C-terminal citrullinated peptide alters antigen-specific APC:T cell interactions leading to breach of immune tolerance.

In rheumatoid arthritis, the emergence of anti-citrullinated autoimmunity is associated with HLA-antigen-T cell receptor complexes. The precise mechanisms underpinning this breach of tolerance are not well understood. Porphyromonas gingivalis expresses an enzyme capable of non-endogenous C-terminal citrullination with potential to generate citrullinated autoantigens. Here we document how C-terminal citrullination of ovalbumin peptide323-339 alters the interaction between antigen-presenting cells and OTII T cells to induce functional changes in responding T cells. These data reveal that C-terminal citrullination is sufficient to breach T cell peripheral tolerance in vivo and reveal the potential of C-terminal citrullination to lower the threshold for T cell activation. Finally, we demonstrate a role for the IL-2/STAT5/CD25 signalling axis in breach of tolerance. Together, our data identify a tractable mechanism and targetable pathways underpinning breach of tolerance in rheumatoid arthritis and provide new conceptual insight into the origins of anti-citrullinated autoimmunity.

Christensen House: A Case Study for Inclusive Decision-making within Professional Associations.

Accounts of dental history in Queensland are few and almost invariably authored by those who either held or hold power. The focus is 'who, what, when' rather than 'why and how'. House-related developments as a case study provide an opportunity to assess aspects of the Australian Dental Association Queensland Branch's (ADAQ) model of administration in the early 1970s. The authors use literature review and historical methods. The ADAQ's articles of association, codes of conduct and memoranda centralized Brisbane-based authority and elite leadership into its management. The ADAQ council's decision to build Christensen House in Brisbane, prompted by the posthumous benevolence of George Christensen, was informed, logical, measured and appeared timely. The advocates for the house were innovative, optimistic, resolute, and well-intentioned, with their design and selected location of the building being appropriate. However, the decision occurred at a time of latent discontent within the membership, many of whom did not support the project financially. Distance in Queensland dictates that provincial members either accept or tolerate Brisbane-based centralized authority within ADAQ administration. Nonetheless, when it comes to policy warranting membership subscription, the Christensen House experience demonstrates that the modus operandi of the ADAQ council should be, as far as possible, inclusive, and representative.

Colin Robertson, Smile A While: Dentistry, History, Theater and Golf.

Many commentators argue that, until the 1980s, Brisbane and Queensland were cultural backwaters within the Australian context. However, with the hosting of the highly successful XII Commonwealth Games (1982) and World Expo 88 (1988) and with the development of the Queensland Cultural (1976-) and South Bank (1974-) Precincts, Brisbane and Queensland cast aside perennial apologism to acquire prominence, maturity, and self-respect. Within these national, state, and municipal settings, the theme, timing, and venue for the 24th Australian Dental Congress (1985) involved risk. Enter a Brisbane dental practitioner, Colin Robertson: a theater critic and a scriptwriter, who possessed competitive and entrepreneurial streaks, a vivid imagination, a steely resolve, and a love of golf. Robertson became an erudite, incisive, and prolific commentator, who penned much of the historical musical Smile A While (aka Smile Awhile) for the abovementioned congress. He contributed to an outstanding Dental Health Week (1980), served on the Australian Dental Association Queensland Branch Council (1981), its Fluoridation Committee (1973) and chaired both its Oral Health Education Committee (1981) and the Congressional Entertainment Division within the Congress Organizing Committee (1982-1985). Accordingly, the authors use historical methods to expose and explore a scarcely acknowledged narrative within dental history in Queensland.

James Meyrick Croker: A Model for Professional Behavior.

