Two-stage extraction by partial grinding of impacted mandibular third molar in close proximity to the inferior alveolar nerve

BACKGROUND Extraction of impacted third molars often leads to severe complications caused by damage to the inferior alveolar nerve(IAN).AIM To proposes a method for the partial grinding of an impacted mandibular third molar(IMM3)near the IAN to prevent IAN injury during IMM3 extraction.METHODS Between January 1996 and March 2022,25 patients with IMM3 roots near the IAN were enrolled.The first stage of the operation consisted of grinding a major part of the IMM3 crown with a high-speed turbine dental drill to achieve sufficient space between the mandibular second molar and IMM3.After 6 months,when the root tips were observed to be away from the IAN on X-ray examination,the remaining part of the IMM3 was completely removed.RESULTS All IMM3s were extracted easily without symptoms of IAN injury after extraction.CONCLUSION Partial IMM3 grinding may be a good alternative treatment option to avoid IAN injury in high-risk cases.

Successful surgical extraction of an impacted mandibular third molar in a patient treated with head & neck radiotherapy and chemotherapy for oral cancer

Osteoradionecrosis(ORN),a pathological condition characterized by a nonvital bone occurring in the site of radiation injury,is one of the significant risks following extraction of highly impacted third molar teeth in patients treated with head&neck radiotherapy for oral cancer.Therefore,the surgery’s meticulous planning is essential to avoid such complications.This case report describes a 63-year-old male patient diagnosed with an impacted lower third molar(tooth#38)with concurrent basal cell carcinoma of the right ear and squamous cell carcinoma of the right vocal cord treated with radiotherapy.Taking into account the patient’s health status,a minimally invasive osteotomy and a corono-radicular separation procedure were performed.This procedure allowed us to reduce the risk of mandibular ORN.Three years later,the healing was complete,and the situation was stable.

A Sectioning Technique for Extraction of Impacted Third Molar by Using a Straight Handpiece and Carbide Bur: Case Report

Extraction of the lower third molar is one of the most common procedures performed in oral surgery. In general, impacted tooth extraction involves sectioning the tooth’s crown and roots. In order to divide the impacted tooth so that it can be extracted, high-speed air turbine drills are frequently used. However, complications related to air turbine drills may occur. In this report, we propose an alternative tooth sectioning method that obviates the need for air turbine drill use by using a low-speed straight handpiece and carbide bur. A 21-year-old female patient presented to the institute’s dental hospital complaining of symptoms localized to the left lower third molar tooth that were suggestive of impaction. After physical examination, tooth extraction of the impacted left lower third molar was proposed and the patient consented to the procedure. The crown was divided using a conventional straight low-speed handpiece and carbide bur. This carbide bur can easily cut through the enamel of crown. On post-operative day number five, suture was removed and the wound was extremely clear. This technique could minimise intra-operative time and reduce the morbidity associated with air turbine drill assisted lower third molar extraction.

Comparison of an alveolar expansion technique and buccal guttering technique in the extraction of mandibular third molar. A Pilot Study

Background: The over-ambitious use of surgical drills for almost every case of third molar impaction is on the increase in most established oral surgery centers. The purpose of this study was to assess and compare the severity of post operative symptoms of swelling and pain that accompany the use of surgical drill in the buccal guttering technique and the non application of drill in an alveolar expansion technique. Methods: Consecutive patients with bilateral impacted lower third molars not associated with pericoronitis were included in the study, a total of 10 patients were included in the study. Extraction of both impacted third molars was done consecutively on the same day under local anaesthesia. Post operative morbidities that were assessed clinically are swelling and pain. Results: A total of 10 patients, 70% were females and males were 30%. Age range was 27 - 35 yrs.Out of the eight patients that had the two different techniques, 7 preferred the use of the alveolar expansion technique in which drill was not used. There were statistically significant differences in swellings between these two techniques, (p 0.01). Conclusions: To avoid excessive swelling and pain from over-ambitious cut-ting of soft tissues and drilling of bone, alveolar expansion technique should be considered first in pa-tients with less dense bone.

