Membrane stretch and salivary glands — facts and theories

Cell shape in salivary glands is affected by mechanical forces. In the acini and ducts cell shape is modified by the contractions of the myoepithelial cells in both the secretory and ductal portions of the glands. At the organ level shape changes are due to muscle contraction during mastication, food intake and speech. All these factors may cause some degree of stretching of salivary cell membranes. Recent studies suggest that physical forces influence signal fansduction, gene expression, secretory function, cell differentiation and proliferation. Here we overview membrane stretch-activated cellular events. Evidence from a variety of tissues suggests that mechanical forces may alter the properties of acinar cells leading to cytoskeletal reorganisation, changes in ion fluxes, modulation of secretory activity and subsequent release of transmitters such as ATP. Transmitters released from acinar cells may modulate the secretory activity of salivary tissue, and interact with classical regulatory pathways.     

Sinus Grafts: Science and Techniques—Then and Now

Introduction

Sinus lifts have been around for more than four decades now, and the amount of changes that we have seen in techniques and armamentarium coupled with the advent of newer materials is worth taking note of.

Materials and Methods

A complete review of the literature was done since the advent of ways and means to augment the posterior maxilla with a run through of various advantages and disadvantages of the same.

Conclusion

In conclusion, we can say that this procedure is today very predictable and offers clinicians a possibility to rehabilitate the posterior maxilla with implant-based solutions.

     

Juvenile idiopathic arthritis—and now?

Aim

To conduct a systematic literature review on the impact of juvenile idiopathic arthritis (JIA) on craniofacial morphology.

Materials and methods

Several electronic databases (PubMed, Medpilot, Web of Science, DIMDI) were systematically searched for studies that were published up to and including May 2011. In addition, a manual search of the orthodontic and rheumatologic literature was conducted, and reference lists of the selected articles were checked for relevant publications. The identified articles were independently assessed by two investigators and selected according to a three-step process (title/abstract/full text).

Results

After completion of the selection procedure, 19?articles were identified possessing great heterogeneity. In most of them, no differentiated analysis of the various JIA subtypes was performed, and type-specific analyses according to mandibular joint effects were seldom. Additional factors such as patient age, disease duration, medication, previous orthodontic treatment as well as the inclusion of a control group were also highly inhomogeneous, which made a meta-analysis of the data impossible. Nevertheless, it appears as if JIA patients tend to develop a hyperdivergent vertical jaw base relationship and a skeletal Class?II pattern.

Conclusion

Due to the heterogeneous patient samples, it is currently not possible to draw a differentiated conclusion on the influence of various types of JIA on craniofacial morphology.     

Dental regeneration and materials—a partnership

Considerable focus on the biocompatibility of dental materials over the last three decades has provided a platform for a wealth of studies on the cellular and molecular responses of the cells of the pulp to injury, both from the disease process and from subsequent restorative intervention. These studies have been fundamental to understanding not only how we can achieve a biocompatible response during restoration of dental disease but also how we can exploit the pulpal cellular responses to achieve wound healing and tissue regeneration in the dentine–pulp complex. This article examines the responses of the pulp to injury and the events leading to tissue regeneration. As new biologically based regenerative therapies emerge for the dental tissues, it is important that these develop in partnership with more traditional approaches using dental materials.     

Perioperative Laboratory and Diagnostic Testing—What is Needed and When?

Preoperative patient evaluation is an essential component of any surgical practice. A complete history and physical, along with appropriate diagnostic tests, are performed routinely to ensure a safe and predictable delivery of care. Oral and maxillofacial surgeons use this principle in everyday practice. Regardless of type of surgery and practice (office-based dentoalveolar surgery, orthognathic surgery, trauma, elective aesthetic surgery), oral and maxillofacial surgeons must formulate a decision-making process and a treatment plan regarding the perioperative management of patients. The anesthetic plan and the surgical plan must be assessed preoperatively.     

