A 15-year unique observational study of intraligamentary local anaesthesia for posterior mandibular extractions.

Introduction Intraligamentary local anaesthesia (ILA) with articaine is described as an effective alternative to inferior alveolar nerve block (IANB) for extraction of posterior teeth in the mandible, with reduced risk of complications.Aim To investigate ILA with 4% articaine and conventional syringe as a unique method for providing tooth extractions in the posterior mandible.Materials and methods All consecutive teeth to be extracted in the posterior mandible were recruited to the study, within exclusion criteria, between 2002 and 2017 in one London NHS and private dental practice. Four percent articaine was given by ILA with a conventional syringe slowly at two points lingual and two points buccal adjacent to each tooth. Extraction procedures were all performed flapless. Heavily broken-down teeth (n = 43) were extracted by sectioning of roots, guttering and elevation with luxators using socket preservation techniques. Demographic, quantitative and qualitative data were collected at initial appointments and up to 15 years at review.Results The median age was 64 years (interquartile range 17). Teeth extracted included 272 mandibular molars and second premolars, due to periodontal disease (34%), irreversible pulpitis (29%) or posterior tooth fracture (27%). The majority of extractions were second molars (44%), followed by first molars (29%), second premolars (17%) and third molars (10%). Sufficient anaesthesia was achieved within five minutes for all extractions. Procedures lasted less than 30 minutes. Patient feedback reported that the extraction using ILA was quicker than expected and painless, with limited anaesthesia of tissues other than the teeth to be extracted. Numeric rating scale (NRS) scores for pain (0-10) were all less than 3. No complications were recorded.Conclusion The ILA anaesthetic technique is effective for the purpose of a broad range of posterior tooth extractions in the mandible and within certain clinical parameters. It mitigates risks, including nerve injury and cardiovascular disturbances, associated with repeated IANB. This is the largest study of its kind and is conducted in primary care.

Surgical techniques for the removal of mandibular wisdom teeth.