Transfer learning-based super-resolution in panoramic models for predicting mandibular third molar extraction difficulty: a multi-center study

Background:This study aims to predict the extraction difficulty of mandibular third molars based on panoramic images using transfer learning while employing super-resolution(SR)technology to enhance the feasibility and validity of the prediction.Methods:We reviewed a total of 608 preoperative mandibular third molar panoramic radiographs from two medical facilities:the First Affiliated Hospital of Zhengzhou University(n=509;456 in the training set and 53 in the test set)and the Henan Provincial Dental Hospital(n=99 in the validation set).We conducted a deep-transfer learning network on high-resolution(HR)panoramic radiographs to improve the longitudinal resolution of the images and obtained the SR images.Subsequently,we constructed models named Model-HR and Model-SR using high-dimensional quantitative features extracted through the Least Absolute Shrinkage and Selection Operator method.The models’performances were evaluated using the receiver operating characteristic curve(ROC).To assess the reliability of the model,we compared the results from the test set with those of three dentists.Results:Model-SR outperformed Model-HR(area under the curve(AUC):0.779,sensitivity:85.5%,specificity:60.9%,and accuracy:79.8%vs.AUC:0.753,sensitivity:73.7%,specificity:73.9%,and accuracy:73.7%)in predicting the difficulty of extracting mandibular third molars.Both Model-HR(AUC=0.821,95%CI 0.687–0.956)and Model-SR(AUC=0.963,95%CI 0.921–0.999)demonstrated superior performance compared to expert dentists(highest AUC=0.799,95%CI 0.671–0.927).Conclusions:Model-SR yielded superior predictive performance in determining the difficulty of extracting mandibular third molars when compared with Model-HR and expert dentists’visual assessments.

Post-surgical evaluation of dry socket formation after surgical removal of impacted mandibular third molar—A prospective study

Aims & Objectives: This study was performed to evaluate the incidence, risk factors (age, sex, infection, radiographic difficulty of the extraction, tobacco use) contributing to the development of dry socket and clinical features following surgical removal of impacted mandibular third molar. Materials and Methods: The study included 63 patients during period of September 2009 to September 2011 in the age group of 18 to 53 years with impacted mandibular third molars all of which were surgically removed under local anesthesia by the same operator. Following surgery all patients received a single dose of 4 mg corticosteroid intravenously and similar prescriptions for analgesics, antibiotics and postoperative instructions. All patients were reviewed at 3rd and 7th day postoperatively. Results: In this study incidence of dry socket was 6.3%. We also noticed onset of symptom mostly appeared within 48 hours. Postoperatively pain, bare bone and halitosis were the most significant clinical feature at 3rd postoperative day and pain, empty socket and bare bone were most significant clinical feature at 7th postoperative day. Variables like right 3rd molar impaction, patients mean age between 19 - 32 years, female, preoperative infection, radiographically difficult impaction and habitual tobacco users showed a higher incidence of dry socket formation. Conclusion: Incidence of dry socket formation is multifactorial and therefore, there is need to evaluate all factors, with special attentions in handling these patients to reduce the incidence of dry socket formation.

Endoscopic extraction of a metal key impacted within the appendix

Ingested foreign bodies are rarely impacted in the appendix.They may be clinically latent or cause complications such as appendicitis or intestinal perforation,thus requiring prompt and appropriate therapy.A case is reported of a psychiatric,but in other respects asymptomatic,patient who presented with an ingested metal key deeply impacted within the appendix.The patient underwent urgent coloscopy for retrieval.Initially all conventional endoscopic instruments proved ineffective and the key was finally extracted using a simple manoeuvre, described herein.

The Buccal Lid Approach for Removal of Impacted Mandibular Molars—When, How and Why?

Background: The surgical removal of impacted mandibular molars represents one of the most prevalent procedures carried out by the oral and maxillofacial surgeon. Despite its prevalence, unusual impaction location of mandibular molars necessitates alternative extraction approaches. One of the methods described for extraction of deeply impacted molars is the bony lid approach which was first presented for surgical endodontic treatment of mandibular molars. The aim of this study was to evaluate the outcome of the bony lid approach in extracting mandibular molars. In addition, critical clinical key points, new aspects while performing this procedure, indications and contraindications are discussed. Materials and Methods: 9 patients were treated with the bony lid technique. A retrospective analysis of medical charts was conducted to evaluate the results of surgery. Results: The operative technique described in the article was successfully carried out in 12 cases of impacted mandibular molars. No incidence of permanent sensory deficit was recorded. In one patient, an infection mandated the removal of the bony lids. In all other cases the healing process was uneventful. Conclusion: The bony lid technique has many advantages over alternative extraction methods and should be considered as a treatment option in cases of critical proximity between an impacted tooth and the inferior alveolar nerve.