Anatomical study and clinical application of fibular osteocutaneous flap —For maxillo-mandibular reconstruction and dental implant installation—

Anatomical investigation on the fibular osteocutaneous flap from 60 legs of 30 cadavers, and clinical study of ten patients reconstructed by these flaps were retrospectively discussed, based on results from the anatomical investigation. Conclusions are as follows:

Lip and Mentalis Activity and its Influence on Incisor Position—a Quantitative Electromyographic Study

Abstract

In order to investigate both the relationship between perioral muscular activity and tooth position and also the clinical indicators of this activity, two quantitative EMG studies were carried out. The first investigated the reproducibility of the method in 16 adults. Subsequently, a study employing the same protocol was conducted on 41 subjects with untreated malocclusions. Activity was measured during speech, whilst chewing biscuit, swallowing saliva, resting, and in those subjects with incompetent lips, during lip-seal. In addition to the EMG recordings, measurements were taken from study models, lateral skull radiographs and of the clinical lip heights. In general, between visits random variability was sufficiently small for the method to be applied experimentally. The results suggest that the effects of perioral muscular activity are determined by the presence or absence of competent lips. This was despite similar levels of activity in both groups except during chewing. Resting activity did influence incisor position in subjects with competent lips but the intermittent activity from chewing, speaking and swallowing, did not. No clinical indicators of the level of perioral activity were found.     

Psychological stress-relieving effects of chewing — Relationship between masticatory function-related factors and stress-relieving effects —

Purpose

The objective of the present study was to investigate the relationship between masticatory function-related factors (masticatory performance, occlusal contact area, maximum bite force, number of chewing strokes, and muscle activity) and the stress-relieving effects of chewing.

Multiple tumours of the salivary glands—Terminology and nomenclature

Multiple tumours of the salivary glands are very rare and their combinations according to histological classification of the tumours, localisation and origin (origin in independent topographical areas or in the same tissue) are diverse.The following two categories can be distinguished: common occurrence of multiple salivary gland tumours with identical histology, or with different histology. In either group the tumours can be unilateral or bilateral, synchronous or metachronous. The most common multiple tumours with an identical histology are Warthin tumours and pleomorphic adenomas. Bilateral occurrence has been observed especially in oncocytomas, acinic cell carcinomas and basal cell adenomas. In the group of multiple tumours with differing histology, Warthin tumours and pleomorphic adenomas show a number of combinations with other adenomas or carcinomas of the salivary glands. Notable also is the simultaneous occurrence of salivary gland tumours with other oral tumours or extraglandular tumours, especially thyroid carcinomas and breast carcinomas.Multiple salivary gland tumours must be distinguished by nomenclature from tumours with biphasic differentiation and hybrid tumours. Tumours with biphasic differentiation are defined as regular, recurring mixtures of two cellular components in the same tumour and have a corresponding term in the tumour classification. Hybrid tumours are very rare and are composed of two different tumour entities within the same topographical area. Each of the tumour entities conforms with an exactly defined tumour category.     

Tissue expanders for soft tissue reconstruction in the head and neck area—requirements and limitations

Objectives

The repair of skin defects in the head and neck region still poses a significant problem for many clinicians. Tissue expansion is described as a treatment option providing good color, texture, and thickness match of the expanded skin. Unfortunately, the complication rates for tissue expansion range from 0 to 48 %. Therefore, the purpose of this study was to investigate risk factors for the use of tissue expanders in head and neck reconstructions.

Materials and methods

Forty-nine patients with skin deficits in the head and neck area underwent tissue expansion. Sixty-two implanted expanders were analyzed regarding the various complications and the success rate.

Results

The success rate of treated patients was 37 (75.5 %) of all 49 included patients. The most frequent cause for the skin deficit was a tumor resection near the tip of the nose followed by skin deficits resulting after craniectomy. Interestingly, a higher number of expanders and a larger volume were significantly associated with a worse outcome. There was a trend of association between larger defect size and failure, too.

Conclusions

The internal tissue expansion is a suitable technique for skin reconstruction in the head and face area. Compared to distant or free flaps, it often offers a better cosmetic outcome. In very large defects (>100 cm²) or when more than two expanders are needed, the failure rate increases. In these cases, other treatment options are recommended.

Clinical relevance

The internal tissue expansion is a suitable technique for skin reconstruction in the head and face area.     