The rationale that underpins volunteering has long fascinated behavioral scientists. James Meyrick Croker's personal life, professional career and community engagement conform to the classic twentieth century model for professional behavior. Accordingly, the authors use historical methods of investigation to evaluate the influences on and the legacies from a remarkable contribution to the professions and the community. The narrative demonstrates elements of altruism, collaboration, conviction, compassion, drive, entrepreneurialism, familial and grammar school influence, leadership, pragmatism and vision. Croker's professional and community service was multi-organizational. Concurrent demands on his time warranted discipline, energy and expertise. For the behavioral scientist, achievement, affiliation, nature and nurture appear relevant to the outcome. Available archives provide no evidence of ego-driven motivation. Leadership style was transformational not transactional. Major legacies to the national and state Australian Dental Associations are ADAQ Christensen House (1972-1980), the eventual financial stability for the Australian Dental Association Queensland Branch, formal dental assistant training, policies of the Australian and Queensland Councils of Professions, a notable Goddard Oration and the successful 24th Australian Dental Congress.

Solochrome cyanine: A histological stain for cobalt-chromium wear particles in metal-on-metal periprosthetic tissues.

Metal-on-metal (MoM) hip arthroplasties produce abundant implant-derived wear debris composed mainly of cobalt (Co) and chromium (Cr). Cobalt-chromium (Co-Cr) wear particles are difficult to identify histologically and need to be distinguished from other wear particle types and endogenous components (e.g., haemosiderin, fibrin) which may be present in MoM periprosthetic tissues. In this study we sought to determine whether histological stains that have an affinity for metals are useful in identifying Co-Cr wear debris in MoM periprosthetic tissues. Histological sections of periprosthetic tissue from 30 failed MoM hip arthroplasties were stained with haematoxylin-eosin (HE), Solochrome Cyanine (SC), Solochrome Azurine (SA) and Perls' Prussian Blue (PB). Sections of periprosthetic tissue from 10 cases of non-MoM arthroplasties using other implant biomaterials, including titanium, ceramic, polymethylmethacrylate (PMMA) and ultra-high molecular weight polyethylene (UHMWP) were similarly analysed. Sections of 10 cases of haemosiderin-containing knee tenosynovial giant cell tumour (TSGCT) were also stained with HE, SC, SA and PB. In MoM periprosthetic tissues, SC stained metal debris in phagocytic macrophages and in the superficial necrotic zone which exhibited little or no trichrome staining for fibrin. In non-MoM periprosthetic tissues, UHMWP, PMMA, ceramic and titanium particles were not stained by SC. Prussian Blue, but not SC or SA, stained haemosiderin deposits in MoM periprosthetic tissues and TSGT. Our findings show that SC staining (most likely Cr-associated) is useful in distinguishing Co-Cr wear particles from other metal/non-metal wear particles types in histological preparations of periprosthetic tissue and that SC reliably distinguishes haemosiderin from Co-Cr wear debris.

European Society of Endodontology position statement: Use of cone beam computed tomography in Endodontics: European Society of Endodontology (ESE) developed by.

This Position Statement represents a consensus of an expert committee convened by the European Society of Endodontology (ESE) on the use of Cone Beam Computed Tomography (CBCT) in Endodontics. This paper is an update of the ESE CBCT position statement which was published in 2014 (European Society of Endodontology 2014, https://doi.org/10.1111/iej.12267). Recent review articles provide more detailed background information and the basis for this position statement. It is intended that this position statement will be updated at least every 4-5 years to keep abreast of relevant research. The aim of this paper is to provide clinicians with evidence-based guidance on the application of CBCT in Endodontics. Since 2014, there has been an increase in the number of clinical studies confirming the positive impact of CBCT on treatment planning, decision-making when reviewing cases and reduced practitioner stress levels.

Cone beam computed tomography in Endodontics - a review of the literature.

The use of cone beam computed tomography (CBCT) in the diagnosis and/or management of endodontic problems is increasing and is reflected in the exponential rise in publications on this topic in the last two decades. The aim of this paper is to: (i) Review current literature on the endodontic applications of CBCT; (ii) Based on current evidence make recommendations for the use of CBCT in Endodontics; (iii) Highlight the areas in which more research is required.

