MINI-IMPLANT SUPPORTED OVERDENTURE IN A PATIENT WITHDOWN SYNDROME: A CASE REPORTR.D. Vaithilingam, R. Mahmood. Mini-implantsupported overdenture in a patient with DownSyndrome: .a case report.. Annal Dent Univ Malaya2009; 16: 37-42.

ABSTRACT'

The presence of macroglossia, a tendency towards poorcooperation and the inability to adapt to compl~tedental prostheses due to motor and mental deficienciesmakes the oral rehabilitation of Down Syndromepatients difficult. This article reports on the use of miniimplant supported overdenture to rehabilitate a DownSyndrome patient who had difficulty adapting to hisnew mandibular complete denture. The patient's abilityto cooperate during treatment as well as themaintenance of an optimal oral hygiene practiceenabled mini-implants to be inserted and maintained20 months post insertion as evidenced by clinical andradiological findings. To the author's knowledge, thisis the first reporting of a successful mini implantsupported overdenture in a Down Syndrome patient.

Key words: Down syndrome; mIlll implants;overdenture

INTRODUCTION

Down Syndrome, also known as trisomy 21 aridmongolism, was first described by John LangdonDown (I). It is a.genetic condition caused by an extrachromosome 21 which results in variolls systemic andoral anomalies as well as learning disabilities and acharacteristic appearance (1).' Dental featuresassociated with Down Syndrome include open mouthposture due to underdevelopment of the middle thirdof the face and. poor muscle tone, macroglossia,delayed development and eruption of the teeth,hypodontia., mtcrodontia, .hypocalcification andhypoplastic defects, reduced caries risk and highincidence of severe periodontal disease (2-5). Theincreased frequency of periodontitis is d~e in a largepart to poor oral hygiene (6) and an exaggeratedimmune-inflammatory response (7) of the oral tissues.Therefore, the most common dental problem faced bythese patients in their mid-30s is extreme tooth mobilityleaving no choice but extraction (8).

The management of missing teeth in Down·Syndrome patient's poses a challenge due to thepresence of macroglossia, a tendency towards poorcooperation and the inability to adapt to completedental prostheses due to motor and mental deficiencies(9). The replacement of missing teeth with dental

Case .Report

R.D. VaithiIi ngam I, R. Mahmood2

I Senior Lecturer,~. Department of Oral Pathology,

Oral Medicine & Periodontology,Faculty of Dentistry, University of Malaya,50603 Kuala Lumpw; Malaysia.

- Phone: +603.-79674803Fax: +603-79674531

- E-ma£ rathna@/fm.edu.my

2 Clinical Specialist,Seremban Den(al Clinic, .lalan Rasah,Seremba,n, 70300 Negeri Sembilan,Malaysia

Corresponding author: Rathna Devi Vaithilingam

-implants may overcome some of these problems andprov,ide .patients with a stable prostheses.

Over the past decade, endoss€ou's impr-ants ofincreasingly smaller diameters have been introducedinto the field of dentistry.'Small dental implants (SOls)in the range of 2.75mm to 3.3mm diameter have beenshown to be viable alternatives in cases of limitedanatomical.geography (10). Mini dental implants(MDls), which (!re smaller than their SDI counterparts,have been introduced. The titanium-aluminium-vanadium alloy of these mini implants provides extrastrength required for long term application (11). TheMDls, with diameters in the range of 1.8mm'to 2.4mm,have a survival rate of 95.1 % for supporting full lowerdentures, over a mean duration of 2.9 implant-years(12). Mazor and colleagues (13) followed 32 mini-implants which were used for stabilization of full lowerdentures with immediate loading over a 3-year periodand reported a survival rate of 94%. A multicenteranalysis using MDls found similar results with successrates of approximately 91% (14).

This article reports on the use of mini implants inI

a Down Syndrome pati'ent who was initially treated forperiodontitis and who had difficul.ty adapting to hisnew mandibular complete denture.

