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Background: Augmentation mentoplasty with implants is an extremely rewarding procedure. Bone resorption is almost unavoidable. The high-risk factors for chin bone resorption have not been explored in the past. This study aimed to analyze and evaluate the factors influencing bone resorption after augmentation mentoplasty with implants using three-dimensional imaging., Methods: We retrospectively analyzed preoperative craniofacial Computed Tomography scan data from 105 patients who underwent mandibular implantation surgery and 108 patients who did not. We also examined the extent to which different factors influenced the occurrence of bone resorption in the chin area., Results: Patients with silicone gel implants are more prone to bone resorption than those with Medpor implants. Patients who experienced bone resorption had thicker mentalis muscles than those who did not experience bone resorption (6.35 ± 1. mm vs. 5.73 ± 1.25 mm, P < 0.05), and thinner cortical bone (3.25 ± 1.65 mm vs. 5.22 ± 2.04 mm, P < 0.05). Additionally, implants placed above the mandibular bone were more likely to induce bone resorption than those placed below it., Conclusions: This study is the first to systematically reveal the impact of implant type, placement position, mentalis muscle thickness, and cortical bone thickness on bone resorption after chin augmentation surgery. For patients with thicker mentalis muscles and thinner cortical bones, greater attention should be paid to the occurrence of bone resorption. Choosing silicone implants or placing the implants higher on the mandible can help reduce the occurrence of bone resorption. This study can assist clinicians in selecting appropriate treatment methods, thereby reducing post-implantation bone resorption., Level of Evidence Iii: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors   www.springer.com/00266., Competing Interests: Declarations. Conflict of interest: The authors declare no potential conflicts of interest concerning the research, authorship, or publication of this article. The authors declare that they have no conflicts of interest to disclose. Statement of Human and Animal Rights, or Ethical Approval: This study was approved by the Ethics Committee of the Plastic Surgery Hospital of the Chinese Academy of Medical Sciences and Peking Union Medical College. Ethic Files specific ID numbers: 2024(44). Informed Consent: All patients were informed and agreed to this study., (© 2024. Springer Science+Business Media, LLC, part of Springer Nature and International Society of Aesthetic Plastic Surgery.)

Background: Chin prosthesis implantation, a cosmetic procedure to correct chin asymmetry, depression, or retraction, is generally safe and simple. However, its long-term effects on surrounding tissues are a concern. This study aimed to use three-dimensional (3D) scanning to classify the mentalis muscle shapes and assess the impact of prosthesis implantation on these muscles., Method: This study evaluated 450 eligible female participants. Using three-dimensional imaging, data on the types, thickness, width, and length of the left and right mentalis muscles were collected and summarized. The impact of chin prosthesis on these muscle dimensions was assessed using analysis of variance, and the effect on muscle type was determined using χ 2 test., Results: Chin implant placement affected the mentalis muscles, resulting in increased length, thickness, and width. The subjects' mentalis muscles were categorized into 3 types and divided into 7 subtypes. χ 2 test results indicated that implantation influences the classification of these muscles., Conclusion: Recognizing how implant placement affects the mentalis muscle can guide the development of treatments to mitigate these changes. Additionally, understanding the muscle's morphology enables more precise treatment approaches for patients., (Copyright © 2024 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.)

Facial feminization is a complex undertaking requiring skill in both craniofacial and aesthetic plastic surgery. As in aesthetic procedures, understanding the patient's goals and setting realistic expectations in light of an individual's anatomy is critical. Both soft tissue and bone must be addressed to adequately soften masculine facial features. This article delves into specific anatomic areas and delineates some of the pathways to successful outcomes., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Objective: To determine if compression sites of the facial nerve correlate with immediate postoperative outcomes in patients with hemifacial spasm (HFS), and if changes in the waveform of abnormal muscle response (AMR) during microvascular decompression (MVD) for HFS can predict the postoperative course., Methods: In this retrospective review, we evaluated 50 patients with HFS who underwent AMR monitoring during MVD. The ratios of amplitude and duration of AMR waveforms were computed by comparing baseline with final examinations. Vascular compression sites were categorized into four portions of the facial nerve. Postoperatively, we classified patients into two groups based on symptom relief as those whose symptoms disappeared immediately (DI group), and those whose symptoms disappeared gradually (DG group)., Results: The compression sites significantly correlated with postoperative outcomes at discharge (p < 0.001) but not with outcomes after 6 months of MVD. Lower duration ratios of AMRs from the mentalis muscle were significantly associated with an increased chance of classification into the DI group based on the results of multivariate logistic regression analysis (p = 0.017)., Conclusions: Relationship between compression sites and immediate outcomes could provide useful information to surgeons for predicting if symptoms will resolve over long term. Moreover, changes in AMRs recorded from the mentalis muscle could predict the postoperative course of HFS., Significance: These findings can help surgeons evaluate the changes in AMR amplitude and duration during MVD for HFS., Competing Interests: None., (© 2024 International Federation of Clinical Neurophysiology. Published by Elsevier B.V.)