BACKGROUND: Pathology relating to mandibular wisdom teeth is a frequent presentation to oral and maxillofacial surgeons, and surgical removal of mandibular wisdom teeth is a common operation. The indications for surgical removal of these teeth are alleviation of local pain, swelling and trismus, and also the prevention of spread of infection that may occasionally threaten life. Surgery is commonly associated with short-term postoperative pain, swelling and trismus. Less frequently, infection, dry socket (alveolar osteitis) and trigeminal nerve injuries may occur. This review focuses on the optimal methods in order to improve patient experience and minimise postoperative morbidity. OBJECTIVES: To compare the relative benefits and risks of different techniques for surgical removal of mandibular wisdom teeth. SEARCH METHODS: Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health Trials Register (to 8 July 2019), the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library; 2019, Issue 6), MEDLINE Ovid (1946 to 8 July 2019), and Embase Ovid (1980 to 8 July 2019). We searched ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform for ongoing trials. We placed no restrictions on the language or date of publication. SELECTION CRITERIA: Randomised controlled trials comparing different surgical techniques for the removal of mandibular wisdom teeth. DATA COLLECTION AND ANALYSIS: Three review authors were involved in assessing the relevance of identified studies, evaluated the risk of bias in included studies and extracted data. We used risk ratios (RRs) for dichotomous data in parallel-group trials (or Peto odds ratios if the event rate was low), odds ratios (ORs) for dichotomous data in cross-over or split-mouth studies, and mean differences (MDs) for continuous data. We took into account the pairing of the split-mouth studies in our analyses, and combined parallel-group and split-mouth studies using the generic inverse-variance method. We used the fixed-effect model for three studies or fewer, and random-effects model for more than three studies. MAIN RESULTS: We included 62 trials with 4643 participants. Several of the trials excluded individuals who were not in excellent health. We assessed 33 of the studies (53%) as being at high risk of bias and 29 as unclear. We report results for our primary outcomes below. Comparisons of different suturing techniques and of drain versus no drain did not report any of our primary outcomes. No studies provided useable data for any of our primary outcomes in relation to coronectomy. There is insufficient evidence to determine whether envelope or triangular flap designs led to more alveolar osteitis (OR 0.33, 95% confidence interval (CI) 0.09 to 1.23; 5 studies; low-certainty evidence), wound infection (OR 0.29, 95% CI 0.04 to 2.06; 2 studies; low-certainty evidence), or permanent altered tongue sensation (Peto OR 4.48, 95% CI 0.07 to 286.49; 1 study; very low-certainty evidence). In terms of other adverse effects, two studies reported wound dehiscence at up to 30 days after surgery, but found no difference in risk between interventions. There is insufficient evidence to determine whether the use of a lingual retractor affected the risk of permanent altered sensation compared to not using one (Peto OR 0.14, 95% CI 0.00 to 6.82; 1 study; very low-certainty evidence). None of our other primary outcomes were reported by studies included in this comparison. There is insufficient evidence to determine whether lingual split with chisel is better than a surgical hand-piece for bone removal in terms of wound infection (OR 1.00, 95% CI 0.31 to 3.21; 1 study; very low-certainty evidence). Alveolar osteitis, permanent altered sensation, and other adverse effects were not reported. There is insufficient evidence to determine whether there is any difference in alveolar osteitis according to irrigation method (mechanical versus manual: RR 0.33, 95% CI 0.01 to 8.09; 1 study) or irrigation volume (high versus low; RR 0.52, 95% CI 0.27 to 1.02; 1 study), or whether there is any difference in postoperative infection according to irrigation method (mechanical versus manual: RR 0.50, 95% CI 0.05 to 5.43; 1 study) or irrigation volume (low versus high; RR 0.17, 95% CI 0.02 to 1.37; 1 study) (all very low-certainty evidence). These studies did not report permanent altered sensation and adverse effects. There is insufficient evidence to determine whether primary or secondary wound closure led to more alveolar osteitis (RR 0.99, 95% CI 0.41 to 2.40; 3 studies; low-certainty evidence), wound infection (RR 4.77, 95% CI 0.24 to 96.34; 1 study; very low-certainty evidence), or adverse effects (bleeding) (RR 0.41, 95% CI 0.11 to 1.47; 1 study; very low-certainty evidence). These studies did not report permanent sensation changes. Placing platelet rich plasma (PRP) or platelet rich fibrin (PRF) in sockets may reduce the incidence of alveolar osteitis (OR 0.39, 95% CI 0.22 to 0.67; 2 studies), but the evidence is of low certainty. Our other primary outcomes were not reported. AUTHORS' CONCLUSIONS: In this 2020 update, we added 27 new studies to the original 35 in the 2014 review. Unfortunately, even with the addition of these studies, we have been unable to draw many meaningful conclusions. The small number of trials evaluating each comparison and reporting our primary outcomes, along with methodological biases in the included trials, means that the body of evidence for each of the nine comparisons evaluated is of low or very low certainty. Participant populations in the trials may not be representative of the general population, or even the population undergoing third molar surgery. Many trials excluded individuals who were not in good health, and several excluded those with active infection or who had deep impactions of their third molars. Consequently, we are unable to make firm recommendations to surgeons to inform their techniques for removal of mandibular third molars. The evidence is uncertain, though we note that there is some limited evidence that placing PRP or PRF in sockets may reduce the incidence of dry socket. The evidence provided in this review may be used as a guide for surgeons when selecting and refining their surgical techniques. Ongoing studies may allow us to provide more definitive conclusions in the future.

Cerebral analgesic response to nonsteroidal anti-inflammatory drug ibuprofen.

