Orodental malformations associated with human MSX1 sequence variants

BACKGROUND

MSX1 sequence variants have been known to cause human tooth agenesis (TA) with or without orofacial clefts. However, their roles during the whole processes of tooth development are not fully understood. This study aimed to characterize a 4-membered family with TA carrying a novel MSX1 pathogenic variant and investigate the disease mechanism.

METHODS

The authors conducted whole exome analysis to define the disease-causing sequence variant. They performed microcomputed tomography, morphometric analyses, transcriptome profiling, and molecular characterization to study the affected teeth and the gene variant.

RESULTS

The authors identified an MSX1 pathogenic variant, p.Glu232∗, in affected family members with TA and concomitant orodental anomalies, namely, prominent maxillary labial frenum, central incisor diastema, median maxillary anterior alveolar cleft, tooth fusion, mandibular molar dysmorphology, thin dentin layer, and slender dental roots. MSX1-defective teeth were not apparently microdontic but had thin dentin layers. The mandibular molars showed a homeotic transformation to maxillary counterparts. Genes involved in extracellular matrix organization and dentinogenesis, such as DMP1 and MMP20, were downregulated in dental pulp tissues of MSX1-defective teeth. The p.Glu232∗-truncated MSX1 properly localized to the nucleus but partially lost its transactivation ability. Analyzing reported cases indicated that truncation sequence variants within the homeobox domain of MSX1 caused a more severe TA phenotype than those outside of the homeobox domain, probably due to dominant negativity compared with haploinsufficiency.

CONCLUSIONS

This study provides in vivo evidence that MSX1 contributes to developmental processes of various orodental tissues in humans.

PRACTICAL IMPLICATIONS

Clinically, hypertrophic labial frenum, incisor diastema, and median maxillary anterior alveolar cleft might be considered diagnostic for MSX1-associated TA.

What is a superior labial frenulum? An anatomical and histological study

Anatomy of the superior labial frenulum (SLF), at first glance, seems to be well established. However, existing studies on the SLF lack description of the incisivus labii superioris (ILS), which cannot be ignored when discussing the SLF. We believe that thorough understanding of the SLF necessitates the anatomical knowledge of the ILS. This study aimed to elucidate the anatomical relationship between the orbicularis oris (OO), ILS, and SLF. A total of 20 formalin fixed human cadaveric specimens were used for gross anatomical and/or histological observation. For histological observation, all specimens were stained with Masson-trichrome. The SLF was a mucosal fold between the gingival mucosa and alveolar mucosa with connective tissue deep to it. The connective tissue attached to the alveolar bone in the junction between the right and left ILS. Skeletal muscle fibers other than orbicularis oris was found in one specimen, which were considered the ILS. During a frenulectomy, removal of the connective tissue bundle is required to prevent recurrence of the high SLF insertion.

Modified frenectomy technique to eliminate the aberrant labial frenum - A report of two cases

Introduction

A modified frenal treatment for aberrant frenum is presented in this report to reduce scar tissue formation and maintain the attached gingiva.

Description

The case report describes two cases in which a V-shaped incision removed the aberrant frenum and then the flaps of the frenum were sutured at the mid line.

Results

The results showed reduced scar tissue in the mid line and the tissue healed with adequate attached gingiva.

Take-Away Lessons

The modified frenotomy technique presented here is ideal for a large frenum that could expose the underlying connective tissue that could reduce the scar tissue formation.

Maxillary Labial Frenum in Preschool Children: Variations, Anomalies and Associated Factors

OBJECTIVE

To investigate the prevalence of morphological and attachment variations of the maxillary labial frenum (MLF) and associated factors in preschool children.

STUDY DESIGN

A cross-sectional study was conducted with 1,313 children aged between zero and five years of age attending public nurseries in the city of Canoas in southern Brazil. Data were collected through a questionnaire addressing demographic, socioeconomic, and behavioral characteristics and a clinical examination of the MLF. Assessments of MLF morphology and attachment were based on the classification systems proposed by Sewerin and Mirko et al., respectively.

