Journal of the Dental Association of South Africa, 48, 235-240. Should impacted third molars be removed? A review of the literature 'WJ van der Linden, 'JF Lownie and PE Cleaton-Jones Division of Maxillo-Facial and Oral Surgery, Department of Surgery, University of the Witwatersrand, Johannesburg and Dental Research Institute, Medical Research Council and the University of the Witwatersrand, Johannesburg Mead (1954) defined an impacted tooth as 1. Lack of space one that is prevented from erupting into posi­ For optimal dental health and function a tion because of malposition, lack of space, or full complement of teeth is required. They other impediments. should be completely erupted and well aligned in their respective dental arches. The impacted third molar has been a point of Each tooth ought to be functional and discussion in the dental literature for many surrounded by healthy, attached gingiva. years - the debatable question is: "..... to Any tooth that has not been able to attain extract or not to extract?” A great deal has this ideal position is regarded as an im­ been written by eminent clinicians for and pacted tooth. against prophylactic extraction of impacted third molars (Laskin, 1969, 1971; Raley, Impacted teeth have a propensity for caus­ Chapnick and Baker, 1977; Goodsell, 1977; ing discomfort and causing pathologic le­ Lyttle, 1979; Bishara and Andreasen, 1983). sio n s. This often leads to confusion in the minds of the general practitioner who has doubts about It is often advisable to remove offending referment or treatment of these patients and third molars rather than to attempt coura­ is not sure whether or not he should abide by geous surgical and restorative procedures the old adage “let sleeping dogs lie”. There that have a poor prognosis and involve the seems to be little doubt that the removal of patient in a great deal of expense and symptomatic impacted third molars is indi­ aggravation. cated. Controversy arises however, regard­ ing the prophylactic removal of asymptomatic 2. Pericoronitis teeth and the debate concerns the likelihood Pericoronitis has been described as an of problems developing in the future. inflammation of the gingival tissues over the crown of a partially erupted molar The prevalence of impacted teeth has been (Laskin, 1969). For practical purposes studied in various population groups. Most pericoronitis can be divided into chronic, studies showed that the frequency of impac­ subacute and acute categories. In chronic tion varies between 17 and 22 per cent (Mead, pericoronitis the patient is largely una­ 1930; Bjork, Jenson and Palling, 1956; ware of a problem except for occasional Haralabakis,1957; Dachi and Howell, 1961; discomfort and possibly a bad taste that Brown e t al., 1982). All of these studies have exudes from under the gum flap from time shown that impacted third molars are the to time. The clinical signs and symptoms most common form of tooth impaction. Some of a subacute pericoronitis is far more studies have suggested that impacted third specific, and a well localised, dull pain is molars are more common in females than in present in the retromolar pad area. The males (Heilman, 1938; Bjork, Jenson and gum is painful, red and swollen. Often Palling, 1956; Pindborg, 1970) and another indentations from the cusps of the upper study that whites have a significantly higher third molars may be seen where they are prevalence than blacks (Brown e t al., 1982). pinching the pericoronal tissues and the adjacent buccal mucosa. A foetid oris is Indications for the removal of impacted or often present and pus can sometimes be unerupted third molar teeth expressed from underneath the gum flap. The submandibular lymph nodes may be There are a number of indications for surgical palpable and tender and mild trismus and removal of these teeth. pain on swallowing may also be present. WJ van der Linden, BDS, MDent (Wits), FFD(SA) (MFOS) Patients suffering from acute pericoronitis JF Lownie, BDS, HDDent, MDent (Wits) are usually in severe discomfort, may be PE Cleaton-Jones, BDS, MB Bch, DA, PhD (Wits) pyrexial and suffering from malaise and Article received: 2 8 /6 /1 9 9 2 approved for publication: 30/9/1992 anorexia. The pain they suffer is severe Journal of the D.A.S.A. — May 1993 WJ van der Linden, JF Lownie & PE Cleaton-Jones and throbbing, preventing them from per­ and possibly entrapment of food resulting forming their normal function, including in the development of caries as well as sleep. Trismus may be marked and swal­ loss of periodontal support in the adjacent lowing very painful. The affected side is tooth. Goodsell (1977) claimed that more often swollen with a tender submandibular second molars are lost due to third molars lymphadenopathy. Intra- orally the gingiva being left in place than for any other rea­ overlying the retro-molar area is inflamed son. In addition, inaccessibility for restora­ and swollen, as well as the adjacent buc­ tion of second molars may influence the