Persistence at 12 months with denosumab in postmenopausal women with osteoporosis: interim results from a prospective observational study.

UNLABELLED: To determine persistence with subcutaneous denosumab every 6 months in women being treated for osteoporosis, we conducted a single-arm prospective, observational study in the United States and Canada. Among 935 patients enrolled, 12-month persistence was 82%, with 66 patients (7%) reporting serious adverse events and 19 patients (2%) reporting fractures. INTRODUCTION: Increased persistence with osteoporosis therapy is associated with reduced fracture risk. Denosumab reduced fracture risk in clinical trials; persistence in community settings is undetermined. This study evaluates persistence with denosumab in community practice in the United States (US) and Canada. METHODS: In a 24-month multicenter, prospective, single-arm, observational study, women being treated for osteoporosis were enrolled ≤4 weeks after the first subcutaneous injection of denosumab. For this 12-month prespecified interim analysis, endpoints include persistence (one injection at study entry and another within 6 months + 8 weeks), attributes associated with persistence (univariate analysis), and serious adverse events (SAEs). RESULTS: Among 935 patients (mean age 71 years), mean baseline T-scores were -2.18 (femoral neck) and -2.00 (lumbar spine); 50% of patients had experienced osteoporotic fracture(s). At 12 months, 82 % of patients were persistent with denosumab. Baseline factors significantly (p < 0.05) associated with higher persistence included use of osteoporosis medications >5 years previously, lumbar spine T-score > -2.5, and treatment by female physicians (US). Lower persistence was associated (p < 0.05) with psychiatric diagnoses including depression, southern US residence, being divorced, separated, or widowed (US), and prior hip fracture (Canada). SAEs were reported in 66 patients (7%); no SAEs of osteonecrosis of the jaw, atypical femoral fracture, fracture healing complications, hypocalcemia, eczema, or hypersensitivity were reported. Nineteen patients (2%) reported osteoporotic fractures. CONCLUSIONS: The 12-month persistence observed in this single-arm open-label study of US and Canadian community practice extends the evidence regarding denosumab's potential role in reducing fracture risk in postmenopausal women with osteoporosis.

A comparison of cone beam computed tomography and periapical radiography for the detection of vertical root fractures in nonendodontically treated teeth.

AIMS: To compare in an ex vivo model, the diagnostic accuracy of periapical radiography and cone beam computed tomography (CBCT) for the detection of artificially induced incomplete and complete vertical root fractures (VRFs), and to determine whether the width of the VRFs had an impact on the diagnostic accuracy of the imaging systems. METHODOLOGY: Incomplete VRFs were induced in 30 nonendodontically treated human mandibular premolar and molar teeth. VRF widths were measured using optical coherence tomography. Complete VRFs were induced in 15 of these teeth. 3D Accuitomo and i-CAT CBCT scans and periapical radiographs were taken prior to and after fracture induction. Receiver operating characteristic (ROC) analysis was carried for each imaging technique. In addition, values for sensitivity, specificity, positive and negative predictive values, inter- and intra-examiner agreement were calculated. RESULTS: In the ROC analysis, both CBCT scanners were significantly more accurate than periapical radiography for the detection of incomplete VRFs (P < 0.05). The overall area under the ROC curve (AUC) values for 3D Accuitomo, i-CAT and periapical radiography were 0.687, 0.659 and 0.540, respectively. The sensitivity of 3D Accuitomo, i-CAT and periapical radiography was 27%, 28% and 3% respectively. Interexaminer agreement for the detection of incomplete fractures with periapical radiographs, 3D Accuitomo and i-CAT was 0.020, 0.229 and 0.333, respectively. Both CBCT scanners were significantly more accurate (P < 0.01) in detecting VRFs of ≥50 µm compared with VRFs of <50 µm. 3D Accuitomo was significantly better than i-CAT in detecting VRFs of <50 µm (P < 0.05). For complete fractures, the AUC values for 3D Accuitomo (0.999) and i-CAT (0.998) were significantly higher (P < 0.05) than for periapical radiography (0.724). CONCLUSIONS: Under the conditions of this ex vivo study, periapical radiographs and CBCT were unreliable for the detection of simulated incomplete VRFs. The widths of the fractures appeared to have an impact on the diagnostic accuracy of CBCT as the detection of VRFs of ≥50 µm was significantly higher than those of <50 µm. The detection of complete fractures was significantly higher for all systems than that of incomplete fractures.

