***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: PURPOSE Damage to the inferior alveolar nerve when extracting lower third molars is often caused by the intimate relationship between the nerve and the roots of the teeth . The technique of coronectomy , or intentional root retention , may minimize this problem . PATIENTS AND METHODS Forty-one patients underwent coronectomy on 50 lower third molars with follow-up of at least 6 months . The technique of coronectomy deliberately protected the lingual nerve as part of the surgical procedure . All roots were left at least 3 mm below the buccal and lingual plates of bone . All patients were radiographed preoperatively , immediately postoperatively , and after 6 months . RESULTS There were no cases of inferior alveolar nerve-involved damage in this study of 41 patients who underwent 50 coronectomies . There was 1 case of transient lingual nerve involvement , probably from the use of the lingual retractor . One patient required subsequent removal of the roots of both lower third molars because of failure to heal , and 1 patient required subsequent removal of a root because of subsequent migration to the surface . Root migration was noted in approximately 30 % of patients over a 6 month period . CONCLUSION Coronectomy appears to be a viable technique in those cases where removal of the whole tooth might put the inferior alveolar nerve at considerable risk of damage . The technique appears to be associated with a low incidence of complications , but subsequent migration of the roots may be an issue in the long term PURPOSE Studies have suggested that coronectomy reduces the risk of inferior alveolar nerve injury ( IANI ) when a close relationship with the inferior alveolar canal is indicated on panoramic imaging . However , the relationship between the inferior alveolar canal and the root are unclear on panoramic imaging . Our aim was to compare coronectomy with traditional extraction for the treatment of m and ibular third molars that had clear high IANI risks as evaluated by dental computed tomography . PATIENTS AND METHODS We design ed a case-control study of subjects with high-risk signs of IANI on panoramic images evaluated by dental computed tomography before enrollment . The 220 patients enrolled were assigned to extraction ( control group , n = 118 ) or coronectomy ( case group , n = 102 ) . RESULTS The mean follow-up time was 13 months in the extraction group and 13.5 months in the coronectomy group . Six IANIs ( 5 % ) were found in the extraction group . In the coronectomy group , 1 patient ( 1 % ) had symptoms of neurapraxia , which disappeared within 1 month . Four remaining roots had signs of postoperative infection , and the patients underwent extraction of the root . No nerve damage result ed in these patients after repeat extraction . CONCLUSIONS Coronectomy might reduce the risk of nerve injury for patients at true high risk of IANI as evaluated by dental computed tomography . A long-term postoperative review is needed to assess the incidence of root migration and the root extraction and infection rates after coronectomy PURPOSE There is no long-term evaluation on the safety of  coronectomy of the lower third molar . The aim of this study was to investigate the 3-year morbidity of coronectomy of the lower third molars and to monitor the behavior and migration pattern of the retained roots after coronectomy . MATERIAL S AND METHODS This was a prospect i ve cohort study . Patients with lower third molars with specific radiographic sign(s ) showing proximity of the roots to the inferior alveolar nerve who underwent coronectomy in a previous r and omized clinical trial were review ed postoperatively in the first week and the third , sixth , 12th , 24th , and 36th months . The morbidities of infection , pain , root eruption , reoperation to remove the root , and the development of any pathology were recorded . The pattern of any root migration was analyzed . RESULTS Ninety-eight patients ( 35 men and 63 women ; mean age , 25.7 yrs ; st and ard deviation , 7.9 yrs ) with 135 coronectomies completed the 36-month review . None presented with infection or pain from the postoperative third month onward . Root eruption causing sensitivity occurred in 3 % ( 4/135 ) of the sample and the erupted roots were removed . None of the reoperated cases presented with a postoperative inferior alveolar nerve deficit . No pathology developed in any of the retained roots after coronectomy . Root migration was noted in most cases in the first 12 months , and all roots stopped migrating from the 24th month onward . The mean root migration at 36 months was 2.8 mm ( st and ard deviation , 1.4 mm ) . CONCLUSIONS This study confirms that retained roots after coronectomy in the lower third molars produce no complications in terms of infection , pain , or the development of pathologies within the first 3 years . Root eruption can occur in a very small percentage of patients and may require reoperation to remove the root OBJECTIVE The objective of this study was to compare the surgical complications and neurosensory disturbances of coronectomy and total excision of lower wisdom teeth with roots in close proximity to the inferior dental nerve ( IDN ) . STUDY DESIGN A r and omized controlled trial was conducted to compare the surgical complications and IDN deficit of  coronectomy and total removal of wisdom teeth . Patients with specific radiographic signs of close proximity of wisdom teeth roots to the IDN were r and omized . RESULTS A