CASE REPORT

A 45 year old male patient (Figure 1) who had beendiagnosed with Down syndrome and otherwise healthywas referred to the Periodontal Unit, Seremban DentalClinic, Malaysia, in January 2007 with a complaint ofmobile teeth. The patient had moderate mental

38 Annals of Dentistry, University of Malaya, Vol. 16 2009

Figure I. The 45 year old Down Syridrome patient.

retardation but was able to understand andcommunicate to an acceptable level. He attended theclinic with his older brother who was also his caregiver.He was independent in 'his oral hygiene practice andbn;shed ,his teeth once a day, using a manualtooth~brush. His dental treatment prior to "this 'Visit wasirregular and mainly to private dental practitionerswhere treatment consisted of extraction's andoccasionally scaling and fillings ..

On examination, his oral hygiene was poor withgeneralized plaque accumulation as well as supra- andsubgingival deposits of calculus. His gingivae wasgenerally erythematous with pocket depths of 5-6 mmon teeth 18, 17,13, 12;24 and 27. Teeth 17,24,27and 44 had Grade 3 mobility. Radiographicinterpretation presented generalized horizontal boneloss of half to two third roO"tlength (Fig~re- 2). There- .

was a high frenal attachment on the mandibularanterior ridge. The patient was diagnosed withgeneralized moderate to advanced chronicperiodontitis.

A comprehensive treatment plan was prepared andafter discussions with his caregiver, it was agreed that17,24,27 and 44 would be extracted. Options for thereplacement of missing teeth such '!csimplant-supportedfixed/ removable maxillary and mandibular prostheseswere also discussed. It was decided that since thecaregiver was unable to afford the cost of implants, thepatient would receiv<; a removable acrylic maxillarypartial and complete mandibular prostheses.Extractions were completed under local anaesthesiawithout any complications. The remaining teeth were18,13,12,11,21 and 22. Oral hygiene instructionswere provided to both the patient and his brother. Anelectric toothbrush was recommended. Over the nextfew weeks, the patient demonstrated excellentimprovements in his oral hygiene. Full mouth scalingand root planing was comgleted.'·

A frenectomy removed the frenal attachment on themandibular anterior ridge to allow th~ proper seatingof his full denture. All surgeries (frenectomy andimplant placements) were done under local anaesthesiaas facilities for intra-venous sedation was unavailablein this town. The family was also reluctant for anyprocedure to be done under general anaesthesia. Thepatient was cooperative throughout these surgeries. Onemonth after the frenectomy (five months after theextractions), impressions of his maxillary andmandijJular arches were taken for the construction ofmaxillary partial and a mandibular full acrylic denture.The completed dentures were issued in June 2007.'Good retention of the prostheses was obtained.However, when the patient was examined a week later,his brother complained that he had a habit of pushinghis mandibular denture out with the tongue. This madeeating and speaking with his dentures difficult.

The treatment was then modified to include animplant-supported mandibular overdenture to securethe denture in place. Due to financial constraints, it was

Figure 2. Panoramic radiograph taken at initial examination.

decided that mini implants would be used and thepresent mandibular full acrylic denture would bemodified.

In August 2007, 4 mini implants (MOL miniimplants, Intra-lock International Inc., US) 2.5mm indiameter and 13 mm in length were placed between theedentulous region 33 and' 43. Following localanaesthesia, a crestal incision was made between 34and 44 and mucopedo,steal flaps were raised. Pilotdrills of 1.2mm diameter followed by 1.5mm diameterwere used to prepqre sites at region of 33, 32, 42 and43. The mini implants were inserted with a fingerwrench. They were ratcheted into position with a torqueof 45N (Figures 3 and 4). The mucoperiosteal flapswere repositioned and sutured. Bleeding was arrestedand post-operative instructions were given to thepatient and his brother.