The detection of vertical root fractures in root filled teeth with periapical radiographs and CBCT scans.

AIM: To compare ex vivo the diagnostic accuracy of cone beam computed tomography (CBCT) with periapical radiography in detecting artificially prepared incomplete and complete vertical root fractures (VRFs) in the presence of a gutta-percha root filling in human teeth. METHODOLOGY: The root canals of 20 extracted human premolar and molar teeth were radiographed and scanned with CBCT before a simulated VRF was induced (group 1). These teeth were radiographed and scanned with CBCT again after an incomplete (group 2) and complete (group 3) VRFs were induced. A suitably sized gutta-percha point was inserted into the prepared root canal prior to each series of radiographs and CBCT scans being taken. RESULTS: There was no improvement in the detection of artificially created vertical root fractures (VRF) in root filled teeth using CBCT compared with periapical radiographs. The overall area under the curve (AUC) value of incomplete and complete VRF was 0.53 for periapical radiography and 0.45 for CBCT (P = 0.034). The overall sensitivity of periapical radiography (0.05) was lower than CBCT (0.57) regardless of the extent of the VRF (P = 0.027). Periapical radiographs (0.98) had a higher overall specificity than CBCT (0.34) (P = 0.027). CONCLUSIONS: Under the conditions of this ex vivo study, periapical radiographs and CBCT were not accurate in detecting the presence and absence of simulated VRF. The imaging artefacts caused by the gutta-percha root filling within the root canal most probably resulted in the overestimation of VRF with CBCT and also the overall inaccuracy of this system.

The parasite fauna of the Patagonian toothfish Dissostichus eleginoides off the Falkland Islands.

The parasite fauna of juvenile Dissostichus eleginoides, while they inhabit the Falkland's shelf, was examined, giving new detailed information on spatial, ontogenic and seasonal variations. A total of 24,943 parasites from 15 different taxa were found in the stomach of 502 individual fish. Parasite species composition and abundance allowed separation of toothfish by area between the north-west and south-east of the Falklands. The digenean, Elytrophalloides oatesi, and the nematodes, Hysterothylacium spp. and Anisakis spp., were the most common, all with a prevalence >20%. For some seasons ontogenic changes in abundance were significant in these three parasite taxa, and this is discussed in terms of ontogenic and seasonal changes in diet. Elytrophalloides oatesi and Hysterothylacium spp. showed spatial and seasonal differences in abundance with greater numbers in the warmer waters of the north-west and during the summer months. Differences in abundance of E. oatesi between the Falklands and other regions indicate its potential for use as a biological tag to study toothfish movements and population structure; however, more seasonal data would be required before this technique could be used.

Clinical features and overall survival of osteosarcoma of the mandible.

Osteosarcoma is the most common bone sarcoma and is typically found in the distal femur, proximal tibia, and proximal humerus. While several factors are known to influence survival, less is known regarding the influence of primary tumor location. This study describes the clinical features and prognosis of mandibular osteosarcoma. The SEER database was utilized to identify cases of mandibular osteosarcoma diagnosed between 2004 and 2015. Sex, age, grade, histological subtype, tumor size, tumor extension, presence of metastasis at diagnosis, and therapeutic intervention were determined. Osteosarcomas originating from other sites were assessed for comparison. There were 164 cases of mandibular osteosarcoma identified, representing 5.5% of all surveyed osteosarcomas. The 2-, 5-, and 10-year overall survival rates were 79.9%, 65.6% and 58.5%, respectively. Survival was worse for patients with older age, larger tumor size, metastatic disease, and absence of surgical resection. Compared to other sites, mandibular osteosarcomas were significantly smaller tumors and were far less likely to metastasize. Mandibular osteosarcoma manifested at an older age than the more common extremity osteosarcomas and presented with smaller tumors. Rates of metastasis of jaw osteosarcoma were much lower than osteosarcoma found in the extremities, while mortality rates were comparable.