Objective: The purpose of this retrospective study was to investigate the effects of Botulinum Toxin-A (BTX-A) injection into the mentalis muscle on the free gingival graft (FGG)., Materials and Methods: Forty patients with keratinized gingiva insufficiency and Cairo's RT 2 gingival recession (formerly classified as Miller class III) in their mandibular central incisors were randomly divided into two groups: FGG and FGG + BTX. Plaque index (PI), gingival index (GI), probing pocket depth (PPD), keratinized gingiva width (KGW), attached gingiva width (AGW), clinical attachment level (CAL), gingival thickness (GT), gingival recession amount (GRA), gingival recession width (GRW), and root closure percentage (RCP%) parameters were measured at baseline and at first, third, and sixth months after the operation., Results: There was no difference in PI, GI, and PPD levels in both groups (p > 0.05). While the change in GT and RCP% levels were found to be statistically significantly higher at FGG + BTX group than FGG group, the change in GRW and CAL levels were statistically significantly lower (p < 0.05)., Conclusion: The findings of this study indicate that BTX-A injection applied to the mentalis muscle after FGG operation may have positive effects in terms of KGW, AGW, GT, RCP%, GRW, and CAL parameters., Clinical Significance: As a result of the fact that BTX-A injection into the mentalis muscle contributed to the nutrition and immobility of FGG, positive developments were obtained in terms of clinical periodontal parameters. BTX-A injection into the mentalis muscle may be an alternative method that increases the success rate of Cairo's RT 2 gingival recession., (© 2023 Wiley Periodicals LLC.)

Objectives: The perioral muscles postural and functional abnormality should be clearly evaluated. The influence of the abnormal function of mentalis muscle on the shape and posture of the mandible was evaluated using a finite element approach., Methods: Finite element analysis was used to create a three-dimensional representation of a human mandible that represents a dry normal mandible with teeth (33-36 gm/cm 2 ). Pressures were applied directly to the labial surface of the mandible's lower anterior dento-alveolar structure reflecting the normal lips muscle function. While on abnormal swallowing pattern, lip muscle force (300 gm\cm 2 ) had been assumed., Results: Shape and postural abnormality of the mandible with malocclusion particularly at the anterior dentoalveolar and basal bone region in sagittal direction as well as inward pressure on the mandibular posterior region., Conclusion: Abnormal perioral muscle function throughout growth and development may result in a shape and postural abnormality of the mandible and a companying malocclusion., Competing Interests: There are no conflicts of interest., (Copyright: © 2023 Journal of Orthodontic Science.)

The mentalis muscle is a paired muscle originating from the alveolar bone of the mandible. This muscle is the main target muscle for botulinum neurotoxin (BoNT) injection therapy, which aims to treat cobblestone chin caused by mentalis hyperactivity. However, a lack of knowledge on the anatomy of the mentalis muscle and the properties of BoNT can lead to side effects, such as mouth closure insufficiency and smile asymmetry due to ptosis of the lower lip after BoNT injection procedures. Therefore, we have reviewed the anatomical properties associated with BoNT injection into the mentalis muscle. An up-to-date understanding of the localization of the BoNT injection point according to mandibular anatomy leads to better injection localization into the mentalis muscle. Optimal injection sites have been provided for the mentalis muscle and a proper injection technique has been described. We have suggested optimal injection sites based on the external anatomical landmarks of the mandible. The aim of these guidelines is to maximize the effects of BoNT therapy by minimizing the deleterious effects, which can be very useful in clinical settings.

