Stable,dynamic, elastic miniplate osteosynthesis in cranio-maxillofacial surgery: evolution of concepts,biomechanical study and applications

An osteosynthesis of the mandible should be called stable when this type of treatment does not need to be supported by intermaxillary fixation, without disturbing the healing process. In that intention, many techniques of osteosynthesis based on different concepts were proposed during the last century. A classification of these concepts was formulated. The adaptive osteosynthesis which is pragmatically i.e. empirical, wherein the goal is immobilizing the fracture by bringing the fragments together and fixing them with rigid screwed plates. The rigid compressive osteosynthesis which is an extrapolation of the ideas of Lane proposed in 1912. The stable dynamic elastic osteosynthesis whose principles, equipment and technique as their applications were developed exclusively through biomeehanical studies. The basic principle was the recovery of mobility by neutralization of detrimental distraction stresses, and reestablishment of favorable compressive stresses providing dynamic physiological stimulations. The biomechanical characteristics of the plates and the screws made possible the use of the fixation of all types of fractures or orthognathic procedures in mandibular surgery. With the application of mini or microplates in other facial bones and the skull, the art of fracture treatment and of reconstructive surgery of the craniomaxillofacial skeleton, including orthognathic and reconstructive surgery with or without bone grafting, has profoundly changed. At the present time, metal plates are sometimes superseded by resorbable plates and screws. Nevertheless, the fundamental biomechanical principles of osteosynthesis and bone healing remain unchanged.     

“True” Versus “Bay” Apical Cysts: Clinical,Radiographic, Histopathologic,and Histobacteriologic Features

IntroductionThis study compared the main clinical, radiographic, and histologic features of true and bay apical cysts.MethodsThe study material comprised 95 biopsy specimens of apical periodontitis lesions obtained attached to the root tip of both untreated and root canal–treated teeth. Clinical and radiographic data were recorded. Specimens were obtained by extraction or periradicular surgery and were meticulously processed for histopathologic and histobacteriologic methods. All cases diagnosed as apical cysts (n = 23) were divided into the true and bay types, which were then compared for tooth location, patient’s sex, lesion size, severity of clinical symptoms, presence of a sinus tract, previous abscess episodes, and prevalence of bacteria in the main root canal lumen and ramifications, on the outer root surface, and within the cyst cavity.ResultsEleven specimens were classified as true (48%) and 12 (52%) as bay cysts. Bacteria were found in all specimens, regardless of the histopathologic diagnosis. Planktonic bacteria were observed in the main root canal in all true cysts and in 11 of 12 (92%) bay cyst cases. Biofilms were detected in the main canal in 10 cases from each diagnostic group and were frequently observed in ramifications. Extraradicular biofilms occurred in a few specimens only. Bacteria were visualized within the cavity of both true (4/11, 36%) and bay (6/12, 50%) cyst specimens. The severity of histologic inflammation was always high. There were no significant differences between true and bay cysts for all the clinical, radiographic, histopathologic, and histobacteriologic parameters assessed.ConclusionsExcept for the morphologic relationship of the cyst cavity with the root canal space, true and bay cysts exhibited no other significant differences in the various parameters evaluated. The 2 cyst types were always associated with an intraradicular infection and sometimes with an extraradicular infection. Findings question the need to differentiate true and bay cysts and do not support the assumption that true cysts are self-sustainable entities not maintained by infection.     

The “Red Line” Conundrum: A Concept Beyond Its Expiry Date?

Introduction George Winter attempted to assess the depth and difficulty of extracting impacted mandibular wisdom molars by describing three imaginary lines drawn on an intra-oral radiograph. Of these lines, the red line is the only one which is measured and great importance is attached to its actual length. Method The authors of this short paper describe the difficulty in drawing this red line accurately through examples. Conclusion The authors believe that Winter’s lines and their interpretation are only of historical value and have no place in contemporary texts on oral surgery.     

The “oral” history of COVID-19: Primary infection,salivary transmission,and post-acute implications

Severe acute respiratorysyndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19, has led to more than 3.25 million recorded deaths worldwide as of May 2021. COVID-19 is known to be clinically heterogeneous, and whether the reported oral signs and symptoms in COVID-19 are related to the direct infection of oral tissues has remained unknown. Here, we review and summarize the evidence for the primary infection of the glands, oral mucosae, and saliva by SARS-CoV-2. Not only were the entry factors for SARS-CoV-2 found in all oral tissues, but these were also sites of SARS-CoV-2 infection and replication. Furthermore, saliva from asymptomatic individuals contained free virus and SARS-CoV-2-infected oral epithelial cells, both of which were found to transmit the virus. Collectively, these studies support an active role of the oral cavity in the spread and transmission of SARS-CoV-2 infection. In addition to maintaining the appropriate use of personal protective equipment and regimens to limit microbial spread via aerosol or droplet generation, the dental community will also be involved in co-managing COVID-19 “long haulers”—now termed Post-Acute COVID-19 Syndrome. Consequently, we propose that, as SARS-CoV-2 continues to spread and as new clinical challenges related to COVID-19 are documented, oral symptoms should be included in diagnostic and prognostic classifications as well as plans for multidisciplinary care.     

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Decoronation: how, why, and when?

Decoronation is a surgical method for treating ankylosed incisors in children and adolescents. The crown and root filling are removed, leaving the root in situ to be resorbed and covered with a mucoperiosteal flap. Early loss of a permanent tooth leads to loss of alveolar bone, especially in buccopalatal width. Decoronation preserves not only the width of the ridge but also the vertical height.     

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Toothbrushing: why, when and how?

Toothbrushing is a widely practiced oral healthcare habit which, in conjunction with fluoride toothpaste, can help to prevent dental caries and periodontal disease. The effectiveness of toothbrushing is dependent on many different factors including frequency and duration of brushing, rinsing habits and brush type. Knowledge of how these factors influence effectiveness will allow the dental professional to give appropriate advice.