Nonopioid agents, such as nonsteroidal anti-inflammatory drugs (NSAIDs), are the most commonly used class of analgesics. Increasing evidence suggests that cyclooxygenase (COX) inhibition at both peripheral and central sites can contribute to the antihyperalgesic effects of NSAIDs, with the predominant clinical effect being mediated centrally. In this study, we examined the cerebral response to ibuprofen in presurgical and postsurgical states and looked at the analgesic interaction between surgical state and treatment. We used an established clinical pain model involving third molar extraction, and quantitative arterial spin labelling (ASL) imaging to measure changes in tonic/ongoing neural activity. Concurrent to the ASL scans, we presented visual analogue scales inside the scanner to evaluate the subjective experience of pain. This novel methodology was incorporated into a randomized double-blind placebo-controlled design, with an open method of drug administration. We found that independent of its antinociceptive action, ibuprofen has no effect on regional cerebral blood flow under pain-free conditions (presurgery). However, in the postsurgical state, we observed increased activation of top-down modulatory circuits, which was accompanied by decreases in the areas engaged because of ongoing pain. Our findings demonstrate that ibuprofen has a measurable analgesic response in the human brain, with the subjective effects of pain relief reflected in two distinct brain networks. The observed activation of descending modulatory circuits warrants further investigation, as this may provide new insights into the inhibitory mechanisms of analgesia that might be exploited to improve safety and efficacy in pain management.

Multivariate decoding of cerebral blood flow measures in a clinical model of on-going postsurgical pain.

Recent reports of multivariate machine learning (ML) techniques have highlighted their potential use to detect prognostic and diagnostic markers of pain. However, applications to date have focussed on acute experimental nociceptive stimuli rather than clinically relevant pain states. These reports have coincided with others describing the application of arterial spin labeling (ASL) to detect changes in regional cerebral blood flow (rCBF) in patients with on-going clinical pain. We combined these acquisition and analysis methodologies in a well-characterized postsurgical pain model. The principal aims were (1) to assess the classification accuracy of rCBF indices acquired prior to and following surgical intervention and (2) to optimise the amount of data required to maintain accurate classification. Twenty male volunteers, requiring bilateral, lower jaw third molar extraction (TME), underwent ASL examination prior to and following individual left and right TME, representing presurgical and postsurgical states, respectively. Six ASL time points were acquired at each exam. Each ASL image was preceded by visual analogue scale assessments of alertness and subjective pain experiences. Using all data from all sessions, an independent Gaussian Process binary classifier successfully discriminated postsurgical from presurgical states with 94.73% accuracy; over 80% accuracy could be achieved using half of the data (equivalent to 15 min scan time). This work demonstrates the concept and feasibility of time-efficient, probabilistic prediction of clinically relevant pain at the individual level. We discuss the potential of ML techniques to impact on the search for novel approaches to diagnosis, management, and treatment to complement conventional patient self-reporting.

Surgical techniques for the removal of mandibular wisdom teeth.

