The prognosis of partial implant supported fixed dental prostheses

ALMOÇO CIENTÍFICO
Apresentação e discussão de Artigo
Uberlândia, 14 de Maio de 2013.
Universidade Federal de Uberlândia
Faculdade de Odontologia
NEPRO - Núcleo de Estudo e Pesquisa em
Reabilitação Oral

OBJETIVOS
• Apresentação do trabalho.
• Discussão do trabalho.
• Questionamentos sobre a qualidade do trabalho.
• Benefícios para o paciente que podem advir do trabalho.

Editor in Chief: Dr. Marco Esposito
Latest issue: Issue 1/2013
Publication frequency: quarterly
Language: English
Impact Factor (ISI): 1.667 (2011) Qualis Capes: B1 -
nterdisciplinar
Official publication of:
The British Society of Oral Implantology (BSOI),
The Italian Society of Oral Surgery and Implantology (SICOI),
The Danish Society for Oral Implantology (DSOI),
The German Association of Oral Implantology (DGI),
The Spanish Society of Implantology (SEI), and the
The British Academy of Implant & Restorative Dentistry (BAIRD).

Paulo Maló, DDS, PhD
Oral Surgery Department, Maló Clinic, Lisbon,
Portugal
Miguel de Araújo Nobre, RDH, MSc Epi
Research and Development, Maló Clinic, Lisbon,
Portugal
Armando Lopes, DDS
Oral Surgery Department, Maló Clinic, Lisbon,
Portugal
THE PROGNOSIS OF PARTIAL IMPLANT-SUPPORTED FIXED DENTAL
PROSTHESES WITH CANTILEVERS. A 5-YEAR RETROSPECTIVE COHORT
STUDY.
Maló P, Nobre M De, Lopes A. The prognosis of partial implant-supported fixed dental prostheses with cantilevers. A 5-year retrospective cohort study. European
journal of oral implantology. 2013 Jan;6(1):51–9

INTRODUCTION
• Cantilever ?????
• Rehabilitation in the posterior zone:
• lack of bone quantity, bone quality or
presence of infection
• lack of bone height and/or crest width
http://www.rockymountainsmilecenter.com/case_of_month.htm

CANTILEVER AS A TREATMENT ALTERNATIVE
• Lack of bone height and crest width
• Avoid surgery – bone augmentation
• Less of 5mm height crest to
mandibular nerver or 5 mm crest to
sinus floor
• Bone width less tham 3 mm
http://www.anatomiafacial.com/saiba_ma
maxilares_desdentados.htm

CANTILEVER A PROBLEM SOLVER
• Anterior region
• Insufficient inter-implant and tooth-implant distances
• Preserve inter-dental papilla and soft tissue architecture
• Achieve good aesthetic standards
http://www.oralhealthgroup.com/news/anterior-implant-
cantilevered-restorations/1000535210/

CANTILEVER SOME PROBLEMS
• Biomechanical Problem
• Stress concentration
• Axial forces, bending moments, microstrains – higher
• Techinical complications in prostheses
• Screw loosening
• Minor porcelain fractures

PURPOSE
• The purpose of this study was to report the 5-year
outcome of implant-supported fixed dental
prostheses with one to two cantilevers. This article
was written following the STROBE (Strengthening the
Reporting of Observational Studies in Epidemiology)
guidelines

MATERIALS AND METHODS
• Maló Dental Clinic – Lisbon
• 174 patients :106 female ,68 male (mean age: 49
years; age range: 17–84 years of age)
• Medical records as rehabilitated with partial implant-
supported fixed prostheses.
http://dental.maloclinics.com/

• Patients included, in need of partial rehabilitation in the maxilla
or mandible and had sufficient amount of bone to place an implant
of at least 7 mm in length.
• Insufficient bone volumes (less than 7 mm bone height to the mandibular
nerve or less than 7 mm bone height below the maxillary sinus floor, or
patients with bone crest width inferior to 3 mm) a cantilever was added
to the prosthesis.

• in the anterior regions, only two implants were placed to restore the four
missing incisors.
• Inter-implant and tooth-implant distances were compromised
• Inter-dental papilla and soft tissue architecture were needed to be
preserved
• Whenever the rehabilitation presented an aesthetic challenge

• Emotional instability , active radiation or chemotherapy were
excluded.
• A total of 225 implants were inserted (Mk II, Mk III and Mk IV
Brånemark system; NobelSpeedy Groovy; and Replace, Nobel
Biocare, Kloten, Switzerland)
• 57 implants with machined surfaces and 168 oxidized surfaces
https://store.nobelbiocare.com/

• The implant diameters ranged from 3.3 mm to 4 mm, and lengths from 7 mm
to 18 mm.
• 9 implants were placed using a 2-stage technique
• 90 implants were placed using a 1-stage technique
• 126 implants immediately loaded