Objective: Interpreting lateral spread response (LSR) during microvascular decompression (MVD) for hemifacial spasm (HFS) is difficult when LSRs observed in different muscles do not match. We aimed to analyze LSR patterns recorded in both the orbicularis oris (oris) and mentalis muscles and their relationships with clinical outcomes., Methods: The data of 1288 HFS patients who underwent MVD between 2015 and 2018 were retrospectively reviewed. LSR was recorded in the oris and mentalis muscles through centrifugal stimulation of the temporal branch of the facial nerve after preoperative mapping. The disappearance of LSR following surgery, clinical outcomes, and the characteristics of LSR in oris were analyzed., Results: After surgery, LSR remained in 100 (7.7%) and 279 (21.6%) of the mentalis and oris muscles, respectively. The postoperative outcome correlated with LSR disappearance in the mentalis, not with that in the oris., Conclusion: LSR patterns differed in each muscle and may not be correlated with clinical outcomes. LSR in the mentalis and oris muscles should be interpreted differently., Significance: We describe a monitoring protocol characterized by preoperative facial nerve mapping, antidromic stimulation, and recording from multiple muscles. We analyze differences in LSRs in the mentalis and oris muscles and suggest technical points for interpretation., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

The mentalis muscle is now considered key structures when performing procedures for rejuvenating the lower face. The aim of this study was to determine the anatomical morphology and location of the mentalis muscle and thereby provide anatomical information for facilitating clinical procedures designed to rejuvenate the lower face. Forty-four adult hemifaces from five Thai cadavers and 21 Korean cadavers were dissected to identify the locations of the mentalis muscle. Sixty-six hemifaces from 33 healthy young Korean subjects were included in an ultrasonographic study. The depth of the mentalis muscle below the skin surface, the thickness of the mentalis muscle, and the distance from the bone to the mentalis muscle were measured at the two points that were 5 mm lateral to the most-prominent point of the chin. The mentalis muscle was classified into two types based to its shape: in type A (86.4%, 38 of the 44 cases) it was dome shaped in three dimensions, while in type B (13.6%, 6 of the 44 cases) it was flat. The mentalis muscle was present mostly at the area 5-10 mm from the midsagittal line and 20-30 mm from a horizontal line connecting the mouth corners. The mentalis muscle was present between depths of 6.7 to 10.7 mm below the skin. This new information about the location of the mentalis muscle may help when identifying the most effective and safe botulinum toxin injection points and depths during esthetic procedures for weakened facial rhytides on the lower face.

The mentalis muscle (MM) arises from the incisive fossa of the mandible, raises and protrudes the lower lip. Here, we aim to characterize responses obtained from MM by supraorbital and median electrical as well as auditory stimuli in a group of 16 healthy volunteers who did not have clinical palmomental reflex. Reflex activities were recorded from the MM and orbicularis oculi (O.oc) after supraorbital and median electrical as well as auditory stimuli. Response rates over MM were consistent after each stimulus, however, mean latencies of MM response were longer than O.oc responses by all stimulation modalities. Shapes and amplitudes of responses from O.oc and MM were similar. Based on our findings, we may say that MM motoneurons have connections with trigeminal, vestibulocochlear and lemniscal pathways similar to other facial muscles and electrophysiological recording of MM responses after electrical and auditory stimulation is possible in healthy subjects.

Cysticercosis, a helminthic disease commonly seen in India, Latin America, Eastern Europe and Southern Africa, results from extraintestinal encystation of the larval form of Taenia solium. It is a condition in which man acts as intermediate host instead of definitive host. The most frequent sites of cysticercosis are subcutaneous layers, brain, muscles, heart, liver, lungs, and peritoneum. Oral cysticercosis is considered rare and cause cystic swellings or nodules in the mouth and a precise clinical diagnosis is not usually established. Here, we report a case of oral cysticercosis in a 32-year-old female occurring in the mentalis muscle presenting as asymptomatic nodule.

For years, the notion of chin ptosis was somehow integrated with the concept of witch's chin. That was a mistake on many levels because chin droop has four major causes, all different and with some overlap. With this article, the surgeon can quickly diagnose which type and which therapeutic modality would work best. In some cases the problem is a simple fix, in others the droop can only be stabilized, and in the final two, definite corrective procedures are available. Of note, in certain situations two types of chin ptosis may overlap because both the patient and the surgeon may each contribute to the problems. For example, in dynamic ptosis, a droop that occurs with smile in the unoperated patient can be exacerbated and further produced by certain surgical methods also. This paper classifies the variations of the problems and explains the anatomy with the final emphasis on long-term surgical correction, well described herein. This article is the ninth on this subject and a review of them all would be helpful (greatly) for understanding the enigmas of the lower face.