Osseointegrated Dental Implants As Alternative Therapy to Bridge
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SCIENTIFIC ARTICLE Osseointegrateddental implants as alternative therapy to bridge construction or orthodonticsin youngpatients: sevenyears of clinical experience Philippe D. Ledermann,DDS Thomas M. Hassell, DDS,PhD Arthur F. Hefti, DDS,PD Abstract Youngpatients often require fixed bridgeworkor orthodontictherapy in cases of traumatic tooth loss or congenitally missing teeth. Dentalimplants represent an alternative to the moreconventional treatment methods.We report positive experienceover a seven-year period with 42 titanium Ha-Ti implants in 34 patients aged 9 to 18 years. Fourteen implants were placed into preparedtooth sockets immediatelyafter traumatic luxation of anterior teeth in 12 patients aged9 to 18 years (medianage 16). Anadditional 22 patients (medianage 15.5, range 11 to 18) also received implants (N = 28), but these wereplaced only after healing of extraction sites, or as substitutes for congenitally missing teeth. Implants remainedin situ for an averageof 7.7 monthsbefore loading. Duringthe healing period, three implants were lost due to additional traumaand one becameinfected. The 38 remainingimplants osseointegrated and since have been loaded for five to 79 monthsin successful function. There was no difference between immediateand delayed implants in clinical success. These experiences demonstratethat appropriate, versatile, osseointegrated implants can provide a successful treatment methodfor youngpatients, without damagingadjacent teeth. (Pediatr Dent 15:327-33, 1993) Introduction Edentulous spaces often exist in children and adoles- the mucosal inflammation that is almost inevitable with cents due to trauma and congenital absence of permanent temporaryacrylic-based partial dentures. In children, the teeth. Traditional therapeutic approaches have included teeth most frequently lost to trauma are the incisors. Orth- removable partial dentures, fixed prostheses with mini- odontic movementof canines mesially to close spaces is mal tooth preparation (e.g., the "Marylandbridge"), and usually esthetically disappointing as well as costly and orthodontic movementof teeth to close spaces. All of time consuming. Perhaps most important is that after a these treatment modalities have distinct disadvantages; tooth is lost, an inescapable sequela is the rapid resorption most are temporary solutions at best and costs can be of alveolar bone. Indeed, in most cases, only a very thin substantial. In recent years, tremendoussuccess in tooth crestal bony lamella remains after healing of the alveolus, replacement has been achieved in adults using root-form with clinically obvious horizontal and orofacial depres- titanium dental implants. This success is due in major part sions. In a child patient missingan incisor, the dentist may to pioneering clinical studies in Scandinavia (for review find implantation impracticable because of inadequate see Branemark, 19831). bone mass at the site if the dentist waits until iaw growth There has been a reluctance to employ implant therapy is complete. Inadequate bone also can seriously compro- in children and adolescents whose jaw growth is incom- mise the esthetic result achieved with conventional bridge- plete. Early attempts to replace teeth in very young pa- worklater. Implant placementas near to the time of tooth tients using vitreous carbon and ceramic implants were loss as possible could obviate these negative consequences. plagued by very poor success.2, 3 These are the likely rea- This paper reports on titanium root-form implants in sons whythe dental literature contains meager informa- children and adolescents, addressing the question of sub- tion about implantology in pediatric dentistry and why sequent alveolar bone growth and positional stability of implant therapy as an alternative to fixed prosthetics or immediate implants--an aspect of implantology about orthodontics in young patients has not been advocated. whichlittle is known. The premise for the present clinical report is that chil- Methods and materials dren and adolescents maybe excellent candidates for tooth- replacement procedures incorporating the newer titanium Typeof implant root-form implants for several important reasons. For The Ha-Ti titanium implant system (Mathys Corpora- example, in the case of a single missing anterior tooth, tion of North America, Charlotte, NC), introduced in 1985, whenthe adjacent teeth are caries free, an implant pre- was used in our patients. The Ha-Ti implant features a cludes the necessity to prepare the teeth to receive bridge- highly polished neck with the dimension of a natural work. A replacement tooth on an implant also precludes tooth, and a step-screw implant shape analogous to a Pediatric Dentistry: September/October1993 - Volume15, Number5 327 Table1. Site of andreason for Ha-Tiimplant placement and possible, an attempt was made to place the implant only success/failurestatistic after the pubertal growth spurt had concluded, as deter- mined from the age graphs of Bj6rk & Skieller. 