• insertion torque of 32 Ncm was obtained or if it was not possible to use
natural teeth as support for the fixed prosthesis during the healing period.
• 149 implants were placed in maxillae and 76 implants in mandibles
• 191 fixed dental prostheses (125 in the maxilla and 66 in the mandible)

SURGICAL PROTOCOL
• A clinical examination with a preoperative panoramic radiograph and a
computed tomography (CT) scan were used to plan the surgery.
• The minimum bone quantity was 7 mm in height and 3 mm in width.
• Pre operative photographs and preliminary irreversible
hydrocolloidimpressions (Orthoprint, Orthodontic Alginate Extra Fast Setting,
Zhermack, Badia Polesine, Italy) were made.

SURGICAL PROTOCOL
• All patients were sedated with 10 mg diazepam (Valium®, Roche, Amadora,
Portugal)
• Antibiotics (amoxicillin 875 mg plus clavulanic acid 125 mg, Labesfal, Campo
de Besteiros, Portugal) were given 1 hour prior to surgery and daily for 6 days
there-after
• local anaesthesia with mepivacaine or articaine chlorhydrate with
epinephrine 1:100,000 (Scandinibsa®2%, Inibsa Laboratory, Barcelona, spain)

SURGICAL PROTOCOL
• 5 mg of cortisone medication (prednisone,Meticorten®, Schering-Plough
Farma, Agualva-Cacém, Portugal) was given daily in a regression mode
from the day of surgery until 4 days postoperatively.
• Ibuprofen, 600 mg, (Ratio pharm, Carnaxide, Portugal) was administered for
4 days postoperatively starting on day 4.
• Analgesic clonixine 300 mg (Clonix®, Janssen-Cilag Farmaceutica,
Barcarena, Portugal) was given on the day of surgery and postoperatively
for the first 3 days if needed.

SURGICAL PROTOCOL
• Antiacid medication (omeprazole, 20 mg, Lisbon, Portugal) was given on the
day of surgery and daily for 6 days postoperatively.
• Implant site preparation followed the standard procedures with the following
modifications: an incision was performed on the palatal side of the crest for
maximum tissue repositioning of the papilla in the maxilla, and the flaps were
kept as small as possible to maximize blood supply.
• The drilling sequence was modified according to bone density in order to
achieve maximum apical anchorage using the implant manufacturer burs

SURGICAL PROTOCOL
• Countersinking was not performed to preserve marginal bone. If an implant
insertion torque of 32 Ncm was achieved, implants were loaded immediately
with provisional acrylic resin prostheses the same day.
• The implant platform was planned to be 0.8 mm above the bone crest for
Mk II, Mk III and Mk IV implants .
• Or flush to the bone crest for Nobelspeedy implants.

SURGICAL PROTOCOL
• Bicortical anchorage was established whenever possible.
• The soft tissues were readapted and sutured back into position with 4-0 non-
resorbable sutures (Broun, Aesculap, Tuttlingen, Germany)

PROSTHETIC PROTOCOL
• The abutment choice at surgery was made according to the surgery staging
technique:
• Cover screws were used when implants were submerged (9 implants)
• Healing abutments, Estheticone abutments, Miruscone abutments or multi-
unit abutments (Nobel Biocare AB) were used when a 1-stage technique
was used (90 implants);
• Estheticone abutments, Miruscone abutments or multi-unit abutments were
used when implants were loaded immediately (126 implants).

MAINTENANCE AND FOLLOW UP
• The patients with immediately loaded implants were placed on a soft food
diet for 2 months.
• Ten days after surgery, the sutures were removed, and evaluations were
performed regarding hygiene and implant stability (for immediately loaded
implants or those placed with a 1-stage technique).
• The procedure was repeated 2 months (except for implants inserted with a
2-stage technique)
• 4 months after surgery until a stable situation was secured
• After this period, the patients were recalled every 6 months for maintenance.

FINAL PROSTHETIC PROTOCOL
• Final prostheses delivered typically after 6 months
• Consisting mainly of screw-retained metal ceramic fixed dental prostheses in
the posterior regions
• Cemented or screw retained Procera® ceramic fixed dental prostheses
(zirconia, Nobel Bio-care) in the anterior regions.

OUTCOME MEASURES
• Prosthesis success was measured by function
• Implant success 4 criteria :
• I-Support for reconstruction
• II-Stable when tested (once a year)
• III-no sign of pain or infection
• IV-no radiolucent areas around the implant (periapical or orthopantomografy)
• Mechanical Complications : fracture or loosening of mechanical and
prosthodontics components – follow up after 1 – 3 – 5 years

OUTCOME MEASURES
• Biological complications: peri-implant pathology (presence of peri-implant
pockets ≥ 5 mm
• Bone loss of ≥ 2 mm)
• Soft tissue inflammation (present or absent)
• Fistula formation (present or absent).

