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.

Combined orthodontic-orthognathic management of a patient with generalized short root anomaly and anterior open bite.

Short root anomaly is a rare dental disorder affecting tooth root development. It is characterized by reduced root-to-crown ratios (1:1 or less) and rounded apices. The short roots introduce a potential complication during orthodontic treatment. This case report describes managing a girl with generalized short root anomaly, an open bite, impacted maxillary canines, and a bilateral crossbite. In the first phase of treatment, the maxillary canines were extracted, and the transverse discrepancy was corrected with a bone-borne transpalatal distractor. In the second phase of treatment, a mandibular lateral incisor was removed, fixed appliances were placed in the mandibular arch, and bimaxillary orthognathic surgery was performed. A satisfactory result was obtained without further root shortening, adequate smile esthetics, and 2.5-year posttreatment stability.

Assessment of craniofacial maturation in preadolescents with cleft lip and/or palate using the cervical vertebral maturation method.

OBJECTIVES: Aberrant growth of the maxillomandibular complex in patients with cleft lip and/or palate (CL/P) can be managed with dentofacial orthopaedics. However, no consensus has been reached regarding timing and evolution of the maturational stages. Therefore, the aim of this study is to determine if patients with CL/P have an increased risk for delayed craniofacial maturation. MATERIALS AND METHODS: A sample of 246 cleft patients and 210 non-affected individuals was retrospectively compiled. Cephalometric radiographs taken between the ages of 10 and 14 years (girls) and 12 and 16 years (boys) were collected and assessed with the cervical vertebral maturation (CVM) method. RESULTS: In boys, no significant association between the presence of CL/P and a CVM score of CS3 or higher was observed in any age subsample. This was similar for a CVM score of CS5 or higher. Girls in the CL/P group had a significant lower probability of having a CVM score of at least CS3 in the subsample with age 11 to 12 (p = 0.001) and a borderline non-significant lower probability of having a CVM score of at least CS5 in the subsample with age 12 to 13 (p = 0.055). CONCLUSIONS: The current study demonstrated a discrete delay in skeletal maturation before the pubertal growth spurt of (pre)adolescents with CL/P, especially girls. This delay was less apparent at the end of the pubertal growth spurt. CLINICAL RELEVANCE: This research suggests that the craniofacial maturational stages relevant for dentofacial orthopaedic treatment in cleft patients, especially girls, occur at higher chronological age. Further research must quantify this delay, investigate its clinical significance, and determine its effect on the timing of dentofacial orthopaedic treatment.

The effect of manual lymphatic drainage on patient recovery after orthognathic surgery-A qualitative and 3-dimensional facial analysis.

OBJECTIVE: The aim of this study was to investigate the effect of manual lymphatic drainage (MLD) on postoperative facial swelling and pain. STUDY DESIGN: A randomized, single-center, prospective, 2-arm clinical trial with blinded endpoint assessment was set up. Patients were enrolled from the Maxillofacial Department of the Ghent University Hospital (Belgium) between January 2015 and March 2018. Both the intervention group (n = 13) and the control group (n = 13) received the same postoperative care; in addition, the intervention group underwent 6 sessions of MLD after orthognathic surgery. Three-dimensional facial scans were performed and questionnaires administered on postoperative days 3, 7, 14, 30, 90, and 180. A linear mixed model was performed, and statistical significance was assumed at the 5% level. RESULTS: In total, 26 patients (mean age 29 years; range 16-57 years) were included for statistical analysis. A faster decrease in swelling in the intervention group was observed on 3-dimensional scans. Furthermore, patients receiving MLD reported reduction in swelling and pain within the first month after surgery. However, no statistically significant difference could be detected in these observations (P > .05). CONCLUSIONS: Within the limitations of this study, no statistically significant difference could be found between patients treated with or without MLD after orthognathic surgery with regard to swelling and pain.

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.

Orthodontic Management of a Migrated Maxillary Central Incisor With a Secondary Occlusal Trauma.

INTRODUCTION: Normal or excessive occlusal forces exerted on teeth with a reduced periodontal support might result in a secondary occlusal trauma. This type of injury is diagnosed based on histological changes in the periodontium. Multiple clinical and radiographic indicators are, therefore, required as surrogates to assist the presumptive diagnosis of a (secondary) occlusal trauma. CASE PRESENTATION: In this case report, the diagnosis, management, and the 1-year follow-up of a secondary occlusal trauma of a maxillary central incisor are described. The occlusal relationship was rehabilitated with fixed orthodontic appliances and was further stabilized with both fixed and removable retainers. CONCLUSIONS: A combined periodontal-orthodontic approach for a secondary occlusal trauma allows the rehabilitation of periodontal, occlusal, and esthetic parameters. Twelve months after the end of the active orthodontic treatment, a combination of fixed and removable retainers showed to be effective in retaining the treatment outcome.

The in vitro remineralizing effect of CPP-ACP and CPP-ACPF after 6 and 12 weeks on initial caries lesion.