RESULTS

The most prevalent patterns were simple MLF (63.8%) and gingival attachment (51.1%). Morphological abnormalities were found in 21.6% of the preschoolers and 25.4% exhibited abnormal frenal attachment. Abnormalities in MLF morphology were more prevalent among girls (p = 0.003) and a significant reduction was found with the increase in age (p < 0.001). Attachment abnormalities were significantly more prevalent among girls (p < 0.001), the white ethnic group (p = 0.005), and children who used a pacifier (p = 0.007) and also reduced significantly with the increase in age (p < 0.001).

CONCLUSION

Demographic and behavioral characteristics were associated with MLF morphology and attachment. The reduction in the prevalence of the outcomes with the increase in age suggests that surgical interventions in the first years of life may constitute overtreatment.

Upper-lip laser frenectomy with a diode laser in a pediatric patient: a case report

The case report aims to describe the parameters of performing upper labial frenectomy with the use of diode laser beams without infiltrated local anaesthesia. A 6-year-old patient was referred by the orthodontist for assessment of the upper anterior labial frenum. The dental treatment plan reported only the presence of caries on deciduous teeth and seals on the first permanent molars. The clinical examination reported the presence of a high attachments of labial frenum with a pathologically attachment and the presence of a diastema supports this theory. The laser used to remove the frenulum was a diode laser used with a wavelength of 980 nm with 320 microns of fiber in contact with a power of 2.0 W in continuous wave mode. The clinical examination showed an acceptable healing by secondary intention of the wound and the initial functional recovery of a physiological upper lip movements. The patient reported that the procedure was well tolerated. The diode laser can be used with good result for the removal of pathological frenum. The diode laser can be used in pediatric dentistry because of its application, adequate coagulation, no need for sutures and less inflammation and pain.

Longitudinal evaluation of diastema closure in patients submitted to labial frenectomy in different phases of the mixed dentition: A historical cohort

BACKGROUND

There is a controversy in the literature concerning the indications for frenectomy to treat interincisal diastema. Aims and Objectives: The aim of this study was to evaluate the spontaneous closure of the interincisal diastema in patients submitted to upper labial frenectomy (ULF) during the mixed dentition.

MATERIALS AND METHODS

Records from patients treated between 2009 and 2014 in the course of Pediatric Dentistry Surgery at Fundecto-USP were evaluated to select those that were submitted to ULF during the mixed dentition using the Chelotti technique. Initial clinic characteristics and radiographic data related to the abnormal upper labial frenum were collected. The patients were called for a return visit to evaluate the diastema closure. The prevalence of children with diastema reduction after the frenectomy was determined by descriptive analysis. Logistic regression was used to evaluate the association between exposure factors and diastema reduction. Results: From 449 eligible records, 53 were selected and 25 were in a return visit. It was not possible to find association between the exposure factors and diastema closure.

CONCLUSION

There is no relation between the time of surgery intervention and diastema closure. However, the intervention during the mixed dentition led to a partial diastema reduction in 80% of the cases.

Evaluation of Patient's Perceptions, Healing, and Reattachment After Conventional and Diode Laser Frenectomy: A Three-Arm Randomized Clinical Trial

Objective: The aim of this study is to compare the conventional and diode laser techniques in terms of patient's perceptions, epithelization, reattachment, and periodontal clinical parameters in the treatment of abnormal papillary frenum. Materials and methods: Forty-eight patients with abnormal papillary frenum were enrolled in the study. Patients were randomly assigned into three groups; conventional frenectomy operation (C group), diode laser-assisted frenectomy (L group), and diode laser-assisted frenectomy with conventional horizontal incision on the periosteum (L + P group). Postoperative pain, discomfort in speaking, and chewing scores were assessed with visual analogue scale (VAS) at postoperative 3rd hour and on days 1, 7, 14, 21, and 45. Epithelialization process of the wound surface was evaluated by hydrogen peroxide solution applied to the wound on days 7, 14, 21, and 45 following operations. The distance between the frenum attachment point and mucogingival junction (FMGJ) was recorded at baseline, postoperative 45th day, and 6th month to assess the reattachment of the frenum. Plaque index, gingival index, bleeding on probing, and probing depth were recorded at baseline and postoperative 7th, 14th, 21^st, and 45th days. Results: On the 1st and 7th day after operation, VAS pain score in the C group was significantly higher than in the L and L + P groups (p < 0.017). Difficulty in speaking and chewing scores were significantly lower in the L and L + P groups compared to the C group at postoperative 3rd hour and 7th day (p < 0.017). The FMGJ and epithelization period demonstrated no difference among the groups at any time point (p > 0.05). Conclusions: Our results suggest that diode laser provides better postoperative patient's perceptions than the conventional technique in frenectomy operation. In addition, both conventional and laser-assisted frenectomy surgeries prevent the frenum reattachment regardless of periosteal horizontal incision.