cal and pharyngeal tissues. The clinical quality of restoration and so increase the features of the subacute variety are usu­ potential for carious pulpal exposure and ally present in a more severe form. If dental abscess formation, with all the en­ untreated this infection is likely to spread suing possible complications. into the adjacent tissue spaces, and if occurring bilaterally and not controlled with The early removal of impacted third mo­ antibiotics at an early stage, can develop lars results in a better prognosis for the into life threatening submandibular, second molar because bony defects cre­ sublingual, submental and parapharyngeal ated by surgical removal of teeth in young space infection or Ludwig’s Angina. adults fill rapidly and more completely than in older individuals (Marmary e t a/., Hendrix and Tall (1971) claim that well 1986). over 75 percent of all young adults with partially erupted or impacted third molars Developing third molars have been impli­ develop pericoronitis. Kay (1970) and Rud cated in causing root resorption of adja­ (1970) believe that 10 per cent of third cent second molar teeth. Nitzan, Keren molars extracted are afflicted with and Marmary, (1981) reported a preva­ pericoronitis. Radiologically, pericoronitis lence of 7,5 percent, with a striking male will only be observed if there has been predominance, in resorption of roots of osseous destruction distal to the second second molars caused by pressure from and also the third molars. This usually adjacent mainly asymptomatic third mo­ occurs following recurrent bouts of lars. They postulated that, apart from pres­ pericoronitis and can be seen as a sure, there are other elements — probably radiolucent area either on the mesial or systemic factors which play an active part the distal aspects of the impacted or em­ in resorption. They also found that root bedded third molar, that has no distinct resorption mainly occurred in patients cortical outline. On the distal aspect of the under the age of 30 years, and so sug­ partially erupted third molar, a flame shape gested that in attempting to prevent root radiolucency is indicative of the presence resorption of an adjacent tooth, extraction of an osteitis, due to recurrent pericoronitis. of the impacted tooth after this age will (Langland, Langlais and Morris; 1982). have little bearing on the development of These infections also tend to be more resorption of the adjacent second molar severe with each recurrence (Rud, 1970). tooth root. Fitzgerald (1953) has described peri­ coronitis arising in an unerupted, appar­ 4. Caries and internal resorption of the ently completely embedded third molar, impacted tooth and postulated that there might be a minute Dental caries as well as internal or exter­ fistula connecting it to the oral cavity nal resorption of an impacted tooth is an thereby permitting the ingress of oral mi­ indication for its removal (Lyttle 1979). crobes. This theory is supported by Baab, Unless a minimally impacted tooth is serv­ Morton and Page (1984) who reported a ing a vital function such as an abutment for most unusual case of an unerupted, em­ a partial denture or a sole remaining, func­ bedded third molar that presented for treat­ tional molar tooth, these teeth ought to be ment because of pulpitis due to a large extracted. Endodontic therapy of such carious lesion in the crown of an embed­ teeth has a poor prognosis due to the ded tooth, presumably due to the ingress inaccessibility of the canals, as well as the of cariogenic bacteria through the fistula. often complex nature of the root canal The authors have noted similar paradoxi­ s yste m . cal situations in their own experience. 3. Damage to adjacent teeth 5. Facilitation of orthodontic or periodon­ Due to their position in the dental arch and tal treatment relative inaccessibility for routine oral hy­ The influence of third molars on the dental giene procedures, impacted partially arch is still controversial (Hannah 1978). If erupted teeth allow a build-up of plaque posterior movement of first and/or second Tydskrif van dieT.V.S.A. — Mei 1993 236 Third molar removal molars is required, to facilitate retraction and radicular cysts. The odontogenic or to avoid impacting third molars, it may keratocyst and lateral periodontal cysts be deemed advisable to remove third are developmental in origin and the im­ molars before starting retraction proce­ pacted status of the widsom tooth has little dures (Bishara and Andreasan 1983). The bearing on the pathogenesis of these cysts. area of controversy involves the indication for advi- sing removal of impacted third Ackerman, Cohen and Altini, (1987) re­ molars to prevent future crowding of lower viewed the development of the paradental anterior teeth, or to cause the forward cyst, and linked it specifically to the par­ relapse of the posterior movement of both tially erupted third molar that had under­ first and second molars following ortho­ gone several episodes of pericoronitis.