BACKGROUND: The surgical removal of mandibular wisdom teeth is one of the most common operations undertaken in oral and maxillofacial surgery. The most common indication for surgery is infection about a partially erupted tooth that is impacted against bone or soft tissues. Other indications include unrestorable caries, pulpal and periapical pathology, fracture of the tooth and cyst development, amongst others. Most commonly the benefits of surgical removal of a wisdom tooth include alleviation of the symptoms and signs of pericoronitis and its potential consequences. However, surgery is frequently associated with postoperative pain, swelling and trismus. Less commonly complications include infection, including dry socket, trigeminal nerve injuries and rarely fracture of the mandible. OBJECTIVES: To compare the relative benefits and risks of different techniques for undertaking various aspects or stages of the surgical extraction of mandibular wisdom teeth. SEARCH METHODS: We searched the Cochrane Oral Health Group's Trials Register (to 21 March 2014), CENTRAL (The Cochrane Library 2014, Issue 1), MEDLINE (OVID) (1946 to 21 March 2014) and EMBASE (OVID) (1980 to 21 March 2014). We searched ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform for ongoing trials. There were no restrictions regarding language or date of publication in the electronic searches. SELECTION CRITERIA: RCTs comparing surgical techniques for removal of mandibular wisdom teeth. DATA COLLECTION AND ANALYSIS: Two review authors conducted assessment of relevance, risk of bias and data extraction. Study authors were contacted for additional information. RRs were used for dichotomous data and MDs for continuous data, unless the event rate was very low and Peto ORs were used. The pairing of the split-mouth studies was taken into account in the analysis for both dichotomous and continuous outcomes, and parallel group and split-mouth studies were combined using the generic inverse variance method. Random-effects models were used provided there were more than three studies (fixed-effect models otherwise). MAIN RESULTS: A total of 35 trials (2569 patients) were included. The interventions under consideration fell into seven broad categories, with many comparisons including only a small number of trials. Twenty-one of the trials were assessed at high risk of bias, the remaining 14 as unclear. The results are described in the summary of findings tables.Triangular flaps were associated with a 71% reduction in alveolar osteitis at one week (RR 0.29, 95% CI 0.11 to 0.78; three trials, moderate quality) and reduction in pain at 24 hours (MD -0.21, 95% CI -0.32 to -0.10; two trials, moderate quality) compared with envelope flaps. There was no evidence of a difference in overall infection rates, in maximum mouth opening or in permanent sensation. However, there was some evidence that residual swelling after one week was slightly increased in the triangular flap groups compared to envelope flap types (MD 0.66 mm, 95% CI 0.26 to 1.07; two trials, low quality). We found no data on temporary sensation, or adverse events.There was low quality evidence from two studies, looking at the use of a retractor during third molar surgery, to indicate more cases of temporary altered sensation (up to one month) when a retractor was used (Peto OR 5.19, 95% CI 1.38 to 19.49; two trials, low quality). One study reported that this did not persist for more than six months in either group. We found no data for use of a retractor on other primary outcomes or adverse effects (including fracture of the mandible).Due to the small number of studies, the different comparisons evaluated, the variable outcomes reported and the paucity of useful data for all primary outcomes we were not able to draw any conclusions concerning bone removal in third molar surgery.There was insufficient evidence from single studies of very low quality on irrigation method (manual versus mechanical) or irrigation volume (low or high) to determine whether there were differences or not for the outcomes of alveolar osteitis or postoperative infection. We found no data for any of the other primary outcomes.There was insufficient evidence (low to very low quality) that any wound closure technique (primary versus secondary) was superior to another for the outcomes of alveolar osteitis, postoperative infection or maximum mouth opening achieved after seven days, or reactionary bleeding. There was evidence that secondary wound closure was associated with reduced pain at 24 hours (MD 0.79, 95% CI 0.35 to 1.24; four trials, moderate quality) and slightly reduced swelling after one week (MD 0.33, 95% CI 0.09 to 0.57; seven trials, moderate quality).We found no data on other primary outcomes.There was some evidence that the use of a surgical drain was associated with less postoperative swelling (MD -0.90, 95% CI -1.62 to -0.19; five trials, moderate quality) and greater maximum mouth opening one week after surgery (MD 3.72 mm, 95% CI 2.84 to 4.59; two trials, moderate quality). There was insufficient evidence from a single study (low quality) to determine whether the presence of a drain made any difference to pain at 24 hours postoperation. There were no data for the other primary outcomes.Although two RCTs compared coronectomy with complete extraction, flaws in the design and the unit of analysis of these studies meant that there were no reliable data available for inclusion. AUTHORS' CONCLUSIONS: The thirty-five included trials looked at a range of different surgical techniques. The comparisons related to seven broad aspects of the surgical procedures for impacted mandibular third molars: type of surgical flap raised, use of retractors, techniques for bone removal, wound irrigation, wound closure, wound drainage, and complete/incomplete tooth removal. The quality of the body of evidence for each of these comparisons was very low to moderate due to the small number of trials and patients, and the majority of the trials being at high risk of bias (65%) with the remainder at unclear risk of bias.The evidence for making changes to surgical practice is therefore limited. However, it is useful to describe the state of the research evidence supporting practice so that surgeons can make an informed choice in adopting new techniques, or continuing with established techniques.

Interventions for iatrogenic inferior alveolar and lingual nerve injury.