OBJECTIVE: The aim of this in vitro study was to determine the effects of remineralization promoting agents containing casein phosphopeptide-stabilized amorphous calcium phosphate (CPP-ACP), or CPP-ACP in combination with fluoride (CPP-ACPF) on artificial white spot lesions (WSLs) after 6 and 12 weeks. METHODOLOGY: White spot lesions were created on 123 sectioned premolars (246 specimens) with a demineralization solution during a 96 hours pH-cycling regime. Two experimental groups were created: a CPP-ACP group (Tooth Mousse™), and a CPP-ACPF group (Mi Paste Plus™). Additionally, two control groups were created, one using only a conventional toothpaste (1450 ppm fluoride) and another one without any working agents. All teeth were also daily brushed with the conventional toothpaste except the second control group. Tooth Mousse™ and Mi Paste Plus™ were applied for 180 seconds every day. The volume of demineralization was measured with transverse microradiography. Six lesion characteristics regarding the lesion depth and mineral content of WSLs were also determined. RESULTS: The application of CPP-ACP and CPP-ACPF had a significant regenerative effect on the WSLs. Compared to Control group 1 and 2 the volume of demineralization after 6 weeks decreased significantly for CPP-ACP (respectively p<0.001 and p<0.001) and CPP-ACPF (respectively p=0.001 and p=0.003). The same trend was observed after 12 weeks. For the CPP-ACPF group, WSL dimensions decreased significantly between 6 and 12 weeks follow-up (p=0.012). The lesion depth reduced significantly after application of CPP-ACP and CPP-ACPF but increased significantly in the Control groups. Mineral content increased for CPP-ACP and CPP-ACPF after an application period of 12 weeks, but this was only significant for CPP-ACP. CONCLUSIONS: Long-term use of CPP-ACP and CPP-ACPF in combination with a conventional tooth paste shows beneficial effects in the recovery of in vitro subsurface caries lesions.

The in vitro remineralizing effect of CPP-ACP and CPP-ACPF after 6 and 12 weeks on initial caries lesion

Abstract Objective: The aim of this in vitro study was to determine the effects of remineralization promoting agents containing casein phosphopeptide-stabilized amorphous calcium phosphate (CPP-ACP), or CPP-ACP in combination with fluoride (CPP-ACPF) on artificial white spot lesions (WSLs) after 6 and 12 weeks. Methodology: White spot lesions were created on 123 sectioned premolars (246 specimens) with a demineralization solution during a 96 hours pH-cycling regime. Two experimental groups were created: a CPP-ACP group (Tooth Mousse™), and a CPP-ACPF group (Mi Paste Plus™). Additionally, two control groups were created, one using only a conventional toothpaste (1450 ppm fluoride) and another one without any working agents. All teeth were also daily brushed with the conventional toothpaste except the second control group. Tooth Mousse™ and Mi Paste Plus™ were applied for 180 seconds every day. The volume of demineralization was measured with transverse microradiography. Six lesion characteristics regarding the lesion depth and mineral content of WSLs were also determined. Results: The application of CPP-ACP and CPP-ACPF had a significant regenerative effect on the WSLs. Compared to Control group 1 and 2 the volume of demineralization after 6 weeks decreased significantly for CPP-ACP (respectively p<0.001 and p<0.001) and CPP-ACPF (respectively p=0.001 and p=0.003). The same trend was observed after 12 weeks. For the CPP-ACPF group, WSL dimensions decreased significantly between 6 and 12 weeks follow-up (p=0.012). The lesion depth reduced significantly after application of CPP-ACP and CPP-ACPF but increased significantly in the Control groups. Mineral content increased for CPP-ACP and CPP-ACPF after an application period of 12 weeks, but this was only significant for CPP-ACP. Conclusions: Long-term use of CPP-ACP and CPP-ACPF in combination with a conventional tooth paste shows beneficial effects in the recovery of in vitro subsurface caries lesions.

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.

An esthetic evaluation of unilateral canine substitution for a missing maxillary lateral incisor.

OBJECTIVES: The aim of this study is to determine whether variation in size, morphology, and color of a unilateral substituted maxillary canine has influence on the dentogingival attractiveness perceived by dental professionals and laypeople. MATERIALS AND METHODS: A frontal clinical photograph of a patient with unilateral canine substitution was used as standard picture. Five different series were created by modification of following parameters with a raster graphics editor (Photoshop CS 6): (1) width, (2) color, (3) gingival margin height, and (4) crown tip morphology of the substituted canine and (5) the gingival margin height of the neighboring first premolar. For each parameter, the photograph deviating the most from the standard photograph, was combined into a final series. Four groups of examiners (orthodontists, periodontists, dentists, and laypeople) were asked to rank the photographs from most to least attractive. RESULTS: One hundred seventy-four examiners ranked the photographs in order of attractiveness. Overall, a darker canine color (mean rank 4.36 ± 1.03) and a more pronounced canine tip morphology (mean rank 3.47 ± 1.11) were significantly ranked as most unattractive (P < .05). The gingival height of the neighboring premolar was ranked as least unattractive by all groups of examiners (mean rank 1.30 ± 0.74). CONCLUSIONS: Darker canine color and a pronounced tip morphology of a substituted canine are rated as the most unattractive by dental professionals and laypeople. CLINICAL SIGNIFICANCE: The present study showed that the canine color and crown tip morphology are important parameters when considering unilateral canine substitution, both for professionals and laypeople. There is a general preference in favor of canines with a light color and a reduced incisal tip.