Incidence, risk factors, and outcomes of osteonecrosis of the jaw: integrated analysis from three blinded active-controlled phase III trials in cancer patients with bone metastases.

BACKGROUND: Osteonecrosis of the jaw (ONJ) has been reported in patients receiving bisphosphonates for metastatic bone disease. ONJ incidence, risk factors, and outcomes were evaluated in a combined analysis of three phase III trials in patients with metastatic bone disease receiving antiresorptive therapies. PATIENTS AND METHODS: Patients with bone metastases secondary to solid tumors or myeloma were randomly assigned to receive either s.c. denosumab (120 mg) or i.v. zoledronic acid (4 mg) every 4 weeks. On-study oral examinations were conducted by investigators at baseline and every 6 months. Oral adverse events were adjudicated by an independent blinded committee of dental experts. RESULTS: Of 5723 patients enrolled, 89 (1.6%) patients were determined to have ONJ: 37 (1.3%) received zoledronic acid and 52 (1.8%) received denosumab (P = 0.13). Tooth extraction was reported for 61.8% of patients with ONJ. ONJ treatment was conservative in >95% of patients. As of October 2010, ONJ resolved in 36.0% of patients (29.7% for zoledronic acid and 40.4% for denosumab). CONCLUSIONS: In this combined analysis of three prospective trials, ONJ was infrequent, management was mostly conservative, and healing occurred in over one-third of the patients. Educating physicians about oral health before and during bone-targeted therapy may help reduce ONJ incidence and improve outcomes.

Evolutionary change in the brain size of bats.

It has been widely recognized that mammal brain size predominantly increases over evolutionary time. Safi et al. [Biol Lett 2005;1:283-286] questioned the generality of this trend, arguing that brain size evolution among bats involved reduction in multiple lineages as well as enlargement in others. Our study explored the direction of change in the evolution of bat brain size by estimating brain volume in fossil bats, using synchrotron radiation X-ray tomographic microscopy. Virtual endocasts were generated from 2 Hipposideros species: 3 specimens of Oligocene Hipposideros schlosseri (∼35 Ma) and 3 of Miocene Hipposideros bouziguensis (∼20 Ma). Upper molar tooth dimensions (M(2) length × width) collected for 43 extant insectivorous bat species were used to derive empirical formulae to estimate body mass in the fossil bats. Brain size was found to be relatively smaller in the fossil bats than in the average extant bat both with raw data and after allowing for phylogenetic inertia. Phylogenetic modeling of ancestral relative brain size with and without fossil bats confirmed a general trend towards evolutionary increase in this bat lineage.

A new classification of mandibular fractures.

There is no accepted method of reporting mandibular fracture that reflects incidence, treatment and outcome for individual cases. As most series include anatomical site only for all fractures, the aim was to establish a new method to report fractures based on a systematic review of the literature and an internal audit. The classification proposed is: Class I; condyle, II; angle, IIc; II+condyle, III; body/symphysis, IIIc; III+condyle, IV; multiple fractures not including condyle, IVc; IV+condyle, V; bilateral condyle±other fracture(s). A total of 10,971 adult and 914 paediatric cases were analyzed through systematic review, and 833 from the regional audit. Only 32% (14/44) of reported series could be reclassified which, when added to the audit data, showed Class IV was most common (29%), with similar proportions of Class III, Class IIIc and Class II (18-23%). External validation (literature review) in terms of treatment and outcome was non-informative, but the internal validation (audit) demonstrated an increasing requirement for adding maxillomandibular fixation (MMF) to open reduction and internal fixation (ORIF) as class increased. The heterogeneity of data reporting found in the systematic review confirms the need for a classification such as this, likely to enhance comparison of varying management protocols.