The patient was reviewed five days after surgery.Healing of the surgical site was uneventful. Themandibular overdenture was fitted onto the miniimplants by creating a depression over the location ofthe mini implant heads. The housings were placed onthe implant heads and picked up to the overdentureusing self-curing intra-oral resin with the patient incentric occlusion (Figures 5, 6 and 7). The overdenturewas stable and the patient was able to function, whiletalking and eating without pushing the appliance outof his mouth with his tongue. The patient and hisbrother were instructed on mini implant and denturehygiene. Throughout the treatment, the patientmanaged to maintain good oral hygiene. The patientwas placed on regular maintenance review where oralhygiene instr'uctions were reinforced and prophylaxiscompleted. Twenty months post-loading with regularfollow-ups, the mini implants and dentures arefunctioning well (Figures 8, 9 and 10). Radiographsshow an increase in peri-implant marginal bone loss ofapproximately one to-two threads from the time ofinsertion. the success of the mini-irl1plants jn this casewere based on the criteria s'et forth· by Buser andcolleagues (15) which includes the absence ofpersistent subjective complaints such as pain, foreignbody sensation, or dysesthesia; the absence of recurrentperi-implant infection with suppuration; the absence ofmobility and the absence of a continuous radiolucencyaround the implant. '

DISCUSSION

The severity of oral diseases in patients with DownSyndrome together with their psychomotor andcognitive disabilities requires a comprehensivetreatment plan including the overall management ofeach individuals oral hygiene programme. Thismanagement depends on the patient's ability tocooperate during treatment as well as the maintenanceof an optimal oral hygiene practice (16). In this casereport, the patient has demonstrated a g'ood oral

Mini-implant supported overdenture 39

hygiene practice throughout his treatment. Themaintenance of good oral hygiene was a requirementfor the placement of mini implants as it enabled the

/ 'l,' ..~,.·..L~,··r.~·

Figure 3. Periapical radiographs of lower right quadranttaken immediatedly after mini implant placement.

Figure 4. Periapical radiographs of lower left quadranttaken immediatedly after mini implant placement.

40 Annals af Dentistry, University af Malaya, Val. 162009

Figure 5. Housing 'locators placed over mini implants.

I:!.

r I

- - Figure 6. Mandibular overdenture with self-cured housing locators.

Figure 7. The Down syndrome patient using his prosthesis in centric occlusion.Note the good oral hygiene. Stains on the upper anterior teeth were

caused by chlorhexidine mouthrinse.

Figure 8. Mini-implants at'20 months post-loading showinghealthy peri-implant soft tissue.

Figure 9. PeriapicaJ'radiographs showing mini implants atlower right quadrant 20 months post-loading, There is anincrease in peri-implant, marginal bone loss of approximatelyone to two threads from the time of insertion.

Figure 10. Periapical radiographs showing mini implants atlower left quadrant 20 months post-loading. There is anincrease in peri-implant marginal bone loss of approximatelyone to two threads from the time of insertion,

Mini-implant supported overdenture 41

peri-implant tissues to remam constantly healthy(17,18).

Complete dentures are contraindicated for patientswho lack adequate muscle control or cognitive skillsto fully adapt to the prosthesis (16). A study of patientswith different disabilities, including mental retardation,illustrated how implant-supported prostheses producedrelatively good results which contributed to improvedaesthetics and oral function (17). As has been shownin thi~ case report, treatment with mini implantsupported overdenture served to not only increase thepatient's comfort but also allowed him to improve hisfunction- in terms of speech and mastication with theadded benefit of reduced cost.

. Mos! patients -with mental or physical disabilitiesmay require consciQus se"dation or even generalanaesthesia for 'surgery to be undertaken. In this casehowever, the patient proved to be cooperative duringhis initial frenectomy procedure as well as during mini-implant placement. This was achieved through verbalcommunicative efforts throughout his treatment.

One of the more important factors responsible forimplant failure is poor bone quality and quantity (19).Patients with Down Syndrome are prone to developosteoporotic bone (20,21). In the present case however,there was o.nly peri-implant marginal bone loss ofapproximately one to.two threads at twenty months,post-loading as compared to the initial post-surgicalbone levels. The success of the mini implants o~er atwenty lTIonth period in this Down Syndrome patientindicates that these osteoporotic alveolar boneproblems are not always encountered.

Numerous case reports have provided evidence ofsuccessful I ° year' treatment outcomes usingcon:>:,entional implants in special care patients (21-23).Long-term studies of, mini implants show a 94.2%survival rate over a 5 year period in healthy adults(12,24). The present case reporthas shown that a miniimplant supported overdenture can survive over' aperiod of twenty months in a Down Syndrome patient.

CONCLUSION

Mini implants with good oral hygiene can successfullybe used to support overdentures in Down Syndromepatients.

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