BACKGROUND: Iatrogenic injury of the inferior alveolar or lingual nerve or both is a known complication of oral and maxillofacial surgery procedures. Injury to these two branches of the mandibular division of the trigeminal nerve may result in altered sensation associated with the ipsilateral lower lip or tongue or both and may include anaesthesia, paraesthesia, dysaesthesia, hyperalgesia, allodynia, hypoaesthesia and hyperaesthesia. Injury to the lingual nerve may also affect taste perception on the affected side of the tongue. The vast majority (approximately 90%) of these injuries are temporary in nature and resolve within eight weeks. However, if the injury persists beyond six months it is deemed to be permanent. Surgical, medical and psychological techniques have been used as a treatment for such injuries, though at present there is no consensus on the preferred intervention, or the timing of the intervention. OBJECTIVES: To evaluate the effects of different interventions and timings of interventions to treat iatrogenic injury of the inferior alveolar or lingual nerves. SEARCH METHODS: We searched the following electronic databases: the Cochrane Oral Health Group's Trial Register (to 9 October 2013), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 9), MEDLINE via OVID (1946 to 9 October 2013) and EMBASE via OVID (1980 to 9 October 2013). No language restrictions were placed on the language or date of publication when searching the electronic databases. SELECTION CRITERIA: Randomised controlled trials (RCTs) involving interventions to treat patients with neurosensory defect of the inferior alveolar or lingual nerve or both as a sequela of iatrogenic injury. DATA COLLECTION AND ANALYSIS: We used the standard methodological procedures expected by The Cochrane Collaboration. We performed data extraction and assessment of the risk of bias independently and in duplicate. We contacted authors to clarify the inclusion criteria of the studies. MAIN RESULTS: Two studies assessed as at high risk of bias, reporting data from 26 analysed participants were included in this review. The age range of participants was from 17 to 55 years. Both trials investigated the effectiveness of low-level laser treatment compared to placebo laser therapy on inferior alveolar sensory deficit as a result of iatrogenic injury.Patient-reported altered sensation was partially reported in one study and fully reported in another. Following treatment with laser therapy, there was some evidence of an improvement in the subjective assessment of neurosensory deficit in the lip and chin areas compared to placebo, though the estimates were imprecise: a difference in mean change in neurosensory deficit of the chin of 8.40 cm (95% confidence interval (CI) 3.67 to 13.13) and a difference in mean change in neurosensory deficit of the lip of 21.79 cm (95% CI 5.29 to 38.29). The overall quality of the evidence for this outcome was very low; the outcome data were fully reported in one small study of 13 patients, with differential drop-out in the control group, and patients suffered only partial loss of sensation. No studies reported on the effects of the intervention on the remaining primary outcomes of pain, difficulty eating or speaking or taste. No studies reported on quality of life or adverse events.The overall quality of the evidence was very low as a result of limitations in the conduct and reporting of the studies, indirectness of the evidence and the imprecision of the results. AUTHORS' CONCLUSIONS: There is clearly a need for randomised controlled clinical trials to investigate the effectiveness of surgical, medical and psychological interventions for iatrogenic inferior alveolar and lingual nerve injuries. Primary outcomes of this research should include: patient-focused morbidity measures including altered sensation and pain, pain, quantitative sensory testing and the effects of delayed treatment.

Quantifying the test-retest reliability of cerebral blood flow measurements in a clinical model of on-going post-surgical pain: A study using pseudo-continuous arterial spin labelling.