Clinical Effect of Resistance-free Removal of the Bone Embedded Mandibular Third Molar

[Objectives] To shorten the time of removal of the bone embedded mandibular third molar,reduce the complications of tooth extraction,and explore a surgery method of resistance-free removal of the mandibular third molar. [Methods] A total of 50 patients with bone embedded mandibular third molar needing to be removed were selected. A 45° elevation turbine and a long tungsten steel drill were used to remove the mesial,buccal,and distal resistances. When necessary,tongue side and root resistance was removed,and the third molar was removed when there was basically no resistance around it. The removal time was recorded,followed up for 10 d,and the postoperative reaction was observed. [Results] The bone embedded mandibular third molars were removed for all patients within 15 min,and there was no serious postoperative reaction,all patients showed high satisfaction. [Conclusions]The method of resistance-free removal of the bone embedded mandibular third molar can significantly shorten the removal time,reduce the fear of patients,and ease pain of patients.

Ultrasonic piezotome surgery: is it a benefit for our patients and does it extend surgery time? A retrospective comparative study on the removal of 100 impacted mandibular 3rd molars

Aim of the study was to evaluate if there is a constant and significant reduction in traumaticity when mas- sively traumatic oral surgical procedures such as the removal of third molars are conducted with only ul- trasonic surgical devices (Piezotomes) expressed in a reduction of postsurgical pain and swelling on the patient’s side since such clinical experiences by the authors suggested this. Since oral surgeons criticize a higher time consumption for surgeries with Piezoto- mes also the objective time consumption was evalu- ated and compared to the traditional methods. Mate- rial and Methods: 56 female and male patients were selected that already underwent a removal of an im- pacted third mandibular molar on one side with rota- ry instruments by bone destructive burring with a still persisting comparable third mandibular molar on the contralateral side complaining about recur- rent pain episodes and were already documented for pain and swelling before. The ultrasonic surgical re- moval with the Piezotome was conducted with a buc- cal osteotomy of the compacta lateral to the impacted third molar, preservation of the resected compacta in saline solution, removal of the third molar by single or multiple dentotomy and full anatomical restitution of the surgical site with the preserved buccal com- pacta. The swelling was documented by kephalome- try 24/48/72 hours and 1 week post surgery, the pain index by the total consumption of ibuprofen-400 mg—tablets. Lesions of the mandible nerve were documented. Netto surgery time was taken from the first incision to the last suture of the procedure. Re-sults: 6 patients had to be excluded from evaluation due to incomplete post surgical follow up. A signify-cant (***, p > 0.999) decrease in pain and swelling of 50% was detected both for the parameters swelling and pain with Piezotome-surgery. No lesions of the mandible nerve were detected with Piezotome sur- gery whereas surgery with rotary instruments re- sulted in 16% hypesthesia at least up to one week. Although netto surgery time was approximately 50% longer when done with the Piezotome at the begin-ning the time consumption normalized with the growing experience of the surgeons back to the time schedule when surgery was performed with rotary instruments revealing no significant differences (-, p < 0.73). Conclusions: The results of this retrospective study suggest that Piezotome-surgery is superior in atraumaticity and soft-tissue safety compared to tra- ditional procedures with burs and grants the patients significantly less post surgical pain and swelling. Al- though—as it is with all new surgical tools and pro- tocols—surgery time is longer at the beginning when purely working with ultrasonic surgical devices time consumption reduces to normal values after a learn- ing curve.

Concrescence of maxillary second molar and impacted third molar:A case report

BACKGROUND Morphological anomalies of teeth,including talon cusp,dens evaginatus,gemination,fusion,concrescence,root dilaceration,and taurodontism,always involve changes in the enamel,cementum and dentin.Diagnosing concrescent teeth through routine clinical examination alone is difficult,and most cases of concrescence are found accidentally during extraction.A definite preoperative diagnosis of concrescence would contribute to a better treatment plan and fewer undesirable complications CASE SUMMARY A 47-year-old woman who complained of left maxillary first molar loss for half a year presented to our department seeking treatment by dental implant restoration.Panoramic radiography and cone-beam computed tomography(CBCT)showed an unclear boundary between the distal root of the second molar and the mesial root of the third molar.The teeth were extracted under local anesthesia,and a definite diagnosis of concrescence was made by histopathological examination.CONCLUSION CBCT is a useful tool for diagnosing and planning the management of tooth concrescence and may be beneficial for reducing unnecessary complications.

Role of third molars in orthodontics

The role of third molars in the oral cavity has been extensively studied over the years. Literature includes numerous diagnostic and treatment alternatives regarding the third molars. However, an issue that has not been discussed at the same level is their involvement in orthodontic therapy. The aim of this study is to present a review of the contemporary literature regarding the most broadly discussed aspects of the multifactorial role of third molars in orthodontics and which are of general dental interest too.