Upper Lip Tie and Breastfeeding: A Systematic Review

BACKGROUND

Upper lip tie (ULT) articles have been recorded in Medline since 1998, while "labial frenum" articles have been recorded since 1946.

OBJECTIVE

to study the existing medical literature on ULT (or labial frenum or fraenum) as they relate to breastfeeding.

MATERIALS AND METHODS

Medline search engine was used to determine and subsequently retrieve all articles published on ULT from 1946 to 2018. Key-words of upper lip tie OR labial frenum were used for the search. We also used Google Scholar and Embase to widen our search, and used the PRISMA criteria for systematic reviews (SRs). Articles were classified as case reports (or series), reviews, editorials (or opinions), cohort studies, clinical trials (nonrandomized), randomized controlled trials (RCT), and SRs according to Medline's own classification. We systematically summarized all articles published to date.

RESULTS AND CONCLUSION

No RCT were found, and the evidence for routine ULT release in infants with breastfeeding difficulties is poor. The classification system proposed by Kotlow has not been found reliable both in terms of inter and intraobserver agreement and in terms of predicting the severity of the breastfeeding difficulties.

Evaluation of patient perceptions after frenectomy operations: A comparison of neodymium-doped yttrium aluminum garnet laser and conventional techniques in the same patients

Background

The aim of the present study was to compare the level of postoperative discomfort between labial frenectomy done by neodymium-doped yttrium aluminum garnet (Nd: YAG) laser and the conventional technique and evaluate the differences in the levels of postoperative pain and functional complications such as eating and speaking between these two methods.

Materials and Methods

Forty patients requiring labial frenectomy in both jaws were included in the study. One side of each patient was treated with laser, whereas the other side was treated with the conventional technique and all surgeries were performed by the same surgeon. Postoperative pain and functional complications were evaluated for each patient and recorded using a visual analog scale on the operation day and postoperative 1, 3, 7 and 10 days.

Results

The results indicated that patients treated with the Nd: YAG laser had lower levels of postoperative pain and were more comfortable while chewing and speaking at the operation day and postoperative 1^st day (P < 0.05).

Conclusion

The results suggest that Nd: YAG laser application during oral soft-tissue surgery provides better patient perceptions and less postoperative pain compared to conventional surgery.

Using the diode laser in the lower labial frenum removal

Using the diode laser in the lower labial frenum removal.

OBJECTIVE

The aim of this study is to assess the advantages of the use of diode laser to removal inferior labial frenum.

METHODS

The treatment with the diode laser was proposed to a female patient of 32 years old in good general health having an abnormal inferior labial frenum that causes retracting of the gingival margin. The incision was carried out with diode laser at a wavelength of 940 nm and was removed the frenum mucosa and the deep tissue constitute of connective fiber and muscle fiber. Before the surgery wasn't used the local anesthetic and after the cutting wasn't necessary the use of suture.

RESULTS

The wound had a good healing without scar. The patient didn't have pain and bleeding during the healing and she didn't report complications. It wasn't necessary the use of antibiotic and anti-inflammatory.

CONCLUSIONS

The use of lasers has proved effective in the removal of labial frenum because it offers several advantages for the patient than traditional surgery.