Quantitative evaluation of aerosol generation from upper airway suctioning assessed during tracheal intubation and extubation sequences in anaesthetized patients.

BACKGROUND: Open respiratory suctioning is defined as an aerosol generating procedure (AGP). Laryngopharyngeal suctioning, used to clear secretions during anaesthesia, is widely managed as an AGP. However, it is uncertain whether upper airway suctioning should be designated as an AGP due to the lack of both aerosol and epidemiological evidence. AIM: To assess the relative risk of aerosol generation by upper airway suctioning during tracheal intubation and extubation in anaesthetized patients. METHODS: This prospective environmental monitoring study was undertaken in an ultraclean operating theatre setting to assay aerosol concentrations during intubation and extubation sequences, including upper airway suctioning, for patients undergoing surgery (N=19). An optical particle sizer (particle size 0.3-10 µm) sampled aerosol 20 cm above the patient's mouth. Baseline recordings (background, tidal breathing and volitional coughs) were followed by intravenous induction of anaesthesia with neuromuscular blockade. Four periods of laryngopharyngeal suctioning were performed with a Yankauer sucker: pre-laryngoscopy, post-intubation, pre-extubation and post-extubation. FINDINGS: Aerosol was reliably detected {median 65 [interquartile range (IQR) 39-259] particles/L} above background [median 4.8 (IQR 1-7) particles/L, P<0.0001] when sampling in close proximity to the patient's mouth during tidal breathing. Upper airway suctioning was associated with a much lower average aerosol concentration than breathing [median 6.0 (IQR 0-12) particles/L, P=0.0007], and was indistinguishable from background (P>0.99). Peak aerosol concentrations recorded during suctioning [median 45 (IQR 30-75) particles/L] were much lower than during volitional coughs [median 1520 (IQR 600-4363) particles/L, P<0.0001] and tidal breathing [median 540 (IQR 300-1826) particles/L, P<0.0001]. CONCLUSION: Upper airway suctioning during airway management was not associated with a higher aerosol concentration compared with background, and was associated with a much lower aerosol concentration compared with breathing and coughing. Upper airway suctioning should not be designated as a high-risk AGP.

Safety of zoledronic acid and incidence of osteonecrosis of the jaw (ONJ) during adjuvant therapy in a randomised phase III trial (AZURE: BIG 01-04) for women with stage II/III breast cancer.

The AZURE trial is an ongoing phase III, academic, multi-centre, randomised trial designed to evaluate the role of zoledronic acid (ZOL) in the adjuvant therapy of women with stage II/III breast cancer. Here, we report the safety and tolerability profile of ZOL in this setting. Eligible patients received (neo)adjuvant chemotherapy and/or endocrine therapy and were randomised to receive neither additional treatment nor intravenous ZOL 4 mg. ZOL was administered after each chemotherapy cycle to exploit potential sequence-dependent synergy. ZOL was continued for 60 months post-randomisation (six doses in the first 6 months, eight doses in the following 24 months and five doses in the final 30 months). Serious (SAE) and non-serious adverse event (AE) data generated during the first 36 months on study were analysed for the safety population. 3,360 patients were recruited to the AZURE trial. The safety population comprised 3,340 patients (ZOL 1,665; control 1,675). The addition of ZOL to standard treatment did not significantly impact on chemotherapy delivery. SAE were similar in both treatment arms. No significant safety differences were seen apart from the occurrence of osteonecrosis of the jaw (ONJ) in the ZOL group (11 confirmed cases; 0.7%; 95% confidence interval 0.3-1.1%). ZOL in the adjuvant setting is well tolerated, and can be safely administered in addition to adjuvant therapy including chemotherapy. The adverse events were consistent with the known safety profile of ZOL, with a low incidence of ONJ.