Clinical significance of computed tomography assessment for third molar surgery

Surgical extraction of the third molar is the most commonly performed surgical procedure in the clinical practice of oral surgery.Third molar surgery is warranted when there is inadequate space for eruption,malpositioning,or risk for cyst or odontogenic tumor formation.Preoperative assessment should include a detailed morphologic analysis of the third molar and its relationship to adjacent structures and surrounding tissues.Due to developments in medical engineering technology,computed tomography(CT)now plays a critical role in providing the clear images required for adequate assessment prior to third molar surgery.Removal of the maxillary third molar is associated with a risk for maxillary sinus perforation,whereas removal of the mandibular third molar can put patients at risk for a neurosensory deficit from damage to the lingual nerve or inferior alveolar nerve.Multiple factors,including demographic,anatomic,and treatment-related factors,influence the incidence of nerve injury during or following removal of the third molar.CT assessment of the third molar prior to surgery can identify some of these risk factors,such as the absence of cortication between themandibular third molar and the inferior alveolar canal,prior to surgery to reduce the risk for nerve damage.This topic highlight presents an overview of the clinical significance of CT assessment in third molar surgery.

Extraction Timing of Heavily Destructed Upper First Permanent Molars

The first permanent molar as the first permanent tooth in the mouth and with a general insufficient oral hygiene of the children, is commonly subject to significant compromise which may arise due to caries or endodontic complication, or from developmental anomalies such as hypoplasia. Compromised teeth with questionable prognosis may result in short- and long-term clinical dilemmas. The aim of this research is to highlight the factors that require careful consideration when a compromised UFPM is detected and the importance of timely UFPM extraction to ensure the mesial drift of the upper second permanent molar (USPM) to fulfill the space of the extracted UFPM without any orthodontic intervention. For this purpose 52 heavily destructed UFPMs were extracted at age of 10.5 years old, 44 (84.6%) USPMs erupted exactly distal to the second premolar while only 7 (13.4%) USPMs erupted 1 mm distal to the second premolar. Clinically it is recommended to extract the heavily destructed upper first molars at age of 10.5 years old to ensure the complete closure of the extraction space by the passive mesial drift of upper second permanent molar.

Research on Feature Extraction of Remnant Particles of Aerospace Relays

The existence of remnant particles, which significantly reduce the reliability of relays, is a serious problem for aerospace relays. The traditional method for detecting remnant particles-particle impact noise detection （PIND）-can be used merely to detect the existence of the particle; it is not able to provide any information about the particles＇ material. However, information on the material of the particles is very helpful for analyzing the causes of remnants. By analyzing the output acoustic signals from a PIND tester, this paper proposes three feature extraction methods： unit energy average pulse durative time, shape parameter of signal power spectral density （PSD）, and pulse linear predictive coding coefficient sequence. These methods allow identified remnants to be classified into four categories based on their material. Furthermore, we prove the validity of this new method by processing P1ND signals from actual tests.

Vertical direction impaction of kissing molars:A case report

BACKGROUND Kissing molars(KMs)are a scarcely reported form of molar impaction in which the occlusal surfaces contact each other within a single dental follicle and the roots point in opposite directions.The direction of KMs impaction is generally tilted.KMs with vertical direction impaction have not been reported in the literature.CASE SUMMARY A 25-year-old female visited a dentist for right maxillary wisdom teeth extraction and was diagnosed with two vertically impacted KMs in the left mandible on panoramic radiography.After cone-beam computed tomography examination confirmed no secondary complication,the patient chose to undergo observation and regular follow-up.A literature review of KMs revealed that vertical impacted KMs are rare;high-quality evidence regarding their prevalence is still lacking.At present,the causality of KMs is controversial.In this study,we have tried to provide a detailed definition of KMs to allow an accurate evaluation of their prevalence and classification based on their impaction direction which may be related to their pathogenesis.The treatment plan of KMs depends on the condition and location of the affected teeth and associated complications;they may be either directly extracted or treated using a multidisciplinary approach including maxillofacial surgeons and orthodontists.CONCLUSION KMs are a rare clinical condition of impacted teeth with unclear pathogenesis.Vertically impacted KMs were seldom reported.Reasonable definition and classification of KMs can help in the understanding of their causes and prevalence.