Three-dimensional architectural and structural analysis—a transition in concept and design from Delaire's cephalometric analysis

The aim of this study was to present a systematic sequence for three-dimensional (3D) measurement and cephalometry, provide the norm data for computed tomography-based 3D architectural and structural cephalometric analysis, and validate the 3D data through comparison with Delaire's two-dimensional (2D) lateral cephalometric data for the same Korean adults. 2D and 3D cephalometric analyses were performed for 27 healthy subjects and the measurements of both analyses were then individually and comparatively analyzed. Essential diagnostic tools for 3D cephalometry with modified definitions of the points, planes, and measurements were set up based on a review of the conceptual differences between two and three dimensions. Some 2D and 3D analysis results were similar, though significant differences were found with regard to craniofacial angle (C1–F1), incisal axis angles, cranial base length (C2), and cranial height (C3). The discrepancy in C2 and C3 appeared to be directly related to the magnification of 2D cephalometric images. Considering measurement discrepancies between 2D and 3D Delaire's analyses due to differences in concept and design, 3D architectural and structural analysis needs to be conducted based on norms and a sound 3D basis for the sake of its accurate application and widespread adoption.     

Chondroma in temporomandibular region—case report and therapeutic considerations

Purpose

Chondromas are benign tumors composed of mature hyaline cartilage. These tumors are quite common in the bones of the hands and feet but extremely rare in jaw bones, and few such cases are reported in the literature. The aim of the present study was to carry out a literature review and present a clinical case of a patient with a chondroma in the right mandibular condyle treated with excision of the tumor.

Conclusions

The importance of early diagnosis and treatment in order to impede or minimize any lasting effects is discussed.     

Diabetes mellitus and odontogenic infections—an exaggerated risk?

INTRODUCTION: The diabetic host is considered to be at an increased risk for the development of odontogenic infections due to his medically compromised state. This perceived risk of higher infections often results in dentists delaying much-needed surgical treatment in this patient population. DISCUSSION: A critical examination of literature does not seem to support the role of diabetes mellitus as a definitive risk factor for odontogenic infections. A simplistic extrapolation of infection rates observed in other sites may not be justified in the orofacial region.     

Clinical performance and chemical-physical properties of bulk fill composites resin —a systematic review and meta-analysis

Objectives: The objective of this study was to perform a meta-analysis of clinical and laboratory studies to compare the performance of bulk-fill and conventional composite resins in terms of polymerization shrinkage, polymerization stress, cusp deflection, marginal quality, degree of conversion, microhardness, flexural strength, fracture strength and clinical performance. Data: One hundred three articles were included in this study, and the Peto method was used to compare the bulk-fill and conventional composites using the RevMan software. Sources: Searches were performed in the PubMed and Scopus databases. Study selection: Laboratory studies and randomized clinical trials comparing one of the previous detailed outcomes between bulk-fill and control composites were included. Conclusions: The bulk-fill composite resins showed less shrinkage, polymerization stress, cusp deflection and microhardness than conventional composites, while both materials presented a similar marginal quality, flexural strength and fracture strength. Also, bulk-fill materials with regular viscosity showed similar shrinkage. The conversion of bulk-fill materials with flowable consistency were similar to conventional composite resins with a thickness of up to 2 mm and greater than conventional composites with a thickness greater than 2 mm. Despite these in vitro differences, the clinical performance of bulk-fill and conventional composite resins was similar in randomized clinical trials, with one to ten years of follow up. In conclusion, the bulk-fill materials show better or similar performance to the conventional materials in clinical trials and laboratory studies in terms of volumetric shrinkage, polymerization stress, cusps deflection and marginal quality, with the only exception being the lower level of microhardness observed for bulk-fill composites with thickness up to 2 mm.     

Incidence and patterns of maxillofacial trauma—a retrospective analysis of 3611 patients—an update

Background

Maxillofacial fractures occur in a significant proportion worldwide and can occur as an isolated injury or in combination with other severe injuries including cranial, spinal, and upper and lower body injuries requiring prompt diagnosis with possible emergency interventions. The epidemiology of facial fractures varies with regard to injury type, severity, and cause and depends on the population studied. Hence, understanding of these factors can aid in establishing clinical and research priorities for effective treatment and prevention of these injuries.