Mechanical biofilm disruption causes microbial and immunological shifts in periodontitis patients.

Periodontitis is characterized by subgingival biofilm dysbiosis, inflammation and tissue destruction. Current treatment involves mechanical biofilm disruption known as non-surgical periodontal therapy (NSPT). This study sought to characterise the impact of treatment on microbial diversity and overall community, and the parallel impact on host inflammation in the oral cavity. Fourty-two periodontitis patients were included in this study, with periodontal clinical parameters, subgingival plaque and saliva samples collected at baseline and 90 days after treatment. Salivary cytokines were quantified, and subgingival plaque was analysed using 16S rRNA sequencing. After treatment, there were marked health-associated alterations in microbial composition and diversity, including differential abundance of 42 genera and 61 species. These changes were accompanied by substantial clinical improvement (pockets ≥ 5 mm, 27.50% to 9.00%, p < 0.001) and a decrease in salivary IL-1ß (p < 0.001)-a putative marker of periodontal inflammation. Despite significant reductions in disease associated anaerobes, several genera (Fusobacterium, Prevotella, Tanenerella, Treponema) remained present and formed a distinct subnetwork associated with residual disease. Collectively, this study shows that current periodontal treatment results in partial restoration of a healthy microbial ecosystem, but features of biofilm dysbiosis and host inflammation remain in some patients, which were surprisingly independent of clinical response.

Outcomes of microvascular composite reconstruction for mandibular osteoradionecrosis.

The aim of this retrospective study was to compare outcomes and reconstruction-related complications in patients receiving a composite free flap reconstruction of the mandible for ORN with those reconstructed for other indications. The records of all patients who underwent composite reconstruction of a mandibular defect at Aintree University Hospital, Liverpool, were reviewed and analysed. Based on radiotherapy exposure and ORN history, the study cohort was divided into three separate case-matched groups. Local wound healing issues were markedly more common in the ORN setting, as was infection and subsequent osteosynthesis plate(s) removal. Free flap survival was similar among all three case-matched groups. Advanced mandibular ORN may be safely and predictably reconstructed with composite free flaps, and that while the rate of local complications is greater than non-irradiated, and non-ORN case-matched controls, the free flap survival rate compares favourably.

Systematic review of lingual nerve retraction during surgical mandibular third molar extractions.

The lingual nerve is at risk of damage during mandibular third molar (M3M) surgery. Current trends to avoid lingual retraction and prevent injury to the nerve run counter to the surgical principles of locating and protecting important structures. To our knowledge, the last review of this subject only considered repurposed lingual retractors such as the Howarth. Other studies have reported the use of purpose-built retractors with improved outcomes for lingual nerve injuries. This systematic review aims to assess the current view regarding lingual nerve retraction in M3M surgery. A search of PubMed and Web of Science using the key words "lingual", "nerve", "retractor", and "retraction" returned 118 results, 10 of which were selected for inclusion (nine original research papers and one systematic review). The data comprised 16,133 M3M extractions using no lingual retractor, repurposed, and purpose-built retractors. No lingual retraction showed a 0.60% risk of temporary and a 0.08% risk of permanent injury to the nerve. Repurposed retractors showed a 7.9% risk of temporary and 0.41% risk of permanent injury, and purpose-built retractors a 0.56% risk of temporary injury. No reported cases of permanent injury were associated with the use of purpose-built instruments. The evidence suggests that whilst the use of repurposed retractors increases the risk of injury to the nerve, there is no such risk with purpose-built retractors. Current data sets are confounded by the limitations of non-randomised, non-blinded studies, but trends show that lingual nerve retraction with purpose-built retractors may help to prevent permanent injury to the lingual nerve.