SEC. OUTCOME MEASURES
• Peri-implant marginal bone level evaluation was performed on periapical
radiographs (Kodak, Rochester, NY) obtained at implant insertion, 6 months,
and 1 and 5 years.
• Marginal bone level was assessed with image analysis software (Image J
version 1.40g for Windows, National Institutes of Health, Bethesda, MD, USA)
• The reference point :implant platform (the horizontal interface between the
implant and the abutment), and marginal bone remodeling was defined as
the difference in marginal bone level relative to the bone level at the time of
surgery.

• Aesthetic complaints (aesthetic complaints of the patient or dentist)
assessed clinically at each follow-up appointment for the patient and at
prosthetic evaluation, yearly, for the dentist.
• Functional complaints (phonetic complaints, masticatory complaints,
comfort complaints or hygienic complaints) assessed clinically at each
follow-up appointment by collecting the patient’s opinion.

STATISTICAL EVALUATION
• Descriptive statistics were used to classify the variables of interest.
• Survival analysis was performed using the Kaplan–Meyer product limit
estimation

RESULTS
• 16 patients with 21 implants dropped out of the study (9.2% of patients; 9.4%
of implants).

RESULTS
PRIMARY OUTCOME MEASURES
• Prosthesis success: a total of 2 prostheses were lost in 2 patients, rendering a
prosthetic success rate of 99%.
• The 2 prosthetic failures occurred in the anterior segment of the maxilla.
• New implants after 6 months in the first patient, and on the same day of
implant removal for the second patient, with both rehabilitations remaining
in function during the follow-up of the study

RESULTS
PRIMARY OUTCOME MEASURES
• Implant success: a total of 3 implants were lost in 3 patients after 1 and 4
months of follow-up.
• From the 3 implant losses, 2 resulted in the loss of 2 prostheses, rendering a
survival rate estimation of 99.0% at 5 years (Kaplan–Meier).
• The mean survival estimate was 59.4 months (95% CI: 58.6–60.2 months; all
cases were censored at 60 months of follow-up).

RESULTS
IMPLANT LOSSES

RESULTS
PROSTHESES SURVIVAL RATE

• The mechanical complications registered were fracture of the prosthesis and
loosening of prosthetic or abutment screws, with a global frequency of 27.6%
(n = 48 patients) at patient level and 25% (n = 56 implants) at implant level.
• The frequency of prosthesis fractures was 20.7% at patient level (n = 36
patients) and 18.9% at the prosthesis level (n = 36 prostheses).
• The frequency of prosthetic screw loosening was 8.5% at patient level (n = 14
patients) and 7.3% at prosthesis level (n = 14 prostheses) and occurred in 9
provisional prostheses and 5 definitive prostheses.

RESULTS
BIOLOGICAL COMPLICATIONS
• Peri-implant pathologies (with presence of peri-implant pockets of at least 5
mm together with at least 2 mm of bone loss).
• The frequency 2.9% at patient level (n = 5 patients) 2.7% at implant level (n
= 6 implants).
• In 3 patients, these 4 implants were treated successfully with a non-surgical
• The other 2 implants in 2 patients were surgically treated.

RESULTS
MARGINAL BONE LEVEL
9% 50% 81%

DISCUSSION
• A 99.0% prosthetic survival rate at 5 years proves that it is viable to perform
implant-supported fixed dental prosthesis partial rehabilitations with a canti-
lever.
• High frequency of mechanical complications (27.6%) in these types of
rehabilitations, corresponding to 1 for every 4 prostheses.
• Zurdo et al-Systematic review - mean frequency of 20.3% (frequency
range13–26%) for technical complications during the follow-up of these
types of rehabilitations.

DISCUSSION
• Parafunctional habits (13 patients were heavy bruxers)
• Design of the prosthesis (presence of leverage),
• To a lower extent, by the opposing dentition (metal-ceramic implant
supported fixed prostheses in 12 patients).

DISCUSSION
• Marginal bone level are accepted
• Nevertheless, there were 18 implants in 15 patients with a marginal bone loss
over 3 mm after 5 years of function.
• Systemicall problem , smoker ,periodontal and mechanical complications.
• Implant failure – 3 – early stage.

DISCUSSION
• Retrospective design (only one clinic involved) and the low number of
available radiographs at implant insertion and at the 1-year follow-up.
• Number of implants unaccounted for (n = 21) belonging to the group of
drop-out patients (n = 16; 9% of the sample), which could affect the failure
rate as these patients could be expected to have a higher failure rate
compared to the patients complying with the follow-up in the study.
• Prospective clinical trials with long-term follow-up should be performed

CONCLUSION

OBRIGADO

The prognosis of partial implant supported fixed dental prostheses

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