Materials and methods

In this present retrospective study, we provide a comprehensive overview regarding cranio-maxillofacial trauma on 3611 patients to assist the clinician in assessment and management of this unique highly specialized area of traumatology. A preformed pro forma was used to analyze the medical records of patients treated for facial trauma in The Department of Oral and Maxillofacial Surgery, Meenakshi Ammal Dental College and Hospital, Chennai. The distribution according to age, gender, etiology, type of injury, time interval between accident and treatment, loss of consciousness, facial bones involved, pattern of fracture lines, treatment offered, and postoperative complications were recorded and evaluated.

Results

We inferred male patients sustained more injuries mostly in the third decade of age. Road traffic accidents were the most common cause of injury. Mandible was the most commonly fractured bone in the facial skeleton. Soft tissue injuries occurred more in road traffic accidents and upper lip was the commonest site of injury.

Conclusion

Our study provides insights into the epidemiology of facial injuries and associated factors and can be useful not only in developing prevention strategies but also for grading the existing legal regulations and also for framing a more effective treatment protocol.

     

The Expression of MMP—3 and TIMP—1 During Orthodontic Periodontium Remodeling in Rats

目的：观察大鼠正畸牙周组织改建过程中基质金属蛋白酶—3(MMP—3)和金属蛋白酶组织抑制因子—1(TIMP—1)表达的变化，探讨MMP—3及TIMP—1与正畸牙齿移动的关系。方法：在SD成年大鼠上颌右侧第一磨牙与上颌切牙之间安置正畸装置，建立大鼠磨牙移动实验模型。于牙齿移动1、3、5、7、14d后取材分别进行免疫组化染色、图像分析。结果：牙齿移动1d后，牙周组织细胞MMP—3表达增强，5d后MMP—3表达达到高峰，此时破骨细胞脑浆亦呈强阳性表达。以后MMP—3表达有所下降，但仍高于对照组。而TIMP—1于牙齿移动3d后表达开始增强，7d后显著表达。结论：MMP—3及TIMP—1参与了正畸牙周组织改建过程，MMP—3在破骨细胞性骨吸收中起着重要作用。     

Correlation of ultrasound microscopy and Vickers hardness measurements of human dentin and enamel — A pilot study

Objective

To investigate if Vickers microhardness of dentin and enamel correlated with acoustic velocity c(l) or acoustic reflection from the sample’s top (amplitude).

Personalized workflows in reconstructive dentistry—current possibilities and future opportunities

Objectives

The increasing collection of health data coupled with continuous IT advances have enabled precision medicine with personalized workflows. Traditionally, dentistry has lagged behind general medicine in the integration of new technologies: So what is the status quo of precision dentistry? The primary focus of this review is to provide a current overview of personalized workflows in the discipline of reconstructive dentistry (prosthodontics) and to highlight the disruptive potential of novel technologies for dentistry; the possible impact on society is also critically discussed.

Material and methods

Narrative literature review.

Results

Narrative literature review.

Conclusions

In the near future, artificial intelligence (AI) will increase diagnostic accuracy, simplify treatment planning, and thus contribute to the development of personalized reconstructive workflows by analyzing e-health data to promote decision-making on an individual patient basis. Dental education will also benefit from AI systems for personalized curricula considering the individual students’ skills. Augmented reality (AR) will facilitate communication with patients and improve clinical workflows through the use of visually guided protocols. Tele-dentistry will enable opportunities for remote contact among dental professionals and facilitate remote patient consultations and post-treatment follow-up using digital devices. Finally, a personalized digital dental passport encoded using blockchain technology could enable prosthetic rehabilitation using 3D-printed dental biomaterials.

Clinical significance

Overall, AI can be seen as the door-opener and driving force for the evolution from evidence-based prosthodontics to personalized reconstructive dentistry encompassing a synoptic approach with prosthetic and implant workflows. Nevertheless, ethical concerns need to be solved and international guidelines for data management and computing power must be established prior to a widespread routine implementation.