Arterial spin labelling (ASL) is increasingly being applied to study the cerebral response to pain in both experimental human models and patients with persistent pain. Despite its advantages, scanning time and reliability remain important issues in the clinical applicability of ASL. Here we present the test-retest analysis of concurrent pseudo-continuous ASL (pCASL) and visual analogue scale (VAS), in a clinical model of on-going pain following third molar extraction (TME). Using ICC performance measures, we were able to quantify the reliability of the post-surgical pain state and ΔCBF (change in CBF), both at the group and individual case level. Within-subject, the inter- and intra-session reliability of the post-surgical pain state was ranked good-to-excellent (ICC > 0.6) across both pCASL and VAS modalities. The parameter ΔCBF (change in CBF between pre- and post-surgical states) performed reliably (ICC > 0.4), provided that a single baseline condition (or the mean of more than one baseline) was used for subtraction. Between-subjects, the pCASL measurements in the post-surgical pain state and ΔCBF were both characterised as reliable (ICC > 0.4). However, the subjective VAS pain ratings demonstrated a significant contribution of pain state variability, which suggests diminished utility for interindividual comparisons. These analyses indicate that the pCASL imaging technique has considerable potential for the comparison of within- and between-subjects differences associated with pain-induced state changes and baseline differences in regional CBF. They also suggest that differences in baseline perfusion and functional lateralisation characteristics may play an important role in the overall reliability of the estimated changes in CBF. Repeated measures designs have the important advantage that they provide good reliability for comparing condition effects because all sources of variability between subjects are excluded from the experimental error. The ability to elicit reliable neural correlates of on-going pain using quantitative perfusion imaging may help support the conclusions derived from subjective self-report.

Beyond patient reported pain: perfusion magnetic resonance imaging demonstrates reproducible cerebral representation of ongoing post-surgical pain.

Development of treatments for acute and chronic pain conditions remains a challenge, with an unmet need for improved sensitivity and reproducibility in measuring pain in patients. Here we used pulsed-continuous arterial spin-labelling [pCASL], a relatively novel perfusion magnetic-resonance imaging technique, in conjunction with a commonly-used post-surgical model, to measure changes in regional cerebral blood flow [rCBF] associated with the experience of being in ongoing pain. We demonstrate repeatable, reproducible assessment of ongoing pain that is independent of patient self-report. In a cross-over trial design, 16 participants requiring bilateral removal of lower-jaw third molars underwent pain-free pre-surgical pCASL scans. Following extraction of either left or right tooth, repeat scans were acquired during post-operative ongoing pain. When pain-free following surgical recovery, the pre/post-surgical scanning procedure was repeated for the remaining tooth. Voxelwise statistical comparison of pre and post-surgical scans was performed to reveal rCBF changes representing ongoing pain. In addition, rCBF values in predefined pain and control brain regions were obtained. rCBF increases (5-10%) representing post-surgical ongoing pain were identified bilaterally in a network including primary and secondary somatosensory, insula and cingulate cortices, thalamus, amygdala, hippocampus, midbrain and brainstem (including trigeminal ganglion and principal-sensory nucleus), but not in a control region in visual cortex. rCBF changes were reproducible, with no rCBF differences identified across scans within-session or between post-surgical pain sessions. This is the first report of the cerebral representation of ongoing post-surgical pain without the need for exogenous tracers. Regions of rCBF increases are plausibly associated with pain and the technique is reproducible, providing an attractive proposition for testing interventions for on-going pain that do not rely solely on patient self-report. Our findings have the potential to improve our understanding of the cerebral representation of persistent painful conditions, leading to improved identification of specific patient sub-types and implementation of mechanism-based treatments.

Distal cervical caries in the mandibular second molar: an indication for the prophylactic removal of the third molar?

AIMS: Distal cervical caries (DCC) in mandibular second molar teeth are responsible for the removal of up to 5% of all mandibular third molars. Our aim was to identify the clinical features of these patients. METHODS: We evaluated the records of 100 patients who had 122 mandibular third molars removed because of distal cervical caries in the second molar. RESULTS: Eighty-two percent of third molars had a mesial angulation of between 40 degrees and 80 degrees. The peak age for removal of third molars was 5 years later than in other studies and patients had better dental health than average. The incidence of distal cervical caries DCC has been shown to increase with age. CONCLUSION: Distal cervical caries is a late phenomenon and has been reported only in association with impacted third molars. The early or prophylactic removal of a partially erupted mesio-angular third molar could prevent distal cervical caries forming in the mandibular second molar.