Influence of Masticatory Functional Loss on the Remodeling of Alveolar Bone in Rats

There is plenty of literature on masticatory function and its impact on maxillofacial development. However, the influence of masticatory hypofunction on bone turnover in the alveolar bone has hardly been studied. This study aimed to clarify the influence of tooth loss and soft diet on the alveolar bone turnover during the growth period. Three-week-old Wistar rats were randomly divided into the following three groups: Hard diet group (rats raised on solid standard diet), Powder diet group (rats raised on powdered standard feed diet), and Extraction group (rats raised on powdered standard diet with maxillary molars extraction). BV, BMC, and BMD in the cancellous bone of M1 were measured using micro-CT analysis. To analyze the histological bone turnover, we prepared non-decalcified thin sections of alveolar cancellous bone when rats were 20 weeks old. On three-dimensional constructed images, the experimental groups (the Powder diet and Extraction groups) showed expansion of the medullary cavity of the interradicular septum of the first molar compared to controls (the Hard diet group). BV, BMC, and BMD were significantly lower in the experimental groups, with the difference from controls being greater in the Extraction group. On histomorphometric analysis, the bone mass parameters, bone formation parameters, and bone mineralization parameters were significantly lower in the experimental groups compared to controls. The bone resorption parameters were significantly higher in the experimental groups. From this study, we found that soft diet and tooth loss might worsen the bone microstructure, reduce osteogenesis, and promote bone resorption in alveolar bone.

Basic density, extractive content and moisture sorption properties of Pinus pinaster wood infected with the pinewood nematode, Bursaphelenchus xylophilus

The pinewood nematode（PWN）, Bursaphelenchus xylophilus, has become one of the most severe threats to pine forest worldwide. Nematodes, migrating through resin canals and feeding on the living cells, induce rapid metabolic changes in ray parenchyma cells, create cavitation areas, decrease xylem water content and oleoresin exudation, and cause necrosis of parenchyma and cambial cells. This study focused on the impact of PWN infection on technological parameters of wood and evaluated the impact of anatomic and biochemical incidences of tree defense reactions on basic density, extractive content and moisture sorption properties of Pinus pinaster wood.Samples of infected and uninfected wood were studied.The presence of nematodes reduced wood basic density by2 % and decreased the total content of extractives in infected wood as compared with uninfected（5.98 and8.90 % of dry wood mass, respectively）. Extractives in infected trees had inverse distribution along the trunk as compared with uninfected trees. The adsorption isotherms for infected and uninfected wood had similar positioning.We recorded differences（some statistically significant） in the equilibrium moisture content of infected and uninfected wood under varying environmental conditions. Despite the verified differences in wood basic density, extractive content and moisture sorption properties, the overall conclusion is that the PWN had a slight impact on these characteristics of wood.

A Case Report of Kissing Molars Class III

Kissing molars (KMs), first reported by Van Hoof in 1973, refer to molars with occlusal surfaces that contact each other in a single follicular space while their roots extend in opposite directions. This is a case of a 20-year-old male who presented with complaints of right mandibular molar pain with cold water contact and occlusion. Panoramic and cone-beam computed tomography (CBCT) images revealed impaction of the right mandibular third and fourth molars, with the occlusal surfaces contacting each other while the roots extended in opposite directions. KMs are classified according to the impaction of the mandibular first and second molars (Class I), second and third molars (Class II), and third and fourth molars (Class III). Our patient was considered Class III. Given the patient’s preference for surgical treatment, successful teeth extraction and extirpation were performed under intravenous sedation. The patient’s postoperative course was unremarkable. We describe a case of KMs Class III with a cystic variant assessed by panoramic and CBCT images. We additionally review all KMs Class III reported in the literature.

Loss of Masticatory Function Affects Morphology of the Tooth Root in Rats

Masticatory hypofunction and soft food affect the tooth rows, occlusion, and jawbone. This study aimed to clarify the influence of tooth loss and a soft diet on morphology of the tooth root during the growth period. We divided 3-week-old Wistar rats into the following three groups: Hard diet group (rats raised on solid standard diet), Powder diet group (rats raised on powdered standard feed diet), and Extraction group (rats raised on powdered standard diet with maxillary molars extraction). Length, width, cross-sectional area, and volume of the root of the mandibular M1 and M2 were measured using micro-CT analysis. Non-decalcified thin-slice specimens of sagittal sections of the M1 were obtained at the age of 20 weeks, and the roots were observed. The root length of all roots in the Extraction group was significantly longer than that in the other groups. The root width and cross-sectional area at the apical side 1/4 of all roots in the Extraction group were significantly smaller than those in the other groups. The root volume of the M1 mesial root in the Extraction group was significantly smaller than that in the other groups. This study clarified that when masticatory stimulus in the immature teeth is reduced by the extraction of opposing teeth and a powder diet, the root length increases due to the promotion of cellular cementum addition at the apex, and the root width and cross-sectional area decrease due to the suppression of cellular cementum addition at the apical side 1/4 of the roots.