6-9 This is Site Numberof Implants reflected in the average age of the patients at time of Maxilla implant placement (Table 2). Right central (#8) 16 The decision to implant immediately after tooth loss or Left central (#9) 12 to wait a certain period of time was madecase-by-case by the surgeon on the following basis: Rightlateral (#7) 5 1. Immediate implants were placed: Left lateral (#10) 5 ¯ In patients with traumatic tooth loss, if they were Right canine (#6) 1 treated within 72 hr after the incident; or Left canine (#11) 1 ¯ If teeth were extracted for reasons not involving osseous alveolar pathology (e.g., pulpitis, Mandible nontreatable tooth fracture); or 1 Right first premolar(#28) ¯ In cases of iatrogenic tooth loss, e.g., failed end- Left first premolar(#21) 1 odontic therapy not associated with infection. Total numberof implants 42 2. Delayed implants were placed: ¯ In cases of congenitally missing teeth if the overly- Reasonsfor implant placement ing retained primary tooth was mobile, immedi- ately after removingthe primary tooth; or Tooth loss due to trauma 25 ¯ In edentulous spaces in which a primary tooth had Congenital absence of permanenttooth 10 been missing for more than one year and the per- Rootresorption, fracture, etc. 7 manent tooth was congenitally absent; or ¯ If a tooth had to be extracted and there was clinical Total numberof implants 42 or radiographic evidence of pathology of the al- Success~failurestatistic veolus. Placement of the implant was delayed in such cases until the site healed, normally 2-3 Total numberof implants placed 42 months. Implants lost due to trauma 3 The alveolar ridge was examined clinically and radio- graphically for sufficient alveolar width. Guided tissue 1 Implants lost due to infection regeneration procedures1°," were used to enhance osse- Numberof successful implants 38 (90%) ous support in two cases that exhibited bony dehiscence after the implant was completely inserted. The procedure involved® placing individually trimmed pieces of Gortex ® natural tooth root. All superstructure elements are high- (W.L. Gore and Associates, Tucson, AR) or Vicryl (John- precision prefabricated and are interchangeable. The Ha- son & Johnson, New Brunswick, NJ) membrane over the Ti implant system has been described in detail as applied portion of the implant that was exposed due to bony in adult patients.4, ~ dehiscence, overlapping compact bone on both sides of the defect. Membraneswere affixed using resorbable Placementof implants sutures, then the mucosa was sutured to place over the From May 1985 through May1992, 42 Ha-Ti implants membraneand the implant healing cap. We attempted to were placed in 34 subjects, aged 9 to 18 years. The risks of obtain primary closure of the mucosaover each implant. the procedure and alternative treatment options were fully However, in some cases the implant healing cap became explained to the patients and the patients’ parents, who exposed during the postoperative course. All patients acknowledgedinformed consent in writing by signing the received an antibiotic postsurgically: Rovamycine® final treatment plan. Thirty-eight of the implants were (Spiramycin, Spezia, Switzerland, 250 mg, 2 tid, for four used to replace maxillary central and lateral incisors. Other days) and a nonsteroidal analgesic (mefenamic acid, sites were canines and premolars (Table 1). Whenever Ponstel®, Parke Davis, 250 mg, 2 tid, two to four days prn). Suture removal was per- Table2. Ageof patientsat timeof implantplacement by gender formed 8-10 days post- Gender Implants~Patients Mean+ SD(Years) Median(Years) Range(Years) surgically, at which time the wound was carefully in- Female 24/18 14.2 + 2.4" 14 9 - 18 spected and cleansed with an Male 18/16 16.1 1.6" 16 13 - 18 aqueous 0.2% chlorhexidine Both 42/34 15.1 + 2.2 16 9 - 18 solution. Implants in the maxilla ¯ P = 0.021. were permitted to remain 328Pediatric Dentistry: September/October 1993- Volume15, Number5 Table3. Ageof patientsat timeof implantplacement by typeof implant tested three times in succes- sion, and the meanPeriotest Implant Type Implants~Patients Mean+ SD (Years) Median(Years) Range(Years) value recorded. Peri-implant Delayed 28/22 15.1 + 2.0" 15.5 11- 18 tissue health was evaluated Immediate 14/12 15.1 2.7" 16 9 - 18 and quantified at the mesial, distal, and buccal aspects of Both 42/34 15.1 + 2.2 16 9- 18 the implant by measuring ¯ P = 0.993. the sulcus fluid flow rate as described1B by R6din et al. Table4. Lengthof healingperiod by gender Standard filter paper strips