total of 231 patients underwent surgery for 349 lower wisdom teeth ( 171 coronectomies , 178 controls ) ; 16 coronectomies failed and were removed in total . Nine patients in the control group presented with IDN deficit , compared with 1 in coronectomy group ( P = .023 ) . Pain and dry socket incidence was significantly lower in the coronectomy group , and there were no statistical differences in infection rate between the 2 groups . Reoperation of one coronectomy case was performed owing to persistent root exposure . CONCLUSION There are fewer complications in terms of IDN deficit , pain , and dry socket after coronectomy , but the infection rate is similar to that of total excision PURPOSE The purpose of this study was to determine the incidence of inferior alveolar nerve ( IAN ) damage after surgical removal of lower third molars  , to identify the causes , and to construct a predictive model to assess the risk of IAN injury . STUDY DESIGN We performed a nonr and omized forward prospect i ve study of 946 consecutive out patients subjected to surgical extraction of 1117 lower molars in the University of Barcelona Oral Surgery Department . Preoperative , intraoperative , and postoperative data were gathered , and suspected causal factors of IAN damage were identified by using nonparametric tests , the Pearson chi-square test , and the Fisher exact test . Logistic regression predicted the risk of IAN injury . RESULTS Although only 1.3 % of the extraction s caused temporary nerve damage , 25 % of the lesions were permanent . All of the following significantly increased the risk of IAN damage ( P < .05 ) : age , the radiologic relationship between the apices and the m and ibular canal , deflection of the root when approaching the m and ibular canal , distal ostectomy , the distance of the apices of the third molar to the m and ibular canal , ostectomy , crown sectioning , pain during root luxation , primary closure of the wound , prolonged operating time , bleeding , exposure of the nerve , and postoperative ecchymosis . The first 4 factors were included in a predictive logit model . CONCLUSIONS Patient age , ostectomy of the bone distal to the third molar , the radiologic relationship between the roots of the third molar and the m and ibular canal , and deflection of the m and ibular canal increased the risk of IAN damage . Older patients were at a higher risk for suffering permanent injuries We r and omised 128 patients who required operations on m and ibular third molars and who had radiological evidence of proximity of the third molar to the canal of the inferior alveolar nerve to one of two operations : extraction [ n=102 ] , and coronectomy [ n=94 ] . Some roots were dislodged during intended coronectomy and were therefore removed , result ing in two subgroups ( successful coronectomy n=58 , and failed coronectomy n=36 ) . The mean ( S.D. ) follow up was 25 ( 13 ) months . Nineteen nerves were damaged ( 19 % ) after extraction , none after successful coronectomy , and three ( 8 % ) after failed coronectomy ( p=0.01 ) . The incidence of dry socket infection was similar in the three groups ( 10/102 , 10 % , 7/58 , 12 % , and 4/36 , 11 % , respectively ) . No root required removal or reoperation . To our knowledge this is the first clinical trial of the efficacy of coronectomy in preserving the inferior alveolar nerve . The length of follow up was about 2 years , which for the assessment of delayed eruption of the root fragments is not sufficient as this process may continue for up to 10 years . However , it seems that coronectomy reduces the incidence of injury to the inferior alveolar nerve without increasing the risk of dry socket or infection PURPOSE Close proximity of the inferior alveolar nerve ( IAN ) to the third molar roots can result in nerve injuries during extraction of third molars . Consequently , it is necessary to determine the relationship of the nerve and roots to avoid damage to the IAN . Computed tomography scans are widely used to determine the correct relationship between the IAN and lower third molars . PATIENTS AND METHODS The study consisted of 10 patients with 16 lower third molars in close relationship with the IAN who were divided into a study group and a control group . The patients in the study group were treated via coronectomies performed with endodontic treatments . The patients in the control group underwent coronectomies without endodontic treatment . The patients were followed up for at least 1 year . RESULTS We had to extract 7 of the roots because of the infection in 8 patients belonging to the study group , which were treated endodontically . Moreover , there were 3 cases of IAN damage because of the extraction in the study group . However , in the control group , no infection was determined and IAN damage was absent . CONCLUSION Coronectomy appears to be a reliable technique to protect the IAN from damage . This procedure has a low incidence of complications . Endodontic treatment does not affect the success of this method according to our results 
    Output:
    
RESULTS AND DISCUSSION Coronectomy results in significantly lesser loss of sensitivity of the inferior alveolar nerve and prevents the occurrence of dry socket .
No statistically significant differences were observed in the incidence of pain and infection between coronectomy and complete surgical extraction .
Coronectomy is indicated when the m and ibular third molar is in contact with the inferior alveolar nerve and complete removal of the tooth may cause nerve damage