Replacing a single missing mandibular incisor?

 initial x-ray showing extensive caries

Restoring a missing lower central incisor can be extremely challenging for a dentist. Most implant designs are wider than this tooth and the resulting implant restorations can be too wide at their emergence profile ( the width at the gingival portion of the implant crown).

radiographic image of another patient's single tooth implant
Note that diameter of the neck is slightly wider than the adjacent tooth.


  Prepping the remaining  lower anterior teeth can present an additional challenge, since lower anterior teeth can sometime be too small in diameter to prepare properly for ceramometal crowns or bridges without weakening the remaining tooth structure or necessitating the need for multiple root canals and post and cores.

When confronted with a patient with a missing lower anterior tooth and an adjacent teeth with extensive decay, most of my collogues at our Study club would seriously consider extraction of the remaining lower incisors and their subsequent replacement by two implant fixtures ( placed in positions of teeth #26 & #23 )so that a of a four unit implant supported fixed bridge could be fabricated..

I am treating just such a patient at my office and have recently completed his the restoration of his lower anterior teeth.  His lower anterior teeth were extensively decayed and some would present a challenge to restore He has a propensity for rapid onset caries and he was placed on a regimen of rinsing with  Carifree mouth rinse every day with the expectation that this might help. All of the carious lower anterior teeth were excavated,  all caries was removed and glass inomer restoration were placed to temporarily restore them (glass ionomer fillings release flouride and can inhibit future recurrent decay). Care was taken not to expose any of the pulps of these teeth . Excavations were partly carried out with small spoon excavators and extremely gentle hand pressure. Dycal was place over near exposures.

After consultation with Dr. Philip Pack, a Periodontist I work closely with, we decided that his anterior teeth would best be served by crown lengthening, so that his teeth would have sufficient sound tooth structure at their base to allow for predictable full coverage restorations. We decided that it would be best if these could be fabricated with margins that finished at his resulting gingival levels in order to make it less likely for him to experience recurrent decay.

It was felt that tooth number 25 ( his lower right central incisor) should be removed since it had an extremely poor prognosis and would really be a candidate for full coverage.  All six lower anterior teeth were treatment planned for full coverage, since my patient expressed an interest in saving them and not having a large and expensive four unit implant bridge. Instead we treatment planned a zirconium and porcelain four unit bridge to replace tooth number 25, with abutments of #23,24 and 26. Teeth numbers 22 and 27 were treatment planned for single zirconium and porcalain crowns as well.

 The six anterior teeth were prepped in conservative fashion and a six unit provisional prosthesis was frabricated with jet acrylic and the help of a vacuum form made from a study model of his existing teeth. Subsequently, Dr. Pack removed tooth #25 and performed crown lengthening for teeth #22-27.

xray of prepared teeth with temporaray in place

After this we waited an additional three months to allow for healing and his lower anterior teeth were reprepared with margins placed at his repositioned gingiva and his temporary was extended to cover the freshly prepared tooth surfaces. Since Zirconium restorations can be finished with a 45 degree chamfer and are strong enough to allow a minimal gingival preparation I kept my preparations extremely conservative at the base , but still was able to reduce sufficient tooth structure, at the incisal one half of the preparations, to allow room for a layer of emax porcelain.

After custom staining , his resulting restoration was highly aesthetic and quite remarkable, considering all of his lower anterior teeth remained vital and without any of the problems that may have resulted from the type of preparations a ceramometal restoration might have required ( sensitivity or devitalization of the prepared teeth).  My patient ( and his wife) were quite satisfied. As John Kois sometimes says: "It was a good day for dentistry!"

Final restoration #'s 22-27 (lower front six teeth-#25 is missing)







from Ask Dr. Spindel - http://lspindelnycdds.blogspot.com/2018/05/replacing-single-missing-mandibular.html - http://lspindelnycdds.blogspot.com/

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