (reported from 1996 to 2017) were identified after an eligibility assessment. The assessment of the 3D images was performed with landmark-dependent analyses, mostly supported by superimposition of the pre- and postoperative images. A wide spectrum of superimposition techniques has been reported. The reliability of these assessment methods was often not reported or was insufficiently reported. CONCLUSIONS: Soft tissue changes subsequent to a surgical or an orthopedic intervention can be quantified on 3D surface images using assessment methods that are primarily based on landmark identification, whether or not followed by superimposition. Operator bias is inherently enclosed in landmark-dependent analyses. The reliability of these methods has been insufficiently reported.

The evaluation of the transport medium for extracted premolars prior to cryopreservation: a systematic literature review.

Prior to cryopreservation, a tooth is transported from a contaminated oral environment to the tooth bank. Our objective was to identify all studies reporting or investigating a transport protocol prior to the cryopreservation of teeth, in terms of decontamination of the subjects. The systematic literature search (1970-2017) was based on MEDLINE via PubMed, Web of Science and the Cochrane Library. The reference lists of the included studies and the Science Citation Index were used for hand searching (snowballing). Only studies reporting the transport conditions of the transplant were included. Language restrictions for English, Dutch or French were applied. The search led to 14 eligible studies. Almost all studies were laboratory studies, so the methodological quality of evidence was low. The majority of the included studies was performed by only five different research groups and the number of subjects varied between 1 and 120 teeth. In general, the teeth were stored in a tissue culture medium supplemented with fetal calf serum and/or different combinations of antibiotics and/or antimycotics. The teeth were transported cooled (4 °C) or at room temperature, for a period of time not exceeding 24 h. Only three studies reported the irrigation of the teeth with phosphate buffered saline prior to the transport. The optimisation of the decontamination during transport was investigated in three studies (from 1971, 1980 and 1982). It was concluded that the literature on this topic is scarce, and the decontamination protocol for teeth, prior to cryopreservation has not been validated recently.